Patent Grant
10549341
The following relates to producing amorphous, ultra-microcrystalline microcrystalline and crystallite structure of ferrous and non-ferrous metals by using the technique of rapid solidification, the technique of air pumping cover working chamber, high ejection speed of low temperature liquid nitrogen, an extremely thin liquid film ejection, and the technique of continuous casting.
Embodiments of the invention are developed from Chinese patent application No. of 200410002605.0 and title of “L, R, C method and device for casting amorphous, ultra-microcrystalline, microcrystalline and the like metal profiles” (hereinafter referred to as patent L, the following specification of patent L refers to the specification of the invention with publication No. of CN101081429B), and it's the further improvement of patent L which is hereby incorporated by reference. The embodiments of the present invention are more mature and advanced, with simpler equipment, cheaper cost and better product performance compared to patent L.
The first “R”—represents room temperature. “R” is the first capital letter of room temperature.
The second “R”—represents rapid solidification. “R” is the first capital letter of rapid solidification.
“C”—represents continuous casting. “C” is the first capital letter of continuous casting.
The operating parameters of the embodiments of the present invention and the patent L are both with a temperature of t=−190° C., a pressure of p=1.877 bar, a thickness of liquid nitrogen spray h=2 mm, a maximum liquid nitrogen ejection speed of kmax=30 m/s. The operating parameters of working chamber of patent L is at a constant temperature of tb=−190° C. and at a constant pressure of pb=1 bar. The temperatures “t” of liquid nitrogen ejected and “tb” of working chamber are both −190° C. in order to avoid the heat exchange among air in working chamber, equipment and liquid nitrogen ejected because all the temperatures of them are −190° C. when liquid nitrogen ejected to small length metal slab Δm of solidified and cool casted amorphous, ultra-microcrystalline, microcrystalline pulled from the outlet of hot casting mold, and the ejected liquid nitrogen comes into contact with the small length metal slab at cross section (the cross section C shown in
But, does the temperature of air in working chamber and temperature of device really need to be at a constant low temperature of tb=−190° C.? How much space is needed in the working chamber? Can the temperature of room air, higher or lower than the temperature of room air be adapted to the temperature of working chamber? The process of endothermic gasification phase transition of small length metal slab Δm pulled from the outlet of hot casting mold and the ejected liquid nitrogen at the cross section C has heretofore not been adequately addressed.
An aspect relates to providing an R, R, C method and equipment for casting amorphous, ultra-microcrystalline, microcrystalline and the like, metal profiles.
The following is developed from patent L and is the further improvement of patent L. The embodiments of the present invention is more mature and advanced, with simpler equipment, cheaper cost and better product performance compared to patent L.
The first “R”—represents room temperature. “R” is the first capital letter of room temperature.
The second “R”—represents rapid solidification. “R” is the first capital letter of rapid solidification.
“C”—represents continuous casting. “C” is the first capital letter of continuous casting.
Some of the embodiments will be described in detail, with reference to the following figures, wherein like designations denote like members, wherein:
1. The Size of Workspace of Working Chamber.
The working principle of the embodiments of the present invention and patent L are both: in the time interval Δτ corresponding to the different cooling rate Vk in getting amorphous, ultra-microcrystalline, microcrystalline, liquid nitrogen is ejected to the cross section (the cross section C shown in
Ld1=Kmax·Δτ=30×1.74×10−4 (m/s)·s
Ld1=5.22 mm
The liquid steel of small length metal slab Δm is solidified and cooled into 0.23 C amorphous steel slab with the maximum thickness of Emax=8.9 mm when the ejection length of liquid nitrogen is 5.22 mm.
In the patent L, the corresponding ejection length of liquid nitrogen Ld2 can be calculated using the same calculation method when continuous casting an amorphous steel slab with a width of B=1 m and a thickness of E=5 mm. The ejection lengths of liquid nitrogen Ld3 and Ld4 can also be calculated respectively when continuous casting a 0.23 C ultra-microcrystalline steel slab with a width of B=1 m, a maximum thickness of Emax=18 mm, a width of E=10 mm, Δm=0.0636 mm, and cooling rate Vk=2×106° C./s. The ejection lengths of liquid nitrogen Ld5 and Ld6 can also be calculated respectively when continuous casting a 0.23 C microcrystalline steel slab (1) with a width of B=1 m, a maximum thickness of Emax=25.5 mm, a width of E=5 mm, Δm=0.0899 mm, and cooling rate Vk=106° C./s.
The Ld1, Ld2, Ld3, Ld4, Ld5, Ld6 are as follows:
amorphous steel slab (Vk=107° C./s, Emax=8.9 mm, E=5 mm)
Ld1=5.22 mm Ld2=2.94 mm
ultra-microcrystalline steel slab (Vk=2×106° C./s, Emax=18 mm, E=10 mm)
Ld3=26.1 mm Ld4=14.5 mm
microcrystalline steel slab (1) (Vk=106° C./s, Emax=25.5 mm, E=5 mm)
Ld5=52.2 mm Ld6=10.2 mm
It can be concluded that on the basis of the above data, the heat exchange of heat absorption and gasification process of ejected liquid nitrogen only occurs in a small workspace at the outlet of hot casting mold when casting amorphous, ultra-microcrystalline, microcrystalline metal profiles with different brands and specifications. The size of workspace can be initially determined as follows:
width B=1.1 mm, length L=0.1 m, height H=0.1 m.
