High strength cold-rolled plate with excellent formability and production method thereof

Abstract

The invention provides a high strength cold-rolled plate with excellent formability, containing: no more than 0.0040% of C, 0.02-0.15% of Si, 0.20-1.00% of Mn, 0.02-0.09% of P, 0.015-0.06% Ti, 0.01-0.05% of Nb, and the rest being Fe. The production method comprises: smelting, continuous casting, hot-rolling, cold rolling and continuous annealing, wherein the heating temperature of the hot-rolled billet is 1170-1270 DEG C, the finishing temperature of hot-rolling is 850-960 DEG C, and the coiling temperature is 650-760 DEG C; the cold rolling reduction percent is 60-82%; the annealing temperature is 760-880 DEG C, the thermal insulation time is 60-210s, the slow-cooling segment temperature is 630-700 DEG C, and the fast-cooling exit temperature is 300-500 DEG C; and the levelling elongationrate is 0.5-1.0%. The high strength steel plate containing phosphorus of the invention has the features of low carbon, microalloying and purity. The steel added with a certain amount of Nb and Ti hashigher plasticity. Using relevant rolling and annealing technique, the indexes of performance of the steel achieves the demand of high strength automobile stamping parts.

Description

technical field [0001] The invention belongs to the technical field of iron and steel products, and in particular relates to a high-strength cold-rolled plate with excellent formability and a production method thereof. Background technique [0002] Automobile factories at home and abroad generally use mild steel such as St13 and St14 as stamping parts for automobiles. This type of steel is easy to deform during the stamping process, but due to its low strength, its ability to resist collisions and dents is low, and its safety performance is not good, so Not conducive to the protection of drivers and passengers. [0003] The use of high-strength steel plates can not only solve such problems, but at the same time, due to the increase in the strength of the steel, the thickness of the steel plate can also be reduced, thereby reducing the weight of the car. In today's energy shortage, it can effectively reduce oil consumption and improve resource utilization. , It is also condu...

AI Technical Summary

Problems solved by technology

[0004] At present, the process of producing high-strength steel using phosphorus as the main strengthening element has been reported at home and abroad. Although the process is similar, there are obvious differences in the implementation methods

[0005] Some designs use high manganese content, the disadvantage is that the anisotropy of steel is large

For example, the application number is 99118334.7, and the Chinese patent titled "High-strength phosphorus-added steel and its manufacturing method" adopts a design scheme of high-carbon, phosphorus-added, no alloying elements, and the segregation of phosphorus at the grain boundary , to achieve the purpose of grain refinement, and to increase the strength of the steel. The plasticity index of the product produced by this method is not good, resulting in poor formability of the steel during deep processing.

For example, the application number is 200510051717.X, and the Chinese patent titled "High-strength cold-rolled steel plate and its manufacturing method" adopts high Mn and high Als, and the Als content is 0.1% to 1.0%, and it needs to be added during smelting A large amount of aluminum and iron increases the cost