Carbon steel containing vanadium and titanium and manufacture method thereof

Abstract

The invention provides carbon steel containing vanadium and titanium and a manufacture method thereof. The manufacture method comprises the following steps of: primarily melting molten steel; when C content of the molten steel is 0.05-0.10 percent, P content is not more than 0.015 percent and S content is not more than 0.020 percent, tapping to a steel ladle; during the tapping, regulating the Si content of the molten steel to be 0.17-0.37 percent and the Mn content to be 0.70-1.00 percent, and regulating the oxygen content of the molten steel to be below 0.0020 percent; controlling the Als content of the molten steel to be 0.015-0.025 percent, wherein the Als represents acid dissolved aluminum; regulating the oxygen content of the molten steel to be below 0.0010 percent in a steel ladle refining furnace; regulating the Ti content of the molten steel to be 0.005-0.010 percent and the V content to be 0.02-0.04 percent; and regulating the C content of the molten steel to be 0.17-0.23 percent so that the carbon steel is obtained, wherein the carbon steel comprises the following components in percent by weight of 0.17-0.23 percent of C, 0.17-0.37 percent of Si, 0.70-1.00 percent of Mn, 0.005-0.010 percent of Ti, 0.005-0.010 percent of Als, 0.02-0.04 percent of V and the balance of Fe and unavoidable impurities.

Description

technical field [0001] The invention relates to a carbon steel and a manufacturing method thereof, in particular to a vanadium-titanium-containing carbon steel that can be used in a high-pressure boiler and a manufacturing method thereof. Background technique [0002] 20MnG steel is a high-quality carbon structural steel in the Chinese national standard GB5310-2008 (seamless steel pipes for high-pressure boilers), and its chemical composition is basically the same as that of SA-210C steel in ASTM / ASME technical specifications. GB5310-2008 stipulates that 20MnG steel contains 0.17% to 0.23% of C by weight, 0.17% to 0.37% of Si, 0.70% to 1.00% of Mn, no more than 0.025% of P, no more than 0.015% of S, no more than 0.20% Cu, not more than 0.25% Cr, not more than 0.25% Ni, not more than 0.15% Mo and not more than 0.08% V. [0003] Recent studies have shown that controlling the Al content of boiler steel in a very low range is the key to the production of boiler steel. The main ...

AI Technical Summary

Problems solved by technology

This part of nitrogen is fixed by Al, otherwise nitrogen will exist in the steel in the form of free state, which will increase the timeliness of the steel, reduce the impact resistance, and seriously cause premature failure of the steel

[0006] To sum up, in the existing 20MnG steel production technology, the low Alt (full aluminum) route should be adopted; however, too low Alt will cause a certain amount of free nitrogen in the steel, which will increase the aging of the steel and reduce the durability. Impact performance, serious will cause premature failure of steel