Although the workspace is very small, the workspace is actually much smaller during heat absorption and gasification process of ejected liquid nitrogen. When liquid nitrogen ejected to the cross section of small length metal slab Δm pulled from the outlet of hot casting mold, the ejected liquid nitrogen absorbs heat conducted from the liquid metal end of small length metal slab Δm and ejected liquid nitrogen gasifies into low temperature nitrogen with a temperature of t=−190° C. and pressure of p=1.877 bar immediately. The low temperature nitrogen is taken away from the surface of metal slab and exhausted out of working chamber under a powerful exhaust system. It is impossible for ejected liquid nitrogen to move forward on the surface of metal slab and the subsequent ejected liquid nitrogen is gasified and exhausted when arriving at the cross section. Therefore, the ejection length of liquid nitrogen does not exist actually. Given the size of workspace, it is still necessary because an exhaust hood is needed in a powerful exhaust system. The size of exhaust hood can be determined by reference to the size of workspace. Only ejected liquid nitrogen, low temperature nitrogen produced by the heat absorbing and gasifying of ejected liquid nitrogen, amorphous, ultra-microcrystalline, microcrystalline metal slabs pulled and casted from the outlet of hot casting mold and air in the exhaust hood are in the exhaust hood. There are no other equipment and devices being set in the exhaust hood. The ejected liquid nitrogen only exchanges heat with the liquid metal end of small length metal slab Δm pulled from the outlet of hot casting mold instead of exchanging heat with the air in the workspace of exhaust hood if some technical measures are adopted in the workspace of exhaust hood. The ejected liquid nitrogen cannot exchange heat with other equipment and devices for no other equipment and devices being set in the exhaust hood. By doing this, the working principle and condition of casting amorphous, ultra-microcrystalline, microcrystalline metal profiles by the heat absorption and gasification of ejected liquid nitrogen of the embodiments of the present invention are consistent with that in patent L which occurs in working chamber. Accordingly, the exhaust hood can replace the huge working chamber with constant temperature and pressure in patent L. The embodiments of the present invention and patent L can both cast continuously qualified amorphous, ultra-microcrystalline, microcrystalline metal profiles with different brands and specifications.
2. Heat Absorption and Gasification Process of Ejected Liquid Nitrogen.
A gas phase boundary E-C-A-K which is called gas saturation curve is obtained by connecting E, C, A and K. The gas phase of carbon dioxide is on the right of the gas saturation curve. A liquid phase boundary F-D-B-K which is called liquid saturation curve is obtained by connecting F, D, B and K. The liquid phase of carbon dioxide is on the left of the liquid saturation curve. The horizontal line in the saturation curve range of E-C-A-K-B-D-F is the constant temperature and pressure curve of the heat absorption and gasification process of liquid carbon dioxide. These constant temperature and pressure curves exist actually and keep stable when doing experiment on carbon dioxide. Not only with carbon dioxide, but an endothermic effect exists during any liquid gasification process. The heat absorption in the liquid gasification process of liquid mass per unit mass is called latent heat of gasification. The heat absorption and gasification process curve of the ejected liquid nitrogen at the cross section of small length metal slab Δm pulled from the outlet of hot casting mold in the workspace of exhaust hood in the embodiments of the present invention are constant temperature and pressure curve same as the horizontal lines B-A, D-C, F-E in
According to the thermophysical properties of liquid nitrogen provided in annex 2 on pages 26/29 of specification of patent L[2], the thermophysical properties of liquid nitrogen at a temperature of t=−190° C. and a pressure of p=1.877 bar are as the table below.
In the table above:
V′—volume of liquid nitrogen, the volume of 1 Kg liquid nitrogen at t=−190° C. and p=1.877 bar.
V′=1.281 dm3/Kg.
V″—volume of nitrogen produced by the gasification of 1 Kg ejected liquid nitrogen at t=−190° C. and p=1.877 bar.
V″=122.3 dm3/Kg.
r—latent heat of liquid nitrogen, that is heat that 1 Kg ejected liquid nitrogen absorbs at t=−190° C. and p=1.877 bar to gasify into nitrogen.
r=190.7 KJ/Kg.
The Table shows that the volume of 1 Kg liquid nitrogen in the condition of t=−190° C. and p=1.877 bar V′ is 1.281 dm3/Kg during the heat absorption and gasification process at the cross section (the cross section C shown in
The thermophysical properties of liquid nitrogen are provided in annex 2 on pages 26/29 of specification of patent L.
The first group:
t1=−146.9° C., p1=33.96 bar, V1′=V1″=3.289 dm3/Kg, r1=0 KJ/Kg.
The point C is the critical point. C-f is the gas phase boundary (gas saturation curve). C-e is the liquid phase boundary (liquid saturation curve). The area between line C-e and C-f is a liquid-gas coexistence zone which is an area of heat absorption and gasification of liquid nitrogen.
The third group:
t3=−165.16° C., p3=13.03 bar, V3′=1.56 dm3/Kg, V3″=18.22 dm3/Kg, r3=142.8 KJ/Kg.
According to
The fifth group:
t5=−190.16° C., p5=1.877 bar, V5′=1.281 dm3/Kg, V5″=122.3 dm3/Kg, r5=190.7 KJ/Kg.
The parameters in the fifth group is the working parameters in embodiments of the present invention and patent L.
The amorphous, ultra-microcrystalline, microcrystalline metal profiles at the temperature of t2=−190° C. can be casted continuously by patent L. The working principle and condition of casting amorphous, ultra-microcrystalline, microcrystalline metal profiles in embodiments of the present invention are consistent with that in patent L.
When casting 0.23 C amorphous, ultra-microcrystalline, microcrystalline small length steel slab Δm with maximum thickness Emax or thickness E, in time interval Δτ corresponding to the different rapid solidification and cooling rate Vk, liquid nitrogen ejector 5 ejects liquid nitrogen at corresponding temperature and pressure of t=−190° C., p=1.877 bar with a quantity of Vmax or V to the cross section C of small length metal slab Δm in working chamber of exhaust hood. In accordance with the constant temperature and pressure curve e-f, the ejected liquid nitrogen absorbs all the internal heat of the liquid steel of small length steel slab Δm from initial rapid solidification and cooling temperature t1=1550° C. to ending cooling temperature t2=−190° C. Thus producing 0.23 C amorphous, ultra-microcrystalline, microcrystalline small length steel slab Δm with temperature t=−190° C., thickness of Emax or E. 0.23 C amorphous, ultra-microcrystalline, microcrystalline metal profiles with different specifications can be casted continuously by repeating the process.
Traction mechanism 6 pulls 0.23 C amorphous, ultra-microcrystalline, microcrystalline small length steel slab Δm with temperature t=−190° C. out of exhaust hood 8 into atmosphere, and the small length steel slab Δm completes the whole rapid solidification and cooling casting process to cast amorphous, ultra-microcrystalline, microcrystalline small length steel slab Δm continuously. Even though the small length steel slab Δm is pulled out of exhaust hood 8 into atmosphere, it has no effect on the casting of 0.23 C amorphous, ultra-microcrystalline, microcrystalline steel slab.
