In the world of industrial piping, selecting the wrong material can lead to either unnecessary costs or catastrophic failure. When it comes to threaded pipe flanges, the two most popular contenders are ASTM A105 (Carbon Steel) and SS316/316L (Stainless Steel).
Which one is right for your system in Texas or your water plant in Queensland? Let’s break it down.
ASTM A105 Carbon Steel: The Industrial Workhorse A105 forged carbon steel is the standard for ambient and higher-temperature service in pressure systems.
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Best For: Oil and gas utilities, non-corrosive industrial processes, and high-pressure steam.
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Pros: High strength-to-weight ratio and significantly lower cost than stainless steel.
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Cons: Susceptible to rust if not coated or galvanized.
SS316 Stainless Steel: The Corrosion Expert For environments exposed to salt, chemicals, or extreme moisture, SS316 threaded flanges are the gold standard.
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Best For: Marine applications (especially in the Gold Coast or Florida), chemical processing, and food-grade systems.
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Pros: Superior resistance to pitting and chloride corrosion.
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Cons: Higher initial investment.
When to Use Threaded Connections? Regardless of material, a 1 inch threaded flange or a 1 1/2 threaded flange is ideal for:
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Small-bore piping systems (NPS 4 and below).
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Hazardous areas where welding sparks (hot work) are prohibited.
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Low-vibration lines where a secure, tapered NPT seal is required.
Pressure & Temperature Ratings Both materials follow the ASME B16.5 standard for dimensions and pressure-temperature ratings. However, a Class 150 A105 flange will have a different pressure limit at elevated temperatures compared to an SS316 flange. Always consult the [Blind Flange Dimensions Chart] or our technical team for specific limits.
Local Availability for Rapid Projects We maintain a full range of both materials to support local infrastructure:
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USA Stocks: Our Texas and North Carolina hubs are stocked with 1" and 1.5" A105 NPT flanges.
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Australia Stocks: For coastal projects in the Northern Rivers or Far North Queensland, we recommend our [Stainless Steel Threaded Flanges] available in Sydney.
Conclusion If budget is the priority and the environment is dry, A105 is your winner. If you are dealing with salt air or chemicals, invest in SS316.
