Alloy Composition: "Combustalloy"

[SMF1964]

Does anyone have any material specs (chemical composition) for the Alstom alloy "Combustalloy"? I've got an approximate from a portable alloy analyzer (17Cr-4Mo-3Mn) but I'm looking for better detail, like carbon content, etc. As you can probably surmise, Alstom is not really forthcoming with their specs.

 

[metengr]

SMF1964;
Please provide more specifics. Since it is Combustalloy, is this material located in a boiler? What is the part?

 

[SMF1964]

It is a hardfacing type alloy that is applied via welding to the surface of our coal mill rolls.

 

[metengr]

We have AP re-build our mill rolls and hardface them for wear resistance. I believe the hardfacing is applied by an outside vendor (Southern Tempering), sub-contracted by AP, who uses the SAW process. Give me some time and I can try to track down the hardfacing filler metal composition. I am going on memory here, but I believe the carbon was high to achieve the 55-60 HRc hardness. I know the hardfacing is loaded with surface cracks because it is so brittle. However, it seems to perform acceptably in service for our mill .

 

[SMF1964]

It seemed to perform acceptably in service, until a 2 foot x 5 inch swath peeled off and got the rest of the mill all gebooggered up. It looks rather cool, since it fractured all along the columnar grains of the weld. Any information you can provide, I would appreciate. Thanks.

 

[SMF1964]

5% carbon (that's 5%, not 0.5 or 0.05). No wonder it cracks when you weld it.

 

[EdStainless]

These alloys are supposed to crack when you overlay them. That is their stress relief mechanism. Often they are applied in multiple layers.
The two suppliers that I know of are Stoody and Deloro. Both of them make iron based Cr carbide hardfacing alloys.
After all, you need enough carbon to convert the Cr into carbides. Some of these alloys are 10-12% C.

= = = = = = = = = = = = = = = = = = = =
Corrosion never sleeps, but it can be managed.

http://www.trenttube.com/Trent/tech_form.htm