Method for producing steel for plastic mold through high-temperature and high-pressure process
The production of steel for plastic molds under high temperature and high pressure technology has solved the problems of high production costs and uneven hardness in traditional processes, and achieved uniform hardness and good plate shape.
Patent Information
- Application Number
- CN202510173335.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-17
- Publication Date
- 2025-06-10
AI Technical Summary
The production process of traditional plastic mold steel is long, has high cost, and is uneven hardness, which affects the shape of the plate.
High-temperature and large-pressure technology is used to produce steel for plastic molds, including molten iron pretreatment, converter smelting, LF furnace refining, VD vacuum degassing, 3500 wide slab continuous casting, slow cooling of casting blank stacking, slab heating, high-temperature and large-pressure and backtempering.
It effectively ensures the hardness uniformity and good plate shape of steel for plastic molds, reduces production costs, and improves production efficiency.
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Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of steel for plastic molds, and particularly relates to a method for producing steel for plastic molds by a high-temperature large reduction process. Background Art
[0002] Traditionally, steel for plastic molds is delivered in a quenched or quenched + tempered or normalized + tempered state. Such steel plates have high hardness and stable properties, but the production process flow is long and the cost is high. From the perspective of economy, the high-temperature large reduction process can effectively improve production efficiency and reduce production costs. Moreover, at high temperatures, the rolling deformation resistance is small and the deformation penetration is large, which can effectively deform to the core. For plastic mold steel, the hardness change from the core to the surface layer is small and the hardness is uniform. Summary of the Invention
[0003] In view of this, the purpose of the present invention is to provide a method for producing steel for plastic molds by a high-temperature large reduction process, which can effectively ensure uniform hardness and good plate shape of the steel for plastic molds, so as to solve the above problems.
[0004] To achieve the above purpose, the technical solution adopted by the present invention is: a method for producing steel for plastic molds by a high-temperature large reduction process, the weight percentages of the chemical components of the steel for plastic molds are: C: 0.36 - 0.39%, Si: 0.25 - 0.30%, Mn: 1.0 - 1.2%, P ≤ 0.015%, S ≤ 0.010%, Cr: 0.15% - 0.16%, and the balance is Fe and unavoidable impurities. The method includes the following steps: hot metal pretreatment, converter smelting, LF furnace external refining, VD vacuum degassing, 3500 wide slab continuous casting, slab stacking and slow cooling, slab heating, high-temperature large reduction, and tempering.
[0005] Preferably, the high-temperature large reduction process includes: the starting rolling temperature is 1050 - 1080°C, the single-pass reduction rate ≥ 12%, the cumulative reduction rate is greater than or equal to 66%, the finishing rolling temperature ≥ 950°C, and after rolling, it is stacked and cooled for 24 h.
[0006] Preferably, in the tempering process, the tempering temperature is 550°C - 600°C, the tempering coefficient is 3.0 min / mm, and after the steel plate is taken out of the furnace, it is stacked and cooled for 24 h.
[0007] Preferably, the Rockwell hardness of the steel plate is 28 - 32 HRC, and the hardness difference in the thickness direction of the steel plate ≤ 2 HRC.
[0008] The beneficial effect of the present invention is: it provides a method for producing steel for plastic molds by a high-temperature large reduction process, which can effectively ensure uniform hardness and good plate shape of the steel for plastic molds. Detailed Embodiments
[0009] The present invention will be further described in detail below in conjunction with specific embodiments: Example 1. In this example, the composition of the die steel is in weight percentage ratio, including the following components shown in Table 1, with the balance being Fe and unavoidable impurities.
[0010] Table 1 Composition of the steel plate in this example (mass fraction) % The production process route of the die steel for plastic molds using the high-temperature large reduction process in this example includes top and bottom combined blown converter, LF furnace external refining; VD vacuum degassing; continuous casting of 3500 wide slab; stacking and slow cooling of the cast slab; heating of the slab; high-temperature large reduction; tempering; among which, the high-temperature large reduction and tempering processes are shown in Table 2.
[0011] Table 2 Process system for 50mm in this example The Rockwell hardness of the die steel produced by the high-temperature large reduction process is 28 - 32 HRC, and the hardness difference in the thickness direction of the steel plate is ≤ 2 HRC.
[0012] Example 2. In this example, the composition of the die steel is in weight percentage ratio, including the following components shown in Table 1, with the balance being Fe and unavoidable impurities.
[0013] Table 1 Composition of this example (mass fraction) % The production process route of the die steel for plastic molds using the high-temperature large reduction process in this example includes top and bottom combined blown converter, LF furnace external refining; VD vacuum degassing; continuous casting of 3500 wide slab; stacking and slow cooling of the cast slab; heating of the slab; high-temperature large reduction; tempering; among which, the high-temperature large reduction and tempering processes are shown in Table 2.
[0014] Table 2 Process system for 50mm in this example The Rockwell hardness of the die steel produced by the high-temperature large reduction process is 28 - 32 HRC, and the hardness difference in the thickness direction of the steel plate is ≤ 2 HRC.
[0015] The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.
Claims
1. A method for producing steel for plastic molds by high temperature and high pressure reduction process, characterized in that: The weight percentage of the chemical composition of the steel for plastic molds is: C: 0.36-0.39%, Si: 0.25-0.30%, Mn: 1.0-1.2%, P≤0.015%, S≤0.010%, Cr: 0.1.5%-0.1.6%, and the balance is Fe and inevitable impurities. The method comprises the following steps: molten iron pretreatment, converter smelting, LF refining outside the furnace, VD vacuum degassing, 3500 wide slab continuous casting, slow cooling of slab stacking, slab heating, high temperature and large reduction, and tempering.
2. The method for producing plastic mold steel by high temperature and large reduction process according to claim 1, characterized in that: The high temperature and large reduction process includes: starting rolling temperature of 1050-1080°C, single pass reduction rate ≥12%, cumulative reduction rate greater than or equal to 66%, final rolling temperature ≥950°C, and stack cooling for 24 hours after rolling is completed.
3. The method for producing plastic mold steel by high temperature and large reduction process according to claim 1, characterized in that: In the tempering process, the tempering temperature is 550°C-600°C, the tempering coefficient is 3.0min / mm, and the steel plate is pile-cooled for 24 hours after being taken out of the furnace.
4. The method for producing plastic mold steel by high temperature and large reduction process according to claim 1, characterized in that: The Rockwell hardness of the steel plate is 28-32HRC, and the hardness difference in the thickness direction of the steel plate is ≤2HRC.