Influence of preheating on strength of pipes produced on gas electric welding mills

Given are the results of the research regarding the influence of the preheating up to 300-700 deg C on the strength of the 12Kh18N10T steel welded pipes. Using a non-melting (tungsten) electrode, 3x2.5; 40x3.0; 51x2.5 and 57x2.5 mm pipes were welded in argon and argon-helium mixture. It is shown that the pipes produced by welding, either with or without preheating, have a considerably high strength at loading with the internal pressure (540-1120 kg/cm2). This strength approaches the strength of the seamless pipes, therefore they may be scheduled for use in important structures