No, Carbon and Stainless-Steel Flanges are not the same. Stainless Steel flanges have high alloy content added for the prevention of rust. Carbon Steel flanges don’t have steels with added alloying elements for rust prevention.
Stainless Steel flanges are much more expensive than Carbon flanges. Both kinds of flanges are used for different purposes and cannot be compared. Carbon Steel flange is stronger than stainless steel flange and more prone to rusting.
Some of the carbon steels are hot rolled, cold rolled, angle grooves, silicon wires, etc., whereas some of the stainless steels are 200 series, 300 series, 400 series, etc.
The most common grades of Carbon Steel Flanges available are ASTM A3015, ASTM A182, ASTM A105, ASTM A694. In Carbon Steel flanges, the carbon content is up to 2.1% in weight.
Carbon Steel A105 has forged carbon steel flange components; therefore, they are used in fittings, valves, pressure systems, etc., at baseline and high-temperature service conditions. Similarly, A694 is the most brutal carbon steel flange.
It is rigid to the high-pressure fluid transmission of oil and gas piping. Because of this forged fitting manufacturers have to design stronger steel to hold out against both cryogenic and high temperatures.
On the other hand, there are also different grades to stainless steel flanges depending upon the material composition and mechanical properties.
The ASTM A182 Weld Neck flange is made up of super ferritic material that has good corrosion-resistant properties and is composed of low carbon. Its applications are utility scrubber assemblies, acid production, fertilizer production, etc. These are also ideal for low-pressure applications.
These are also ideal for piping systems or vessels for which regular inspection is required.
We cannot even connect a carbon steel flange to a stainless-steel flange because these are two different metals with different corrosion potentials. So, they should be kept electrically isolated to protect the piping from electrolytic corrosion.
Some of the Carbon Steel Forged Fittings Manufacturers Are:
- Western Steel Agency
- Viha Steel & Alloys
- Metalica Forging Inc.
- Dinesh Industries, etc
Some of the Stainless Steel Flanges Manufacturers Are:
- Shanghai Metal Corporation (SMC)
- Kalikund Steel and Engineering Co.
- Skyland Metal and Alloy Inc.
Which is Better?
Carbon Steel flanges have comparatively higher carbon content than stainless steel flanges due to which Carbon Steel flanges have a lower melting point. The high carbon content also makes them more malleable. Moreover, carbon steel flanges have better durability and heat distribution properties than stainless steel flanges.
However, Carbon Steel Flanges also have Certain Limitations.
- These could not be used in services over 425 degrees Celsius.
- Because of their strength, carbon steel flanges are challenging to work with.
Characteristics of Good Flanges:
- Simple and efficient in operation
- High-Pressure Ratings
- Capacity to withstand extreme temperature and resist corrosion.
- Quality should be at par with the actual standards.
- Favorable to Rust, Chemicals, and other environmental factors.
Read more: Purpose of Forged Stainless Steel Flanges