How to inspect the quality of straight seamless steel pipe

　　Common straight seamless steel pipe materials: Q195, Q215, Q235, Q345B, X42, X52, X60, the next steel model, such as Q235, Q represents the yield limit of this material, followed by 235, which means the yield value of this material, about 235mpa. The yield value of the material decreases with the increase of the thickness of the material. Due to the moderate carbon content, better comprehensive properties, better strength, plasticity and welding properties, the most widely used.

　　According to the rules of gb/t3091-2001 seamless steel pipe for low pressure fluid transportation, the outer quality of steel pipe should be lubricated, and there should be no folding, crack, lamination and lap welding. The surface of the steel pipe is allowed to have minor defects such as scratch, weld dislocation, burn and scar, which do not exceed the negative error of the wall thickness. It is allowed that the wall thickness of the welding seam is thickened and the inner weld bead exists.

　　The mechanical property test, flattening test and flaring test should be carried out for the straight seamless steel pipe, and the requirements of specification and rules should be met. The steel pipe shall be able to accept certain internal pressure, and 2.5MPa pressure test shall be carried out when necessary, and no leakage shall be observed for one minute.