According to the above analysis, a conclusion is drawn that, embodiments of the present invention can completely substitute patent L to cast amorphous, ultra-microcrystalline, microcrystalline metal profiles with different brands and specifications and an ending temperature t2=−190° C. The calculation formula and program of production parameters in patent L also apply to embodiments of the present invention in casting amorphous, ultra-microcrystalline, microcrystalline metal profiles with an ending temperature t2=−190° C. The production parameters of rapid solidification and cooling casting process to produce amorphous, ultra-microcrystalline, microcrystalline steel listed in Table 3-Table 8 and amorphous, ultra-microcrystalline, microcrystalline aluminum listed in Table 9-Table 14 also apply to embodiments of the present invention. The production parameters are no longer listed in embodiments of the present invention.
The Table of thermophysical properties in embodiments of the present invention show that, the volume of ejected liquid nitrogen is V′=1.281 dm3/Kg, the latent heat is r=190.7 KJ/Kg, and the ejected liquid nitrogen gasifies into low temperature nitrogen with a temperature of t=−190° C., a pressure of p=1.877 bar and a volume of V″=122.3 dm3/Kg. It has to be noticed that the working condition of the low temperature nitrogen is t=−190° C. and p=1.877 bar when the latent heat is r=190.7 KJ/Kg. If the latent heat is not r=190.7 KJ/Kg, the working condition of the low temperature nitrogen is not t=−190° C. and p=1.877 bar. Therefore, the latent heat r=190.7 KJ/Kg must be adopted to determine the quantity of heat ΔQ2max absorbed by the maximum ejection volume ΔVmax of liquid nitrogen during complete gasification based on the formula ΔQ2max=ΔVmax·r/V′, or the working condition of low temperature nitrogen produced by the heat absorption and gasification process cannot be t=−190° C. and p=1.877 bar and the constant temperature and pressure heat absorption and gasification process of casting amorphous, ultra-microcrystalline, microcrystalline metal profiles cannot be guaranteed. This is an important point to be noticed in the application of embodiments of the present invention.
To ensure the working condition of working chamber 8 in exhaust hood at constant temperature and pressure of t=−190° C., p=1.877 bar, the following technical measures are needed for the ejection system of liquid nitrogen:
1). it requires that the working condition of ejected liquid nitrogen is t=−190° C. and p=1.877 bar when liquid nitrogen ejector 5 ejects liquid nitrogen to the cross section C of small length steel slab Δm shown in
2). when designing and manufacturing a powerful exhaust system, the exhaust amount of exhaust system should be set in accordance with the maximum low temperature nitrogen Vgmax and Vg corresponding to the t=−190° C., p=1.877 bar in Table 3-Table 14 of patent L and the following tables of embodiments of the present invention. And the amount of low temperature nitrogen exhausted can be appropriately adjusted. When the exhaust system exhausts Vgmax and Vg out of working chamber 8 of exhaust hood timely and rapidly to ensure that the low temperature nitrogen in working chamber 8 of exhaust hood is at t=−190° C., p=1.877 bar, the phase change of heat absorption and gasification of the ejected liquid nitrogen is in accordance with the constant temperature and pressure curve e-f and amorphous, ultra-microcrystalline, microcrystalline metal profiles with different brands and specifications are casted continuously.
3). the requirements about exhaust system in patent L are fully applicable to the exhaust system in embodiments of the present invention.
The exhaust hood of the powerful exhaust system is set at the outlet of hot casting mold. When casting 0.23 C amorphous, ultra-microcrystalline, microcrystalline steel slab with width of 1 m, the size of exhaust hood is determined as follows:
the width B=1.2 m, the length L=0.1 m, and the height H is determined by the specific location of exhaust hood at the outlet of hot casting mold. The final size and location is determined by production test.
3. Ending Temperature t2 of Rapid Solidification and Cooling
In patent L, the ending temperature of rapid solidification and cooling t2=−190° C. when casting amorphous, ultra-microcrystalline, microcrystalline metal profiles, because the temperatures of ejected liquid nitrogen and working chamber are both −190° C. But if the ending temperature is t2=−190° C., the amorphous, ultra-microcrystalline, microcrystalline metal profiles need to cool down to t2=−190° C. at a cooling rate Vk after cooling down to normal ambient temperature when casting amorphous, ultra-microcrystalline, microcrystalline metal profiles using embodiments of the present invention and patent L. While these metal profiles usually work in normal ambient temperature. It is not necessary for these metal profiles to solidify and cool down to −190° C. It is uneconomical to consume ejected liquid nitrogen to make these metal profiles cool down from ambient temperature to −190° C. Amorphous, ultra-microcrystalline, microcrystalline metal profiles are used in the equipment, such as the space station, large passenger aircraft working at low temperature, cars, rail vehicles working in extremely cold area. The ending cooling temperature can be t2=−190° C., −100° C. . . . and the temperature of product is −190° C., −100° C. . . . to cast amorphous, ultra-microcrystalline, microcrystalline metal profiles using embodiments of the present invention. The performance of products can be tested whether they meet the requirement of low temperature environment. In addition, to make further research, 25° C., 200° C., 500° C. can be determined to be the ending temperature t2 when casting amorphous, ultra-microcrystalline, microcrystalline metal profiles in embodiments of the present invention.
The heat exchange between the ejected liquid nitrogen in working chamber 8 of exhaust hood and the heat conducted from liquid metal end of small length metal slab Δm are researched under a condition that ending temperatures are t2=−100° C., 25° C., 200° C., 500° C. and the working chamber 8 of exhaust hood in
The production parameters, casting 0.23 C amorphous, ultra-microcrystalline, microcrystalline small length steel slab with maximum thickness Emax and other thickness E at the condition of ending temperature t2, can be calculated as follows:
the production parameters and thermophysical properties of 0.23 C steel slab are as follows:
Please refer to the pages 24/29˜26/29 of specifications in patent L about the values of λcp, Ccp and ρcp.
Thermophysical properties of ejected liquid nitrogen
t—temperature of ejected liquid nitrogen, t=−190° C.
p—pressure of the ejected liquid nitrogen at t=−190° C., p=1.877 bar
V′—volume of 1 Kg ejected liquid nitrogen at t=−190° C. and p=1.877 bar, V′=1.281 dm3/Kg
V″—volume of nitrogen produced by the gasification of 1 Kg ejected liquid nitrogen at t=−190° C. and p=1.877 bar, V″=122.3 dm3/Kg
r—the latent heat at t=−190° C. and p=1.877 bar, that is heat that 1 Kg ejected liquid nitrogen absorbs at t=−190° C. and p=1.877 bar to gasify into nitrogen, r=190.7 KJ/Kg
Kmax the maximum ejection speed of ejected liquid nitrogen, Kmax=30 m/s
h—the thickness of ejected liquid nitrogen layer, h=2 mm.
