A kind of high-performance medium manganese trip steel and the method for low-temperature processing thereof

Abstract

The invention discloses high-performance medium-manganese TRIP steel and a low-temperature processing forming method thereof, and belongs to the technical field of ultrahigh-strength steel. The methodcomprises the following steps of heating the cut medium manganese steel ingot to 600-800 DEG C and carrying out heat preservation for 0.5-1.5 hours, carrying out two-phase zone rolling, carrying outair cooling; then heating to 600-800 DEG C, and preserving heat for 5-10 minutes; transferring the medium-manganese TRIP steel plate subjected to austenitizing treatment to a stamping die, wherein thetemperature is reduced to by 50-100 DEG C, carrying out stamping forming, and carrying out pressure maintaining for 10-30 seconds, cooling to 180-250 DEG C along with the die; and heating to 250-450DEG C, preserving heat for 10-30 minutes, and carrying out air cooling, and obtaining a high-performance medium-manganese TRIP steel forming part. According to the method, the two-phase region is rolled, so that the C / Mn is prepared in advance and then is processed by a subsequent Q and P process, so that the C / Mn is prepared. According to the forming method, the rolling efficiency and the surfacequality of the stamped part are improved, the strength of the manufactured stamped part is high, the comprehensive performance is excellent, and the requirements of the target of the automobile industry are met.

Description

technical field [0001] The invention belongs to the technical field of ultra-high-strength steel, and in particular relates to a high-performance medium-manganese TRIP steel and a low-temperature processing and forming method thereof. Background technique [0002] Since the beginning of the 21st century, with the intensification of energy crisis and environmental problems, energy saving and safety have become the development trend of the automobile manufacturing industry. In order to achieve energy saving and emission reduction while meeting safety requirements, the application of advanced high-strength steel stamping parts for automobiles has been greatly promoted. At present, the more mature stamping material for automobiles is boron steel, such as 22MnB5. In the hot stamping process, 22MnB5 is heated to 950 ° C to obtain a full austenite structure, and then transferred to the stamping die for rapid quenching. Austenite will completely transform into martensite structure...

AI Technical Summary

Problems solved by technology

However, there are still some problems: (1) hot-rolled sheet has low yield strength (400-700MPa) and thick oxide layer, resulting in poor surface quality of stamping parts; (2) cold-rolled medium manganese steel has large The elastic modulus, although it has excellent surface quality compared with hot rolling, but due to the large rebound of medium manganese steel in the cold rolling process, the rolling efficiency is reduced; (3) In order to consider the continuity of production, the current hot stamping The austenitizing annealing time of manganese steel is often less than 10min, but the optimum heat treatment time of medium manganese steel is longer (≥30min), because the short annealing time will lead to insufficient distribution of C / Mn, austenite The content and stability are relatively low, which will reduce the surface quality of stamping parts

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