Low-cost steel strip with yield strength of 400mpa and its production method

Abstract

The invention discloses a low-cost yield strength 400MPa-grade steel strip and a production method thereof. The steel strip contains the following components in percentage by weight: 0.18-0.22% of C, 0.20-0.40% of Mn, less than or equal to 0.020% of S, less than or equal to 0.025% of P, less than or equal to 0.03% of Si, 0.015-0.035% of Als, 0.0009-0.0030% of B and the balance being Fe and inevitable impurities. The steel strip, on the basis of low-silicon manganese and boron microalloying thinking, can reduce raw material cost, and can be produced through a thin slab casting and rolling process; thickness specification is 1.0-3.5mm; the steel strip has the characteristics of being simple to smelt, relatively low in cost, stable in physical performance and applicable to industrial mass production. The steel strip, by controlling smelting through low-silicon manganese and boron microalloying, reduces cost, improves utilization rate of lower equipment through continuous casting high pulling speed, reduces cost by directly charging a continuous casting slab, guarantees surface quality of product by controlling temperature of a heating furnace, and meets physical performance of the product by optimizing a hot rolling process; the steel strip has the characteristics of being simple in process, low in cost and applicable to industrial mass production.

Description

technical field [0001] The invention relates to a steel strip, especially a low-cost steel strip with a yield strength of 400MPa and a production method thereof. Background technique [0002] With the serious excess of steel production capacity, the competition among major steel enterprises is becoming increasingly fierce, the internal cost control awareness of enterprises is constantly strengthening, and the steel production chain is constantly pursuing refined management and the production of high value-added products. In the production of traditional low-alloy high-strength steel, the strength of the steel is mainly increased by increasing the manganese content and its alloy elements such as niobium, vanadium, titanium, etc., especially the steel with a yield strength of 400MPa. The traditional process increases the manganese content through extensive control. To improve the strength, the requirements of the hot rolling process are not strict enough. In addition to impro...

AI Technical Summary

Problems solved by technology

[0003] At present, the method of increasing manganese to improve strength has been used in production, but the high production cost cannot meet the fundamental interests of various enterprises

It is desirable to realize the production of low-cost high-strength steel by obtaining ultra-fine grain structure, but this method cannot be used in mass production of enterprises; the temperature range of Ar3 is narrow in the composition design of Q235 grade steel, and it cannot be used in the hot rolling process. Precise control; secondly, the load of the last two rolling mills in the hot rolling process is too large, which requires too much equipment and is not conducive to the control of the shape of the steel coil; thirdly, the increase in the load of the rolling mill is likely to cause production accidents