Page 20 of Stainless Steel Tube Fittings by Lokring

® technol og y c or p or a t i on note this document supersedes previous versions of fs40-t and fs-300 qualified matching tube shall be types 316/316l or 304/304l and conform to seamless or electric resistance welded erw construction of astm a269 and/or a213 discontinuities at the longitudinal weld seam of erw tube can provide a leak path if not removed poor welding can result in a visible depression or suck-back poor weld bead removal can result in a raised portion or a flat spot at the weld only install lokring fittings on erw tube in which the weld bead has been drawn or sanded smooth and is not visible to the naked eye tubing systems containing the tubing components listed may establish design pressures up to and including the ambient maximum design pressure given for temperatures from ­325 to 100 deg f for asme b31.3 except where noted based on the use of seamless tube with allowable stresses of 20,000 psi ambient temperature system design pressure ratings must be de-rated when using erw welded and/or l grade tubing with lower allowable stress in fatigue testing assemblies consisting of a lokring coupling and two equal length tube tangents on either side of the coupling were fabricated using standard lokring installation procedures a uniform bending moment was applied to the assembly inducing a bending stress in the assembly equal to or greater than the tube minimum yield strength 38,000 psi one complete bending cycle consists of bending the assembly to one side of the neutral axis to the specified value and then back again through the neutral axis to the specified value on the opposite side and then back to the neutral axis all assemblies exceeded 30,000 complete bending cycles without leakage and many greatly exceeded this value consult factory for other details this communication and any information drawn from it are the confidential property of lokring technology corporation and are provided to you for a specific purpose the information may not be copied exhibited or provided in any form to others without the written consent of lokring technology corporation www.lokring.com copyright 2004 lokring technology corporation all rights reserved tube fitting pressure table and application guide 4.06 fs40-t 07-19-04

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