Butt welding flange is not easy to deform, sealed well, widely used, has the corresponding rigidity and elasticity requirements and reasonable butt welding thinning transition, welding distance from the joint surface is large, the joint surface from welding temperature deformation, it takes a more complex cough body structure, suitable for pressure or temperature fluctuations of the pipeline or high temperature, high pressure and low temperature pipeline, Generally used for PN greater than 2.5MPa pipe and valve connection; Also used to transport expensive, flammable, explosive medium pipeline.
Butt welded flange is generally made by forging or forging process. When the steel plate or section steel is used, the following requirements must be met:
1.The butt welding flange should be inspected by ultrasonic, without delamination defects;
2.Should be cut into strips along the direction of steel rolling, welded into a ring through bending, and the surface of the steel to form a cylinder of the ring. Steel plate shall not be machined directly into neck butt welding flange;
3.The butt weld of the ring should adopt full penetration weld;
4. The butt weld of the ring shall undergo post-welding heat treatment, and be subjected to 100% ray or ultrasonic inspection, which shall meet the II requirements of JB4730 and the ultrasonic inspection shall meet the I requirements of JB4730.
The slope of the outer neck of the butt welding flange should not be greater than 70°. Technical parameters of butt welding flange are strictly controlled during production and welding to ensure that it can play its role and value fully in production and use.
1.NPS：DN15-DN3000, 1/2"-120"
2.Pressure Rating：CL150-CL2500, PN2.5-PN420
3.Standard: EN, DIN, JIS, GOST, BS, GB
4.Material：
①Stainless Steel: 31254, 904/L, 347/H, 317/L, 310S, 309, 316Ti, 321/H, 304/L, 304H, 316/L, 316H
②DP Steel: UNS S31803, S32205, S32750, S32760
③Alloy steel: N04400, N08800, N08810, N08811, N08825, N08020, N08031, N06600, N06625, N08926, N08031, N10276
