CN-119932284-B - Production method of 1500MPa high-corrosion-resistance hot stamping stainless steel cold-rolled strip steel

Abstract

The invention relates to a production method of 1500MPa high corrosion resistant hot stamping stainless steel cold rolled strip steel, which comprises the following chemical components: 0.06% -0.10%, si:0.08 to 0.12 percent of Mn:0.8 to 1.2 percent, less than or equal to 0.012 percent of P, less than or equal to 0.005 percent of S, and Cr:12.8% -13.5%, N:0.04% -0.08%, als:0.02% -0.04%, V:0.08 to 0.12 percent, nb:0.03 to 0.06 percent, and the balance of Fe and impurities. The production method comprises the working procedures of molten iron pretreatment, smelting, refining, continuous casting, hot rolling, spheroidizing annealing, acid washing, cold rolling and hot stamping forming; the invention is suitable for mass production operation, and the product has the characteristics of high strength, good toughness and good stamping performance, and the thickness specification of the finished product is 1.0-3.0 mm; the thin-specification strip steel produced by the method has high quality stability and is suitable for preparing hot formed parts.

Inventors

• ZHANG YU
• HE YI
• LIU HUASONG
• PAN DONG
• DAI CHUNDUO
• ZHANG XIANGYU
• Yan Zhiran
• GUO XIAODONG
• WANG KAIMENG

Assignees

• 鞍钢集团北京研究院有限公司

Dates

Publication Date

20260505

Application Date

20250217

Claims (2)

1. 1. A production method of 1500MPa high corrosion resistant hot stamping stainless steel cold rolled strip steel is characterized in that the chemical components of strip steel are C：0.084%～0.10%、Si：0.08%～0.12%、Mn：0.8%～1.2%、P≤0.012%、S≤0.005%、Cr：12.8%～13.5%、N：0.04%～0.08%、Als：0.02%～0.028%、V：0.08%～0.12%,Nb：0.03%～0.06%, weight percent, and the balance is Fe and unavoidable impurities, the production method comprises the steps of molten iron pretreatment, smelting, refining, continuous casting, hot rolling, spheroidizing annealing, acid cleaning, cold rolling and hot stamping forming, and the specific control is as follows: 1) Steelmaking, namely smelting molten iron by adopting a converter or an electric furnace after pretreatment, and refining outside the furnace to obtain refined molten steel; 2) Continuous casting, namely controlling the target temperature of a continuous casting tundish to be 20-35 ℃ above the liquidus temperature, adopting a weak cooling system for secondary cooling, wherein the secondary cooling water volume is 220-230L/min, adopting dynamic light rolling, the rolling reduction is 4-12 mm, and the thickness of a continuous casting billet is 70-200 mm; 3) The hot rolling is carried out, wherein the heating temperature of a casting blank is 1180-1280 ℃, after descaling by high-pressure water, the rough rolling adopts multi-pass rolling, the thickness of an intermediate blank is 30-50 mm, the total rolling reduction rate of finish rolling is more than or equal to 85%, the final rolling temperature of hot rolling is 900-950 ℃, the coiling temperature is 670-750 ℃, and the thickness of a hot rolled plate is 4-10 mm; 4) Spheroidizing annealing, namely performing cover annealing treatment on the hot rolled plate, wherein the annealing temperature of the cover annealing is 850-870 ℃, the heat preservation time is 6-12 h, and air cooling to room temperature after the heat preservation is performed with the cover to below 400 ℃; 5) Acid washing, namely removing oxide skin on the surface of the hot rolled plate through acid washing; 6) Cold rolling, namely cold rolling after pickling, wherein the cumulative rolling reduction is 30% -48.5%, and the flattening elongation is controlled to be 0.5% -1.2%; 7) Hot stamping forming, namely hot stamping forming is carried out after uncoiling and blanking of the cold rolled coil, and the hot stamping forming is concretely as follows: (a) Austenitizing the steel, namely heating the cold-rolled sheet to 980-1050 ℃, and preserving heat for 3-10 min; (b) The steel material is transferred, namely the heated cold-rolled sheet is quickly transferred into a hot stamping forming die, the transfer time is controlled to be 5-15 s, the hot stamping forming die is preheated to 50-200 ℃, and the cooling speed after hot stamping forming is 0.1-0.3 ℃ per second; (c) The hot stamping forming, wherein the dwell time of the hot stamping forming is controlled to be 5-10 s; (d) Demolding, wherein the demolding temperature is less than or equal to 250 ℃; the tensile strength Rm of the finished strip steel product is more than or equal to 1500MPa, the pitting potential is more than or equal to 0.05V SCE .
2. 2. The method for producing 1500MPa high corrosion resistant hot stamping stainless steel cold rolled strip steel according to claim 1, wherein the thickness of the strip steel finished product is 1.0-3.0 mm.

