1300 MPa-grade high-elongation low-delay cracking sensitivity hot forming steel and production method thereof

Abstract

The invention discloses 1300 MPa-grade high-elongation low-delay cracking sensitivity hot forming steel and a production method thereof. The 1300 MPa-grade high-elongation low-delay cracking sensitivity hot forming steel comprises the following components in percentage, by weight, 0.14 to 0.18 percent of C, 1.50 to 2.0 percent of Si, 1.0 to 1.5 percent of Mn, less than or equal to 0.01 percent of P, less than or equal to 0.005 percent of S, 0.025 to 0.070 percent of Als, 1.0 to 1.4 percent of Cr, 0.20 to 0.50 percent of Ni, 0.020 to 0.050 percent of Ti, 0.020 to 0.050 percent of Nb, 0.20 to 0.40 percent of Cu, 0.002-0.005% of B, and the balance of Fe and inevitable impurities. The tensile strength of the hot forming steel is larger than 1300 MPa, by adding Ni, Cu, Nb, titanium and other alloys and increasing the austenite content in the steel through the partitioning process in the quenching process, the hot forming steel has high extensibility and low hydrogen-induced delayed cracking sensitivity, the hot forming steel is applied to an upper automobile body and a lower automobile body of an automobile to manufacture structural parts and safety parts, the weight of an automobile body can be reduced, and the safety of a driver and passengers can be effectively protected.

Description

technical field [0001] The invention belongs to the field of high-strength steel production in the metallurgical industry, is especially suitable for the production of hot-formed high-strength steel, and specifically belongs to hot-formed steel. Background technique [0002] With the rapid development of the automobile industry, lightweight and safety have become the main direction of the development of the automobile industry. The use of hot-formed steel is currently the most effective measure to improve the safety of automobile crashes, and it is also an important way to reduce weight. At present, low-carbon Mn-B steel plate is the most widely used. After quenching, its structure becomes uniform martensite, and its strength reaches 1300MPa. It is used in A-pillar, B-pillar, front and rear bumpers, hinge reinforcement plates, and door anti-collision beams. , middle channel and other parts. [0003] However, as the strength increases, the problem of delayed cracking of ste...

AI Technical Summary

Problems solved by technology

Delayed cracking often occurs suddenly when the applied stress level of the material is significantly lower than its yield strength. Due to the brittle fracture, the energy absorption effect of the steel is greatly reduced, which often leads to more serious damage and consequences.

Images