Helical steel pipe deviations and tolerances
- Apr 08, 2018 -

A, spiral steel pipe deviation: In the production process, because the actual size is difficult to achieve the nominal size requirements, that is, often greater than or less than the nominal size, so the standard specified in the actual size and nominal size between the allowable difference.

  

The difference is called positive deviation of positive value, and negative deviation is negative.

  

B, Spiral pipe tolerance: The standard specified in the positive and negative deviation values of the absolute value of the sum is called tolerance, also known as "tolerance belt." Deviations are directional, i.e., "positive" or "negative", and the tolerances are not directional, so it is wrong to call the deviation value  "positive tolerance " or "negative tolerance ".