Understanding JIC 37° Flare Fittings in Industrial Hydraulics

JIC 37° flare fittings remain the industry standard for high-pressure hydraulic systems. This guide covers material selection, torque specifications, and installation best practices.

Why 37° Flare?

The 37° flare angle provides optimal metal-to-metal sealing under vibration and thermal cycling. Unlike compression fittings, JIC connections rely on precise cone-to-cone contact between the fitting nose and the flared tube end.

Material Selection

Carbon steel JIC fittings are suitable for most industrial applications. For corrosive environments — marine, chemical processing, or food-grade washdown — specify stainless steel 316 with passivated finish.

Installation Best Practices

• Use a calibrated torque wrench; over-torquing can crack the flare
• Inspect flare quality before assembly — cracks or uneven flares cause leaks
• Apply compatible thread sealant only on NPT threads, never on the flare face
• Allow for thermal expansion in long hose runs

Common Failure Modes

Leaks typically result from damaged flares, incorrect torque, or mixing incompatible thread standards. Always verify thread pitch and flare angle before installation.