Electric welding rod for welding large scale low temperature spherical tank steel

Abstract

The invention relates to an electric welding rod for welding large scale low temperature spherical tank steel, consisting of a core welding-wire, an electrode covering and adhesive. The electric welding rod is manufactured according to the conventional manufacturing technique of the electric welding rod; the strength and the toughness of the electric welding rod can be enhanced by strictly controlling the lower percentage composition of S and P in auxiliary materials of the core welding-wire and the electrode covering. The invention has the advantages that the ultralow hydrogen sodium type electric welding rod has high strength and toughness, good welding technological properties, easy arc initiation, soft voltaic arc, little splatter, convenient slag detachability, delicate shaped weld mark, beautiful appearance and all-position welding; deposited metal is well purified and thinned, and has excellent low-temperature impact ductility and cracking resistance, low content of diffusible hydrogen as well as good performances of hot crack and cold crack resistance as well as reheating crack resistance; the welded deposited metal adapts to wide range of heat treatment parameter and has good actual construction adaptability, thus being applicable to welding a spherical tank, especially large scale spherical tanks made of propylene, ethylene and LPG.

Description

Technical field: [0001] The invention relates to metal welding materials, in particular to an electric welding electrode used for welding large-scale low-temperature spherical tank steel. Background technique: [0002] With the rapid development of my country's petrochemical industry, there is a great demand for various types of large cryogenic spherical tanks for storing liquefied petroleum gas, natural gas, ethylene, and propylene. As the volume of the spherical tank increases, it is required to increase the lower limit of the tensile strength level of the steel plate to reduce the thickness of the spherical shell plate used. In the manufacture of large cryogenic spherical tanks, in addition to the quality requirements for steel plate materials, there are also strict requirements for the performance of supporting welding materials. At present, my country has adopted domestically imported 610MPa low-welding crack-sensitivity high-strength steel plates to manufacture large-...

AI Technical Summary

Problems solved by technology

At present, my country has adopted domestically imported 610MPa low-welding crack-sensitivity high-strength steel plates to manufacture large-scale low-temperature spherical tanks at -50°C, but the welding materials used largely rely on foreign imports, especially in the manufacture of large-scale low-temperature vinyl spherical tanks. It is all dependent on imports. The main problem is that at the lowest service temperature of the spherical tank, the deposited metal and weld metal of domestic welding materials cannot reach the low-temperature impact absorption power in the welded state and after long-term high-temperature welding stress-relieving treatment. According to the requirements, it is easy to have a single low value, crack resistance and reheat crack resistance, etc., which cannot meet the needs of manufacturing large-scale low-temperature spherical tanks. For example, the current J607RH electrode in my country has a tensile strength of 610MPa and can meet the low temperature of -20 °C. Spherical tank steel standard requirements, but low temperature impact toughness can not meet the grade requirements of ≥60J at -60°C, the measured value is Akv (impact energy -60°C) = 35J

Images