THE BASICS OF STEEL FLANGES
Stainless steel flanges provide an easy access for cleaning, inspection or modification. They usually come in round shapes but they can also come in square and rectangular forms. The flanges are joined to each other by bolting and joined to the piping system by welding or threading and are designed to the specific pressure ratings; 150lb, 300lb, 400lb, 600lb, 900lb, 1500lb and 2500lb.
A flange can be a plate for covering or closing the end of a pipe. This is called a blind flange. Thus, flanges are considered to be internal components which are used to support mechanical parts.
Each flange material is to be considered for its application prior to ordering, this is due to the structural integrity of the application that the flange will be used on.
Currently, the most common materials for flanges are:
• ASTM A105/A266 Gr.2 (high temperature carbon steel flanges)
• ASTM A350 LF1 to LF3 (low temperature carbon steel flanges)
• ASTM A694 Gr. F42/F52/F56/F60/F65 (high yield carbon steel flanges to match API 5L linepipes)
• ASTM A182 Gr. F1/F2/F5/F9/F11 Cl.2/F12 Cl.2/F22 Cl.3/F91 (alloy steel flanges)
Stainless / Duplex Steel
• ASTM A182 F304/304L, 316/316L, 321, 347, 348 (stainless steel flanges), 904/904L
• ASTM A182 F51 (duplex flanges)/F53-F55 (superduplex flanges)
Nickel Alloys / Superalloys
• ASTM B166 UNS NO6600 (Inconel 600)
• ASTM B564 UNS N06625 (Inconel 625)
• ASTM B425 UNS-NO8800 (Incoloy 800)
• ASTM B564 UNS N08825 (Incoloy 825)
• ASTM B160 UNS N0200 (Nickel 200)
• ASTM B564 UNS N04400 (Monel 400)
• ASTM B564 UNS N10276 (Hastelloy C-276)
• ASTM B381 Gr.2 (Titanium)
In industry, flanges, including stainless steel flate flanges, stainless steel slip on flanges, and stainless steel weld neck flanges, form a vital connecting link for piping, valves and other equipment. They provide an easy point of access for cleaning, inspection, modification, and for necessary repairs. A flanged joint provides a strong seal in a closed system, and is made by bolting together a gasket flanked by two flanges.
In heavy industry, these flanges need to be especially resilient or they can prove to be the weak point in a system. It is important therefore, to ensure that the flanges you are choosing are up to the task.
Why are stainless steel flanges preferred for industrial use?
In all metal applications, corrosion is a constant consideration. Rust, chemicals and other environmental factors all take their toll on metals. Therefore, the choice of flange would need to be resistant to these factors. Stainless steel outperforms other metal flanges – including carbon steel – due to its high resistance to corrosion.