Splee
Dead characteristics: Show irregular or regular local indentation and meat on the longitudinal surface of the steel pipe. The shapes are nuclear, strip, horizontal pressure injuries, tilted skin, fragmented, iron dumb -shaped, etc.
cause:
① The surface of the finished rack rolls of the tensor is sticky on the surface of the roll.
② Scars or other foreign bodies are pressed on the surface of the steel pipe to fall off.
③ The thermal steel pipe is injured or scratched.
④ Trocaying injuries and printed by the transverse movement or sawing device.
judge:
General tube: Wall thickness ≤8mm indentation depth does not exceed 90% of negative deviations, and wall thickness> 80% of 80% of the depth of 8mmm indentation shall not exceed 1.0mm.
Boiler tube: The maximum value of the wall thickness is 0.6mm.
Oil suite: The indentation depth must not exceed half of the wall thickness bias. The maximum depth value of the depth at the S≥10mm does not exceed 0.6mm, and the maximum depth of the maximum of S <<10mm does not exceed 0.5mm.
Straightway
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.
Informal
Dead characteristics: The cross section of the steel pipe is not round.
Cause: Improper adjustment of clamping force when sawing, incorrect installation of the finished rack and working rack of the tensor. improper.
Uneven wall thickness
Dead characteristics: The maximum value of the wall thickness of the steel pipe on the same section, the minimum value exceeds the positive deviation and negative deviations, or the name of the nominal wall thickness is ± 8-10% (the upper limit of the thick wall tube is taken in the thin wall tube)
Reasons: The perforation is expected to meet the requirements. The tube end surface is incisive, the heating of the tube is unsatisfactory, the tube is heated unevenly, the perforated equipment is not adjusted properly, and the rolling machine is not adjusted properly.
bending
Defective characteristics: The steel pipe is not straight along the length of the steel pipe, and the end of the steel pipe is bent.
Reason: The last few hole -type central lines of the tensor are misplaced. The distribution of refined rolling pores in the tensor is unreasonable. The cooling method of Zhang Duan tube is not reasonable or the temperature is too high when cutting.
