The Function Of Copper In Stainless Steel Pipes

Stainless steel welded pipes have a heat resistance limit. Beyond this limit, they will definitely fail.

Generally, the heat resistance of 201 stainless steel welded pipes is up to 315 degrees Celsius, while for 304, the limit is 650 degrees Celsius. If the temperature surpasses this threshold, heavy metals in the material will precipitate, causing deformation in the pipe due to creep. Therefore, stainless steel pipes should be used below the corresponding temperature limit; otherwise, they will fail. With an increase in nickel content, the heat resistance of pipes can be enhanced, so 304 have a slightly higher heat resistance compared to 201.

The usage environment of 201 and 304 stainless steel welded pipes is temperature restricted. Hence, customers need to pay attention to this issue. Special heat-resistant stainless steel pipes are required in high-temperature environments, as ordinary decorative pipes may not meet product requirements.

Some users often encounter a situation where, for example, some 201 stainless steel welded pipes can be processed into bends or expanded to a certain extent, while others may crack when bent or expanded. Why is there such a difference even though they are both 201 pipes?

The main reason here lies in the difference in copper content in 201 stainless steel welded pipes. Stainless steel is an alloy material, and when evaluating the quality of stainless steel, it's generally based on the proportion of nickel and chromium in the material—the higher, the better. For example, 201 material consists of 1% nickel and 13% chromium, while 304 material consists of 8% nickel and 18% chromium. The corrosion resistance of 304 is better than that of 201.

However, the copper content in 201 stainless steel welded pipes significantly affects the ductility of the pipes. In the steel strip of 201 material, the quality varies depending on the level of copper content, which can be categorized as high copper content steel strip, medium copper content steel strip, and low copper content steel strip. The higher the copper content, the better the stability and ductility of the pipe, resulting in significant price differences.