ERW Welded Pipe With Anti Rust Coating
Electric resistance welding (ERW) pipes refer to a group of welding processes such as spot and seam welding that produce coalescence of faying surfaces where heat to form the weld is generated by the electrical resistance of material combined with the time and the force used to hold the...
Electric resistance welding (ERW) pipes refer to a group of welding processes such as spot and seam welding that produce coalescence of faying surfaces where heat to form the weld is generated by the electrical resistance of material combined with the time and the force used to hold the materials together during welding. Some factors influencing welding temperatures are the proportions of the workpieces, the metal coating or the lack of coating, the electrode materials, electrode geometry, electrode pressing force, electrical current and length of welding time. Small pools of molten metal are formed at the point of most electrical resistance (the connecting or "faying" surfaces) as an electrical current (100–100,000 ) is passed through the metal. In general, resistance welding methods are efficient and cause little pollution, but their applications are limited to relatively thin materials.
ERW Pipe Manufacturing Process
Electric resistance welded (ERW) pipe is manufactured by cold-forming a sheet of steel into a cylindrical shape. Current is then passed between the two edges of the steel to heat the steel to a point at which the edges are forced together to form a bond without the use of welding filler material.
Uncoiling, End Shearing And Welding
The slitted coil is uncoiled at the entry of ERW mill and the ends are sheared and welded one after another. This results in a single endless strip.
The slitted coils are initially formed into U shape and after that into a cylindrical shape with open edges utilizing a series of forming rolls.
In this stage, the open edges are heated to the forging temperature through high-frequency, low-voltage, high current and press welded by forge rolls making perfect and strong but weld without filler materials.
If required, the welding portion and heat affected zone is put to normalizing and then are cooled down in a air cooling bed.
After water quenching, slight reduction is applied to pipes with sizing rolls.
This results in producing desired accurate outside diameter.
In cutting stage, the pipes are cut to required lengths by flying cut off disc/saw cutter.
End Facing And Bevelling
This is usually stage, where the pipes ends are faced and bevelled by the end facer.
All these processes are continuous with automatic arrangements. These plain ended tubes further go for processing as per the customer requirements such as galvanizing, threading, black varnishing and more.
ERW welde pipe standard and Steel Grade:
API 5L: Grade A, Grade B, X42, X46, X52, X56, X60, X65, X70, X80
ASTM A 53: Grade A, Grade B, Grade C, Type F, Type E
EN 10210: S235JRH; S275J0H, S275J2H; S355J0H, S355J2H; S275NH, S355NH; S275NLH, S355NLH
Size and Specification of ERW welded steel pipe
Outer Diameter： 1/2" - 28"
Wall Thickness： 2-18mm
Length： Random Length, Fixed Length, SRL, DRL