Brief Introduction of ASTM A500/A 500M-Part 2

Today let’s continue to discuss the tolerance of the structural tubing on the Specification.

  1. Permissible Variations in Dimensions.
  2. Outside Dimensions:
  3. Round Structural Tubing-the outside diameter shall not vary more than ±0.5%, the measurement shall be made at positions at least 2 in. (5cm) from the ends of the tubing;
  4. Square and Rectangular Structural Tubing-the outside dimensions shall according to table 3,

when OD is 2 1/2 in. (65mm) or under, the tolerance is ±0.02in. (0.5mm)

When OD is over 2 1/2in. to 3 1/2in.(65-90mm), the tolerance is ±0.025in. (0.6mm)

When OD is over 3 1/2in. to 5 1/2in.(90-140mm), the tolerance is ±0.03in. (0.8mm)

When OD is over 5 1/2in.(140mm), the tolerance is ±0.01in.

The measurement shall be made at positions at least 2 in. (5mm) from the ends of the tubing.

  • Wall Thickness:

The minimum wall thickness at any point of measurement on the tubing shall be not more than 10% less than the specified wall thickness. The maximum wall thickness, excluding the weld seam of welded tubing, shall be not more than 10% greater than the specified wall thickness. For the square and rectangular tubing’s wall thickness measurement shall apply only to the centers of the flats.

  • Length:

Structural tubing is normally produced in random length 5 ft (1.5m), multiple lengths, and in specific lengths. When the length is 22ft (6.5m) and under, the tolerance is -13/+6mm, when the length over 22ft (6.5m), the tolerance is -19/+6mm, but if the purchase list has other requirements for this, that need to the purchaser and supplier negotiation.

  • Straightness – The tolerance of the unit pipe is: 1/8in. times the number of feet of total length divided by 5 (10mm times the number of meters, and divided by 5). For example, the structural tubing unit length is 6m, the straightness is 10*6/5=12mm.
  • Squareness of sides – This is for square and rectangular structural tubing, adjacent sides shall be square (90°), with a permissible variation of ±2° max.
  • The radius of Corners – For Square and rectangular structural tubing, the radius of each outside comer of the section shall not exceed three times the specified wall thickness.
  • Twist – For square and rectangular structural tubing, the twist of each meter from 1.3mm to 2.8mm according to different sizes.

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