High-ductility and high-formability cold-rolled DH590 steel and production method thereof

Abstract

The invention discloses high-ductility and high-formability cold-rolled DH590 steel and a production method thereof. The steel comprises 0.08%-0.14% of C, 1.2%-2.2% of Mn, 0.35%-0.75% of Si, 0.02%-0.50% of Al, 0.03%-0.45% of Cr, 0.02%-0.25% of Mo, 0-0.01% of P, 0-0.01% of S, 0-0.03% of Nb and the balance iron and inevitable impurities. The heating temperature of a casting blank is 1200-1300 DEG C,the initial rolling temperature is 1100-1180 DEG C, the final rolling temperature is higher than or equal to 910 DEG C, and the coiling temperature is 550-700 DEG C; the cold rolling reduction rate is 50%-90%; the continuous annealing temperature is 750-850 DEG C, the annealing time is 10-600S, the slow cooling outlet temperature is 660-730 DEG C, the rapid cooling rate is higher than 20 DEG C / S,the rapid cooling outlet temperature is 300-420 DEG C, the overaging temperature is 300-420 DEG C, and the overaging time is 30-3600S; and the finishing elongation is 0.3%-0.6%. A finished steel plate has high ductility and high formability.

Description

technical field [0001] The invention belongs to the technical field of cold-rolled steel, and relates to a cold-rolled DH590 steel with high ductility and high formability and a production method thereof. Background technique [0002] In the automotive industry, higher requirements have been put forward for body weight reduction, emission restrictions, and safety standards. In order to better serve users, the automotive industry has more and more demands for parts with high formability. Traditional dual-phase steels are difficult to meet the requirements of high-drawability complex punching cups, and TRIP steels are widely used due to high alloy content and expensive production costs. DH steel is the English abbreviation of Dual Phase Steels with Improved Formability, which was first mentioned in the VDA 239-100 cold-formed steel plate standard issued by the German Association of Automobile Manufacturers in 2016. DH steel has good formability due to the introduction of a ce...

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Problems solved by technology

[0003] Patent document CN 109402355 A discloses a 600MPa grade hot-rolled TRIP type dual-phase steel and its preparation method. Its main chemical components are: C: 0.12%-0.14%, Si: 0.3%-0.4%, Mn: 1.5%- 1.7%, Al: 0.35%~0.45%, P≤0.014%, the production process mainly adopts hot rolling process, the plasticity of this patented product is poor, A 80 The elongation after breaking is only 24%, and no cold-rolled products are involved

[0004] Patent document CN 103827332 B discloses a TRIP-type martensitic dual-phase steel and an ultra-high-strength steel workpiece using it. Its main chemical components are: C: 0.1%-0.7%, Si: 0.5%-2.5% , Mn: 0.5% ~ 3.0%, Cr: 0.5% ~ 2.0%, Mo≤0.5%, Al: 0.04% ~ 2.5%, the production process mainly adopts cold rolling and continuous annealing process, the strength level is 1500MPa, the product is extended and expanded Poor performance, it is difficult to meet the performance requirements of complex stamping parts

[0005] Patent document CN 107747039 A discloses a cold-rolled dual-phase steel with high hole expansion performance and its preparation method. Its main chemical components are: C: 0.10%-0.50%, Si: 0.1%-0.5%, Mn: 1.60%- 2.00%, V: 0.01% ~ 0.03%, Al: 0.02% ~ 0.06%, P≤0.020%, S≤0.015%, N≤0.006%, the production process is cold rolling continuous annealing system, the patented product is low yield strength Limited in formability and ductility than duplex steels

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