X120 pipeline steel with low crack sensitivity and high toughness and manufacturing method thereof

Abstract

The invention discloses X120 level pipeline steel with low crack sensitivity and high toughness and a production method. The X120 level pipeline steel comprises the following designed components (wt%): 0.02-0.08wt% of C, 1.5-2.1wt% of Mn, at most 0.5wt% of Si, at most 0.018wt% of P, at most 0.0020wt% of S, 0.01-0.02wt% of Ti, 0.04-0.11wt% of Nb, at most 0.08wt% of V, 0.0030wt% of B, 0.01-0.04wt% of Als, 0.1-0.40wt% of Mo, 0.3-0.5wt% of Ni, at most 0.40wt% of Cu, at most 0.30wt% of Cr and the balance of Fe and unavoidable filth. The invention meets the following formulae: the sum of Mo, Ni, Cuand Cr is smaller than or equal to 1.4 and the sum (Pcm) of C, Si / 30, (Mn+Cu+Cr) / 20, Ni / 60, Mo / 15, V / 10 and 5B is smaller than or equal to 0.23; and the production method comprises the following steps: smelting; heating a continuous casting blank to 1,100-1,250 DEG C; roughly rolling and controlling the finishing temperature at 1,000-1,100 DEG C; finely rolling and controlling the finishing temperature at 800-900 DEG C; resting a steel plate for 10-60 seconds; and cooling with the final coldness temperature of at most 450 DEG C. The invention has little content of the added alloy as well as low cost and crack sensitivity of the steel plate and is beneficial to large-scale production.

Description

technical field [0001] The invention relates to steel for oil and gas pipelines and a production method thereof, in particular to X120 grade pipeline steel with low crack sensitivity and high toughness and a production method thereof. Background technique [0002] In order to save the construction investment of pipeline engineering and reduce transportation costs, it is more economical and reasonable to use high-strength grade pipeline steel. With the increase of pipeline transportation pressure, the requirements for the reliability of pipeline steel are getting higher and higher, that is, high strength, high low temperature crack arrest toughness and good welding performance are required. At present, X70 and X80 pipeline steels have been widely used in various oil and gas pipeline projects, but the pipeline construction and operation costs are relatively high. In order to further reduce the cost of pipeline construction and operation, people have developed X100 and X120 gr...

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to solve the problem that X120 grade pipeline steel has high alloy composition design and strict production process control requirements, which is not conducive to large-scale production, and provides a kind of alloy with less added alloy content, low cost, simple production process, and low crack sensitivity of the steel plate. , low crack sensitivity and high toughness X120 pipeline steel with ultra-high strength and high toughness, suitable for large-scale production and production method thereof

Images