About Astm A53 Seamless Steel Pipe Allowable Deviation Of Outer Diameter Wall Thickness

The permissible deviation of the outer diameter and wall thickness of seamless steel pipe is not the same as that of different standards. In recent years, the proportion of seamless steel pipe used in our country is getting bigger and bigger, and due to its wide range of uses, the quality of seamless steel pipe also puts forward high requirements, in which the deviation of the outer diameter and wall thickness of seamless steel pipe is one of the important indexes of its quality. Wall thickness deviation will directly affect the use of seamless steel pipe.

In the production process, due to the actual size is difficult to achieve the nominal size requirements, that is, often larger or smaller than the nominal size, so the standard provides for the actual size and the nominal size of the actual size of the difference between the allowable. Difference for the positive value is called positive deviation, difference for the negative value is called negative deviation.

Seamless steel pipe wall thickness can not be the same everywhere, in its cross-section and the longitudinal body of the objective existence of wall thickness is not the same phenomenon, that is, uneven wall thickness. In order to control this unevenness, we are examples of it, such as GB/T8162 standard seamless steel pipe in the outer diameter of more than 50 millimeters that the permissible deviation in the outer diameter of plus or minus 1%, seamless steel pipe outer diameter is generally on the difference, such as 60 millimeters in the outer diameter of the seamless steel pipe that the permissible deviation of the outer diameter of plus or minus 0.06 millimeters for qualified. Wall thickness allowable deviation of plus or minus 12.5%, such as wall thickness of 4 mm that the allowable deviation range of 4 * 12.5% = 0.5 mm.

Such as ASTM A53 standard seamless steel pipe, the outer diameter is greater than 48.3 mm when the permissible deviation of the outer diameter of plus or minus 0.4 mm -0.79 mm, the wall thickness of the permissible deviation of plus or minus 12.5%.