Wire rod for pipeline steel gas shielded welding wire and manufacturing method of wire rod

Abstract

The invention relates to a wire rod for a pipeline steel gas shield welding wire and a manufacturing method of the wire rod, the wire rod comprises the following elemental components in percentage by mass: 0.06-0.09% of C, 0.55-0.80% of Si, 1.45-1.60% of Mn, 0.008-0.015% of S, 0.85-0.95% of Ni, 0.060-0.085% of Ti, 30-70ppm of O and the balance of Fe and inevitable impurity elements, and the impurity elements comprise less than or equal to 0.003% of P, less than or equal to 0.002% of Sb, less than or equal to 0.002% of Sn and less than or equal to 0.003% of As. The microstructure of the wire rod is ferrite and pearlite, TiO2 inclusions distributed in a dispersed mode exist in the microstructure, the size of the TiO2 inclusions is stably smaller than 5 micrometers, and the number of the inclusions in unit area is stably larger than 35 / mm < 2 >. The tensile strength of the wire rod is stable to be smaller than or equal to 700 MPa, the area reduction is larger than or equal to 65%, good plasticity is achieved, and direct drawing operation with the area reduction rate reaching 95% or above can be carried out. The manufacturing method comprises the steps of molten iron pretreatment, molten steel primary smelting, LF refining, square billet continuous casting, square billet heating and rolling and wire rod cooling.

Description

technical field [0001] The present invention relates to a steel wire / coil wire and a manufacturing method thereof, in particular to a wire rod for welding wire and a manufacturing method thereof. Background technique [0002] In recent years, with the construction of large-scale pipeline projects such as the second and third lines of the West-East Gas Pipeline in China, especially the large-scale application of X80 high-grade pipeline steel, the development of pipeline steel has been greatly promoted. Compared with the development of pipeline steel materials, domestic welding The development of materials is relatively backward, there is no series of varieties, and the quality needs to be improved. With the improvement of pipeline steel grade and wall thickness, the welding process and welding performance of girth weld are stable, especially the difficulty of weld fracture toughness control has further increased, making girth welding technology an important problem hindering ...

AI Technical Summary

Problems solved by technology

[0002] In recent years, with the construction of large-scale pipeline projects such as the second and third lines of the West-East Gas Pipeline in China, especially the large-scale application of X80 high-grade pipeline steel, the development of pipeline steel has been greatly promoted. Compared with the development of pipeline steel materials, domestic welding The development of materials is relatively backward, there is no series of varieties, and the quality needs to be improved

With the improvement of pipeline steel grade and wall thickness, the welding process and welding performance of girth weld are stable, especially the difficulty of weld fracture toughness control has further increased, making girth welding technology an important problem hindering the development of pipeline steel to high grades

In addition, with the continuous improvement of the pipeline level and the increasing construction of national large-scale pipeline projects, traditional manual electrode welding and submerged arc welding can no longer meet the needs of pipeline construction automation and high-efficiency welding operations. The application in pipeline construction, matching this, it is necessary to develop wire rods for pipeline steel gas shielded welding wire to meet the requirements of fully automatic gas shielded welding welding process and weld performance stability, to speed up the development of my country's oil and gas pipeline construction, but also to solve Solved the problem of long-term dependence on imports of welding consumables for pipeline steel girth welding

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