China Suppliers Factory ASME B16.5 Class 150 Carbon Steel Lap Joint Flange (LJF) for Pipe Connection
Material Grade
Carbon Steel
ASTM A105 / A105N
ASTM A350 LF2 / LF3
ASTM A694 F42 / 46 / 56 / 60 / 65
ASTM A350 LF2 / LF3
ASTM A694 F42 / 46 / 56 / 60 / 65
Stainless Steel
ASTM A182 F304 / 304L / 304H, 316 / 316L, 310S, 317, 347, 904L
ASTM A182 F51, F53, F44
ASTM A182 F51, F53, F44
Alloy Steel
ASTM A182 F11 / 12 / 5 / 9 / 91 / 92
Sealing Face
RF | FF | FTJ
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Frequently Asked Questions
Q
What is the difference between ASTM A105 and ASTM A105N?
A
ASTM A105 is a standard specification for carbon steel forgings used in piping components, while ASTM A105N indicates that the material has undergone a normalizing heat treatment process, which improves its mechanical properties and toughness for higher-pressure applications.
Q
When should I choose Stainless Steel (e.g., 316L) over Carbon Steel (e.g., A105)?
A
Stainless steel grades such as 316L are preferred in corrosive environments, high-purity applications, or where resistance to oxidation and chemicals is required. Carbon steel like A105 is more suitable for general-purpose, non-corrosive piping systems where cost efficiency is a priority.
Q
What are Duplex and Super Duplex stainless steel grades (F51, F53, F44)?
A
F51 (Duplex 2205), F53 (Super Duplex 2507), and F44 (6Mo) are high-performance stainless steel grades offering excellent resistance to pitting, crevice corrosion, and stress corrosion cracking. They are widely used in offshore, marine, and chemical processing industries.
Q
What applications are Alloy Steel grades (F11, F12, F91, F92) typically used for?
A
Alloy steel grades such as ASTM A182 F11, F12, F91, and F92 are designed for high-temperature and high-pressure service. They are commonly used in power generation, boiler systems, and petrochemical plants where elevated temperature strength and creep resistance are critical.
Q
What is the difference between RF, FF, and FTJ sealing faces?
A
RF (Raised Face) is the most common sealing face, concentrating bolt load on a smaller gasket area for a better seal. FF (Flat Face) is used when connecting to cast iron or non-metallic flanges to prevent flange bending. FTJ (Full-Face Tongue and Groove Joint) provides a more precise and secure seal, ideal for high-pressure or critical applications.
Q
How do I select the right material grade for my piping project?
A
Material selection depends on several key factors: operating temperature and pressure, the type of media being transported (corrosive, high-purity, etc.), environmental conditions, and applicable industry standards or codes (such as ASME, ASTM, or API). Consulting with a qualified engineer or our technical team is recommended to ensure the optimal grade is selected for your specific application.









