1. Appearance difference
The difference between customized seamless elbows and welded elbows is the presence or absence of welds, and the thickness of customized seamless elbows is not uniform relative to the thickness of welded elbows. 
2. Differences in molding process
The process for using customized seamless elbows is the same as for welded elbows. The difference is that the manufacture of elbows is divided into welding, stamping, pushing and casting. Customized seamless elbows are made of seamless steel pipes, without welds, and without welded elbows. Welded elbows are made of steel plates made by bending and different welding processes.

3. Different uses
Customized seamless elbows are mainly used in the machinery industry as pipes or structural parts for conveying fluids, while jointed elbows are mainly used in the construction industry, such as low pressure fluids such as water, natural gas and compressed air. But the pressure piping involved is seamless.
4. Available size differences
For most customized seamless elbow manufacturers, their initial seamless elbow size is 24 inches with an OD of 609.6 mm. In contrast, welded elbows do not have these limitations and can range in size from 1-1/2 inches 48.3mm to 100 inches 2540mm.
5. The price is different
Because the seamless production process is more complicated, the price is more expensive than the seam elbow, and the seam is mainly made of secondary welding of steel plates (steel strips), which is cheap and versatile.