difference between astm a312 and astm a358
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What is the ASTM A312 specification?
ASTM A312 is the standard specification for seamless, straight-seam welded, and heavily cold-worked austenitic stainless steel pipe designed for high-temperature and general corrosive service. Common grades include 304/304L and 316/316L, widely used in fluid transport for oil, gas, and water applications.
Click to download ASTM A312 (Free PDF)
What is the ASTM A358 specification?
ASTM A358 is a standard specification for electric-fusion-welded (EFW) austenitic chromium-nickel stainless steel pipe intended for high-temperature and general corrosive service. It covers various grades (e.g., 304, 316, 321) often used in chemical, petrochemical, and power generation industries.
Click to download ASTM A312 (Free PDF)
Key Differences Between ASTM A312 and ASTM A358:
| Feature | ASTM A312 | ASTM A358 |
| Full Title | Seamless, Welded, and Heavily Cold Worked Austenitic Stainless Steel Pipes. | Electric-Fusion-Welded (EFW) Austenitic Chromium-Nickel Stainless Steel Pipe. |
| Manufacturing Process | Seamless (SMLS) or Automatic Welded. | Electric Fusion Welded (EFW) using a plate and a welding machine. |
| Filler Metal | Not allowed during the welding process. | Mandatory (filler metal is added to the weld joint). |
| Pipe Diameter Range | Typically 1/8" to 30". Focused on small to medium sizes. | Typically 8" to 72"+. Focused on large diameters. |
| Wall Thickness | Standard Schedules (Sch 5S to Sch 80S/160). | Often used for heavy-wall applications (Custom thicknesses). |
| Welding Classes | No specific classes; categorized by SMLS or Welded. | 5 Classes (Class 1 to Class 5) based on joint type and X-ray. |
| Radiographic Test (RT) | Not mandatory (Optional/per agreement). | Mandatory for Class 1, 3, and 5 (X-ray testing). |
| Joint Efficiency | 1.0 for SMLS; 0.85 - 1.0 for Welded. | Varies from 0.7 to 1.0 based on the Class and RT. |
| Main Application | General industrial fluid transport, chemicals, and food processing. | Large-scale piping, pressure vessels, and high-pressure/temperature steam lines. |
ASTM A312: Small to Medium Diameter, General Industrial Fluid Transport
Fine Chemicals and Pharmaceutical Industries
Food and Beverage ProcessingWhat is the difference between ASTM A790 and A312?
High-Pressure Instrumentation Piping
Seawater Desalination and Water Treatment
ASTM A358: Large Diameter, Heavy Industry, and Pressure Systems
ASTM A358 primarily addresses large-diameter (typically NPS 8" and above) and heavy-wall stainless steel piping.
Petroleum Refining Main Pipelines: Main trunk lines used to connect large-scale reactors and process towers.
Power Plant Boilers and Steam Piping
Heavy-Duty Pressure Vessel Connections: Main inlet and outlet headers for industrial reactors and pressure tanks.
Large-Scale Municipal Facilities: Main pumping and conveyance headers for large wastewater treatment plants.
What is the difference between astm A778 and astm A312?
ASTM A312 and ASTM A778 are both stainless steel pipe specifications, but they differ primarily in heat treatment, intended application, and manufacturing. A312 is used for high-pressure, general-use applications and requires heat treatment. Conversely, ASTM A778 is intended for low-pressure/corrosive service, is unannealed, and features better fabrication for thin-walled pipes.
What is the difference between ASTM A790 and A312?
The primary difference between ASTM A790 and ASTM A312 lies in their alloy types and strength characteristics. ASTM A790 covers seamless and welded ferritic/austenitic (duplex) stainless steels, which possess high strength (yield strength > 450 MPa) and exceptional corrosion resistance. In contrast, ASTM A312 covers seamless and welded austenitic (300-series) stainless steels, designed specifically for general corrosive environments and high-temperature service conditions, and features a relatively lower yield strength (approximately 205 MPa).
We maintain a substantial inventory of ASTM A312 stainless steel pipes, covering grades 304 and 316L in sizes ranging from NPS 1/2" to 12". For large-diameter, high-pressure systems, Gnee offers large-diameter electric fusion welded (EFW) pipes accompanied by 100% X-ray inspection reports. Based on plate thickness, we can customize non-standard wall thicknesses to meet your specific requirements; this approach not only guarantees the necessary pressure strength but also offers cost savings of over 30% compared to large-diameter seamless pipes.
