A kind of vanadium microalloying 600mpa grade low temperature steel bar and its production method

Abstract

The invention provides a vanadium microalloyed steel for 600MPa grade low-temperature reinforcement and a production method thereof, the components C: 0.04-0.10%, Si: 0.20-0.40%, Mn: 1.30-1.80%, P≤0.008%, S ≤0.008%, Ni: 1.00~2.50%, V: 0.15~0.25%, Als: 0.020~0.040%, [H]≤0.00015%, T.O≤0.0020%, and the rest are Fe and unavoidable impurity elements. Compared with the prior art, the present invention adopts vanadium microalloying, electric furnace steelmaking, LF furnace refining, RH vacuum degassing, full protection casting, bar mill on-line quenching self-tempering process, and the surface layer of the produced steel bar is tempered wire The core is granular bainite, and the depth of tempered sorbite on the surface is ≥ 1 / 5 of the radius. This multiphase structure makes the steel bar have good strength and toughness.

Description

technical field [0001] The invention belongs to the technical field of low-temperature steel bars for concrete structures of various low-temperature storage tanks such as LNG, and in particular relates to a vanadium microalloyed 600MPa grade steel for low-temperature steel bars and a production method thereof. Background technique [0002] In recent years, with the promulgation and implementation of the national "Energy Development Strategic Action Plan (2014-2020)", the proportion of my country's liquefied natural gas (LNG) consumption has increased significantly, and LNG low-temperature storage tank construction projects in coastal port cities have been launched continuously. demand has greatly increased. The low-temperature steel bar is mainly used for the construction of the concrete structure inside the outer tank of the LNG storage tank. It plays a role of support and reinforcement for the outer tank, and when the internal filling -165 ℃ low-temperature liquid leaks, it...

AI Technical Summary

Problems solved by technology

There are deficiencies: (1) Ni content is too high, which greatly increases production cost, which is not conducive to market promotion and application; (2) Ti has strong oxidizing property and unstable yield, which is easy to cause large fluctuations in mechanical properties, which is not conducive to the improvement of product quality. Stablize

Images