The difference between ERW steel pipe and seamless pipe

The biggest difference between ERW steel pipe and seamless pipe is that there is a weld in ERW steel pipe, which is also the key to the quality of ERW steel pipe. Modern ERW steel pipe production technology and equipment, due to the international, especially the United States and other years of unremitting efforts, making the seamless ERW steel pipe has been relatively satisfactory solution. Some people have divided the seamless ERW steel tube into geometric seamless and physical seamless. Seamless geometry is to eliminate internal and external burrs of ASTM A53 Sch40 ERW Steel Pipe For Construction Building.

　　Because of the structure of the internal burr removal system and the continuous improvement and perfection of the cutting tools, the internal burr removal of large and medium caliber steel pipe has been better treated. Inner burrs can be controlled at -0.2mm ~ O.5mm. Physical seamlessness refers to the difference between metallographic structure and base metal in the weld, which leads to the decrease of mechanical properties in the weld zone. Measures should be taken to make it uniform and uniform.

　　The high frequency welding thermal process of ERW steel tube results in the temperature gradient near the edge of billet, and the melting zone, semi-melting zone, superheated structure, normalizing zone, incomplete normalizing zone and tempering zone are formed. In the superheated zone, austenite grains grow up sharply because of the welding temperature above 1000 C. Hard and brittle coarse grains will be formed under cooling condition. In addition, the existence of temperature gradient will produce welding stress.