A matching welding rod for low temperature steel containing ni

Abstract

The invention provides a welding rod containing low temperature steel containing Ni. A coating of the welding rod at least comprises, by mass, 40-50% of marble, 18-25% of fluorite, 2-5% of barium carbonate, 2-5% of silica powder, 0.5-1.0% of lithium carbonate, 0.5-1.0% of rare earth fluoride, 0.5-1.0% of borax, 2-5% of manganese metal, 2-5% of atomized silicon iron, 2-4% of rare earth silicon iron, 3-6% of ferrotitanium, 0.5-1.0% of aluminum magnesium alloy, 9-11% of nickel powder and 0.4-1.0% of sodium alga acid. Sodium potassium silicate is added into the coating of the welding rod formed by mixing the components according to the ratio, an H04E welding core is coated with the coating through a welding rod coating machine, an electric welding rod is dried by a drier and set, the deposited metal diffusible hydrogen content of the electric welding rod is effectively controlled, the deposited metal diffusible hydrogen content is 3.5ml / 100g, and the standard requirement for an ultralow hydrogen welding rod is met.

Description

technical field [0001] The invention relates to a welding rod matched with Ni-containing low-temperature steel, which belongs to the field of welding materials. Background technique [0002] The 3.5Ni low-temperature pressure vessel steel (ASME grade SA203E) used at -100°C is a commonly used steel in foreign countries. The United States, Japan and Germany have already used it for -80°C and -101°C vessels. China used to rely entirely on imports of this steel . Only in 1978, combined with the ethylene project with an annual output of 115,000 tons, a semi-industrial test of 3.5Ni steel was carried out by Taiyuan Iron and Steel Company. In 1984, in the "coal gasification project" project of the national major technical equipment scientific and technological breakthrough, the low-temperature 3.5Ni steel application project was determined. In 1986, the localization of 3.5Ni steel was included in the "Seventh Five-Year Plan" research project of the Ministry of Metallurgy. The 3.5...

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Problems solved by technology

However, the electrodes matched with 3.5Ni in the prior art often have the following disadvantages: when the welding current is too large or the energy of the vertical welding line is large, it is easy to cause the increase of proeutectoid ferrite and the coarsening of grains in the weld metal. This leads to the adverse consequences of decreased toughness; the sulfur content of the weld metal is large, and the inclusions cannot be effectively controlled, resulting in a decrease in low-temperature impact toughness; the coating has poor moisture absorption resistance; the coating is not easy to remove slag

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