Electric welding rod with novel slag system for welding 9Ni steel for storage tanks of LNG (liquefied natural gas) ships

Abstract

The invention discloses an electric welding rod with a novel slag system for welding 9Ni steel for storage tanks of LNG (liquefied natural gas) ships. The electric welding rod comprises a core wire and a coating. The coating is coated on the surface of the core wire, the core wire comprises, (in wt%), lower than or equal to 0.02% of C, lower than or equal to 0.01% of S, lower than or equal to 0.01% of P, higher than or equal to 99.0% of Ni and lower than or equal to 0.50% of other elements, and the total quantity of various compositions of the core wire is 100%; the coating comprises, by weight, 10-20% of marble, 15-25% of rutile, 4-10% of fluorite, 1-5% of titanium dioxide powder, 1-5% of potassium cryolite powder, 10-25% of chromium metal, 3-10% of manganese metal, 8-15% of ferro-molybdenum, 1-5% of ferrotungsten, 1-5% of ferrotitanium, 5-10% of ferroniobium, 0-3% of organic matters and 0-3% of soda ash, and the total quantity of various powder compositions of the coating is 100%; the various powder compositions are proportionally uniformly mixed with water glass to obtain a mixture, the mass of the water glass accounts for 22%-30% of the total mass of the coating, the mixture is fed into an extrusion press and is coated on the core wire, and the mixture and the core wire are baked at a low temperature and then are baked at a high temperature to obtain the electric welding rod. The electric welding rod has the advantages that electric arcs are stable during welding, the electric welding rod is low in splashing and good in slag removing property, formed weld joints are attractive, and an all-position welding effect can be realized.

Description

technical field [0001] The invention relates to a nickel-based welding material, in particular to a new slag-based nickel-based welding electrode suitable for welding 9Ni steel (also known as 9%Ni steel) for LNG ship storage tanks. Background technique [0002] LNG (Liquefied Natural gas, liquefied natural gas) ship refers to a special ship that transports LNG from the liquefaction plant to the receiving terminal. Since LNG is natural gas cooled to a liquid state of -163°C, LNG ships must keep it at -163°C during transportation. Therefore, the working environment requires that the materials used to manufacture LNG ships have better low-temperature toughness and better strength in low-temperature environments. [0003] 9Ni steel among nickel-based low-temperature steels is the only medium-alloy low-carbon martensitic low-temperature steel that can serve at -196°C. Its impact absorption energy can reach 200-300J at -196°C. The material with the best toughness under certain c...

AI Technical Summary

Problems solved by technology

At present, 9Ni steel has been widely used in low-temperature cryogenic equipment, but there are few welding materials matching 9Ni steel welding, which greatly limits the development of 9Ni steel welding technology.

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