Differences Between Seamless elbow and Welded elbow

Seamless elbow is manufactured by the seamless steel pipe, through hot push, press or extrusion processes, no seam on the elbow body.
Welded elbow is manufactured by welded steel pipe, same processes with seamless elbow.But there is a seam on the elbow body.

Huayue tells you the differences between seamless elbow and welded elbow on raw material, manufacturing processes, performances, appearances, sizes, applications, cost prices etc.

How is Seamless elbow made.

The production of seamless elbow mainly adopts the hot push technology.Hot push elbow forming technology is to use special elbow push system core machine, mold and heating device, to set on the mould of billet in pushing forward movement, under the impetus of the machine in motion is heated and hole enlargement and forming process.Hot push elbow deformation characteristics are based on volume before and after plastic deformation rule of metal materials determine the pipe diameter, pipe diameter elbow diameter, through the core module and control the deformation of the process, make the inner arc compressed metal flow, the compensation to other parts of the thinned by hole diameter, wall thickness uniform Angle is obtained.

Hot push elbow forming technology has a good appearance, uniform wall thickness and continuous operation, suitable for the characteristics of mass production, thus become the main forming methods of carbon steel, alloy steel elbow, and also the application in some of the specifications of the stainless steel elbow forming.

How is Welded elbow made

The raw materials for welded elbow are welded steel pipe and iron plates.It is also used hot push technology to produce elbows with welded steel pipe.Normally, elbow diameter below DN600 is produced by steel pipe.Diameter more than DN600 requires steel plate production.The manufacturing processes first bending the steel plate, then welded into circular, square and other shapes. Welded steel elbow has the characteristics of high production efficiency, low cost and saving material.

Why Should You Prefer To Buy Seamless Steel elbows?

The reason why most of the people prefer seamless elbows over welded elbows is that seamless elbows can withstand extremely high pressure without cracking. But the seam or welded pipes cannot do the same as the welded points are vulnerable to cracking up under high pressure. Furthermore, it is very easy to accurately calculate the pressure of seamless elbows. Seamless elbows are also thinner and lighter than welded ones, and they also have uniformity of shape as they are made up of uniform extrusion of an alloy. If you are looking to buy the best quality of seamless elbows, you should use Huayue ASTM A234 WPB seamless steel pipe elbows.

Seamless vs welded steel pipe elbow differences summary

Seamless steel pipe elbow and ERW welded steel pipe elbow have some differences as below:

1. Appearance difference

The biggest difference between seamless elbows and welded elbows are whether there is a weld, but  now many of the welded steel pipes will be polished off the welding seam before they leave the factory.The elbow that is made out of this steel pipe is invisible to the welding seam.There are a lot of exporter sell this kind of fake seamless elbow to customers.This kind of elbow is difficult to distinguish with the naked eye, and it needs to use professional testing tools.For now,false seamless elbow often appears in the area below the diameter of DN600.

2. Molding process differences

The process of using seamless steel pipe and welded steel pipe is the same process.
The difference is the welded elbow made of steel plate, through bending and different welding processes.

3. Performance and Usage

Seamless steel pipe elbow has better pressure capacity, strength is higher than welded steel pipe elbow. So it is widely applied in high pressure equipment, and thermal, boiler industries.
Generally the welding seam of the welded steel pipe elbow is the weak point, the quality affect overall performance.

In general, welded steel pipe elbows can withhold 20% less working pressure than seamless ones. This reliability is the prime factor why people go for seamless steel pipe elbow. As a matter of fact, all the industrial pipelines are done with seamless pipe elbows only because the elbows undergo extreme thermal, chemical and mechanical workloads. Welded elbows are more preferred in aerospace, automobile and electronics industries where the budget is comparatively low, and so is the work pressure put on the pipeline.

4. Available Sizes differences

For most of seamless steel pipe elbow manufacturers in China, they produce original seamless pipe elbow sizes maximum OD in 24 inch, 609.6 mm.On the contrary, welded steel pipe elbow don’t have these limitations, sizes available from 1-1/2 inch 48.3mm to 100 inch 2540 mm.

5. Cost and prices

Usually the seamless steel pipe elbow cost is higher than welded steel pipe elbow, because the raw material, manufacturing equipment and processes. But sometimes by the market pressure, welded elbow is more expensive, so if you met this situation, don’t hesitate to purchase the seamless steel pipe elbow for the same dimensions.