The material standards and chemical requirements of stainless steel pipes mainly include the ASTM A312 standard, which specifies the general requirements for austenitic stainless steel seamless and welded steel pipes. Among them, TP304 and TP310S are the two most common materials for stainless steel pipes.
TP304 stainless steel
TP304 stainless steel, also known as 18-8 stainless steel (containing 18% chromium and 8% nickel), is a general-purpose stainless steel. Its chemical composition includes:
Carbon: ≤0.08%
Silicon: ≤1.0%
Manganese: ≤2.0%
Phosphorus: ≤0.035%
Sulfur: ≤0.030%
Nickel: 8.0~11.00%
Chromium: 18.00~20.00%
TP304 stainless steel is widely used due to its excellent corrosion resistance, heat resistance and good mechanical properties. Its manufacturing process includes two types: seamless pipe and welded pipe. Seamless pipes are manufactured by hot rolling, cold rolling or extrusion processes and are suitable for harsh environments such as high pressure and high temperature; welded pipes are made by rolling and welding, which is lower in cost, but may not perform as well as seamless pipes in some high-demand situations.

TP310S stainless steel
The chemical composition of TP310S stainless steel includes:
Carbon: ≤0.08%
Silicon: ≤1.5%
Manganese: ≤2.0%
Phosphorus: ≤0.035%
Sulfur: ≤0.030%
Nickel: 19.00~22.00%
Chromium: 24.00~26.00%
TP310S stainless steel is often used in high temperature environments and has excellent oxidation resistance and corrosion resistance. Its specifications range from outer diameter 57mm~1626mm and wall thickness 1.2mm~60mm.