A production method of high surface quality ultra-high strength steel

Abstract

The invention discloses a production method of high-surface-quality ultra-high-strength steel. The steel production process route is molten iron pretreatment→converter smelting→LF refining outside the furnace→VD vacuum treatment→continuous casting→heating→rolling→straightening→quenching →tempering→finishing→performance inspection→flaw detection; the chemical composition percentage of steel is C=0.15~0.20, Si≤0.10, Mn=1.0~1.50, P≤0.012, S≤0.003, Nb=0.010~0.030% , V=0.015~0.040, Ti=0.010~0.025, Als=0.020~0.045, Cr=0.15~0.25, Mo=0.50~0.80, Ni=0.15~0.25, B=0.0008~0.0025, CEV≤0.60, the balance is Fe and other trace elements. Steel plates with a thickness specification of 6-25mm and a width of 1500-3800mm are produced. The performance indicators meet the Q1100E requirements of GBT28909-2012, the surface quality is good, and there are no pitting and pit defects caused by the pressing of oxide scales.

Description

technical field [0001] The invention belongs to the technical field of steelmaking, and in particular relates to a production method of high-surface-quality ultra-high-strength steel. Background technique [0002] With the development of large-scale and lightweight construction machinery and equipment, the strength level of steel plates continues to increase, and the quality requirements for steel plates are also getting higher and higher, including mechanical performance indicators and internal and external quality. Due to the harsh service environment of construction machinery, most of them are painted to prevent rust and corrosion. Before painting, the workpiece needs to be puttyed and polished, and the process is complicated and long. In order to improve production efficiency, reduce labor intensity of workers, reduce production costs, and reduce intermediate processes such as putty, more and more enterprises have put forward strict requirements for the surface quality o...

AI Technical Summary

Problems solved by technology

[0003] Chinese patent CN 106702270 discloses a "thick-gauge, high-surface-quality hot-rolled flat plate and its manufacturing method". The invention produces a hot-rolled flat plate with a thickness specification of 14-25mm and a strength level of 210-400MPa, and the rolling temperature is 950~ 1080°C, finish rolling temperature 800-980°C, coiling temperature 500-680°C, ultra-fast cooling section cooling intensity 50-80°C / s, front laminar flow cooling intensity 10-30°C / s, which involves steel strength Low grade, cooling at a high cooling rate after rolling may cause bending accuracy or cracking of the material during processing

Chinese patent CN 102764760 discloses "a method for manufacturing hot-rolled steel sheets with high surface quality", through blank grinding, small reduction rolling, phosphorus removal process optimization, post-rolling air cooling and transportation protection, the production yield strength is 345MPa High-grade low-alloy steel, involving low-strength steel, needs to grind the billet before rolling, many processes, high cost, not suitable for fast-paced mass production