A kind of 420mpa grade h-shaped steel and its preparation method

Abstract

The invention provides 420 MPa-grade high-strength low-yield-ratio H-shaped steel and a preparation method thereof. The H-shaped steel is prepared from, by weight, 0.11%-0.15% of C, 0.20-0.35% of Si, 1.35%-1.50% of Mn, 0%-0.035% of P, 0%-0.025% of S, 0.25%-0.30% of Cu, 0.40%-0.45% of Cr, 0.20%-0.30% of Ni, 0.20%-0.30% of Nb and the balance iron and a micro quantity of impurities. According to the 420 MPa-grade high-strength low-yield-ratio H-shaped steel and the preparation method thereof, by combining the optimized component design with heating control, it becomes possible to produce the 420 MPa-grade high-strength low-yield-ratio H-shaped steel under the high finish rolling temperature technological condition, and mass production of the 420 MPa-grade high-strength low-yield-ratio H-shaped steel is achieved. The 420 MPa-grade high-strength low-yield-ratio H-shaped steel is good in mechanical property, the yield strength of the H-shaped steel is higher than 427 MPa, the tensile strength of the H-shaped steel is higher than 641 MPa, and the yield ratio of the H-shaped steel is 0.64-0.67.

Description

technical field [0001] The invention relates to the field of metal smelting, in particular to a 420MPa low-yield ratio H-shaped steel and a preparation method thereof. Background technique [0002] With the increasing use of H-shaped steel for construction, higher requirements are put forward for the steel materials used. At present, there is no requirement for the yield strength ratio of H-shaped steel used in construction. When carrying a large load, the safety performance will be greatly reduced. [0003] Low yield ratio H-beams are mainly used in buildings, bridges, power station equipment, water conservancy, energy, chemical industry, lifting and transportation machinery and other steel structures with high seismic requirements. This steel has a low yield ratio, which can effectively absorb deformation loads, thereby improving the safety performance of steel structures in extreme environments. At the same time, the product is formed by one-time hot rolling without wel...

AI Technical Summary

Problems solved by technology

[0004] In recent years, domestic low-yield ratio steel plate production technology has become increasingly mature, and large-scale production has been formed. However, due to the particularity of H-beam production, in the production process of H-beam, continuous casting, rolling, post-rolling cooling and post-rolling heat treatment, etc. The process cannot reach the control level of plate production, which limits the production of low-yield-ratio H-beams and severely restricts the development of high-quality H-beams for construction in my country