Ultimate Flange Selection Guide

Ultimate Flange Selection Guide : Confirm Four Working Conditions First to Avoid Wrong Selection

35% of industrial pipeline leakage accidents are caused by mismatched flange working parameters in petrochemical, water treatment and power plant projects. Many engineers pick flange types directly without checking service data, leading to gasket blowout, thermal deformation and corrosion damage. Four core parameters including medium property, working temperature, design pressure and nominal diameter DN must be confirmed before any flange specification confirmation.

Firstly, fluid medium decides raw material grades. Carbon steel A105 flanges fit clean water and compressed air; 316L stainless steel is ideal for seawater and weak acid pipelines; Duplex 2205 or Hastelloy flanges are required for strong corrosive chemicals. RTJ groove facing is mandatory for toxic & flammable fluid to prevent leakage.

Secondly, operating temperature controls material toughness. Carbon steel and 304 SS work at -20℃~200℃; A182 F22 alloy welding neck flanges serve high-temperature steam over 350℃; LF2 low-temperature forged WN flanges are designed for cryogenic LNG service down to -196℃ against brittle fracture.

Thirdly, pressure rating follows ASME B16.5 Class 150/300/600 or EN PN standards. Flange rated pressure should exceed system maximum working pressure with 15% safety margin. Class150 fits low-pressure water supply, while petrochemical high-pressure pipeline requires minimum Class600 specification.

Fourthly, nominal diameter DN defines flange structure: SW socket weld & TH threaded flanges for DN≤50 small bore; WN & SO flanges for DN50-DN600; ASME B16.47 large diameter flanges over DN700.

As a professional China-based forged flange manufacturer, we provide free custom selection solution according to your project parameters.