casting 440C stainless steel hardness 1

The hardness should be about Rc57-59 after tempering, so perhaps a little harder as-cast. You'll have to grind these parts.

Flounder1395,
I've asked this before but you may not have seen it. Is there an ASTM (or similar) casting spec for 440C, or do you cast to the wrought spec? Nobody else seemed to know an answer.

Thanks

Bruv

bruv,

We are not casting to an ASTM spec. The best information I have gotten is from our casting house. The say the hardness should be 48 Rc. We had some parts come in at 67 Rc. The say it could be some separation during the casting process. We are going to anneal the parts before we machine. It seems to be the safest route.

I have experience with sand castings and we manufactured refiner discs for paper pulp refining in this alloy. High hardness values were obtained only after a hardening and tempering treatment. As cast hardnesses were never this high. Perhaps since the investment cast parts are small and slender,faster cooling or heat dissipation caused the high hardness values. Also before grinding these castings it is essential to homogenize these castings or else grinding cracks occur.

We are not aware of a cast equivalent,but process this as 440C with the same chemistry and no mention about mechanical properties.

Flounder, You were getting carbide separation.
This method is used in some knife blades. The carbide separation along with the dendritic structure makes for a "toothy" edge when sharpened.

I did search, and came up with the same awnser you did: anneal first.

For more information on cast stainless steel blades, do a google search for "Boye Dendritic Steel" or "Dendritic Stainless steel"