Stainless steel pipes are one of the most widely used materials in various industries requiring high corrosion resistance and durability. The utilization of fabricated stainless steel products in various applications has increased in recent years, as they offer many benefits, such as excellent performance, resistance to oxidation, and easy maintenance. In manufacturing stainless steel pipes, it is essential to use standardized materials to ensure product quality and compatibility with certain industrial processes. ASTM A312 and ASTM A358 are the most commonly used stainless steel pipe manufacturing standards. This blog post will help you understand the difference between ASTM A312 and ASTM A358.
ASTM A312 Standard
ASTM A312 is a standard specification for seamless, welded, and cold-worked austenitic stainless steel pipe intended for high-temperature and general corrosive service. It covers dimensions, tolerances, and mechanical properties of various grades of austenitic, austenitic-ferritic, and heat-resisting steel. The grades covered by ASTM A312 include TP304, TP304L, TP304H, TP316, TP316L, TP317, TP321, TP347, TP310S, and others. The seamless and welded pipes have different specifications regarding their chemical composition, mechanical properties, and manufacturing processes.
ASTM A358 Standard
ASTM A358 is a standard specification for electric-fusion-welded austenitic chromium-nickel stainless steel pipe suitable for corrosive or high-temperature service. The pipes under this specification are intended for superheaters, heat exchangers, or condenser tubes. ASTM A358 covers grades such as TP304, TP304L, TP347, TP347H, TP316, TP316L, TP321, and others. The standard requires that the pipes be made by electric fusion welding or submerged arc welding.
Differences Between ASTM A312 and ASTM A358
Chemical Composition
The chemical composition of ASTM A312 and ASTM A358 are very similar. Both contain chromium, molybdenum, and nickel as the primary alloying elements. The main difference is that ASTM A312 has carbon, while ASTM A358 does not.
Mechanical Properties
The mechanical properties of ASTM A312 and ASTM A358 are also very similar. Both have yield strength of approximately 35 ksi and an ultimate tensile strength of about 75 ksi. The main difference between the two is that ASTM A312 has a lower carbon content, which gives it better weldability.
Availability
ASTM A312 and ASTM A358 are both widely available in the market. They can be purchased from a variety of manufacturers and suppliers.
Prices
The prices of ASTM A312 and ASTM A358 vary depending on the supplier and the quantity purchased. However, they are generally more expensive than other grades of stainless steel.
Applications
The primary difference between the two standards lies in their applications. ASTM A312 is used mostly for high-temperature and general corrosive service requiring seamless or welded pipes. In contrast, ASTM A358 is ideal for corrosive or high-temperature service that requires electric-fusion-welded lines. Another difference is in the selection of the grades covered by each standard. ASTM A312 includes a wider range of degrees, including austenitic, austenitic-ferritic, and heat-resisting steel, while ASTM A358 only covers austenitic chromium-nickel stainless steel.
Advantages of Using ASTM A312 and ASTM A358 Pipes
Stainless steel pipes manufactured under ASTM A312 and ASTM A358 standards have several advantages over other materials. They are highly durable, can withstand harsh environments, and need little maintenance, making them ideal for industrial applications such as food processing, petrochemical, pharmaceutical, and others. Additionally, they offer excellent corrosion resistance, good tensile strength, and easy weldability. Other benefits include good temperature resistance, low thermal expansion, and long service life.
Which Standard to Use between ASTM A312 and ASTM A358?
The choice between ASTM A312 and ASTM A358 largely depends on the product’s intended application. If your application requires general corrosive or high-temperature service, then ASTM A312 is the right standard. However, if your application requires electric-fusion-welded pipes suitable for corrosive or high-temperature service, then ASTM A358 is the right choice.
Conclusion
In summary, ASTM A312 and ASTM A358 are two important standards for manufacturing stainless steel pipes, with different specifications and applications. While ASTM A312 is used mainly for high-temperature and general corrosive service, ASTM A358 is ideal for corrosive or high-temperature service that requires electric-fusion-welded pipes. The choice of which standard to use depends on the intended application. Regardless, both measures offer several advantages that make them suitable for various industries.
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