Compared to other kinds of steel pipe fitting, Stainless steel pipe fitting has a long service life. The service life of stainless steel pipe fitting can reach 100 years, at least 70 years, as same as the life of buildings. The most outstanding advantage of stainless steel pipe fittings is corrosion resistance. If the stainless steel pipe fittings can be used and maintained correctly in the use process, the service life can be effectively extended.

#1 Effect of material on the service life of pipe fittings

The main difference between 304 and 304L stainless steel material is that the Carbon content of 304 is ≤ 0.08%, while that of 304L is ≤ 0.03%; the Ni content of 316 material is 1% to 2% higher than that of 304L, which is mainly due to the decrease of Cr content and the increase of Mo (MO) by 2% to 3%, so their corrosion resistance and corrosion resistance environment are different.

L represents low carbon, for example, 304L contains less carbon than 304, h and s represent high-temperature resistance, for example, 310S is better than 310 in high-temperature resistance, 304H is better than 304 in heat resistance, and 316 and 316L are marine materials with strong corrosion resistance.

There are two kinds of 304 stainless steel materials: first grade and second grade. The second-grade material is the inferior product of the steel plant. The main difference is that the second-grade material is cheaper than the first-grade material in terms of its surface, nickel content and uneven thickness. The steelworks enter the market after a little treatment, but the quality is not stable.

#2 Influence of forming process on the performance and service life of pipe fittings

“Pipe forming” is the most important step in the pipe production process. With the increase of stress in the process of pipe processing, the accuracy of the pipe is easy to change under the action of stress.

At present, most of the tube manufacturers mainly adopt the “cold extrusion” and “bulging” processes in the forming process. There are differences in the size, wall thickness and function of pipe fittings due to different production processes. Therefore, it is very important to adopt what kind of molding process to maintain the stability of quality and improve production efficiency.