Cracking Fracture Reason Analysis On Welding Seam Of HFW Steel Pipe

HFW pipe with uniform wall thickness,high precision and strong ability to resist collapse,appearance size,low cost advantages,has been widely used in petroleum,natural gas,automotive,chemical and other important areas,and in many ways in various fields has gradually replaced the trend of seamless steel tube,but the real is the most key factors restricting the development of HFW pipe welded pipe weld mechanical properties,and in the process of HFW welded pipe production,flattening the experiment as a fast,efficient,convenient and accurate detection method,is widely used by each big welded pipe company,But really restrict HFW welded pipe development the most critical factor is the mechanical properties of the weld seam.This paper describes the high frequency welding principle and influence factors of the quality of the weld,the commonly used detection methods and standards,and the shape of common compressed fracture,and honeycomb type fracture and brittle two kinds of typical fracture carries on the key analysis and in the honeycomb type fracture.Mainly from the mechanical properties of weld flattening cracked samples,parent material physical and chemical properties,welding technology and other aspects of analysis,the high frequency weld metallographic experiment and semi welded plate edge shape for docking experiments on V type;analysis of metallographic analysis and SEM proved that the oxide residue in the welding seam,cause to reduce the mechanical properties,significantly improved by controlling the half form so that the mechanical properties of the weld butt type I;brittle fracture,physical and chemical properties such as mechanical properties,manufacturing process,raw materials mainly from the weld flattening cracked samples were analyzed,from the analysis of inclusions found in the inclusions in the steel strip,scanning electron microscope found in the analysis of sulfur elements on Weld Fracture,proved that the raw material contains a large number of non metal sulfides,non metal sulfide degrades the mechanical properties of the weld seam,and ultimately cause cracking in flattening experiment.