Straightness of Stainless Steel Pipe

Stainless steel pipe is curved in the length direction, and the degree of curve is called the degree of curvature (Straightness). The curvature specified in the standard is generally divided into the following two types:

A. Local curvature: Use a one-meter straight ruler to lean on the maximum bend of the stainless steel pipe, and measure the chord height (mm), which is the value of the local curvature. The unit is mm/m, and the expression is 2.5mm/m. . This method is also suitable for tube end curvature.

B. Total curvature of the total length: Use a thin rope to tighten from both ends of the pipe, measure the maximum chord height (mm) at the bend of the steel pipe, and then convert it into a percentage of the length (in meters), which is the length of the stainless steel pipe The full-length curvature of the direction.

For example: the length of a stainless steel pipe is 8000mm, and the measured maximum chord height is 30mm, the total length of the pipe should be:

0.03÷8m×100%=0.375%

According to ASTM A999 16. Straightness

16.1 The finished pipe shall be reasonably straight.
16.2 For metal-arc welded pipe, the maximum deviation from a 10-ft [3.0-m] straightedge placed so that both ends are in contact with the pipe shall be 1⁄8 in. [3.2 mm]. For metal-arc welded pipe with lengths shorter than 10 ft [3.0 m], this maximum deviation shall be prorated with respect to the ratio of the actual length to 10 ft [3.0 m].