A production method of submarine pipeline steel x65mo

Abstract

The invention provides a production method of submerged pipeline steel X65MO. The steel is prepared from the following chemical components in percentage by weight: 0.03 to 0.08 part of C, 0.10 to 0.30part of Si, 0.80 to 1.00 part of M, less than or equal to 0.015 part of P, less than or equal to 0.0015 part of S, 0.01 to 0.02 part of Nb, 0.02 to 0.05 part of V, 0.008 to 0.015 part of Ti, 0.10 to0.30 part of Cr, 0.008 to 0.020 part of Al, 0.008 to 0.012 part of N, less than or equal to 0.0005 part of B and the balance of Fe and unavoidable impurities. A key production technology comprises thefollowing steps: pre-treating liquid iron; treating by a converter; carrying out RH vacuum treatment; carrying out RF refining; carrying out continuous casting; hotly conveying and hotly filling; heating and rolling; and cooling. A steel plate produced by the preparation method has good comprehensive performance matching of mechanical properties including strength, plasticity, toughness and the like, technical properties including bending, welding and the like and chemical properties including HIC resistance and the like; the production method is applicable to manufacturing of straight weldedpipes for conveying submerged petroleum and natural gas, and has the advantages of simple production procedures, high efficiency and low cost.

Description

technical field [0001] The invention belongs to the technical field of iron and steel production, in particular to a production method of submarine pipeline steel X65MO. Background technique [0002] Pipeline transportation is the safest, economical and efficient transportation method for oil and natural gas. As resource exploitation extends to areas with harsh geological conditions such as oceans and polar regions, the performance requirements of steel used for pipeline transportation continue to increase. Submarine pipeline steel requires comprehensive properties such as high strength and toughness, good crush resistance, crack arrest resistance, deformation resistance, corrosion resistance, and fatigue resistance. [0003] At present, the use of low-carbon, high-Mn, high-Nb microalloyed pipeline steel has become the mainstream. This type of pipeline steel combined with TMCP process can obtain high strength, good low temperature toughness and crack arrest, such as Japanese...

AI Technical Summary

Problems solved by technology

Due to the high content of Mn and Nb in this kind of pipeline steel, and often adding Mo, Ni, Cu and other precious alloy elements, the alloy cost is high

Moreover, due to the central segregation of Mn and S, it is easy to lead to the formation of banded structures of MnS, which seriously affects the crack arrest performance and corrosion resistance of submarine pipeline steel. For this reason, it is often necessary to carry out Ca treatment to denature inclusions, such as Chinese patent CN105002437B requires steel The Ca content in the medium is 0.0020~0.0035%, and the S content is ≤0.0010%. Sumitomo Metal believes that when the Ca / S ratio is ≥2, the appearance of striped MnS inclusions can be basically suppressed (Ikeda T, et al, Sumitomo Search, 1981, 26: 91-104), however, the low yield of Ca and its violent reaction with molten steel will significantly increase the difficulty of controlling the cleanliness of molten steel and increase production costs