A method for improving the performance stability of the whole coil of niobium-titanium composite strengthened 700mpa girder steel

Abstract

The invention provides a method for improving the performance stability of a whole roll of niobium-titanium composite strengthened 700MPa beam steel. In the method, the niobium-titanium composite strengthened 700MPa beam steel includes the following components in weight percentage: C: 0.06-0.09%, Mn : 1.50~1.85%, Si: 0.05~0.20%, P: ≤0.015%, S: ≤0.005%, Nb: 0.025~0.060%, Ti: 0.070~0.110%, Mo: ≤0.20%, N: 0.0040‑0.0085 %, Al S : 0.025~0.055%, the balance is Fe and unavoidable impurities. The method controls the performance stability of 700MPa girder steel from the multi-process system linkage control of key components in smelting, key rolling temperature control, dense laminar flow cooling mode after rolling, and steel rolling into warehouse box-type stacking slow cooling cooling mode. This method can not only improve the pass rate of the preliminary inspection of product performance, reduce the amount of defective products and agreed materials, and reduce production costs, but also can greatly reduce Kaiping warpage, bending, rolling back angle out-of-tolerance, punching, etc. There are a series of problems such as frequent adjustment of mold clearance and greatly reduced service life, unstable I-beam structural strength, inconsistent degree of thermal cutting deformation, etc.

Description

technical field [0001] The invention relates to the technical field of iron and steel materials, in particular to a method for improving the performance stability of a whole roll of 700MPa beam steel. Background technique [0002] With the development of society and economy, low-carbon, energy-saving, and environmental protection have become the new development direction of the steel industry and the transportation industry. With the advancement of automobile lightweight in the automobile manufacturing industry, the innovation and strength upgrade of the materials used in automobile frame steel have achieved great success. Significant application results. In 2016, GB 1589-2016 issued by the Ministry of Communications made strict regulations on the dimensions, axle load and quality limits of automobiles, trailers and automobile trains. This forces car manufacturers to pursue higher strength and thinner thickness in materials. [0003] The 700MPa grade steel for automobile b...

AI Technical Summary

Problems solved by technology

[0004] At present, the 700MPa-grade beam steel on the market is basically produced by niobium and titanium micro-composite micro-alloy strengthening methods, but due to various factors such as smelting composition, purity of molten steel, rolling temperature and deformation process, the production of 700MPa-grade steel Influence, it will inevitably cause the difference in structure and performance, especially the performance difference between the whole roll and different rolls. , The springback angle of the rolling press is out of tolerance, frequent adjustment of punching die clearance and greatly reduced service life, unstable I-beam structural strength, inconsistent degree of thermal cutting deformation, etc.

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