ERW Pipe is produced in sizes from 1/8 to 24 in NPS. ERW welded pipe is produced from flat sheet metals. ERW pipe is first cold formed into a cylindrical shape and then welded longitudinally. both continuous welded and elctric resistance welded pipe are made by shaping rolls of coiled steel into cylindrical forms and welding along the longitudinal seams. Picture below shows the first step of forming strips into cylindrical shape and then fusing it together in 2nd step.
There are many ways for the electric current to be used for welding the rolled strip. This includes revolving copper disc, fixed alloy Cu contacts and induction coils. These methods raise the temperature of the steel edge to 2600 deg F for effective welding. The rolling process exerts so much pressure that it creates a metal welded seam on the outside and inside. These weld seams are then removed during the finishing process. The welded pipe is heat treated, inspected and hydro tested.
ERW pipe is available in following common specs;
ASTM A53, A135, A252, A500, A795, API 5L and API 5CT.
Most common spec for welded pipe is A53 and API 5L.
What is seamless definition? or seamless meaning? we get this question a lot. Seamless pipe is produced in sizes from 1/8 to 36" nominal. Seamless pipe has no longitudinal seam or weld when compared to ERW pipe. In simple terms the seamless pipe is produced by piercing a solid round billet leaving behind a hollow seamless pipe. There are two main methods of producing seamless pipe.
