A kind of low-cost thick and heavy q355e hot-rolled h-section steel and its manufacturing method

Abstract

The invention discloses a low-cost thick and heavy Q355E hot-rolled H-section steel and a manufacturing method thereof, belonging to the technical field of iron and steel smelting. The hot-rolled H-section steel of the present invention comprises the following components by weight: C: 0.10%-0.18%; Si: 0.10%-0.60%, Mn: 1.00%-1.60%; Nb: 0.03%-0.05%; Ti: 0.01%~0.015%; N: 0.003%~0.005%, the rest are iron and other impurities, the product range of Ti and N is 0.00004%~0.0007%%. In the production process, the total number of finishing passes of the universal machine is controlled to be 9 to 13 passes, the rolling deformation of the last 5 to 3 passes in the finishing rolling is controlled to be 7% to 8%, and the rolling deformation temperature is 880°C to 930°C. . The invention takes the thick Q335E hot-rolled H steel with flange thickness of 50mm-80mm as the product target, proposes a low-cost composition design without adding Ni and V alloy elements, and controls the austenite grain size after rough rolling. Obtain hot-rolled H steel with high strength and high and low temperature toughness.

Description

technical field [0001] The invention belongs to the technical field of iron and steel smelting, and more particularly relates to a low-cost thick and heavy Q355E hot-rolled H-section steel and a manufacturing method thereof. Background technique [0002] Hot-rolled H-beam is one of the main structural steels and plays an important role in social and economic development. With economic development and scientific and technological progress, the construction of a series of large-scale engineering structures such as high-rise buildings, offshore platforms, large-scale all-weather railway traffic, and large-scale bridges has put forward large-scale, high-performance and green requirements for the new generation of hot-rolled H-beams. . At present, my country is still blank for the thick and heavy hot-rolled H-beam products with high-performance flange thickness greater than 50mm. Most of the heavy-duty H-beams used are welded by thick plates, and the safety and convenience of th...

AI Technical Summary

Problems solved by technology

[0003] Due to the limitation of billet size and tooling capacity, heavy hot-rolled H-beams for large-scale structures have small deformation between passes and accumulation, which often leads to coarse grain size, which cannot meet the requirements of strength, plasticity and low-temperature toughness of the material.

In order to obtain the required comprehensive performance, it is often necessary to add noble metal element Ni to improve the low temperature toughness of steel, and to add alloy element V to improve the strength of steel through dispersion strengthening, but the problems caused by this are: (1) Ni It is a precious metal element and a strategic resource, which is scarce and expensive; (2) V is a rare resource in my country, and its price has been controlled by foreign capital, and the price fluctuates greatly, which not only affects steel products, but also loses control over product prices

Therefore, considering the comprehensive consideration of composition design and flange thickness, there is no research and development of low-cost (without alloying elements Ni, V) thick (flange thickness 50-80mm) hot-rolled H-shaped steel that takes into account both strength and low-temperature toughness. to report

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