Analysis of seamless steel pipe size out of tolerance
The super difference of seamless steel pipe size is five cases: uneven wall thickness, wall thickness super difference, outside diameter super difference, bending, length super difference.
The uneven wall thickness of seamless steel pipe refers to the uneven wall thickness of the steel pipe in the same section. There are many reasons for this, such as uneven heating of the tube billet, unadjusted rolling line of the piercing machine, etc., the inspection needs to be measured one by one, and the uneven wall thickness end should be cut out.
Seamless steel pipe wall thickness overdifference refers to the steel pipe wall thickness unidirectional overdifference, there are many reasons, such as uneven heating of the tube billet, improper adjustment of the perforator, etc., the inspection needs to be measured one by one, the end of the overdifference should be removed, the full length of the overdifference should be revised or scrapped.
The outside diameter deviation means that the outside diameter of the steel pipe exceeds the standard, which is caused by excessive wear of the caliper pass, etc., which needs to be measured one by one during inspection and judgment, and the standard should be revised or scrapped.
Bending means that the seamless steel pipe is not straight along the length direction or the end of the steel pipe shows a goosehead bending, the cause is caused by local water cooling during artificial thermal inspection, etc. When the bending degree exceeds the standard during inspection, it can be twice straightened, otherwise it is abandoned and the "goosehead bending" that cannot be straightened should be removed.
Length excess means that the length of seamless steel pipe exceeds the requirements, the cause is that the length of the tube billet exceeds the standard, etc., the inspection and judgment of the long length pipe are cut or revised, and the short length pipe is revised or scrapped.
