Haihao Group could provide many kinds of pipes made by carbon steel,stainless steel and alloy steel like weld steel pipe and seamless steel pipe.And at first in welded steel pipe,you will find different methods of forming process, such as ERW,LSAW,SSAW. So let’s talk about the differences between SAW pipes and ERW pipe.
Electric resistance welded steel pipes ERW steel pipes
What is SAW steel pipe?
SAW steel pipes is short for submerged arc welding steel pipe,it can be classified into longitudinal submerged arc welding steel pipe(LSAW steel pipe) and spiral submerged arc welding steel pipe(SSAW steel pipe).SAW is a manufacturing process using submerged arc welding of steel,this process produces high current density,which prevents the flux layer from losing heat quickly and concentrates in the welding region.Commonly used standard is API 5L.
Submerged arc weld of high quality,high production efficiency,arc and smoke a few characteristics of submerged arc welded pipe is widely used in pressure vessels,pipe manufacturing,beams,low pressure fluid,steel works.
Spiral submerged arc welding steel pipes SSAW pipes
What is ERW steel pipe?
ERW steel pipe is short for electric resistance welded steel pipe,it is welded by high frequency welding certain size strip steel rolled into a round tube and straight seam welded steel pipe.ERW has the characteristics of high efficiency,low cost,material saving and easy automation,it is widely used in aviation,aerospace,energy, electronics,automotive,light industry and other industrial sectors,is an important link in the welding process.
What are differences between SAW pipes and ERW pipes?
In manufacturing processes,we can see SAW pipes (LSAW, SSAW) and ERW pipes have completely different forming and welding methods
SAW steel pipe manufacturing process:
In the single-seam SAW steel pipe,submerged arc welding process is used for welding.In this method,a welding arc is submerged in welding flux.A continuous solid filler wire is input from the outside.The pipe is double-welded, first is inside and then welding from the outside.
In the case of double seam SAW steel pipe,the first two halves are connected by tack welding,which is called fit-up.Double seam saw steel pipe has two opposite weld seam.Both seams are welded from inside and outside of the pipe.
In a spiral SAW pipe,steel plate from the de-coiler is formed in a spiral loop.This spiral loop is then welded from inside and outside of the pipe.Because of the method of manufacture,a wide variety of diameters can be produced. SSAW pipes are used for low-pressure services.
Whereas LSAW pipes are used for medium to high-pressure services.SSAW pipes are less costly compared to LSAW pipe.
ERW steel pipe manufacturing method:
When ERW steel pipe welding process, two electrodes, usually made from copper, are used to apply pressure and current. The electrodes are disc shaped and rotate as the material passes between them. This allows the electrodes to stay in constant contact with the material to make long continuous welds.
Double surface straight seam submerged arc welding steel pipes
As ERW steel pipe and SAW steel pipe in the pipe during forming,welding and process is different,so that two kinds of steel pipe in the performance there are some differences:
1. The surface quality.
Though both SAW pipes and ERW pipes all have weld seam.The welding seam of ERW pipe is flat,smooth and better than SAW(LSAW,SSAW) pipes.In most of the SAW pipes, it is mainly about the weld reinforcement internally and externally.
2.ERW steel pipe weld defect types is less than the SAW steel pipe.
Because of the solvent deposited in SAW,in addition to volume defects it results in more defects.The defects found in ERW steel pipes are only straight welds and wire-line and are easy to inspect.The defects can be noticed easily and the ultrasonic reflection on the surface makes it easier to detect.
3. The residual stress ratio in ERW is lower than SAW pipes.
ERW steel pipe related to SAW steel pipe in residual stress ratio is low.Since ERW pipe deformation in the deformation process more fully,coupled subsequent sizing flat oval,elliptical vertical changes and necking, making ERW pipe residual stress becomes smaller.Physical testing showed that the same specifications,the same material ERW pipe after incision along the axis,the axial and transverse incisions smaller displacement than the SAW pipe.
4.The overall performance.
Although the overall performance of both ERW pipe and SAW pipe are the same,when the pipe becomes defective,the steel scrap and welding can be done on ERW pipe,while it is not the same in case of SAW,which would result in cracking or corrosion.So ERW pipe are more durable than SAW pipe.
Haihao Group could produce all kinds of type steel pipes(seamless steel pipes,welded steel pipes-ERW pipes,SSAW pipes,LSAW pipes,casing pipes,galvanized steel pipes,etc) as per client’s specific requirements;in addition,we also make butt welding pipe fittings(45°/90°/180° elbow,tee,reducer,cap,bend,cross,nipple,outlet,etc) ,forged pipe fittings and forged flanges products,we have perfect heating process with advanced technology and profession technician,if you have any questions,please email us:sales@haihaogroup.com
