Martensitic Stainless Steel 1

[alrose]

I am trying to source martensitic stainless steel plate or forged blocks for machining/fabricating hydro-turbine runners.

I am interested in 13-4 Cr/Ni up to 150 mm thick blocks. We need about 1000 kg in this form. This grade is used for pelton runners/buckets.

Also keen to source 17-4 or 16-5 Cr/Ni grade in plate about 1" thick. Similar quantities for fabrication of francis runners.

The 17-4 or 16-5 are easier for fabrication than 13-4 as they need less preheat during welding. Does anyone know the reason for this?

Thanks

 

[EdStainless]

This is a big question and it involves a lot of stainless metallurgy. Maybe you need to approach this one part at a time. What are your greatest concerns? What are the limiting factors?

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[arunmrao]

I was waiting for some of the knowledgeable members to appear and advise. I have made cast parts in CA6NM for the above applications . But whenever a need arose for thick blocks, I was asked to cast these in the same alloy.

Are ready blocks of 150mm not easily available. Rounds I have seen being commonly used for valve stems.

 

[alrose]

I guess my main question is does anone stock thick plate or forged blocks of 13/4 or 17/4 martensitic stainless? This may be prefuable to casing 13/4 to CA6NM from a point of view of reducing the chance of defects.

So far I have only been able find companies that will do a production run for us and the minimum quantities are quite large.

For interest, I have found an article "Weldability of high tensile martensitic cast steel with 13% Cr and 4% Ni" by W.Gysel that appears to answer why 13/4 is so weldable. Primarily it is by limiting the hardness of the heat effected zone, copensating for the amount of delta ferrite and preventing temper brittle ness. I dont understand all this yet though!

 

[CoryPad]

Ryerson and Jorgensen are two of many distributors that carry 17-4:

http://www.ryerson.com/products-services/stainless.asp

http://www.emjmetals.com/

Regards,

Cory

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[EdStainless]

17-4 and 17-7 are both available in heavy plate. It is easier to weld 17-7, but heat treatment is a bit more work.

= = = = = = = = = = = = = = = = = = = =
Rust never sleeps
Neither should your protection

http://www.trent-tube.com/contact/Tech_Assist.cfm

 

[DALESUTCLIFFE]

try contacting the Swedes who do a lot of heat treated s/steel. Gunnarson's and SSW

 

[gtaw]

Did you work for Obermeyer in the 80's?

I welded on some of the early turbines for H.O.



Best regards - Al