Seamless steel pipe dimension excess can be categorized into five types: uneven wall thickness, wall thickness excess, outer diameter excess, bend, and length excess.
1. Uneven wall thickness of seamless steel pipe refers to uneven wall thickness across the same cross-section of the pipe. This can occur for a variety of reasons, such as uneven heating of the billet or improper adjustment of the piercing machine’s rolling line. Inspection requires measurement of each pipe, and ends with the removal of those pipes with uneven wall thickness.
2. Uneven wall thickness of seamless steel pipe refers to unidirectional wall thickness excess. This can also occur for a variety of reasons, such as uneven heating of the billet or improper adjustment of the piercing machine. Inspection requires measurement of each pipe, and ends with the removal of those pipes with uneven wall thickness. Pipes with excess along the entire length should be reclassified or scrapped.
3. Out-of-diameter seamless steel pipe refers to pipes with an outer diameter exceeding the standard. This can occur for reasons such as excessive wear of the sizing machine’s die. Inspection requires measurement of each pipe, and pipes exceeding the standard should be reclassified or scrapped.
4. Seamless steel pipe bend refers to a non-straightness along the length of the seamless steel pipe, or a goose-head-shaped bend at the end of the pipe. Causes include localized water cooling during manual heat inspection. If the bend exceeds the standard during inspection, it may be straightened a second time; otherwise, it will be scrapped. “Goose-head bends” that cannot be straightened should be removed.
5. Seamless steel pipe length deviation refers to a seamless steel pipe length exceeding the specified length. Causes include excessive billet length. During inspection, long-length pipes are recut or reclassified, while short-length pipes are reclassified or scrapped.
Post time: Aug-29-2025