Stainless steel industrial pipes are essential components across multiple industries due to their excellent mechanical strength, corrosion resistance, and high-temperature tolerance. Depending on the operating environment and technical specifications, commonly used grades include 304, 316, 321, 347, 904L, as well as duplex stainless steels like 2205 and 2507. This article systematically explores the performance, pressure capacities, and application fields of stainless steel pipes to guide proper material selection.

1. Common Stainless Steel Grades and Their Characteristics

•304L stainless steel industrial pipe: As a low-carbon 304 steel, in general, its corrosion resistance is similar to that of 304, but after welding or stress relief, its resistance to intergranular corrosion is excellent, and it can maintain good corrosion resistance without heat treatment.
•304 stainless steel industrial pipe: It has good corrosion resistance, heat resistance, low temperature strength and mechanical properties, good hot processing properties such as stamping and bending, and no heat treatment hardening phenomenon. Uses: tableware, cabinets, boilers, auto parts, medical equipment, building materials, food industry (use temperature -196°C-700°C)
The main features of 310 stainless steel industrial pipe are: high temperature resistance, generally used in boilers, automobile exhaust pipes. Other properties are general.
•303 stainless steel industrial pipe: By adding a small amount of sulfur and phosphorus, it is easier to cut than 304, and other properties are similar to 304.
•302 stainless steel industrial pipe: 302 stainless steel bars are widely used in auto parts, aviation, aerospace hardware tools, and chemical industry. Specific as follows: handicrafts, bearings, sliding flowers, medical instruments, electrical appliances, etc. Features: 302 stainless steel ball belongs to austenitic steel, which is close to 304, but 302 has a higher hardness, HRC≤28, and has good rust and corrosion resistance
•301 stainless steel industrial pipe: good ductility, used for molded products. It can also be quickly hardened by mechanical processing. Good weldability. Wear resistance and fatigue strength are better than 304 stainless steel.
•202 stainless steel industrial pipe: belongs to chromium-nickel-manganese austenitic stainless steel, with better performance than 201 stainless steel
•201 stainless steel industrial pipe: belongs to chromium-nickel-manganese austenitic stainless steel, with relatively low magnetism
•410 stainless steel industrial pipe: belongs to martensite (high-strength chromium steel), with good wear resistance and poor corrosion resistance.
•420 stainless steel industrial pipe: “Tool grade” martensitic steel, similar to Brinell high chromium steel, an ultra-early stainless steel. It is also used for surgical knives and can be made very bright.
•430 stainless steel industrial pipe: ferritic stainless steel, used for decoration, such as automotive accessories. Good formability, but poor temperature resistance and corrosion resistance

2. Pressure Resistance of Stainless Steel Pipes

The pressure capacity of a stainless steel pipe depends on its size (outer diameter), wall thickness (e.g., SCH40, SCH80), and operating temperature. Key principles:
•Thicker walls and smaller diameters yield higher pressure resistance.
•Higher temperatures reduce material strength and pressure thresholds.
•Duplex steels like 2205 offer nearly double the strength of 316L.
For example, a 4-inch SCH40 304 stainless steel pipe can handle approx. 1102 psi under normal conditions. A 1-inch pipe may exceed 2000 psi. Engineers should consult ASME B31.3 or similar standards for accurate pressure ratings.

3. Corrosion Performance in Harsh Environments

Chloride-Rich Environments
304 is prone to pitting and SCC in salt-rich areas. 316L or higher is recommended. For extreme cases like seawater or salt spray, 2205, 2507, or 904L are preferable.
Acidic or Oxidizing Media
316L performs well in weak acids. For aggressive acids like sulfuric or phosphoric acid, choose 904L or high-alloy duplex steels.
High-Temperature Oxidation
For temperatures over 500°C, 304 and 316 may lose effectiveness. Use stabilized grades like 321 or 347 for continuous service up to ~900°C.

4. Major Industrial Applications

Oil & Gas Industry
Used in process piping, heat exchangers, and transport lines. For sour gas and chloride conditions, 2205/2507/904L are preferred. Duplex steels are widely used in heat exchangers for their high strength and corrosion resistance.
Food & Beverage
Smooth surface finish prevents bacterial growth. 304/316L are ideal for dairy, brewing, and sauces. 316L performs better with acidic or salty foods. Pipes are often electropolished for hygiene.
Pharmaceutical Industry
Requires high purity and corrosion resistance. 316L and variants like 316LVM are used for purified water and CIP/SIP systems. Surfaces are typically mirror-polished.

5. Grade Selection Guide by Application