A kind of welding wire for double pass submerged arc welding of 630mpa grade high nb steel

Abstract

The invention discloses a welding wire for 630 MPa grade high Nb steel double submerged arc welding. The welding wire comprises, by mass, 0.04-0.10% of C, no more than 0.15% of Si, 1.50-2.00% of Mn, no more than 0.018% of P, no more than 0.01% of S, 0.20-0.50% of Ni, 0.30-0.50% of Mo+Cr, 0.02-0.10% of Ti, no more than 0.03% of Nb, no more than 80 ppm of O, no more than 0.02% of Als, and the balance Fe. According to the welding wire for 630 MPa grade high Nb steel double submerged arc welding, a Mn-Ni-Mo-Cr alloy system is adopted and combined with means such as Ti and Nb micro-alloying, weaklyalkaline sintered flux is matched, mechanical properties of deposited metal and strength and toughness of a high Nb steel double submerged arc welding joint can be taken into account simultaneously,and the problems such as poor strength and toughness of an existing high Nb steel double submerged arc welding joint are effectively relieved.

Description

technical field [0001] The invention belongs to the technical field of welding processing of metal materials, and in particular relates to a welding wire for double-pass submerged arc welding of 630MPa high-Nb steel. Background technique [0002] With the continuous improvement of steel rolling process, steel with higher Nb content has been continuously applied in consideration of reducing alloy cost. In the case of reducing the content of more expensive alloys (such as Ni, Mo, Cu) and adding 0.04-0.10% Nb, the recrystallization temperature of austenite can be increased, the rolling temperature can be increased, the cooling rate can be increased, and tempering can be carried out after rolling. Precipitation hardening such as NbC occurs in the steel, and the steel reaches the same strength and higher toughness as traditional steel. With the continuous development of the welding process, in many cases, the double-pass submerged arc welding process that penetrates the root (bl...

AI Technical Summary

Problems solved by technology

[0004] For the traditional TMCP process 630MPa grade steel, the submerged arc welding wire used is mainly Mn-Mo series; from the composition point of view, if the Mn-Mo series welding wire is used for welding X80 steel with high Nb and low alloy content, the weld strength and toughness will be difficult. fulfil requirements

Existing welding materials are difficult to take into account the mechanical properties of the weld deposit and the toughness requirements of the double-pass submerged arc welded joint of high-Nb steel. It is necessary to further explore and optimize the welding wire formula suitable for double-pass submerged arc welding of 630MPa high-Nb steel and improve the weld performance

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