The following variables should be considered when ordering tube for use with our twin ferrule compression fittings.
- Tubing material
- Wall thickness
- Surface finish
Tube Selection For Twin Ferrule Compression Fittings (Ringlok)
Note: For tubes with a wall thickness other than those listed below, information regarding safe working pressures can be obtained from our technical department.
Tables that show the maximum working pressures of seamless tubes for use with Ringlok fittings can be found on our main Ringlok Fittings page. Scroll down to Tube Selection to view these tables.
316 Stainless Steel Tubing Selection
Stainless steel tube should be fully annealed and conform to ASTM A269 or equivalent. A maximum hardness of Hv180 (HRB 80) is preferred. However, if harder tube is used Hv200 (HRB 90) is the maximum allowed by ASTM A269.
The working pressures in the tables are based on tubing rated at 75,000 psi minimum U.T.S an allowable working stress of 20,000 psi as specified in ANSI B31.3 1987, for a temperature range of -29C to +38C.
Maximum Working Pressure For Alloy 400 Tubing
For use with Ringlok fittings.
Tubing should be fully annealed and conform to ASTM B165-1987 or equivalent for seamless nickel-copper alloy UNS 4400 Tubing, with a minimum UTS of 70,000 psi and an allowable working stress of 18,700 psi.
The tube shall have a maximum hardness of Hv 170 (HRB 75.)
Remember to always consult a qualified and experienced engineer if you are unsure on tube selection for our twin ferrule compression fitting range.
We can answer your questions Mon-Fri on 01702 600014