This application claims priority to Chinese Patent Application No. 202211330606.2, filed on Oct. 28, 2022, the contents of which are hereby incorporated by reference.
The present application belongs to the technical field of high-manganese steel smelting, and in particular to a method for smelting low-phosphorus high-manganese steel based on reduction dephosphorization of ferromanganese.
High-manganese steel is an alloy steel with manganese content above 10%, with features of strong impact resistance and wear resistance under high-pressure environments, making it an ideal material for the production of wear-resistant materials, and therefore has been widely used in mechanical equipment in metallurgy, mines, building materials, railway, electric power and coal, etc.
In recent years, higher demands have been placed on equipment performance with the rapid development of China's high-speed rail, mining and other industries, as the environment in which the equipment operates has deteriorated dramatically. The high-manganese steel prepared by conventional melting process has a disadvantage of high content of phosphorus (P), which will degrade the mechanical properties and casting performance of the high-manganese steel, reduce the toughness, plasticity and strength of the steel, and induce the occurrence of cold cracking and heat treatment cracking in the high-manganese steel. By reducing the P content, the appearance of cracks and premature failure of parts can be effectively prevented and the service life of the equipment can be improved. The high-manganese steel is one of the specialty steels and is often smelted using electric arc furnace, which combines both oxidative and reductive environments so as to achieve the functions of oxidative dephosphorization and reductive desulphurization of the electric arc furnace. In an oxidative environment of the electric arc furnace, P and other impurity elements are oxidized and removed to a lower level. In the smelting process of high-manganese steel, Mn element comes mainly from the ferromanganese alloy, where the Mn is more active than Fe and can only be added under the reductive atmosphere, i.e., in the reductive period of electric arc furnace smelting, so as to avoid a large amount of oxidative burning loss of Mn element. Since P cannot be removed during the reductive period, about 0.15% of the P element contained in the ferromanganese alloy will all enter the steel and cannot be removed. Therefore, reducing the P content in the molten steel before adding ferromanganese and reducing the P content in ferromanganese is an inevitable way to control the P content of the final product in the high-manganese steel production process.
Patent No. CN102409138A, entitled Process for Manufacturing Alloy Steel for Rail Frog, proposes that the carbon (C) content in steel is controlled to be above 0.50% during rudimentary smelting, the temperature is controlled to be above 1,560 degrees Celsius (° C.), and the oxygen blowing is carried out when the slag has good fluidity, so as to achieve the removal of P. The Chinese Patent No. CN113061798A, titled Smelting Technology of Alloyed High-manganese Steel, proposes that after the furnace charge is completely melted down, oxygen blowing is carried out at a temperature of over 1,560° C. for dephosphorization and decarburization. Both of the two methods of high-manganese steel smelting involve dephosphorization only in the melting and oxidative stages of the electric furnace smelting. However, the P content in steel at the end of the oxidative stage is at least 0.005% according to the current processing technology of electric arc furnace smelting, and the P content in steel increases after ferromanganese is added to steel during the reductive stage, thus the P content of the final product can no longer be reduced even though it complies with the requirements of the relevant product standards. Patent Publication No. CN112813351A, entitled High-manganese steel and Smelting Method Thereof, proposes to smelt high-manganese steel by using manganese metal with a content of over 95% as an alloy, where the P content in the manganese metal is relatively low; even though such a treatment method significantly reduces the P content of the final product, the cost of high-purity manganese metal is extremely high, resulting in a substantial increase in the final cost of the product, which is unfavorable for the long-term mass production and operation.
In response to the above problems existing in the prior art, the present application addresses the technical problem of how to provide a method of smelting high-manganese steel at low costs and effectively reducing a phosphorus (P) content in the steel.
In order to solve the technical problems, the present application adopts the following technical schemes: a method for smelting low-phosphorus high-manganese steel based on reduction dephosphorization of ferromanganese, including the following steps:
with a unit of kilogram (kg);
Optionally, the reducing agent in the S2 is ferrosilicon, or SiC, or silicomanganese alloy, or silicon calcium alloy, or aluminum alloy, with a Si content of 70%-80%.
