The geometric dimensions of the welded tube
blank mainly refer to the width and thickness and their allowable deviations. The longer the length of the welded tube blank, the better the production. The length of the rolled welded tube blank is usually more than 150 meters; it is obviously superior to the strip welded tube blank.
Production practice puts forward such requirements for the allowable deviation of the width of the welded tube blank:
The width of the welded pipe blank is less than 100 mm, and the allowable deviation is not more than ±0.5 mm;
The width of the welded pipe blank is greater than 100 mm, and the allowable deviation is not greater than ±0.5 mm;
It is improper for the allowable width deviation to exceed the above value. If the deviation value is too large, the welding quality and the accuracy of the outer diameter of the steel pipe cannot be guaranteed.
For trimmed strip steel, because the shearing amount is generally 10-15 mm, the allowable deviation value does not need to be too strict, just ±2 mm.
The strip thickness deviation value should be considered corresponding to the allowable deviation value of the finished steel pipe, and the stability of the welded pipe production process and the phenomenon of pipe wall thickness increase during the forming process should also be considered. Welded pipe blanks are supplied strictly according to the allowable thickness tolerance specified in the YB189-64 standard, which can basically meet the requirements of the welded pipe production process.
Tips: In case ASTM A53 Grade B in ERW (electric resistance welded) pipe, the weld seam of A53 ERW pipe shall be done the heat treatment with a minimum 1000°F [540°C]. In this way the no untempered martensite remains.
In case ASTM A53 B pipe in cold expanded, then expansion should not exceed 1.5% of the required OD.