white cast iron vs. ductile iron

[macmet]

i'm looking at using a cast iron material for a high wear component. The wear is occuring where one component overlaps another and sits on it for support. On top of the this, there is probably 100-200 pounds of wood sitting on top.

I was told to look at ductile iron, but I think that a high chrome white iron might be better. Can anyone give me any sort of cost comparison on the two? I would like to contact our supplier to ask them as well, but I'm not sure yet what grade of white iron I should be looking at, any suggestions? Is the top grade of white iron overkill? Has anyone ever used both of these for the same application, and if you did which worked better?

Operating temperature is probably less than 200 deg. C. We currently use 297 HH which is wearing too quickly, but we use continue to use it now because these same components are also used for high temp applications.

The wear we see now is only where metal rests on either another components or on a wear plate below made of HSS.

 

[Tmoose]

I don't have a decent mental picture of your components.

What does the mating surface look like at this point, having already worn out several of the high wear items?

How big is the wear surface? A few hundred pounds of load applied evenly to several square inches of nearly any dis-similar metals could last years if clean and lubricated.

Generally when stuff wears out I'm usually looking at a way to lubricate the surfaces after they are restored to smooth and flat, or even provide some guidance so there is no sliding. Resisting wear with harder or exotic materials is sometimes the only or best solution in an abrasive environment, but If there's contamination, I'd be thinking how to make some basic seals or a bellows to keep it out. A sheet of the various engineered plastics can serve as lube and abrasion resistant sacrificil bearing all in one.

If I absolutely had to run metal-to-metal I might look at the various hard facing weld alloys. Sounds like you may have some old parts to reclaim.