Butt welded elbow

The butt welding elbow is made of steel hot pressing or forging elbow, and its connection form is the butt welding of elbow and steel pipe directly. Elbow divided according to its radius of curvature, can be divided into long radius elbow and short radius elbow; divided by the pressure level to about seventeen, and the American Standard pipe is the same, which is the most commonly used STD and XS two; according to the angle of bend points, there are 45 degrees of butt welding elbow, elbow elbow 90 degrees and 180 degrees elbow and other different angles; divided by material: carbon steel, alloy steel and stainless steel.

Classification of butt welded elbows:

(1) the butt welded elbow can be divided into long radius butt welding elbow and short radius butt welding elbow according to its radius of curvature. The radius of curvature of the long radius butt welded elbow is equal to 1.5 times the outer diameter of the pipe, i.e. R=1.5D. The radius of curvature of the butt welded elbow with short radius is equal to the outer diameter of the pipe, that is, R=1D. The D is the diameter of butt welded elbow and R is the radius of curvature. If there is no special description, the general choice is 1.5D elbow.

(2) if divided by the pressure level to about seventeen, and the American Standard pipe is the same, are: Sch5s, Sch10s, Sch10, Sch20, Sch30, Sch40s, STD, Sch40, Sch60, Sch80s, XS; Sch80, Sch100, Sch120, Sch140, Sch160, XXS, one of the most commonly used STD and XS two.

(3) according to the angle of the elbow, there are 45 degree butt welding elbow, 90 degree butt welding elbow and 180 degree butt welding elbow and other different angle elbow.

(4) materials: carbon steel, alloy steel and stainless steel.

How is the butt welded elbow formed?

1. method: use type forging press machine will be at the end of the pipe or part shall be rushed out, so that the outer welded elbow, commonly used with rotary swaging machine, connecting rod type, roller type.

2. rolling method: generally without mandrel, suitable for thick wall pipe inside round edge. The core is placed in the tube, and the outer roller is pressed by the roller to be used for the machining of the round edge.

3. stamping method: on the punch with taper core, the end of the tube is expanded to the required size and shape.

4. bending method: there are three kinds of commonly used methods, a method called stretch method, another method called stamping method, third roller method, 3 - 4 and two, a fixed roller, a roller adjustment, adjust the fixed roller distance, the finished product is bent pipe.

5.. Method: one is placed in the rubber tube, with compression punch above the tube bulge forming; another method is hydraulic bulging in the middle pipe, filling liquid, liquid pressure into the pipe drum to the shape of corrugated pipe production with the most is this method.

Usually the butt welded elbow is welded at the construction site of the pipeline, which is due to the different welding standards of various types of pipelines, and the on-site welding is required according to the grade of the pipeline welds. There is weld seam in butt weld elbow.

Elbow in the welding operation is completed according to the actual situation of the external environment or pipeline rust or corrosion treatment, in order to avoid the elbow in the weld corrosion or corrosion, caused by the short life-span of elbow.

Elbow before welding, welding elbow to avoid deformation, the group of the whole on both sides of the elbow is looking after the tile ends, reinforced with stainless steel arc plate and keel. According to the conventional welding methods need argon welding, considering the welding cost and waist small shrimp larger diameter, argon is difficult, comprehensive the above factors in welding by inside and outside the two welders and welding symmetrically, which solves the problem of argon, and the shape is also very good. The welding technology of argon spot welding is A022, and the welding wire is HOOCr21Nil0. Argon arc welding is used in the lower layer. Before welding operation, brush the chalk in the 100mm range of the left and right sides of the welding seam to prevent the spatter sticking on the surface of the pipe, and adopt small current before the welding operation. Multilayer, multipass, continuous welding. Overall after welding, the solder joints and splash welded elbow surface was polished on the pre welding finished pad, non-destructive testing, the inner and outer surface of the weld. The pickling and passivation pickling after elbow transport to the installation site, the site behind the installation work.