Dear friends,
Atlast after pushing the sales manager and contacting the design manager directly, I found that the AISI 307 was wrongly indicated in their drawings and that it is a welding wire used for dissimilar welding to be designated as 'AVESTA 307-si'. It is being adapted by these manufacturers for cutting cost on the price of such valves in overall, by a welding overlay on the valve body itself. And having good hardness of 220 BHN and with the usual trim of 13Cr/316/304 the seating/disc hardness difference is taken care of. Incase of maintenance the welding is lapped onsite. No seat rings, threading, seal welding of the rings needed...looks a good idea and it does depend on the type and constructional design aspect of the valve and the fluid system.
The link provide by the Design manager of one of the valve company.
http://www.avestawelding.com/2813.epibrw
Also I found that the AWS designates as 'A 5.2 E 307' of the solid wire type with slight difference in the composition as per AJ Marshall's manganese steel welding info. And another one called 'super 307 / AWS E307-16' from SuperTech, Germany. Looks a lot of variations are available under 307.
The subject valves involved in my case was conventional check valves & NS check valves.
With regards,
Kannan Sundaram.
Dear members,
I would like to know more about AISI 307 which is being used by certain
suppliers as a seating of valves. The suppliers are not able to give the
exact ASTM references, but they say it is ...more or less....equivalent to
X15CrNiMn188(1.4370) of DIN. However I found this DIN material being used
generally to make check valve pins. I am having doubt if it is a
precipitation hardened steel category(which is usually prescribed for
stem/disc/ball/blade/diffuser materials requiring high strength) or a
something related to welding rods.
From my search it looks more of a welding overlay material. However I
could not find any ASTM specification reference of it. Can somebody
specify the same for me to check out the details.
With regards,
Kannan Sundaram.
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