Cracks, folds, scarring, rolling and separation are not allowed on the inner and outer surfaces of JIS G3444 STK500 steel pipe.
These JIS G3444 STK500 steel pipe defects shall be completely cleared, the clearance depth shall not exceed the negative deviation of the nominal wall thickness, and the actual wall thickness at the clearance shall not be less than the minimum allowable value of the wall thickness.
The allowable depth or height of the straight path on the inner and outer surface of the JIS G3444 STK500 steel pipe shall comply with the following provisions.
A) Cold drawing (rolling) JIS G3444 STK500 steel pipe: not more than 4% of nominal wall thickness and the maximum is 0.2mm.
B) Hot rolled (extruded, expanded) JIS G3444 STK500 steel pipe: not more than 5% of nominal wall thickness and 0.4mm at most.
