1,the outer diameter of tolerance
ERW steel pipe, is made of cold bending forming, by reducing 0.6% complete sizing, the basic technological process temperature constant at room temperature, and outside diameter control accuracy and small range, which is conducive to eliminate black buckle;
Seamless steel pipe: the hot rolling molding process, the sizing was completed in about 8000 c, steel tube raw material component, cooling condition and roll cooling condition has great influence on its outer diameter, and outside diameter control is difficult to accurately, and the fluctuation range is larger.
2,the wall thickness tolerance
ERW steel pipe: the hot rolled strip coil as raw materials, modern hot even thickness tolerance can control within 0.05 mm, and seamless steel tube production adopts the round steel perforated way, wall thickness deviation is bigger; then the hot rolling can partly eliminate wall thickness nonuniformity; but at present the most advanced unit can only control within + / -5 ~ 10% t, corresponding to the 8.94 mm thickness of steel pipe.
Seamless steel pipe: the limit of the wall thickness control precision is 0.9 mm
ERW steel tube of raw materials – hot rolled coil in central controlled rolling high precision cold rolling process, to ensure uniform coil parts performance.
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Post time: Oct-29-2019