Anyone have experience investment casting cobalt alloys? Thin sections

Discussion in 'Investment casting Ceramic shell method' started by Lou, Nov 20, 2021.

  1. Lou

    Lou Copper

    Somehow I ended up with a bunch of stellite 6K which is a cobalt alloy with the following properties:

    It's common to use these alloys in hard facing applications, but 6K is hard enough and tough enough to be used to make a nice knife as is seen here:

    it's used a lot for making slitters for cardboard or abrasive fibers as it's basically a suspension of hard carbides in a cobalt binder.

    I've melted it in my induction melter in a silica crucible on occasion and it was extremely "watery" and fluid with not much in the way of surface tension when compared to say, copper or brass, let alone aluminum.

    From what I understand, investment casting this means the aggregate in the shell is zircon. I don't have zirconium silicate but I do have a lot of zirconium dioxide from +16 down to 300-.

    Does anyone have any parameters for thin 1/8" thick castings and suggestions for treeing up multiple knife blanks? As it's annoying to grind and somewhat expensive, I'd like to do near net shape. I will be induction melting it, probably about 5-10 lbs at a pop. Flux recommendations would be awesome too.

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