Summary of the differences between seamless and welded pipes
The API 5L / ASTM seamless steel tube and the ERW welded tube have some differences that we will see below:
1. Difference in appearance
The seamless steel tube uses a billet or cylindrical steel ingot as raw material. The external defects of this billet cannot be removed in the hot rolling process, but can only be polished when the product is finished. In the process to reduce wall thickness, this defect can only be partially removed, but not in its entirety.
The welded pipe is manufactured from a hot rolled (or stretched) roll as raw material. The exterior quality of this roll is equivalent to the exterior quality of the tube, and it is easy to handle. The surface obtained from the rolled roll is of high quality.
Therefore, the surface of the welding tube will always be better than that of the seamless tube.
2. Differences in the molding process
The seamless pipe can only be molded once in the rolling process.
On the other hand, the manufacture of the weld pipe can be made from a sheet or steel plate, which may involve bending, rolling, and other different welding processes.
3. Performance and Use
The seamless steel pipe withstands better pressure levels, so its resistance is greater than that of the ERW pipe with welding. For this reason, it is very common to find this tube in high pressure equipment, or thermal industries that work with boilers.
In general, the seam of the welding tube is its weak point, and this quality affects its final performance.
Usually, welded steel pipes can withstand up to 20% less pressure than seamless ones. This reliability is the main factor that people consider when choosing the seamless tube. In fact, all industrial pipes are made with seamless pipes since they are capable of withstanding extreme thermal, chemical and mechanical loads and levels. Welded pipes are more preferred in the aerospace, automotive and electronics industries, where the budget is relatively lower, as are the pressure levels experienced by the pipes.
4. Differences in sizes available
Most steel tube manufacturers in China produce seamless tubes with an outside diameter (OD) of 20 inches (508 mm). Usually, the average diameter is less than 16 inches (406.4 mm) due to limits on manufacturing equipment. If the customer wishes to buy seamless tubes with sizes larger than these, machinery is used to expand the hot material. However, the quality of the hot expanded tube is not equal to that of the original seamless steel tube.
On the contrary, the welded steel tube does not have these limitations, with available sizes ranging from 1-1 / 2 inches (48.3mm) to 100 inches (2540 mm).
5. Costs and prices
Generally, the cost of seamless pipe is higher than that of welded pipe; This is due to the raw material and the manufacturing equipment and processes used. But sometimes, due to fluctuations in the market, the welded pipe has a higher cost, so if you get to know this type of situation, do not hesitate to buy seamless pipe for the same dimensions.
1. Difference in appearance
The seamless steel tube uses a billet or cylindrical steel ingot as raw material. The external defects of this billet cannot be removed in the hot rolling process, but can only be polished when the product is finished. In the process to reduce wall thickness, this defect can only be partially removed, but not in its entirety.
The welded pipe is manufactured from a hot rolled (or stretched) roll as raw material. The exterior quality of this roll is equivalent to the exterior quality of the tube, and it is easy to handle. The surface obtained from the rolled roll is of high quality.
Therefore, the surface of the welding tube will always be better than that of the seamless tube.
2. Differences in the molding process
The seamless pipe can only be molded once in the rolling process.
On the other hand, the manufacture of the weld pipe can be made from a sheet or steel plate, which may involve bending, rolling, and other different welding processes.
3. Performance and Use
The seamless steel pipe withstands better pressure levels, so its resistance is greater than that of the ERW pipe with welding. For this reason, it is very common to find this tube in high pressure equipment, or thermal industries that work with boilers.
In general, the seam of the welding tube is its weak point, and this quality affects its final performance.
Usually, welded steel pipes can withstand up to 20% less pressure than seamless ones. This reliability is the main factor that people consider when choosing the seamless tube. In fact, all industrial pipes are made with seamless pipes since they are capable of withstanding extreme thermal, chemical and mechanical loads and levels. Welded pipes are more preferred in the aerospace, automotive and electronics industries, where the budget is relatively lower, as are the pressure levels experienced by the pipes.
4. Differences in sizes available
Most steel tube manufacturers in China produce seamless tubes with an outside diameter (OD) of 20 inches (508 mm). Usually, the average diameter is less than 16 inches (406.4 mm) due to limits on manufacturing equipment. If the customer wishes to buy seamless tubes with sizes larger than these, machinery is used to expand the hot material. However, the quality of the hot expanded tube is not equal to that of the original seamless steel tube.
On the contrary, the welded steel tube does not have these limitations, with available sizes ranging from 1-1 / 2 inches (48.3mm) to 100 inches (2540 mm).
5. Costs and prices
Generally, the cost of seamless pipe is higher than that of welded pipe; This is due to the raw material and the manufacturing equipment and processes used. But sometimes, due to fluctuations in the market, the welded pipe has a higher cost, so if you get to know this type of situation, do not hesitate to buy seamless pipe for the same dimensions.
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