Patent Application
20080011394
For a better understanding of the invention and its operation, turning now to the drawings,
In schematic
Heat source 50 recirculates quenchant mixture 45 within cell 20 while maintaining its temperature at approximately 100° C. In a typical installation, liquid 53 shown would consist of preferably typical conventional RAQ-TWT quenching solution sold by Richards Apex, Inc. of Philadelphia, Pa. RAQ-TWT is a proprietary formula containing: polyalkylene glycol—45.5%; polyethylene glycol ester—12%; a proprietary metal working fluid additive—12%, a defoamer—0.5%, and water—30%, with a typical pH of 3-9%. This quenchant solution is diluted to 10% by volume with water prior to use. Other commercial quenching liquids or water could also be used.
Gas 55 contained within gas supply 54 is preferably air but other gases may be used to form quenchant mixture 45. Mixture 45 can be varied by the air flow rate and volume percentage to change the forced convective heat transfer coefficient as shown schematically in
Examples for the thermodynamic wire transformation process for SAE 1090 steel are provided in Table 1 below.
As seen in Table 1, conventional 2 mm SAE 1090 steel wire was processed using a plurality of cells 20-24, containing liquid 53, preferably quenchant RAQ-TWT as described above, diluted to 11 concentration in water by volume. By bubbling gas 55 (preferably air) through liquid 53 at various rates in individual cells 20-24 the breaking loads and tensile strength of wire 11 can be altered.
In Example 1 seen in Table 1, the preferred method utilizes a nominal 2 mm diameter wire (1090 steel) treated with a resulting breaking load of 3600 Newtons (N) and a tensile strength of 1192 Megapascals (MPa). E<ample 6 shows the method with the same 2 mm wire being treated only in cells 20 and 21 and having an increased breaking load of 3947 N with a tensile strength of 1305 MPa. In Example 20, the method employs cells 20, 21, 22, 23 and 24, all utilized with various flow rates and air volumes with the breaking load increasing to 4171 N and a tensile strength increasing to 1381 MPa. All examples shown herein were run at a constant wire speed of 7 meters per minute.
Thus, by increasing the volume or percentage of gas 55 in quenchant mixture 45, improved breaking loads and tensile strengths of 1090 wire can be realized by the described methods.
Examples for the thermodynamic wire transformation process for SAE 1070 steel are provided in Table 2 below while
As seen in Table 2, conventional 1.2 mm SAE 1070 steel wire was processed in a plurality of cells 20-24, containing liquid 53 preferably quenchant RAQ-TWT as described above diluted to 10% concentration in water by volume with gas 55 combining therewith to form quenchant mixture 45.
In Example A, cell 20 was modified to apply a ⅜ inch round spray perpendicular to the wire.
In Examples B-E, cell 20 was modified to apply a 6 inch flat spray parallel (⅛ inch thick) to the wire.
In Examples F-K, cell 20 was modified to apply a pipe spray in the range of 1.5-3 g/m while the wire was encased in a ⅜ inch thick, 4 inch long pipe at various flow rates.
By bubbling gas 55 (preferably air) through liquid 53 at various rates in individual cells 21-24 the breaking loads and tensile strength of wire 11 can be treated with vapors 56.
In Example A, as seen in Table 2, the preferred method utilizes a round spray and nominal 1.2 mm diameter wire (1070 steel) treated with a resulting breaking load of 1289 Newtons (N) and a tensile strength of 1148 Megapascals (MPa). Example D shows the flat spray method with the same 1.2 mm wire being treated only in cell 20 and 22 and having an increased breaking load of 1276 N with a tensile strength of 1168 MPa. In Example G, the method employs a Pipe Spray, a method of full liquid immersion where the hot wire is guided through a pipe filled with liquid, at 3 g/m in cell 20 with the breaking load increasing to 1315 N and a tensile strength increasing to 1197 MPa. In Example I, the method of full liquid immersion employs a pipe spray at 3 g/m (cell 20) and varying flows in cells 21-24 with the breaking load increasing to 1407 N and a tensile strength increasing to 1234 MPa. All examples shown herein were run at a constant wire speed of 12.5 meters per minute.
Thus, as illustrated by increasing the volume or percentage of gas 55 in quenching mixture 45 to various rates improved breaking loads and tensile strengths of the 1070 wire can be realized by the described methods.
The illustrations and examples provided herein are for explanatory purposes and are not intended to limit the scope of the appended claims. Other strand materials and metal shapes and sizes could also be accommodated by obvious changes to the apparatus and processing steps, depending on the requirements of the user.
