The expertise of steel butt welding elbow

Elbow is now the international common standard is the American national standard ANSIB16.9 and 16.28. The standard diameter range is 1/2 "~ 80", the general 24 "are within the use of Seamless Steel Pipe as raw materials, 26" to 80 "are stamping with steel plate after welding. 60mm, the smallest to 1.24mm. Steel with the most carbon steel (20 #), alloy steel and stainless steel, a total of 24 steel. CrMo steel used on the boiler like 15Cr, the amount of relatively large. Diameter range of 2.5 "-60", from 26 "-60" for the three links. Wall thickness of 28: 60mm. Size of the first specification range, the conventional first said big head specifications, say small head size, the largest head of 0.75 " Minimum 0.5 ", the largest head of 60", small head maximum 48 ", 20-60" for the welding, wall thickness 2.8-4.5mm.
Elbow classification
According to its radius of curvature to points, can be divided into Long Radius Elbow and Short Radius Elbow. Long radius elbow refers to its curvature radius is equal to 1.5 times the tube diameter, that is, R = 1.5D. A Short Radius elbow that its radius of curvature is equal to the outer diameter of the tube, ie R = D. Where D is the elbow diameter and R is the radius of curvature. According to the pressure grade, there are about 17 species, and the American pipe standard is the same, there are: Sch5s, Sch10s, Sch10, Sch20, Sch30, Sch40s, STD, Sch40, Sch60, Sch80s, XS; Sch80, Sch100, Sch120, Sch140, Sch160, XXS, the most commonly used are STD and XS two. At the angle of the elbow, there are 45 elbows, 90 elbows and 180 elbows. In this way, the type of elbow is a lot of orders, orders are often taken as follows: such as "LR STD 90 8", said the long radius, the pressure level for the STD, 90 8 "elbow; another example," SR XS 45o 4 "means a 4" elbow with a short radius and a pressure rating of XS, 45o. Above the elbow about the classification of the situation.