1) Using the R,R,C Method and Equipment to Cast 0.23 C Amorphous, Ultra-Microcrystalline, Microcrystalline Steel Slabs and the Determination of the Production Parameters at t2=−100° C.
1. Using the R,R,C Method and Equipment to Cast 0.23 C Amorphous Steel Slabs and the Determination of the Production Parameters.
(1) Determine the Maximum Thickness Emax of the 0.23 C Amorphous Steel Slab Using R,R,C Method and Equipment
The above calculation indicates that when t2=−100° C., Vk=° C./S, Vmax=7200 dm3/min, the 0.23 C amorphous steel slab with maximum thickness Emax=9.13 mm and width B=1000 mm can be casted continuously using R,R,C method and equipment.
(2) Determine the thickness E of the 0.23 C amorphous steel slab using R,R,C method and equipment
The above calculation indicates that when t2 is fixed at t2=−100° C., Vk=107° C./S, the continuous casting speed u is fixed at 11.10 m/min and the thickness of ejected liquid nitrogen layer is fixed at 2 mm, the ejected quantity of liquid nitrogen falls to V=3943.04 dm3/min from Vmax=7200 dm3/min, and the corresponding liquid nitrogen ejection speed drops to K=16.43 m/s. This will cast 0.23 C amorphous steel slab with E=5 mm continuously.
2. Using the R,R,C Method and Equipment to Cast 0.23 C Ultra-Microcrystalline Steel Slabs and the Determination of the Production Parameters
The combination of cooling rates Vk used are 2×106° C./S, 4×106° C./S, 6×106° C./S, 8×106° C./S respectively.
(1) Determine the Maximum Thickness Emax of the 0.23 C Ultra-Microcrystalline Steel Slab Using R,R,C Method and Equipment
The above calculation indicates that when t2=−100, VK=2×106° C./S, Vmax=7200 dm3/min, the 0.23 C ultra-microcrystalline steel slab with maximum thickness Emax=18.4 mm and width B=1000 mm can be casted continuously using R,R,C method and equipment.
(2) Determine the Thickness E of the 0.23 C Ultra-Microcrystalline Steel Slab Using R,R,C Method and Equipment
The above calculation indicates that when the continuous casting speed u is fixed at 4.48 m/min and the thickness of ejected liquid nitrogen layer is fixed at 2 mm, the ejected quantity of liquid nitrogen falls to V=5867.97 dm3/min, and the corresponding liquid nitrogen ejection speed drops to K=24.4 m/s. This will cast 0.23 C ultra-microcrystalline steel slab with E=15 mm, t2=−100, VK=2×106° C./S continuously.
The formulae and programs used for calculating the production parameters at other cooling rate combinations Vk to produce 0.23 C ultra-microcrystalline steel slab with maximum thickness Emax are the same as those for cooling rate Vk=2×106° C./S. The calculation results are listed below. The calculation process will not be repeated herein.
The calculation result of the production parameters of 0.23 C ultra-microcrystalline steel slab with maximum thickness Emax is as follows when VK is 4×106° C./S and t2 is −100° C.:
Δt=1650, Δτ=4.125×10−4 s, Δm=0.04355 mm, u=6.34 m/min, ΔVmax=0.0495 dm3, ΔQ2max=7.369 KJ, Emax=12.92 mm, Vmax=7200 dm3/min, Vgmax=687400.5 dm3/min.
The calculation result of the production parameters of 0.23 C ultra-microcrystalline steel slab with maximum thickness Emax is as follows when VK is 6×106° C./S and t2 is −100° C.:
Δt=1650, Δτ=2.75×10−4 s, Δm=0.03556 mm, u=7.76 m/min, ΔVmax=0.033 dm3, ΔQ2max=4.912 KJ, Emax=10.5 mm, Vmax=7200 dm3/min, Vgmax=687400.5 dm3/min.
The calculation result of the production parameters of 0.23 C ultra-microcrystalline steel slab with maximum thickness Emax is as follows when VK is 8×106° C./S and t2 is −100° C.: Δt=1650° C., Δτ=2.0625×10−4 s, Δm=0.0308 mm, u=8.96 m/min, ΔVmax=0.0248 dm3, ΔQ2max=3.685 KJ, Emax=9.14 mm, Vmax=7200 dm3/min, Vgmax=687400.5 dm3/min.
The formulae and programs used for calculating the production parameters at other cooling rate combinations Vk to produce 0.23 C ultra-microcrystalline steel slab with maximum thickness Emax are the same as those for cooling rate Vk=2×106° C./S. The calculation process will not be repeated herein.
3. Using the R,R,C Method and Equipment to Cast 0.23 C Microcrystalline Steel Slabs and the Determination of the Production Parameters
(1) Determine the Maximum Thickness Emax of the 0.23 C Microcrystalline Steel Slab (1) Using R,R,C Method and Equipment
(2) Determine the Thickness E of the 0.23 C Microcrystalline Steel Slab (1) Using R,R,C Method and Equipment
The formulae and programs using the R,R,C method and equipment used for calculating the production parameters to produce 0.23 C microcrystalline steel slab (2) at t2=−100° C. with maximum thickness Emax are the same as those for microcrystalline steel slab (1). The calculation process will not be repeated herein.
Maximum thickness Emax and the production parameters of 0.23 C amorphous, ultra-microcrystalline, microcrystalline and fine grain steel slabs with t2=−100° C. (B=1 m, h=2 mm) using R,R,C method and equipment are listed in Table 1.
2) Using the R,R,C Method and Equipment to Cast 0.23 C Amorphous, Ultra-Microcrystalline, Microcrystalline and Fine Grain Steel Slabs and the Determination of the Production Parameters at t2=25° C.
The meaning of the determination of the ending temperature t2=25° C. is that, the cooling rate Vk is constant during the process that 0.23 C liquid steel solidifies and cools down from initial rapid solidification and cooling temperature t1=1550° C. to ending cooling temperature t2=25° C. at a corresponding cooling rate Vk (107° C./s, 8×106° C./s-2×106° C./s, 106° C./s, 105° C./s, 104° C./s). The temperatures of 0.23 C amorphous, ultra-microcrystalline, microcrystalline and fine grain steel slabs are 25° C. of which the temperatures and mechanical properties are consistent with the actual working environment. It is suitable for working in the actual work environment.
