Welding elbow is shrimp "turn", it can be in the pipe or plate cutting after welding and become, and its specifications can be large. The number of nodes and the bending radius are determined by the producer. Welding bending is not very smooth, both of the bending radius is not large, generally about 1 times the diameter of the pipe.
Photo of Welded Bend:
Classification of welding elbow, according to its radius of curvature,
45 degree elbow
Can be divided into long radius elbow and short radius elbow. Long radius elbow refers to its radius of curvature is equal to 1.5 times the diameter of the tube, that is, R=1.5D. short radius elbow refers to its radius of curvature is equal to the outer diameter of the pipe, that is, R=D. D in the formula is the elbow diameter, and R is the radius of curvature. The most commonly used for 1.5D elbow, if not specified in the contract is 1D or 1.5D, then it is to optimize the use of 1.5D. GB/T12459-2005, GB/13401-2005, GB/T10752-1995., is the most commonly used executive standard in China.
Pressure grade classification
If according to the pressure level, there are about seventeen, and the United States pipe standards are the same, there are: Sch5s, Sch10s, Sch10, Sch20, Sch30, Sch40s, STD, Sch40, Sch60, Sch80s, XS,; Sch
180 degree welding elbow
80, Sch100, Sch120, Sch140, Sch160, XXS, which is the most commonly used STD and XS two. According to the angle of the elbow, 45 degree elbow, 90 degree elbow and 180. Species as a result of the elbow is a lot, when ordering, order is often taken as described in the following methods: such as "LR STD 90 8", said long radius, pressure rating for STD, 90o 8 "elbow; and as," 45 DEG SR XS 4 "said short radius, pressure rating for the XS and 45 degrees of 4" elbow. The above is about the classification of the elbow. Three links, there are two kinds of general. The diameter of the three equal diameter is equal to the diameter of three links, and both ends are the same diameter, but the diameter of the junction is different from that of the other two diameters. The method is as follows: for the equal diameter three links, such as the "T3" three general, the outer diameter is 3 inches and three inch diameter. For different diameter three links, such as the "T4 x 3.5 x three" means that the same diameter of four inch diameter of 3.5 inches of 4 inch diameter. The pressure level is the same as that of the elbow, and the range is the same.
This is the big head, method. Head size of said method is big diameter multiplied by the head diameter, for example "8 x 6" said big head with a diameter of 8 inches and head diameter is 6 inch head size.
Material division of welding elbow
Carbon steel: A234 WPB ASTM/ASME, WPC
Alloy: A234 WP 1-WP 12-WP ASTM/ASME 11-WP 22-WP 5-WP 91-WP911 15Mo3, 15CrMoV, 35CrMoV
Stainless steel: A403 WP 304-304L-304H-304LN-304N ASTM/ASME
A403 WP 316-316L-316H-316LN-316N-316Ti ASTM/ASME
A403 WP 321-321H ASTM/ASME A403 WP 347-347H ASTM/ASME
Low temperature steel: A402 WPL3-WPL ASTM/ASME 6
High performance steel: A860 WPHY 42-46-52-60-65-70 ASTM/ASME
Welding elbow appearance
As the appearance of the welding elbow, then we say that the appearance of the welding elbow bar. Welding elbow appearance are fixed, of course, the general welding elbow appearance is according to different steel tube and to choose the different knowledge of welding elbow, so, in order to ensure the welding elbow appearance, usually Steel Pipe in the future, if not been yard rain washing off, then welding elbow after high temperature push general weld appearance of the elbow is appear out of the blue, of course, if the rain washed, we in high temperature after heating, heating welding elbow surface color are red. But overall, we guarantee tube is washed by the rain is very difficult, because is yard in summer is rain fog water washed, then push the system out of the welded elbow surface is red, too.
Geometric dimensions include outside diameter, inside diameter and wall thickness. Also requires control
Radius of curvature. For example, the radius length is 1.5D, and the radius of curvature must be within the range of tolerances required. Due to these fittings, most used for welding, in order to improve the welding quality, end vehicles into the groove, leave a certain angle, side band, this requirement is quite strict, edge thick, at an angle of number and range of deviation provisions, geometric size than pipe much many. The surface quality and mechanical properties are basically the same as that of the tube. In order to facilitate welding steel, and the connecting pipe are the same. Fourth, is all the pipe fittings should be through the surface treatment, the inner and outer surface of the oxide scale through shot blasting, and then coated with anticorrosive paint. This is not only for export needs, in addition, in the country is to facilitate the transport to prevent rust oxidation, to do this work. Fifth is the packaging requirements, for small pipes, such as export, you need to do wooden, about 1 cubic meter, this provision in the case the number of elbows about not more than a ton, the standard allows the suit, large sets of small, but the total weight usually do not more than 1 ton. For large to a single package, like 24 "must be a single package. The other is labeled packaging, labeling is to indicate size, number, batch number, manufacturer trademark. In the pipe to be stamped on stamp, and attached to the packing list and the quality book file.