Optionally, a C content in the medium-carbon ferromanganese in the S2 is 1.0%-2.5% of a total mass of the medium-carbon ferromanganese, and a Mn content is 75%-80% of the total mass of ferromanganese.
Optionally, mass proportions of effective components in the SiCa alloy in the S3 is: Si content of 50%-65%, and Ca content of 30%-35%.
Optionally, the composition requirements of steel grades in the S6 include: C accounts for 1.00%-1.20%, Si accounts for 0.40%-0.60%, Mn accounts for 10%-15%, P accounts for less than 0.030% and S accounts for less than 0.010%.
Compared with the prior art, the present application has at least the following advantages:
in the existing high-manganese steel, the P content is basically around 0.035%, which is reduced to around 0.018%-0.022% in the finished steel after adopting the method of the present application; at the same time, the room temperature solid ferromanganese is avoided to be added into the molten steel by pre-melting ferromanganese in the mediate-frequency induction furnace, and the temperature of the molten steel at the end of the oxidative period is properly lowered, thereby saving electric power and reducing the cost to a certain extent.
The FIGURE shows a schematic process illustrating a method of the present application.
The present application is illustrated in further detail below.
The present application provides a method for smelting low-phosphorus high-manganese steel based on reduction dephosphorization of ferromanganese, whereby ferromanganese is smelted in a mediate-frequency induction furnace to reduce the P content in ferromanganese to obtain low-phosphorus ferromanganese in a molten state, then the low-phosphorus ferromanganese is added into an LF ladle refining furnace to be mixed with low-phosphorus molten steel obtained by a oxidative smelting method of electric arc furnace to finally obtain a molten steel with low P content. In the present application, the production mode in the prior art that solid high-phosphorus ferromanganese of normal-temperature is directly added in the reductive period of the electric arc furnace is replaced, so that the P content in the final molten steel is greatly reduced; also, the oxidizability of the dephosphated slags oxidized by the electric arc furnace is utilized to oxidize the negative-valence phosphorus in the dephosphated slags reduced by the intermediate-frequency furnace into high-valence phosphorus, and the obtained phosphorus-containing slag can be used as raw materials for the production of phosphate fertilizer and other products; by adopting the method, the P content in high-manganese steel is effectively reduced, with improved production efficiency, reduced production cost in addition to improved performance of the high-manganese steel.
As shown in the FIGURE, the method for smelting low-phosphorus high-manganese steel based on reduction dephosphorization of ferromanganese includes the following steps:
with a unit of kilogram (kg);
A method for smelting low-phosphorus high-manganese steel based on reduction dephosphorization of ferromanganese includes the following steps:
with a unit of kg.
Embodiments 2-10 adopt the same preparation method as that of Embodiment 1, the difference lies in the quantity ratio of the ingredients and the selection of process parameters, see Table 1 for details.
Table 2 shows the mass ratio of each component of the first slagging agent and the second slagging agent in Embodiments 2-10.
Table 3 shows the phosphorus content of the low-phosphorus high-manganese steel smelted based on reduction dephosphorization of ferromanganese prepared in Embodiments 1-10.
As can be seen from Table 3: the data in Table 3 is the phosphorus content in the finished steel obtained by each embodiment, and the lower the phosphorus content in the finished steel, the more ferromanganese dephosphorization is required.
Finally, the above embodiments serve only to illustrate the technical schemes of the present application and are not intended to be limiting, and although the present application has been described in detail with reference to the preferred embodiments, a person of ordinary skill in the art should understand that modifications or equivalent replacements can be made to the technical schemes of the present application without departing from the purpose and scope of the technical schemes of the present application, which should be covered by the scope of the claims of the present application.
Number | Date | Country | Kind |
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202211330606.2 | Oct 2022 | CN | national |