Wuxi YUTONG

  Precision cold drawn tube   is the carbon, alloy or stainless steel pipe with high precision sizes. Usually it has been made through hot rolling or cold drawn (cold rolling) processes. So precision pipe is a kind of seamless pipe.International standard for precision pipe is   DIN 2391 , which is applied with European standard.As a matter of fact, more steel pipe standard could applied for the precision pipe. Includes DIN2445, EN10305, DIN1630, DIN1629, ASTM A106, ASTM A179, JIS G3445Materials available with 10#, 20#, 35, 45, 40Cr, 25Mn. 37Mn5, St35(E235), St37.4, St45(E255),  St52(E355 ) and etc. For hot rolling precision steel pipe, tolerance of OD is +/- 0.1%.For  cold drawn precision tubes , tolerance allowed in below conditions: Diameters 6mm to 10mm, normal tolerance condition +/- 0.2%, premium tolerance condition +/- 0.15%. 10mm to 30mm, normal tolerance condition +/- 0.4%, premium tolerance condition +/- 0.2%. 30mm to 50mm, normal tolerance condition +/- 0.45%, premium toleran

 As we all know, cold drawn steel tube is usually more expensive than the hot rolled tube, The outer diameter and wall thickness of the hot-rolled seamless steel tube is changing. The outer diameter is larger on one end and smaller on the other hand. The outer diameter and wall thickness alongside the whole steel tube is changing. This is much determined by the hot rolling production process. The process starts from round steel after the big furnace, burning to over 1080 in the round steel punch, the whole round steel is turned into a hollow tube billet. As the whole process takes some time, due to the high temperature, the OD of the pipe’s front end is larger, and wall thickness is thin. When temperature gets lower, wall thickness alongside the pipe becomes slightly thicker. And residual heat will help to calibrate the hot rolling of the tube billet, and the tube billet is rolled into the specified outer diameter. In all, the tolerance of hot-rolled seamless steel tube is relative