pipe (size of the head) the classification and standards

Size of the first segment can be divided into concentric reducer and eccentric reducer can be divided according to the material of carbon steel reducer, stainless steel reducer, alloy steel hose nipples reducer; wall thickness can be divided by thin-diameter pipe and thick-walled diameter pipe, tube or high pressure common reducers reducers, standards can be divided into: GB-diameter pipe, non-standard diameter pipe.
Common standards: ANSI, JIS, DIN, GB, SHJ, HGJ other standards
Common Material: 20 #, 20G, 16MN, 15CRMO, 1CR18NI9TI, 304,316 and so on.

47, commonly used in the daily classification and standards elbow?
Elbow classification methods, according to its radius of curvature can be divided into long radius elbows and short radius elbows. According to the angle of the elbow, there is 45o elbows, bends and 180o with 90o elbow. In terms of pressure levels to points, there are about seventeen kinds, and the American standard pipe is the same, there are: Sch5s, Sch10s, Sch10, Sch20, Sch30, Sch40s, STD, Sch40, Sch60, Sch80s, XS; Sch80, Sch100, Sch120, Sch140, Sch160, XXS, which is the most commonly used two kinds of STD and XS.
Daily elbow can be divided into: hydraulic couplings carbon steel elbow / stainless steel elbow / alloy steel elbow / welded elbow / weld elbow / seamless elbow / thick-walled elbow / high elbow / GB elbow / day Standard elbow / American Standard elbow / German standard elbow / non-standard elbow / non-models Elbow / Reducer Elbow / Equal Elbow / Elbow 45 degree / 90 degree elbow / 180 Elbow / 1D bend head / 1.5D elbow / 2 times the elbow / 4 times elbow (Big Bend) and so on.