In addition, the rapid solidification and cooling of continuously casting process is finished when the liquid steel of small length metal slab Δm solidifies and cools down from t1=1550° C. to t2=25° C. It is unnecessary to cool down from t2=25° C. to t=−190° C. Thus there is no need to eject liquid nitrogen into working chamber 8 of exhaust hood to absorb the internal heat of small length steel slab Δm from t2=25° C. to t=−190° C. The maximum thickness Emax, thickness E and productivity “u” increase correspondingly when equivalent maximum ejection volume Vmax and ejection volume V are used in casting amorphous, ultra-microcrystalline, microcrystalline metal profiles.
The formulae and programs used for calculating the production parameters at t2=25° C. to produce 0.23 C amorphous, ultra-microcrystalline, microcrystalline and fine grain steel slabs are the same as those for t2=−100° C. The t2 of −100° C. in formulae is replaced by 25° C. The calculation process will not be repeated herein. The calculation results are listed below.
3) Using the R, R, C Method and Equipment to Cast 0.23 C Amorphous, Ultra-Microcrystalline, Microcrystalline and Fine Grain Steel Slabs and the Determination of the Production Parameters at t2=200° C.
Recorded in the specifications of patent L in Line 12 on page 25/29(30), the transformation temperature Tg and melting point temperature Tm of amorphous metal has a relationship of Tg/Tm>0.5[1]. For 0.23 C carbon steel, Tg is higher than 750° C., that is, the transformation temperature Tg is one of the temperatures higher than 750° C. Using R,R,C method and equipment, the 0.23 C amorphous steel slab is produced through a rapid solidification and cooling process from t1=1550° C. to t2=200° C. at a cooling rate VK=107° C./S within time interval
In embodiments of the present invention, the 0.23 C liquid steel is required to solidify and cool down from t1=1550° C. to t2=200° C. at a cooling rate Vk and within corresponding Δτ to obtain ultra-microcrystalline, microcrystalline and fine grain steel slabs. The rapid solidification and cooling process in embodiments of the present invention is the same as that in patent L. While the cooling rate of the cooling process from t2=200° C. to ambient temperature 25° C. is no longer the cooling rate Vk corresponding to amorphous, ultra-microcrystalline, microcrystalline and fine grain, but the ambient cooling rate VR200 of the cooling process out of working chamber 8 from t2=200° C. to ambient temperature 25° C. shown in
It is worth noting that, during the cooling process from 200° C. to 25° C., the heat contained in the 0.23 C amorphous, ultra-microcrystalline, microcrystalline, fine grain steel slabs with t2=200° C. is not absorbed by the heat absorption and gasification process of ejected liquid nitrogen but absorbed by the air out of working chamber 8. Therefore, when equivalent maximum ejection volume Vmax and other ejection volume V compared to t2=25° C., −100° C. are used in casting amorphous, ultra-microcrystalline, microcrystalline steel slabs with t2=200° C., steel slabs with thicker Emax and E can be casted and productivity “u” increases correspondingly. The formulae and programs used for calculating the production parameters are the same as those for t2=25° C. The calculation process will not be repeated herein. The calculation results are listed below.
4) Using the R,R,C Method and Equipment to Cast 0.23 C Amorphous, Ultra-Microcrystalline, Microcrystalline and Fine Grain Steel Slabs and the Determination of the Production Parameters at t2=500° C.
It is very necessary to cast 0.23 C amorphous, ultra-microcrystalline, microcrystalline and fine grain steel slabs continuously with t2=500° C. using R,R,C method and equipment. 0.23 C amorphous, ultra-microcrystalline, microcrystalline and fine grain steel slabs with t2=500° C. are produced through rapid solidification and cool casting from t1=1550° C. to t2=500° C. of 0.23 C liquid steel at a cooling rate VK within corresponding time interval Δτ. The problem is that the cooling rate of the cooling process from t2=500° C. to ambient temperature 25° C. is no longer the cooling rate Vk corresponding to amorphous, ultra-microcrystalline, microcrystalline and fine grain, but the ambient cooling rate VR500 of the cooling process out of working chamber 8 from t2=500° C. to ambient temperature 25° C. shown in
On the other hand, during the cooling process from 200° C. to 25° C., the heat contained in the 0.23 C amorphous, ultra-microcrystalline, microcrystalline, fine grain steel slabs with t2=500° C. is absorbed by the air out of working chamber 8. Therefore, when equivalent maximum ejection volume Vmax and other ejection volume V are used in casting amorphous, ultra-microcrystalline, microcrystalline steel slabs, steel slabs with thicker Emax and E than those steel slabs of t2=200° C. and 25° C. can be casted and productivity “u” increases correspondingly. The formulae and programs used for calculating the production parameters are the same as those for t2=200° C. The calculation process will not be repeated herein. The calculation results are listed below.
5) The Values of Maximum Thickness Emax Corresponding to Different Ending Temperatures t2 Using the R,R,C Method and Equipment to Cast 0.23 C Amorphous, Ultra-Microcrystalline, Microcrystalline and Fine Grain Steel Slabs are Listed in Table 22.
The data in Table 22 shows that the maximum thickness Emax of 0.23 C amorphous, ultra-microcrystalline, microcrystalline and fine grain steel slabs increases with the increase of ending temperature t2 from −190° C. to 500° C. The maximum thickness Emax of amorphous steel slabs increases from 8.9 mm to 11.35 mm. The maximum thickness Emax of microcrystalline (1) steel slabs increases from 25.5 mm to 30.79 mm. The maximum thickness Emax of ultra-microcrystalline steel slabs at a cooling rate of VK=2×106 increases from 18 mm to 21.77 mm. The selection of t2 depends on the test, research results and practical needs in actual production.
The R,R,C method and equipment can be used for the continuous casting of various non-ferrous amorphous, ultra-microcrystalline, microcrystalline and fine grain metal profiles (including aluminum alloy, titanium alloy, copper alloy, and the like.). The working principle, formulae and programs used for calculating the maximum thickness Emax to produce 0.23 C amorphous, ultra-microcrystalline, microcrystalline and fine grain steel slabs are the same as those for 0.23 C steel slab. For simplicity, the calculation of maximum thickness Emax of the casted amorphous, ultra-microcrystalline, microcrystalline and fine grain steel slabs with ending temperature t2=25° C. is taken for example for various non-ferrous metal alloys. The calculation process will not be repeated herein. The calculation results are listed in Table 23.
