Key points of steelmaking process control: Use high-quality scrap steel + molten iron to ensure low content of Cu and "five harmful" elements in steel; strengthen dephosphorization and desulfurization, strictly control the target value of chemical composition and smelting temperature as required; ensure sufficient vacuum degree and vacuum treatment time to ensure degassing effect, and strictly control the superheat degree and skin pulling speed of the tundish during continuous casting.
Key points of tube rolling control: strictly control the quality of incoming materials to avoid uneven steel pipe heads caused by excessive inclination of the end face of the ingot and cracks and external scarring of the steel pipe caused by defects such as slag holes on the surface of the ingot; strictly control the heating temperature of the annular furnace and the heating furnace, increase the inspection intensity of adjusting the hot centering of the tube billet, ensure the centering accuracy of the centering hole of the tube billet, and ensure the wall thickness tolerance and unevenness of the wall thickness of the steel pipe; strengthen high-pressure water descaling and protection of the inner and outer surfaces of the steel pipe to ensure the smoothness of the inner and outer surfaces of the steel pipe; to ensure the outer diameter tolerance and outer diameter roundness, a new type of finished product finishing pass is adopted; NDT flaw detection requires that the flaw detection sample pipe be calibrated once every 4 hours.
Key points of tube processing control: strictly control the quenching and tempering temperature of the steel pipe, improve the yield strength of the steel pipe, and reduce the internal stress of the steel pipe; control the hot straightening temperature according to the process requirements to reduce the residual stress on the surface of the steel pipe; hydraulic pressure test pressure, pressure stabilization time; torque, medium control, etc.
eamless steel pipe
