ASTM A182 F1 Alloy Steel Slip On Flange 150LB-2500LB B16.5

ASTM A182 F1 flange is a commonly used chromium molybdenum alloy steel forging under the ASTM A182 standard. This standard provides strict specifications for the material, manufacturing process (forging), chemical composition, mechanical properties, heat treatment, testing (tensile, hardness, impact, etc.), dimensional tolerances, and marking information of flanges.

• Chromium molybdenum low-alloy steel: The addition of chromium and molybdenum elements significantly improves strength, resistance to slow plastic deformation, oxidation resistance, and resistance to slight corrosion such as steam oxidation at high temperatures.
• Good high-temperature strength: Maintains higher strength at temperatures above 300°C compared to carbon steel, making it suitable for demanding high-temperature conditions.
• Weldability: Requires preheating and post weld heat treatment (150-350°C). Stress relief annealing (620-675°C) reduces hardness and residual stress in the welding heat affected zone.
• Machinability: Hardness control after heat treatment provides relatively good machinability.

A slip-on flange is connected to the pipe or fittings by two fillet welds, one inside and one outside the cavity of the flange. These flanges are also called "Hubbed Flanges" and are recognized by their slim, compact shape.

Flanged joints made with slip-on flanges are generally less durable than welding neck flange connections in similar service conditions due to:

• Welding neck flanges feature a tapered hub that distributes mechanical stress more evenly between pipe and flange
• Welding neck joints have only one welding area compared to two in socket weld flanges

Welding neck flanges can connect to both pipes and fittings, while socket weld flanges are suitable for pipes only.