ASTM Pipe Fitting Butt Weld Elbow’s classification way

　　According to the radius of curvature, it can classify long radius pipe elbow and short radius pipe elbow. Long radius pipe elbow means it curvature is 1.5 times as big as the pipe external diameter. R=1.5D short radius pipe elbows means it curvature radius equals to pipe’s external diameter. In common we use 1.5D pipe elbows. If it doesn’t indicate 1D or 1.5D in the contract, the best choice is 1.5D.  In our company , our Pipe-Fittings Standard have ANSI B16.9/16.28,DIN 2605 / 2616,JIS P2311 / 2312,GOST ，etc

　　According to ASTM Pipe Fitting Butt Weld Elbow’s appearance, it appearance is fixed, so , for protect Butt weld pipe elbow’s appearance, when the iron pipe come in ,if it didn’t be washed by rain, then ASTM Pipe Fitting Butt Weld Elbow were processed at high temperature,  as normal ASTM Pipe Fitting Butt Weld Elbow’s appearance present blue, of course, if it be washed by rain, we processed at high temperature, after the procession, pipe elbow’s appearance is red, as a whole , we can’t guarantee it can’t be washed by rain, because in summer the yard always washed by rain, so we infer the pipe elbow’s appearance is red.