Gb straight seam elbow

Gb straight seam elbow  

Gb straight seam elbow is a common pipe fitting in the process of pipeline installation with 45 elbow and 90 elbow.  The bending radius is about 1.0 times the outer diameter of the pipe is called short radius elbow;  About 1.5 times the outer diameter of the pipe is called a long radius elbow. In the pipeline system layout, it is generally appropriate to choose long radius elbow connection, large diameter butt welding elbow before welding, in order to avoid welding deformation, the two ends of the outer tile on both sides of the group into a whole elbow are straightened, with stainless steel arc plate and keel reinforcement.  According to the conventional welding means, argon filling welding is required. Considering the welding cost and the large diameter of shrimp waist pipe, it is difficult to fill argon. Considering the above factors, two welders inside and outside are used for symmetrical welding at the same time, which not only solves the argon filling problem well, but also has a good shape.  Argon spot welding process is adopted.  Argon arc welding is used for the bottom of the lower layer.  Before the welding operation, brush stone chalk within 99mm on the left and right sides of the weld to prevent the surface of the pipe, and use a small current before the welding operation.  Multi-layer multi-channel, continuous welding.  After the overall welding is completed, the welding spot on the surface of the welding elbow is polished, and the pre-welded tiles are nondestructive testing, pickling and passivation are carried out on the internal and external weld surfaces.  Transport the elbow after pickling to the installation site for on-site installation work.  Short radius bends are usually used in tight piping locations or to reduce costs.  When the short radius elbow is used, the working pressure should not exceed the long radius elbow of the same specification.  Straight seam elbows are usually used in large size pipelines with low pressure (design pressure s2.0mpa), water and similar fluid medium conditions.  When the Angle of change direction of single section of inclined elbow is greater than 45, it is not suitable for toxic, can be used in the medium pipeline, or under vibration, pressure pulsation and the pipeline of alternating load due to temperature change.