difference between seamless and welded stainless steel pipes

Basic knowleages of the differences between seamless and welded stanless steel pipe/tube

Stainless steel pipe is one of the most multifaceted metal alloy materials used in manufacturing and fabrication. There are mainly two types of tubes, the seamless stainless steel tube and the welde stainless steel tube. From the requiements of client's projects and budgets, we will clear about which type to use. The two common types of tubing are seamless and welded. Deciding between welded vs. seamless tubing primarily depends on the application requirements of the product. In choosing between the two keeps in mind that first, the tubing must be compliant with your project specifications and that secondly, it must meet the conditions for which the tubing will ultimately be used.

Welded Stainless Steel Pipe and tube

With rolling stainless steel sheet and welding process, the Stainless Steel Welded Pipe can be produced more easily. it can be divided into spot-welded pipes, welded pipes, automatic arc welded pipes or spiral welded pipes and straight seam pipes according to the welding form.

The welded pipe producing process starts with the moving of a steel coil or loop to the proper gauge thickness to frame a level strip. The flat level strip is sliced to the width that relates to the measure of the pipe to be delivered. The pipe is framed by moving the cut curl through a progression of rollers, and the crease of the tube is then welded in an artificially nonpartisan condition. In a welded pipe, the crease or the weld-joint is the weaker piece of the pipe constraining the quality of the pipe to the quality of the weld joint.

From the perspective of production technology, stainless steel welded pipe production equipment is simple, and it is relatively easy to change the product specifications and varieties. The welding process generally uses inert gas shielded arc welding, which reduces the cost by 25% compared with the seamless pipe of the same specification.

Seamless stainless steel pipe

Seamless stainless steel pipes is a long steel with a hollow cross section and no seams around it. The wall thickness is uneven, and the internal and external brightness of the pipe is low.

Seamless tubes are generally made in complex steps starting with the drilled hollows from billets, by cold drawing and cold rolling manufacturing process with cold drawing & cold rolling machines.

To control outside diameter and wall thickness, seamless type dimension is difficult to control compared to welded tube, cold work improves the mechanical properties and tolerances.

Differences between seamless stainless steelpipe and welded stainless steel pipe

1.The original surface

The original surface of the stainless steel welded pipe is better than that of a seamless pipe. As the seamless pipe is made by a hot rolling billet, outer surface defects of the billet cannot be eliminated by the hot rolling process, it can only be polished after the product is finished. Many surface defects are difficult to deal with. The finished product must be completed before processing.

2.The grade that applied

In China, the 201 and 304 are the common grades in the welded stainless steel pipe, you can hardly find 316 type welded stainless steel pipe, as it costs more than the 201 and 304

304 and 316 are the common grade in seamless stainless steel pipe because the seamless stainless steel pipes are most applied in the chemical industry, pressure equipment, and thermal, boiler industries. they require better pressure capacity and higher strength.

3.Thickness and Sizes differences

The welded stainless steel pipe has thinner wall thickness, and more uniform.

The seamless stainless steel pipe has heavy and thick wall thickness.

4.Cost and prices

The cost of welded stainless steel pipes is more affordable than seamless stainless steel pipes and is promptly accessible in long consistent lengths