Astm A139 SSAW Steel Pipe

Astm A139 Welded Spiral Steel Standard Hollow Section Ssaw Steel Pipe

SSAW Steel Pipe (Spiral steel tube) is a spiral welded steel tube made of strip steel coil as raw material, usually formed by warm extrusion, and welded by automatic double-wire double-side submerged arc welding process. The spiral steel tube feeds the strip into the welding tube unit, and after rolling with multiple rollers, the strip is gradually rolled up to form a round tube blank with open clearance. The pressure reduction of the extrusion roller is adjusted so that the weld clearance is controlled at 1~3mm and both ends of the welding joint are flush.Main technological features of spiral steel tube:In the forming process, the steel plate deformation uniformity, the residual stress is small, the surface does not produce scratches. The processed spiral steel pipe has greater flexibility in the size and specification range of diameter and wall thickness, especially in the production of high-steel grade thick wall pipe, This specification covers five grades of electric-fusion (arc)-welded straight-seam or spiral-seam steel pipe in 4" to 92" inclusive with wall thickness up to 1 " inclusive.Pipe having other dimensions may be furnished provided such pipe complies with all other requirements of this specification and the grades of steel of the manufactured pipes. The pipe is intended for conveying liquid, gas, or vapor.Each length of pipe shall be tested by the manufacturer to a hydrostatic pressure that will produce in the pipe wall a stress of not less than 60% of the minimum specified yield point at room temperature.The pressure shall be determined by the following equation : p=2st/d.Test pressure shall be held for not less than 5 sec., or for a longer time as agreed upon between the purchaser and the manufacturer.When agreed upon by the purchaser and the manufacturer and so stated on the order, pipe may be tested :to 1 1/2 times the working pressure with condition it does not exceed 2800-psi, nor shall the maximum fiber stress exceed 85% of minimum yield point of the grade of steel used.to a fiber stress which does not exceed 85% of the minimum yield point of the grade of steel used or exceed 2800-psi test pressure.