The allowable deviation of the outer diameter and wall thickness of seamless steel pipes varies depending on the standard being used. In recent years, the use of seamless steel pipes in our country has increased significantly. Due to its wide range of applications, high quality standards are required, and the deviation of the outer diameter and wall thickness of seamless steel pipes is an important quality index. Deviation in wall thickness can directly impact the use of seamless steel pipes.
During production, achieving the exact nominal size can be challenging, resulting in sizes that are either larger or smaller than nominal. To account for this, the standard allows for a difference between the actual size and nominal size. A positive difference is referred to as positive deviation, while a negative difference is referred to as negative deviation.
The wall thickness of seamless steel pipes is not uniform throughout its cross-section and longitudinal body, resulting in uneven wall thickness. To control this unevenness, we can use examples such as the GB/T8162 standard for seamless steel pipes with an outer diameter of over 50 millimeters. The permissible deviation in the outer diameter is plus or minus 1%. Generally, the outer diameter of seamless steel pipes varies, for instance, a 60 millimeter outer diameter seamless steel pipe has a permissible deviation of plus or minus 0.06 millimeters to be considered qualified. The allowable deviation range for wall thickness is plus or minus 12.5%. For example, if the wall thickness is 4mm, the allowable deviation range is 0.5mm.
Post time: Dec-19-2023