Defective characteristics: grooves that are vertically distributed along the steel pipe.
Cause: When the rolling temperature is low, the top sticky metal scratch the inner surface of the steel pipe, and the top head is severely worn. Poor lubrication or severe wear.
judge:
General tube: The depth of the outer trail does not exceed 90%of the wall thickness deviation of 90%, and the depth of the inner trail does not exceed 70%of the wall thickness bias and the deepening of the deepening of 0.6mm.
Boiler pipes and oil suite: The depth of straight aisle must not exceed 5%of the wall thickness, and the maximum does not exceed 0.4mm.
