ASTM A358 Stainless Steel EFW Pipe.Video
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ASTM A358 Stainless Steel EFW Pipe.Video
Overview of ASTM A358
This specification covers electric-fusion-welded (EFW) austenitic stainless steel pipes intended for high-temperature, high-pressure, or corrosive environments. The pipes are manufactured by welding processes such as high-frequency resistance welding or induction welding and may undergo cold working or heat treatment after welding.
Resistance to high-temperature oxidation and corrosion
| 304 (S30400) | 304 | Cr 18–20, Ni 8–10, C Less than or equal to 0.08 | General-purpose austenitic steel with good atmospheric, freshwater, and mild corrosion resistance. Cost-effective. |
| 304L (S30403) | Low-carbon 304 | Cr 18–20, Ni 8–12, C Less than or equal to 0.03 | Ultra-low carbon version to eliminate risk of intergranular corrosion after welding. Ideal for clean or sensitized environments. |
| 316 (S31600) | 316 | Cr 16–18, Ni 10–14, Mo 2–3, C Less than or equal to 0.08 | |
| 316L (S31603) | Low-carbon 316 | Cr 16–18, Ni 10–14, Mo 2–3, C Less than or equal to 0.03 | Combines Mo-enhanced corrosion resistance with low carbon to prevent intergranular corrosion. Suitable for non-heat-treated welds. |
| 321 (S32100) | 321 (Ti-stabilized) | Cr 17–19, Ni 9–12, Ti Greater than or equal to 5×C, C Less than or equal to 0.08 | Titanium stabilization prevents carbide precipitation. Ideal for long-term use in 430–870 degree environments (e.g., heat exchangers). |
| 347 (S34700) | 347 (Nb-stabilized) | Cr 18–20, Ni 9–13, Nb Greater than or equal to 10×C, C Less than or equal to 0.08 | Niobium-stabilized for enhanced resistance to high-temperature carbide precipitation. Suitable for oxidation resistance in 870–980 degree range. |
| 304/304L | 316/316L | 321/347 | |
|---|---|---|---|
| Greater than or equal to 515 | Greater than or equal to 515 | Greater than or equal to 515 | |
| Yield Strength (σ0.2, MPa) | Greater than or equal to 205 | Greater than or equal to 205 | Greater than or equal to 205 |
| Elongation (δ5, %) | Greater than or equal to 30 | Greater than or equal to 30 | Greater than or equal to 30 |
| Strength at 500 degree (MPa) | Greater than or equal to 140 | Greater than or equal to 150 | Greater than or equal to 160 |
Corrosion and High-Temperature Resistance
Face-centered cubic structure, non-magnetic, corrosion-resistant in air, water, neutral salt solutions, and many organic acids (e.g., nitric acid).
Mo (316 series):
Ti/Nb (321/347): Binds carbon to prevent Cr₂₃C₆ precipitation, eliminating intergranular corrosion-ideal for welded or high-temperature service components.
High-Temperature Resistance
304/304L: Less than or equal to 870 degree for continuous use, Less than or equal to 980 degree for short-term exposure (oxidation resistance).
316/316L: Less than or equal to 925 degree continuously, with Mo enhancing resistance to sulfidation.
321/347: Less than or equal to 980 degree continuous operation (stabilized against Cr carbide precipitation, creep resistance under thermal stress).
Boiler superheaters and reheater piping (high-temperature, high-pressure).
High-purity media transport pipelines (304L/316L – corrosion-resistant, easy to clean).
Flue gas treatment systems, denitrification piping (resistant to high-temperature sulfur-containing gas).
Seawater cooling pipelines (316L for pitting resistance; 317L for crevice corrosion resistance).
High-Frequency Resistance Welding (HFRW).
Post-weld treatments may include cold drawing, annealing (stress relief), or solution annealing (to restore corrosion resistance).
Minimum pressure Greater than or equal to 2.4 MPa (calculated based on pipe diameter and wall thickness).
ASTM A262 Practice E, especially for low-carbon grades like 304L/316L, to validate post-weld corrosion resistance.
| ASTM A312 | Covers both seamless and welded (ERW/EFW/SAW) pipes for a broader range of general service, not limited to high-temp/high-pressure. |
| ASTM A213 | For seamless boiler and superheater tubes, ferritic/austenitic stainless steels; focuses more on high-temperature strength (e.g., TP304H, TP316H). |
| ASTM A790 |
