Method for improving performance stability of whole roll of niobium-titanium composite reinforced 700 MPa girder steel

Abstract

The invention provides a method for improving the performance stability of a whole roll of niobium-titanium composite reinforced 700 MPa girder steel. The niobium-titanium composite reinforced 700 MPagirder steel in the method comprises the following components including, by weight, 0.06%-0.09% of C, 1.50%-1.85% of Mn, 0.05%-0.20% of Si, less than or equal to 0.015% of P, less than or equal to 0.005% of S, 0.025%-0.060% of Nb, 0.070%-0.110% of Ti, less than or equal to 0.20% of Mo, 0.0040%-0.0085% of N, 0.025%-0.055% of AlS and the balance Fe and inevitable impurities. According to the method, the performance stability of the 700 MPa girder steel is controlled in a multi-process system linkage manner from smelting key component control, rolling key temperature control, an after-rolling encryption type laminar cooling mode and a steel roll warehousing box type stacking slow cooling mode. The method not only can improve the performance primary inspection qualification rate of products,reduce the quantity of inferior-quality products and protocol materials and reduce the production cost, but also can greatly reduce a series of problems that decoiling warping is generated, the springback angle of bending and rolling is out of tolerance, a punching die gap is frequently adjusted, the service life is greatly shortened, the structural strength of an I-shaped beam is unstable, and the thermal cutting deformation degree is inconsistent are solved.

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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