Positioning welding
Due to the severe hardening tendency of Carbon Steel API Ball Valve Body and 45 steel, it needs to be preheated before tack welding. The oxygen-acetylene flame is evenly heated to 75~100 °C in the range of 2 times the thickness of the weld on both sides of the weld. (biased to the 45 steel side), measured by the far infrared ray thermometer, without affecting the sealing device.
The scale and rust in the range of 20 mm on both sides of the weld are polished to a metallic luster before welding.
Positioning point 6 is made 50 mm from the edge of both sides of the weld, and the distance between the two points is measured with a caliper to measure the amount of shrinkage.
Back cover welding in Casting Valve Body Supplier
Due to the consideration of the rigidity and plasticity of the material, a small welding parameter, that is, a small welding heat input, should be adopted in the selection of the welding specification. Under the premise of ensuring the quality of the weld, the welding speed is increased as much as possible, the fusion ratio is reduced, and a multi-layer multi-pass six-segment symmetrical welding method is adopted in the deformation; pay attention to measuring the positioning point with a caliper for each welding layer, and performing the shrinkage amount Control until welding is completed. In addition to the first and last, the hammering method is used to eliminate the stress between the other passes.
