Solution strengthening isotropical steel and preparation method thereof

Abstract

Solid solution strengthening isotropy steel, the mass percent of it' s components is : C: 0.03-0.07,Si: <= 0.03, Mn: 0.4-1.0, P: 0.02-0.08, S: <=0.02, N: <=0.005, B: 0.002-0.005, Al: 0.015-0.05, the other is Fe and the impurity, which can be avoided. It' s manufacture method contains the following steps: 1) Smelting, to make billet by casting; 2) Hot reduction of billet, finishing temperature : 830-930deg.C, coiling temperature: 520-620deg.C, 3) Acidwashing, routine acidwashing technology. 4) Cold rolling, the draft is 50-80%, 5) Annealing, heat preserbation temperature: 630-720deg.C. Heat preservation time: 4-30h, to come out from stove when it has been cooled to lower than 200deg.C; 6) Leveling, the cold rolling product will be gained. The routine of solid solution strengthening is used in this patent, and it takes advantage of C and Mn to decrease the sum lever of r value, and adjusts the relative difference of r value on three directions by adding P, some proper technology is also be used to help it, and the ideal isotropy steel can be gained.

Description

technical field [0001] The invention relates to the manufacturing technology of isotropic steel, in particular to isotropic cold-rolled / electrogalvanized / hot-dip galvanized strip steel strengthened by solid solution and its manufacturing method. Background technique [0002] In order to reduce weight and save energy, the automobile industry has put forward higher strength requirements for high formability steel plates in recent years. Isotropic steel means that the Δr value of the steel plate approaches 0 and the r value approaches 1. Isotropy is conducive to the stable flow and mutual coordination of materials in all directions during forming, without being hindered by adjacent hardened areas, and is conducive to obtaining good formability, uniform wall thickness reduction and no earing. [0003] Such as patent number DE3843732, the chemical composition of the disclosed isotropic steel is: C0.03~0.10%, Si≤0.40%, Mn 0.10~1.0%, P≤0.08%, S≤0.02%, ≤0.009%N, 0.015-0.080% Al, 0...

AI Technical Summary

Problems solved by technology

Since N is difficult to control and stabilize in the metallurgical process, it will bring greater difficulty to the actual implementation

The isotropic steel manufacturing method requires the addition of Si, Si is easy to form oxide inclusions, which is not good for stamping performance, especially for thin plates, the impact is particularly serious

Si also reduces the wettability of liquid zinc on the surface of the steel plate, which is not conducive to the adhesion of the zinc layer during hot-dip galvanizing

In addition, the invention requires cooling at a quasi-static ultra-slow cooling rate after recrystallization annealing, which is not conducive to saving energy and reduces the production efficiency of the equipment

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