The calculation process and results of other thickness E of the amorphous, ultra-microcrystalline, microcrystalline and fine grain aluminum slabs will not be repeated herein and the calculation results are not listed. As for the formulae and programs for maximum thickness Emax and other thickness E, and related production parameters are the same as those for 0.23 C amorphous, ultra-microcrystalline, microcrystalline and fine grain steel slabs or profiles. It will not be repeated in the specifications.
4. Description of Several Technical Problems
The continuous molding method in patent L and the patent R (the embodiments of the present invention) is derived from continuous ingot casting. The heat of the liquid steel in crystallizer passes through the thin coating on the surface of crystallizer, the metal walls of crystallizer to the cooling water and is conducted out by the cooling water flowing out of crystallizer. The liquid steel in the crystallizer cools into a red hot steel with a red hot solid steel outer layer and a red hot liquid inner. The traction mechanism pulls out the red hot steel from the crystallizer and sprays water to cool down, thus casting the steel ingot.
The continuous casting method in patent L and patent R uses liquid nitrogen ejector at the outlet of hot casting mold which replaces the crystallizer of continuous ingot device. The liquid nitrogen ejected by the liquid nitrogen ejector cools the liquid steel through the heat absorption and gasification principle. The heat that 1 Kg ejected liquid nitrogen absorbs at t=−190° C. and p=1.877 bar to gasify into nitrogen is 190.7 KJ/Kg. The heat is much greater than the heat absorbed by the metal walls of crystallizer and cooling water. The cooling rate of liquid steel is also much greater than that of continuous casting ingot. The cooling rate of both cannot be matched. While the thickness (10-30 mm) of slabs is smaller than the thickness (>100 mm) of continuous casting ingot. Therefore, there is no doubt to cast steel slab with width of 1 m, thickness of 9.42 mm, 18.9 mm, 26.7 mm, at room temperature t2=25° C. using the rapid solidification and cooling method and equipment in patent R. As for casting the steel slabs with thickness of 9.42 mm, 18.9 mm, 26.7 mm, whether they are amorphous, ultra-microcrystalline, microcrystalline steel slabs depends on the specific technical measures below.
The rapid solidification and cooling method for casting amorphous, ultra-microcrystalline, microcrystalline steel slabs in patent L and patent R are composed of three technical aspects. First, in the amorphous, ultra-microcrystalline, microcrystalline small length metal slab Δm with width B and thickness Emax (E), the heat conducted from the section “A” of liquid metal to the section “C” of solid steel in the time interval Δτ is ΔQmax(ΔQ).
Second, the heat ΔQmax(ΔQ) can be conducted to each surface of the intersection of the outlet of hot casting mold and ejected liquid nitrogen layer from the cross section C in the time interval Δτ. Then ejection volume ΔVmax (ΔV) of liquid nitrogen ejected to and covered on the surface of steel in the time interval Δτ absorbs the heat ΔQmax(ΔQ) through the heat absorption and gasification process and changes into low temperature nitrogen. The low temperature nitrogen is exhausted by a powerful exhaust system from working chamber of exhaust hood to the atmospheric environment. Amorphous, ultra-microcrystalline, microcrystalline steel slabs can be cooled down rapidly and solidification casted through the three technical aspects.
1. Application Conditions of One Dimensional Steady Heat Conduction Formula.
The application conditions of one dimensional steady heat conduction formula must be meet in order to determine the heat ΔQmax(ΔQ) conducted from the section A of liquid metal of small length metal slab Δm to section C. There are two aspects about the application conditions of one dimensional steady heat conduction formula. First, the length Emax(E) of either side of two sections with a distance of Δm of the small length metal slab which is perpendicular to the heat conduction direction (that is the traction direction of traction mechanism) needs to meet the following requirement, Emax(E)>10 Δm. The requirement is explained in detail in patent L and can be met. Second, relative macroscopic motion is forbidden between each section of small length steel slab Δm. Only relative thermal motion between molecules is allowed to conduct heat. There is no problem for the solidified steel slab about the second aspect. The problem is that there is a small part of liquid steel in small length steel slab Δm. Macroscopic convective or turbulent motion of this small part of liquid steel is forbidden, that is, the liquid steel in the whole hot mold cannot generate convection or turbulence at macro level. Or, the heat conducted from section “A” of liquid metal in small length metal slab Δm to section “C” of solid steel is much greater than ΔQ2max(ΔQ2) and one dimensional steady state heat conduction formula can not be established. All the production parameters for amorphous, ultra-microcrystalline, microcrystalline steel slabs calculated in the specification in patent L cannot be used. According to this, high-frequency AC power cannot be used for the electric heating element in the hot mold in order to avoid the convection or turbulence of liquid steel. The inner surface of the hot mold is heated by the electric heating element, ensuring that the liquid steel does not condense on the inner surface of the hot mold so as not to affect the smooth movement of liquid steel in hot mold, also ensuring the surface of steel slab pulled out from hot mold is smooth. In addition, the height difference of two ladles, the placement of liquid steel flowing into mid-ladle, the length of hot mold need to be controlled well when liquid steel in casting ladle flows into mid-ladle. It ensures that there is no relative macroscopic motion of liquid steel in hot mold, the flow to the outlet is a translational and steady, and the flow rate of translation of liquid steel is the traction speed of traction mechanism. After taking the above measures, one dimensional steady heat conduction formula is workable to calculate the production parameters of rapid cooling and solidification process to cast amorphous, ultra-microcrystalline, microcrystalline steel slabs. The production parameters can be used in actual production and produce amorphous, ultra-microcrystalline, microcrystalline steel slabs which are in accordance with the calculation results. A few errors may exist.
2. The Rapid Process of Internal Heat of Steel Slab Conducting to Surface of Steel Slab, and the Structure of Ejection Nozzle of Liquid Nitrogen.
When casting 0.23 C amorphous steel slab using patent R, the production parameters are Δτ=1.525×10−4 s, Δm=0.02935 mm, ΔQ2max=2.7243 KJ, ΔVmax=0.0183 dm3 and Emax=9.42 mm (shown in Table 6 in the embodiments of the present invention). During the production process, liquid nitrogen with thickness h=2 mm is ejected by the ejection nozzle of liquid nitrogen to surface of steel slab that is cooled rapidly, solidified and pulled out from the outlet of the hot mold. The covering effect of ejected liquid nitrogen layer is B=1 m and within the range of 2-3 mm outside the outlet of hot mold. The heat ΔQ2max=2.7243 KJ needs to be conducted from the cross section “C” of small length metal slab Δm=0.02935 mm to the surface of steel slab within the covering effect of liquid nitrogen layer above in the time interval Δτ=1.525×10−4 s. And the heat is rapidly and completely absorbed by the maximum ejection volume ΔVmax of liquid nitrogen through heat absorption and gasification process, thus casting the amorphous steel slab structure with Δm=0.02935 mm and Emax=9.42 mm.
