High manganese hot-dip galvanized steel sheet containing rare earth and manufacture method thereof

Abstract

The invention relates to a high manganese hot-dip galvanized steel sheet containing rare earth and a manufacture method thereof. The high manganese hot-dip galvanized steel sheet comprises the following chemical components by chemical component: 0.4-0.8% of C, 14-20% of Mn, 0.05-0.15% of RE, less than or equal to 0.020% of P, less than or equal to 0.012% of S, 1.0-2.0% of Al, 0.01-0.03% of N, and the balance of Fe and unavoidable impurity, and Mn+20*C are greater than or equal to 30%, and Al+5*Re are greater than or equal to 1.8%. The method employs a cold rolling-continuous annealing for pickling-galvanizing technology, the steel plate yield strength is 450-650 MPa, the tensile strength is 980-1100 MPa, the elongation percentage is more than 50%, structure under room temperature is 100% of austenite, the recrystallization fraction is 80-95%, the delayed cracking performance is good, and the steel sheet has superhigh strength and high mouldability. The steel sheet is especially suitable for vehicle structural members and safety members with high shaping performance and corrosion resistance as well as complex shapes, such as side door beam, bumpers, floor tunnels, various beams and b columns.

Description

technical field [0001] The invention belongs to the field of hot-dip galvanized steel sheets, and specifically relates to a rare-earth-containing high-manganese hot-dip galvanized steel sheet and a manufacturing method thereof. It is used in the manufacture of vehicle structural parts and safety parts with very complex shapes and high requirements on formability and corrosion resistance, such as door anti-collision bars, bumpers, floor channels, various beams and B-pillars, etc. Background technique [0002] Substituting a large number of ultra-high-strength steel plates with a strength above 780MPa to replace traditional automotive steel is the best material solution for automobiles to achieve "weight reduction, energy saving, safety improvement, and lower manufacturing costs", which is of great significance to the construction of a low-carbon society. Among them , The development and application of advanced high-strength automotive steel mainly based on phase transformatio...

AI Technical Summary

Problems solved by technology

However, a certain amount of alloying elements such as Cr, B, Si, and Mo must be added to the steel of this invention, which is not only unfavorable for cost control, but also reduces the thermoplasticity of the material due to elements such as Si, B, poor thermal conductivity of molten steel, and solidification shrinkage of molten steel. Large, it will bring problems in steelmaking, continuous casting, etc., and have a relatively large adverse effect on large-scale production

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