Rare earth-contained high-manganese cold-rolled steel plate and manufacturing method thereof

Abstract

The invention discloses a rare earth-contained high-manganese cold-rolled steel plate and a manufacturing method thereof. The steel plate comprises the following components in percentage by weight: 0.4-0.8% of C,14-20% of Mn, 0.05-0.15% of RE, P not more than 0.020%, S not more than 0.012%, 1.0-2.0% of Al, 0.01-0.03% of N, and the balance of Fe and inevitable impurities; and the steel plate satisfies the conditions that: Mn+20*C not less than 30% and Al+5*RE not less than 1.8%. The steel plate is produced by a cold rolling-continuous annealing process to obtain austenite with 100% of room-temperature microstructure, reaches the recrystallization fraction of 80-95%, the yield strength of 450-650 MPa, the tensile strength of 950-1100 MPa and the ductility of above 50%, is excellent in splitting delay performance, is ultrahigh in strength, and is suitable for a vehicle structural part and a safety part with complex shapes.

Description

technical field [0001] The invention belongs to the field of high-manganese cold-rolled steel, and in particular relates to a rare-earth-containing high-manganese cold-rolled steel plate and a manufacturing method thereof. It has good cracking performance and is suitable for automotive structural parts and safety parts with complex shapes, as well as other related fields. Background technique [0002] Increasing the strength of the steel plate to reduce the thickness of the steel plate is a development trend of the steel plate in recent years. A large number of ultra-high-strength steel plates with a strength of 780MPa or more are used to replace traditional automotive steel, which is the key to achieving "weight reduction, energy saving, safety and The optimal material solution for reducing manufacturing costs is of great significance to building a low-carbon society. Every 10% reduction in vehicle weight can save fuel consumption by 5% to 8%, and at the same time reduce C...

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Problems solved by technology

The performance of the invention steel is superior, but the Mn content is relatively high, and the cost control is relatively unfavorable

[0009] Chinese patent 200810239893.X discloses a P-strengthened TWIP steel and its preparation process, its composition is: C: 0.01-0.08, Mn: 15-35%, Si≤1-6%, Al: 1-6%, P: 0.062-0.2%, the remainder is Fe and impurities. The tensile strength of the steel in this invention is 610-915MPa, the yield strength is 225-610MPa, and the elongation is 45-85.5%. The formability of the steel is superior, but the yield strength and tensile strength The strength is low, it is difficult to meet the requirements of ultra-high-strength steel for future automobiles

In addition, high-strength steel reinforced with P also has great difficulties in welding with other steel types.

[0010] Rare earth elements are generally used in iron and steel metallurgy to improve the shape of inclusions and purify steel. They are hydrogen storage materials with excellent performance. They have a good curing effect on H elements. Adding rare earth elements to improve the delayed cracking resistance of high manganese steel Not yet reported

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