Description

Production method of 1500MPa high-corrosion-resistance hot stamping stainless steel cold-rolled strip steel Technical Field The invention relates to the technical field of production of martensitic stainless steel cold-rolled steel strips, in particular to an industrial manufacturing method of a hot-formed stainless steel plate cold-rolled product with high corrosion resistance, wherein the tensile strength reaches 1500MPa level, the pitting potential is more than or equal to 0.05 VSCE. Background The automobile is light, the fuel efficiency, the running performance and the safety can be effectively improved, and the automobile is one of important concerns in the automobile industry. At present, carbon steel 22MnB5 is generally adopted to produce 1500 MPa-level high-strength parts for automobiles through a hot stamping process, but the problem of oxidization of hot forming steel in the austenitizing process exists. About half of the hot-formed steel sheets used in the world are prevented from oxidation and decarbonization at high temperature by an Al-Si plating layer, which increases the production cost of the hot-formed steel, causes scaling of the surface of a die during hot stamping, affects the life of the die, and increases the cleaning cost. In addition, because of the alloy component characteristics of the carbon steel, the carbon steel needs to be painted for protecting the material from corrosion during the service life, the production process and the cost are increased, and meanwhile, the production process further causes environmental pollution. Stainless steel is receiving increasing attention from the automotive industry due to its low LCA, etc. throughout its life cycle. The stainless steel car body and the ultra-high strength stainless steel structural member are used as car body frameworks, and have the advantages of high strength, corrosion resistance, coating avoidance and the like. The method is applied to hot stamping production, can solve the problems of high-temperature oxidation, die scaling and the like of common carbon steel in the hot stamping process, can reduce the working procedures of acid washing, degreasing, phosphating, painting and the like in the vehicle body manufacturing process, greatly reduces the production and manufacturing cost, meets the requirements of green and environment protection, can recycle the stainless steel by 100 percent without degrading and recycling, has extremely low metal loss during use, reduces the environmental pollution caused by metal corrosion degradation, and has lower full life cycle application cost and greener and environment-friendly property. Because of their high strength properties, hot-formed steels are commonly used for automotive safety components such as front and rear bumpers, door impact beams, and a-, B-, C-, and center tunnel-type components. Because of the demand for light weight, the thickness specification of hot formed steel parts on passenger cars is smaller, and the hot formed steel cold-rolled strip steel is generally adopted for preparation. PCT patent application No. 201880011193.7 discloses a "steel for manufacturing parts by hot forming and the use of the parts". The use of stainless steel to make steel for parts and parts is described. The chemical composition defining the steel grade is ：C≤0.2％,Si≤3.5％,Mn1.5％～16％,Cr8％～14％,Ni≤6％,N≤1％,Nb≤1.2％,Ti≤1.2％,Mo≤2.0％,V≤0.15％,Cu≤2.0％,Al≤0.2％,B≤0.05％., the product of which can be used for transport components of vehicles, also for high-strength crash safety roll bars, or complex structural components such as pillars or fairings, even for anti-graffiti solutions, such as park benches, railway surfaces, and for tableware. However, the composition and the process are limited widely, and the cold-rolled sheet preparation process suitable for mass production operation and production is not provided. Based on the method, the invention provides the high-strength corrosion-resistant hot stamping stainless steel and designs a process path of the cold-rolled strip steel suitable for industrial mass production aiming at the steel type. Disclosure of Invention The invention provides a production method of 1500MPa high corrosion resistant hot stamping stainless steel cold rolled strip steel, which is suitable for large-scale production operation, and the product has the characteristics of high strength, good toughness and good stamping performance, the thickness specification of the finished product is 1.0-3.0 mm, and the thin-specification strip steel produced by the method has high quality stability and is suitable for preparing hot forming parts. In order to achieve the above purpose, the invention is realized by adopting the following technical scheme: A production method of 1500MPa high corrosion resistant hot stamping stainless steel cold rolled strip steel comprises the steps of molten iron pretreatment, smelting, refining, continuous casting, hot rolling, spheroidizing annealing, p