1.5gpa grade high formability and hydrogen embrittlement resistance ultra-high strength automobile steel and preparation method

Abstract

The invention provides a 1.5GPa grade high formability and hydrogen embrittlement resistance ultra-high strength automobile steel and a preparation method. The composition of the automobile steel plate is as follows in weight percentage: C: 0.20%-0.26%, Mn: 2.2%-2.9% , Si: 0.5%~2.0%, Al: 0.02%~1.5%, Cr: 0.20%~0.70%, Mo: 0.10~0.60%, Cu: 0.10~0.60%, P≤0.01%, S≤0.01%, N ≤0.005%, Nb: 0.01%-0.15%, V: 0-0.15%, Ti: 0.01%-0.20%, the balance is Fe and inevitable impurities. The preparation method includes: smelting, continuous casting of medium and thin slabs, hot continuous rolling, pickling and cold rolling, continuous annealing, and skin-passing; the 1.5GPa-grade ultra-high-strength automobile steel plate with enhanced formability and resistance to hydrogen embrittlement prepared by the invention has a yield strength of 1100- 1350MPa, tensile strength 1470~1650MPa, A80 elongation after breaking ≥7.0%, hole expansion rate ≥35%.

Description

technical field [0001] The invention belongs to the technical field of cold-rolled steel, and relates to an ultra-high-strength automobile steel with enhanced formability of 1.5GPa level and resistance to hydrogen-induced delayed fracture and a manufacturing 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 an increasing demand for high-formability spare parts. Traditional multiphase steels are difficult to meet the requirements of complex punching parts with high drawability, and TRIP steels are limited in their widespread use due to the expensive production costs brought about by high alloy content. Enhanced formability multiphase steel (CH steel) steel has good formability due to the introduction of a certain amount of retained austenite, which can overcome the shortcomings of ...

AI Technical Summary

Problems solved by technology

The invention adopts the cold rolling-hot-dip galvanizing production process to produce hot-dip galvanized composite steel with a strength level of 1.1GPa. However, the product has low strength and poor formability, and it is difficult to have both ultra-high strength and good ductility. In practical application, service problems such as hydrogen-induced delayed fracture and forming problems such as stamping cracking are prone to occur

[0005] Based on the above research status, there is an urgent need to solve the problems of poor formability and hydrogen embrittlement of ultra-high-strength automotive steel. This patent aims to develop a new 1.5GPa-level ultra-high-strength automotive steel strip with enhanced formability and hydrogen embrittlement resistance. , the invention can be prepared on the traditional cold rolling production line with a very low alloy cost, providing technical solutions for the majority of automobile manufacturers and steel companies

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