1. Material properties and pretreatment defects
Poor material uniformity (such as carbide segregation, banded structure) leads to wall thickness deviations exceeding 0.2mm during cutting.
Residual stress release in cold-drawn pipes causes elastic rebound; for example, the ovality of a φ50mm thin-walled pipe increases from 0.05mm to 0.15mm after turning.
Instable heat treatment (hardness dispersion ≥ HRC3) results in batch processing dimensional differences exceeding 0.3mm.
2. Equipment and tooling system errors
When the radial runout of the CNC lathe spindle exceeds 0.02mm, a roundness error of 0.03-0.05mm occurs when turning the outer diameter.
A guideway clearance exceeding 0.04mm on a milling machine increases the flange surface flatness error from 0.08mm to 0.15mm.
Using a three-jaw chuck to clamp thin-walled pipes (wall thickness ≤ 3mm) results in ovality exceeding the standard by more than 0.15mm. 3. Tooling System Malfunctions
Weared or improperly selected tools directly lead to decreased cutting accuracy, such as increased taper deviation during boring.
4. Process Control Issues
Improper rolling processes (roll wear, uneven temperature) result in uneven wall thickness or outer diameter deviations.
Incomplete straightening processes cause excessive bending of the steel pipe, increasing installation risks.
5. Measurement and Operational Factors
Inaccurate measuring tools or improper operating procedures cause dimensional deviations.
Inaccurate cutting control leads to length deviations, affecting installation compatibility.
