Allowable deviation of square steel pipe wall thickness:
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When the wall thickness is less than 10mm, it shall not exceed plus or minus 10% of the nominal wall thickness, and when the wall thickness is greater than 10mm, it is plus or minus 8% of the wall thickness, except for the wall thickness of the corner and weld area
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The usual delivery length of square steel pipe is 4000mm-12000mm, and the welding process is mostly 6000mm and 12000mm, while the seamless process is mostly 9000mm-11000mm. Large diameter square steel pipes are allowed to deliver short and non-fixed size products of not less than 2000mm, and can also be delivered in the form of interface pipes, but the buyer should cut out the interface pipes when in use. The weight of short and non-fixed size products shall not exceed 5% of the total delivery volume, and for square tubes with a theoretical weight greater than 20kg\/m, it shall not exceed 10% of the total delivery volume.