Can the heat ΔQ2max be conducted from cross section “C” to each surface of steel slab covered by ejected nitrogen within time interval Δτ?
It should have no problem realizing the heat conduction to surface of steel slab and heat exchange with ejected liquid nitrogen at the surface and surface layers (for example, 1 to 2 mm) of steel slab. Amorphous metal structure can be produced by rapid cooling and solidification process. While the heat in the center of steel slab needs about 5 mm to conduct to the surface of steel slab and to exchange heat with ejected liquid nitrogen. Is the heat exchange among the center of steel slab, the surface of steel slab and ejected liquid nitrogen the same? Are the metal structures the same? According to the principle of heat transfer, the temperature of rapid cooling and solidification steel slab pulled out from hot mold is fixed at t2=25° C. Each channel of the heat conduction from the center of the steel slab to the surface of the steel slab is carried out on the isothermal surface of t2=25° C. The thermal resistance ΔR of heat conduction on the isothermal surface is 0, so there is no resistance of the heat conduction from the center of the steel slab to the surface of the steel slab. That is, the process and rate of the heat exchange of center of steel slab and surface layer of steel slab to surface of steel slab and ejected liquid nitrogen layer are the same. The metal structure of center of steel slab and surface layer of steel slab are the same amorphous metal structure.
The ejection nozzle of liquid nitrogen is required to eject liquid nitrogen layer with thickness h=2 mm uniformly to the upper and lower surfaces of the steel slab with width B=1 m at a ejection speed of Kmax=30 m/s. The angle between the ejected liquid nitrogen and steel slab is initially set as 15° to 30°. The angle is finally determined by the production test. The temperature and pressure is required as t=−190° C., p=1.877 bar when ejected liquid nitrogen intersects to the steel slab.
3. Determine and Regulate the Thickness of Ejected Liquid Nitrogen Layer “h”, the Maximum Ejection Speed Kmax and Ending Temperature t2.
According to the above analysis, it is completely possible to conduct the heat ΔQ2max from the cross section C of Δm to the surface of steel slab, out of the outlet of hot mold and covered by ejected liquid nitrogen, within time interval Δτ. It is the restrictive technical part that whether the ejected liquid nitrogen can absorb all the heat ΔQ2max and transform into nitrogen through heat absorption and gasification process within time interval Δτ. Because the requirement must be met in order to produce the required amorphous, ultra-microcrystalline, microcrystalline metal structure of small length Δm and finally produce amorphous, ultra-microcrystalline, microcrystalline steel slab. The thickness of ejected liquid nitrogen layer h=2 mm and maximum ejection speed of liquid nitrogen Kmax=30 m/s is set according to the requirement. The above values are set in the reference to the cooling pipe parameters of US nuclear power plant. In US nuclear power plant, the pipe diameter of cooling water pipe is 5 mm, the flow rate of cooling water is 30 m/s, and the maximum flow rate of cooling water is 45 m/s.
The thickness of ejected liquid nitrogen layer h=2 mm is determined according to the pipe diameter 5 mm of cooling water pipe in US nuclear power plant. Because the thickness of the cooling water layer involved in the heat absorption, gasification and boiling in the cooling water pipe is equivalent to 2.5 mm. When the heat ΔQ2max conducting from cross section C to the surface of solidified steel slab covered by ejected nitrogen, the heat exchange between ejected liquid nitrogen and the heat ΔQ2max is very fast because the thickness of ejected liquid nitrogen layer is 2 mm and very thin, and the ejection speed is Kmax=30 m/s and very fast. The ejected liquid nitrogen absorbs all the heat ΔQ2max within time interval Δτ and gasifies into nitrogen which is exhausted by the powerful exhaust system (there will be no obstacle by the liquid nitrogen layer with h=2 mm). The liquid steel of small length metal Δm cools down rapidly and solidifies into amorphous, ultra-microcrystalline, microcrystalline metal structure and finally produces amorphous, ultra-microcrystalline, microcrystalline steel slab.
The production parameters can be regulated according to the parameters of cooling water of US nuclear power plant if the effect of rapid cooling and solidification is not good enough with the production parameters h=2 mm, Kmax=30 m/s of ejected liquid nitrogen. The thickness of ejected liquid nitrogen is h=1.3 mm when the maximum ejection speed is Kmax=45 m/s and the maximum ejection volume of liquid nitrogen ΔVmax is fixed at 7200dm3/min. Using the above mentioned production parameters, the effect of rapid cooling and solidification is much better than the production parameters of h=2 mm and Kmax=30 m/s. In view of the above, in the implementation of the patent L and patent R, the ejected system of liquid nitrogen, ejection nozzle of liquid nitrogen, traction mechanism, hot mold and casting ladle and the like should be full considered in designing and manufacturing the equipment. In this way, the likelihood of success is much greater and the regulated range of the production parameters is wider when the production test is carried out.
