An ultra-low hydrogen high toughness welding rod for welding penstocks in hydropower stations

Abstract

The invention provides an ultralow-hydrogen high-toughness welding rod for welding of a water-diversion steel penstock in a hydropower station. A coating of the welding rod comprises, by mass, 40%-50% of marble, 2%-4% of dolomite, 18%-30% of fluorite, 2%-6% of quartz, 1%-3% of dehydrated feldspar, 1%-3% of zircon sand, 2%-4% of potassium titanate, 3%-6% of atomized ferrosilicon, 4%-8% of electrolytic manganese, 7%-12% of ferrotitanium, 1%-3% of light rare earth silicon iron, 0.5%-1.0% of ferromolybdenum, 2%-4% of nickel powder, and 0.5%-1.0% of rare earth fluoride. All the components are mixed according to the ratios to form the coating of the welding rod, potassium and sodium mixed water glass is added, an H04E welding core is coated with the mixture through a welding rod pressure coater, and the coated welding core is dried and shaped to form the electric welding rod. The deposited metal diffusible hydrogen content of the welding rod is 1.8 ml / 100 g, the low temperature impact toughness at minus 20 DEG C is stabilized within the range from 160 J to 180 J, and the welding requirement of the water-diversion steel penstock in a 610 MPa hydropower station can be met.

Description

technical field [0001] The invention relates to an ultra-low-hydrogen high-toughness welding rod for welding a water diversion pressure steel pipe of a hydropower station, and belongs to the field of welding materials. Background technique [0002] The welding of penstock steel pipes for water diversion in hydropower stations is the most important link in the fabrication and installation of metal structures in hydropower stations. The steel pipe base material generally adopts low-alloy high-strength quenched and tempered steel plates with a tensile strength of 610MPa, SUMIPEN610F and NK-HITEN610U2, which are manufactured by Sumitomo and NKK in Japan, respectively. This type of steel has a very reasonable alloy element design, very low C content and S, P impurity content, and a very stable structure. With its good comprehensive mechanical properties and process properties, it has won most of the domestic hydropower penstock market. For example, in the 26 generating units of ...

AI Technical Summary

Problems solved by technology

[0004] However, the welding rods used in the prior art for welding penstocks of hydropower station water diversions often have the following defects: they are prone to spatter during welding, are not easy to remove slag, and the hydrogen content needs to be further reduced; there are many inclusions in the deposited metal, which cannot be used. Stable low temperature impact toughness at -20°C; limited moisture absorption performance of electrode coating

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