Inspection standards for square tube surface quality

Square tube internal and external quality inspection standards:

1. Internal quality inspection:
(1) No defects such as cracks, bubbles, inclusions, etc.
(2) No folding, warping, peeling, peeling or other damage.
(3) There must be no rust, oil or other pollution.

2. External quality inspection:
(1) The surface has high smoothness and no scratches, oxide scale and other pollution.
(2) There are no burrs, cuts, cracks, welding slag and other damages.

(3) Specifications, quantities, and markings meet the requirements.

Square tube size deviation inspection standards:
1. The wall thickness measurement error shall not exceed ±5% of the allowable deviation.
2. The length measurement error shall not exceed the allowable deviation of ±10mm.
3. The outer diameter measurement error shall not exceed ±0.5% of the allowable deviation.
4. The inner diameter measurement error shall not exceed ±1% of the allowable deviation, but shall not exceed 0.5mm.

Square tube angle and curvature inspection standards:
1. Angle: Use angle ruler to measure, and the error shall not exceed the allowable deviation.
2. Curvature: The measurement error using a deflection ruler or millimeter shall not exceed the allowable deviation.

Square tube surface quality inspection standards:
1. There should be no obvious color difference, scratches or peeling on the surface, and there should be no welding slag and carbide.
2. The surface must be clean and free of debris and sediment.
3. If there is a coating on the surface, its adhesion should meet the standard requirements.

To sum up, as an important part of building materials and machinery manufacturing materials, square tubes need to be strictly controlled in quality standards. It is necessary to inspect internal and external quality, dimensional deviation, angle, curvature, surface quality and other aspects to ensure that its quality meets standard requirements to ensure safe use and reliable quality.

Go here to learn more: Square tube size