Welding rod for X60-grade pipeline steel welding

Abstract

The invention belongs to a welding rod for X60-grade pipeline steel welding. The core wire of the welding rod comprises the following components in percentage by weight (wt%): 0.02-0.10% of C, 0.30-0.55% of Mn, 0.015-0.03% of Si, 0.01-0.20% of Cr, 0.01-0.30% of Ni, no more than 0.005% of S, no more than 0.010% of P, 98.675-99.47% of Fe and the balance of impurities; and the coating comprises the following components in percentage by weight (wt%) based on the weight of the core wire: 17.0-21.0% of marble, 8.0-10.0% of fluorite, 2.5-3.0% of feldspar, 2.0-2.5% of quartz, 2.0-3.0% of electrolyticmanganese, 1.5-2.5% of ferrosilicon, 2.5-3.2% of ferrotitanium, 0.3-0.6% of sodium carbonate, 1.5-2.5% of ferrous powder and 0.2-0.5% of nickel powder. The preparation method of the welding rod comprises the following steps: adopting the conventional method to mix a binder which accounts for 10-20% of the weight of the mixed powder material, with the mixed powder material and then coating the mixed materials on the core wire; and finally baking at low / high temperature to obtain the welding rod. During the welding process, the welding rod has the advantages of stable arc, good spreadability ofmolten slag, fewer splashes, easy deslagging procedure, bright welding seams, high tensile strength up to 560MPa, high yield strength up to 450MPa, high elongation rate up to 30%, high average impactenergy value up to 220J at the temperature of -20 DEG C (the minimum value is 150J), strong corrosion resistance, strong low-temperature toughness and strong crack resistance.

Description

technical field [0001] The invention relates to an electric welding rod for welding, in particular to an electric welding rod for X60 grade pipeline steel welding and having good corrosion resistance, high strength and low temperature toughness, and the welding rod can be widely used for X60 grade pipeline steel Welding of steel and other low-alloy steels that have the same composition and strength grade as X60 pipeline steel, and have higher requirements for parathion and low-temperature toughness. Background technique [0002] Pipeline steel is mainly used for the transportation of crude oil, refined oil, natural gas and coal-water slurry. With the adjustment of my country's energy structure and the change of logistics transportation mode, pipeline steel has broad application prospects in my country. [0003] The complex operating environment is an important feature of oil and gas transmission projects, which makes the damage caused by corrosion of oil and gas pipelines d...

AI Technical Summary

Problems solved by technology

Comparing the chemical composition and performance of the above two, it can be seen that the deposited metal of ordinary basic electrode (J507) has poor matching with the alloy system of X60 pipeline steel, and the main alloying elements are manganese (Mn) and silicon (Si). There is a big difference between the content and the content of X60 grade steel coils; the content of sulfur and phosphorus in the deposited metal of ordinary alkaline low hydrogen electrode (J507) is relatively high, especially the content of sulfur, which greatly reduces the corrosion resistance of the weld and crack resistance

At the same time, based on the theory, a large number of experiments and the analysis of some engineering accidents, it is believed that the welding of X60 pipeline steel with ordinary alkaline low-hydrogen electrode (J507) can hardly meet the welding requirements of X60 pipeline steel, especially is the requirement for low temperature toughness