In the implementation of patent L and patent R for the continuous casting of amorphous, ultra-microcrystalline, microcrystalline steel slabs, the heat ΔQ1(ΔQ2) must be fully absorbed by ejected liquid nitrogen in the time interval Δτ. As for the patent L, when ejected liquid just begins to intersect with the solidified steel slab at cross section C and covers on the surface of steel slab, the temperatures of steel slab and ejected liquid nitrogen are both −190° C. with Δt=0. There is no heat exchange between ejected liquid nitrogen and the steel slab because the adherent temperature gradient of the ejected liquid nitrogen layer is 0. Over time within Δτ, the heat ΔQ1(ΔQ2) in small length metal slab Δm is conducted gradually from cross section A to cross section C on the surface of steel slab. The temperature of the surface of steel slab gradually increases, the adherent temperature gradient of the ejected liquid nitrogen gradually increases, and the heat exchange between ejected liquid nitrogen and steel slab is started. The amorphous, ultra-microcrystalline, microcrystalline steel slab with small length metal slab Δm is rapidly cooled and solidified when ejected liquid nitrogen absorbs all the heat of ΔQ1(ΔQ2) through heat absorption and gasification in the time interval Δτ. As for the patent R, when t2 is selected as 25° C. and ejected liquid just begins to intersect with the solidified steel slab at cross section C and covers on the surface of steel slab, the temperatures of steel slab and ejected liquid nitrogen are 25° C. and −190° C. respectively with Δt of 215° C. The adherent temperature gradient of the ejected liquid nitrogen is much greater than that in patent L when Δτ=0. Because the temperature of liquid nitrogen is t=−190° C. which is higher than the boiling point of liquid nitrogen, the liquid nitrogen ejected to the surface of steel slab is in an unstable state. The ejected liquid nitrogen layer is very thin with high adherent temperature gradient. The liquid nitrogen can absorbs heat and gasify into nitrogen as long as there is heat conducting to the surface of steel slab. That is, the rate at which the liquid nitrogen absorbs heat of ΔQ1(ΔQ2) through heat absorption and gasification in the time interval Δτ is faster than that in patent L. Therefore, in the casting of microcrystalline, microcrystalline steel slabs, the rate of rapid cooling and solidification is much easier to implement in patent R compared to patent L. Compared to patent L, patent R is more successful in ensuring rapid cooling and solidification to cast amorphous, microcrystalline, microcrystalline steel slabs. In patent R compared to patent L, the effect of the selection of different t2 is similar to the above situation in the rapid cooling and solidified casting of amorphous, ultra-microcrystalline, microcrystalline steel slab. Therefore, it will not be repeated herein.
4. Preventing the Flow of Liquid Steel from the Outlet of Hot Mold
After the start of liquid nitrogen ejection device, when the cross section B of solid-liquid metal interface moves 0.5 mm away from the outlet of hot mold by the rapid cooling and solidification effect of ejected liquid nitrogen to the liquid steel in hot mold, traction mechanism is started to pull the rapidly cooled, solidified small length metal slab Δm and the subsequent rapidly cooled, solidified steel slab out of the outlet of hot mold. And the cross section b is fixed at the position 0.5 mm away from the outlet of hot mold without change with the rapid cooling and solidification process of liquid steel Δm. Thus, the liquid steel won't flow out from the outlet of hot mold.
When 0.23 C amorphous steel slab is casted at t2=25° C., Δτ is 1.525×10−4 s, Δm is 0.02935 mm and Emax=4.92 mm. Under the rapid cooling effect of ejected liquid nitrogen, at the position 0.5 mm away from the outlet of hot mold in an extremely short time of Δτ, the temperature of a very small length liquid steel a-b (shown in
5. The Feasibility in Implementation of Patent L and Patent R
All the major operations are made in a space 2-3 mm out away from the outlet of hot mold when patent L and patent R are used for production. So it is necessary to monitor closely the situation occurred in the space, wherein to ensure the predetermined temperature of steel slab and constant temperature of rapid cooling and solidification, such as t=25° C. is the most important thing to notice. After doing this, there is no thermal resistance of the heat conduction from the center of the steel slab to the surface of the steel slab. The metal structure of center of steel slab and surface layer of steel slab are the same amorphous, ultra-microcrystalline, microcrystalline metal structures by the heat absorption and solidification of ejected nitrogen liquid. If we cannot do this, there will be difference in metal structure between the center of steel slab and surface layer of steel slab, leading to the decrease in the mechanical properties of the steel slab. To do this, it is required that the liquid nitrogen ejection system, the traction mechanism, the exhaust system, the hot mold and so on are operated strictly according to the production parameters. And this depends on the technical level and the management level of an enterprise. On the other hand, it is feasible to the implementation of patent L and patent R after the strengthening of technical level and management of an enterprise level.
6. Environmental Issues
For steel enterprises, after the implementation of patent L and patent R, the technology and equipment for continuous casting and repeated hot rolling will be replaced by steel slab factory, steel plant and steel tube factory using disposable, fast and simple R,R,C method. The quality of product is excellent, the cost is low and the production environment is very environmentally friendly. After the implementation of patent L and patent R, the strength of microcrystalline steel increased by over 6 times. Producing the microcrystalline steel can make the national steel production capacity decrease from 900 million tons to 150 million tons just in terms of the strength. Thus, how much carbon emissions of national can reduce? How much iron ore, coke and other resources can be saved? The environmental issues will be greatly improved.
The basic principle of R, R, C method and equipment for casting amorphous, ultra-microcrystalline, microcrystalline and the like, metal profiles in embodiments of the present invention is the same as that in patent L. Embodiments of the invention are developed from patent L. But compared to patent L, embodiments of the present invention are more advanced without special requirements of the low temperature of working chamber and insulation technology. Amorphous, ultra-microcrystalline, microcrystalline and fine grain metal profiles of different brands and specifications with thicker thickness of maximum thickness Emax compared to patent L can be casted continuously. The ending temperature t2 of rapid solidification and cooling can be selected according to the temperature requirements of working environment of amorphous, super-microcrystalline, microcrystalline metal slabs or profiles to produce amorphous, super-microcrystalline, microcrystalline metal slabs or profiles which are more suitable in different working environments, while the cost is much lower.
Therefore, although the basic principles of embodiments of the present invention and patent L are the same, embodiments of the present invention have the characteristics of advanced technology, superior performance of product, lower cost and more promising.
It should be noted that the term “comprising” does not exclude other elements or steps and the use of articles “a” or “an” does not exclude a plurality. Also elements described in association with different embodiments may be combined. It should also be noted that reference signs in the claims should not be construed as limiting the scope of the claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2014 1 0165617 | Apr 2014 | CN | national |
This application is a continuation-in-part application to PCT/CN2015/077220, having a filing date of Apr. 22, 2015, based on CN 2014 1016 5617.9, having a filing date of Apr. 23, 2014, the entire contents of which are hereby incorporated by reference.
| Number | Name | Date | Kind |
|---|---|---|---|
| 4590988 | Fukuoka et al. | May 1986 | A |
| Number | Date | Country |
|---|---|---|
| 5316879 | May 1980 | CN |
| 1691994 | Nov 2005 | CN |
| 101081429 | Dec 2007 | CN |
| 101332504 | Dec 2008 | CN |
| 101081429 | Sep 2012 | CN |
| 103894569 | Jul 2014 | CN |
| Entry |
|---|
| International Search Report PCT/CN2015/077220; International Filing Date: Apr. 22, 2015; 2 Pgs. |
| Number | Date | Country | |
|---|---|---|---|
| 20170106436 A1 | Apr 2017 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/CN2015/077220 | Apr 2015 | US |
| Child | 15332360 | US |
