Cold-Stretching MDMT
Cold-Stretching MDMT
(OP)
Hey Everyone:
I know that the 2013 Code recently adopted Cold-Stretching for ASS vessels, but I wanted to confirm the Code allowable limit to the MDMT. I thought the Code says -320 deg. F is the lowest it can be used at, but I was hoping someone could determine where that comes from? Do any of the European Codes allow using Cold-Stretched vessels to store liquid hydrogen?
I know that the 2013 Code recently adopted Cold-Stretching for ASS vessels, but I wanted to confirm the Code allowable limit to the MDMT. I thought the Code says -320 deg. F is the lowest it can be used at, but I was hoping someone could determine where that comes from? Do any of the European Codes allow using Cold-Stretched vessels to store liquid hydrogen?





RE: Cold-Stretching MDMT
It is known that austenitic stainless steel work hardens and thereby increases the yield strength when deformed plastically at room temperature. The increased yield strength results in higher allowable design stress for the rules where design stresses are controlled by design margins to yield strength only (i.e. no design margin applied to ultimate tensile strength). This concept has been used successfully for many years in the Swedish Pressure Vessel Code and has been recognized for several years in some of the European countries such as in Germany. In the recently developed European standard prEN 13458, similar rules have been incorporated. Additionally, in the new ISO cryogenic vessel standard being developed under ISO TC / 58/ 220 Committee, the same rules are being incorporated. These rules are similar to Swedish, ADM ,prEN 13458 and AS1210 Codes.
RE: Cold-Stretching MDMT
I have been trying to get my hands on the ISO or the European Code to try and dig into this folder. I believe the ASME Code limits you to -320 F, but I am hoping to go colder and maybe even design using Cold Stretching a Liquid Hydrogen vessel at low pressures. Problem I have is the Code only examines the vessel using normal Code design equations and then provides you with the stretch pressure and strain rate info to follow, along with the process. Has anyone seen any good papers on using cold stretched 304L for liquid hydrogen temps? Or fracture toughness studies on cold stretched ASS?
RE: Cold-Stretching MDMT
http://www.absa.ca/IBIndex/ib13-008.pdf
file:///C:/Users/owner/Downloads/ASME_BPVC_Update_Website_Flyer.pdf
RE: Cold-Stretching MDMT
MANDATORY APPENDIX 44
COLD STRETCHING OF AUSTENITIC STAINLESS STEEL PRESSURE
VESSELS
44-2 GENERAL REQUIREMENTS
(a) The use of this Mandatory Appendix is contingent
upon approval from the user or the user’s designated
agent.
(b) Vessel wall thickness shall not exceed 1.2 in.
(30 mm).
(c) Minimum design metal temperature (MDMT) shall
not be colder than −320°F (−196°C).
RE: Cold-Stretching MDMT
RE: Cold-Stretching MDMT
RE: Cold-Stretching MDMT
When you cold work you will get some martensite formation. This material is brittle, has a DBTT, and may be sensitive to hydrogen embrittlement.
I have seen cold formed vessels made from 219 used for LH service. But I have only ever seen small ones.
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P.E. Metallurgy, Plymouth Tube