Some knowledge about the roundness tolerance of steel pipe & tube

Home >> Profile Bending Machine >> >>Some knowledge about the roundness tolerance of steel pipe & tube

Some knowledge about the roundness tolerance of steel pipe & tube

Specifications

Some knowledge about the roundness tolerance of steel pipe & tube
Some knowledge about the roundness tolerance of steel pipe & tube

Pipes and tubes are usually measured by the outside diameter dimension – or OD. One might think that a 2.0 inch OD tube would measure 2.0 inches and a 6.5 inch OD tube would measure 6.5 inches. However, machines today cannot hold dimensions precisely to the nominal value, and because of that there must be acceptable degrees of variations. In other words, every dimension on a blueprint is subject to variations from the nominal value and so is “roundness”. But “out of roundess” measurement can be contained.

Detail

Tubes, pipes or solids will have a range of values that would be acceptable and considered as ‘x’ nominal OD. Roundness tolerance (+/- 0.01 inch) would mean the difference between major OD and the minor OD throughout the profile should not be greater or less than 0.01 inches.

When bending round profiles to a certain radius, the greater the OD to bend radius, the higher ovality should be expected.

American Society of Mechanical Engineers ASME states the following, “on section B31.1-2001 104.2 Curved Segments of Pipe (B) For ferrous material, when the radius of a bend is 5 nominal pipe diameters or greater, and the nominal wall thickness of the pipe is schedule 40 or thicker, the difference between maximum and minimum diameters shall not exceed 8% of average measured outside diameter of the pipe before bending.”

As a guideline, we consider 5% ovality as an acceptable measurement. That said, the ovality should always be discussed and determined by the end user prior to rolling. The table below can be used as reference for expected ovality when bending hollow pipe or tube.


Angle,Beam,Tube,Channel,Pipe,Bar,Tee,Steel Section Bending Tolerances


About Us

Nantong Borisbang Industrial Technology (NBIT) rooted in Haian County of Jiangsu Province,China. The main production section bending machine. NBIT was founded in 2001 and has more than 17 years experience in this field.

Nantong Borisbang Industrial Technology (NBIT) is your specialist and technology partner for powerful and future-proof bending machines and bending solutions.Having a solid trained technical team with a wide range of quality Section Bending Machines, and On-Time Deliveries, we have been accumulating happy customers worldwide.

Our core focus and specialisation is in the Section Bending Machines.

Over the years, the Company has grown multifold and currently exports to several countries in Sweden, Germany, England, Thailand, Iran, Korea, Vietnam, Russia, Malaysia, Dubai, Saudi, Arabia, India, South Africa, United Arab Emirates, Singapore, Uzbekistan.