Stainless JIC 37° Flare Fittings

A 37° flare joint seals metal to metal — the fitting's cone is pressed onto the flared face of the tube by the nut alone, with no elastomer to cover a poor fit. In 316 that seat is harder and springs back more, so the flare must be clean and round and the nut pulled up steadily rather than driven home. A scored or oval flare weeps under pressure instead of settling.

Corrosion resistance here lives in the metal, not on it: the molybdenum that separates 316 from 304 holds off chloride pitting, and a cut or scratched surface re-passivates rather than rusting from the mark. Dimensions still follow SAE J514 and ISO 8434-2, so stainless mates steel — but expect several times the price, a lower pressure rating size for size, and slower supply on odd shapes.

Where it's specified

• Offshore deck equipment — salt spray strips plating off a steel nut long before the joint wears out
• Chemical transfer skids — the seat is bare metal, the same alloy chosen to resist the fluid
• Assemblies that are dismantled — a sound flare re-seats repeatedly with no finish to lose
• Washdown areas — parts can be hosed and left wet with no coating to break down

Range and materials. Male and female 37° ends in unions, elbows, run and branch tees, crosses, bulkheads, swivels and plugs, dash -02 through -32, machined from 316/316L with conversions to NPT, SAE ORB, ORFS, BSPP and metric. Nothing is plated; the finish is the material.

Ordering notes. Austenitic threads gall — under load the flanks cold-weld and the nut seizes before the seat is tight. Lubricate the nut thread and the back of the flare with anti-seize, start every joint by hand, and finish with a wrench, never an impact tool. Match dash size to tube OD, and rate the joint from the stainless figure, not the steel one.