Graham Hill ECHA Microbiology
David Armstrong - Lloyds Register EMEA
Steve McCoy Special Metals
(Robin Oakley) opened the meeting.
1.1 High Strength Alloys in the Presence of CP Subsea and the Requirements for Preventing Hydrogen Cracking, Charlie Barraclough, Commtech Associates
1.2 Microbially Influenced Corrosion in both Oil Lubricated and Sea Water Lubricated Stern Tube Systems, Graham Hill, ECHA Microbiology
(Rolls Royce) asked whether anyone had experience with martensitic stainless
steels (particularly 12% Cr) and the influence of hardness/tempering temperature
upon EAC (specifically hydrogen assisted cracking) susceptibility in marine
environments. In addition any
experience of EAC failures of these types of material due to excessive hardness.
Francis (RF Materials) said he had had experience of 17/4PH bolts cracking when
operating at a temperature of 74°C and splashed with seawater. Tests were
carried out on a number of heat treated conditions of the bolts and it was found
that the heat treatment which gave lowest strength (0.2% Proof Strength
725MPa) was the one which was able to survive this environment. It is a
fact that strength has to be sacrificed if resistance to SCC is required.
It was recommended that reference be made to Sedricks book on stainless steel
corrosion (A.J.Sedricks The Corrosion Stainless Steel Steels, J
Wiley 1979) for details of the performance of different stainless steels and the
particular conditions when stress corrosion occurs. If stress corrosion
cracking is known to be a potential problem for a stainless steel in a
particular environment, then fracture mechanics testing would be recommended to
find out the threshold stress which needs to be considered.
2.2 The Chairman announced the recent death of Brian Angel (MoD), who had been a member of the Marine Corrosion Club (as it was then) in the early days. He had been based at Holton Heath, and many of the MCF would have known him, including for his book on corrosion behaviour, materials & marine environments.
4.1 Developments (over 25yrs) and Current Practices in Metal Sprayed Coating for Corrosion Protection, Terry Lester, Metallisation (25th anniversary hot topic)
4.2 Corrosion Control and Materials Selection for Optimized Oil and Gas Asset Life, Janardhan Saithala, GL Noble Denton
The Chairman closed
the meeting at approx. 3:30 pm
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