1. The former is a steel pipe made by welding steel plate or strip after crimping. The latter is made by casting steel ingots or solid tube billets and then by hot rolling, cold rolling or cold drawing.

2. The strength of the small diameter welded pipe is lower than that of the stainless steel pipe. The production process is simple, the production efficiency is high, there are many varieties and specifications, and the equipment cost is small. With the continuous improvement of the quality of welding seams, the variety and specifications of small-diameter welded pipes have been increasing, and stainless steel pipes have been replaced in many fields.

3. The blank of the small-diameter welded pipe is a steel plate or strip steel, and a narrow blank is produced.

4. Small-diameter welded pipes are mainly used for oil and natural gas pipelines. The stainless steel tube has a hollow portion and is lightweight. It is an economical steel that is widely used in the manufacture of structural parts and mechanical parts, such as oil drill pipes, automobile drive shafts, bicycle frames, and steel scaffolds for construction.

5. The rolling direction of the vertical coil of the small-diameter welded pipe is not the direction of the vertical axis of the steel pipe, and the rolling direction of the stainless steel pipe is perpendicular to the axial direction of the steel pipe. Small-diameter welded pipe materials have better crack resistance than stainless steel pipes.