Machining of mp35 superalloy
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  1. #1
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    Default Machining of mp35 superalloy

    Hi all,

    At our machine shop, we mostly machine 316 stainless, 304 stainless, inconel 625, and titanium 6al4v. We just got a job to make parts (lathe job) out of mp35. I was looking up this material and its composition is mostly cobalt with a lot of nickel, molybdenum, and chromium. How tough is this stuff to turn? How similar is it to inconel 625? I'm pretty sure the RockwellC is over 50, so it is a lot harder than inconel, which is relatively soft. Any thoughts on this material?

    Thanks

    Chris

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    Never heard of MP35, but I used to cut a lot of cobalt heavy superalloys in a previous life, like Haynes 188 and 282. They can make Inco look like easy by comparison, especially in the raw forged condition. All the same techniques and tooling apply, you'll just get worse tool life because it's a lot more abrasive. I would start at the lower end of the SFM range and have plenty of inserts at the ready.

    If you're not already using ceramics to rough I would recommend them as well, always had good luck with NTK for ceramic button turning inserts. Sandvik's S05F carbide grade was also a winner for finishing.

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    Yeah I'm getting wildly different speeds and feeds from various sources (books, internet, etc).

    Has nobody machined this material? MP35 specification AMS 5845

    It is 35% cobalt, 35% nickel, with the rest being chromium and molybdenum. No iron

    Thanks,

    Chris

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    CNC hacker,

    The inconel 625 we run is usually 12-13 inch diameter on the lathe. It is a raw forging and it is tough as nails. What's funny about ceramics is that we decided to try greenleaf wnmg no 2 radius ceramic inserts awhile back (forget the grade but it was recommended by greenleaf for inco 625) and the inco 625 tore those inserts up. We ran it with coolant (greenleaf told us to run coolant with lathe but dry in mill). The carbide actually held up better and lasted longer. We ended up returning all the inserts to greenleaf.

    We did run all the speeds and feeds and depth of cut recommended by greenleaf. The insert was wiped out after 1 cut. When their recommendations didn't work, we played around with speeds, feeds, doc and couldn't find anything that worked.

    Those inserts were over $30.00 per piece.

    I'd be willing to try ceramics again but if I'm paying that much for inserts, they better work with the mfg's speeds and feeds recommendation.

    If somebody with more experience running ceramics can provide insight to possibly what I was doing wrong, please feel free to chime in.

    Thanks,

    Chris

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    Quote Originally Posted by cgrim3 View Post
    CNC hacker,

    The inconel 625 we run is usually 12-13 inch diameter on the lathe. It is a raw forging and it is tough as nails. What's funny about ceramics is that we decided to try greenleaf wnmg no 2 radius ceramic inserts awhile back (forget the grade but it was recommended by greenleaf for inco 625) and the inco 625 tore those inserts up. We ran it with coolant (greenleaf told us to run coolant with lathe but dry in mill). The carbide actually held up better and lasted longer. We ended up returning all the inserts to greenleaf.

    We did run all the speeds and feeds and depth of cut recommended by greenleaf. The insert was wiped out after 1 cut. When their recommendations didn't work, we played around with speeds, feeds, doc and couldn't find anything that worked.

    Those inserts were over $30.00 per piece.

    I'd be willing to try ceramics again but if I'm paying that much for inserts, they better work with the mfg's speeds and feeds recommendation.

    If somebody with more experience running ceramics can provide insight to possibly what I was doing wrong, please feel free to chime in.

    Thanks,

    Chris
    The #1 problem with ceramics is that it hits a sharp entry edge. you must chamfer all edges, all fillets must be interpulated.
    the cnmg wnmg and most other shapes inserts are for supper light cuts again the edge and fillet stuff mentioned above is a must.
    round inserts are the best and last the longest.

    we used them all the time in late 80's and early 90's on all the super alloys 625 inco was one of the easy ones, 718 was butter compared to that haynes and mars were a tad tougher than both.
    we did parts to around 36" dia with ceramics down to 1" both on CNCS lathes and hand lathes.
    we picked out corners with carbide as well as finished with carbide.

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    Hi Delw,

    Do you use coolant when turning with ceramics? Also, what kind of doc were you taking and do you remember your speeds and feeds? One thing that also makes the inconel 625 we work with so tough is that it is a raw forging. I really would like to get the ceramics to work though. We are a father/son business, and my dad always said that the round button inserts always chattered way more than the other inserts because of the larger radius. Did you have that problem?

    We almost always use carbide wnmg no 2 radius and cnmg no 2 radius for roughing.

    Thanks,

    Chris

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    Quote Originally Posted by cgrim3 View Post
    Hi Delw,

    Do you use coolant when turning with ceramics? Also, what kind of doc were you taking and do you remember your speeds and feeds? One thing that also makes the inconel 625 we work with so tough is that it is a raw forging. I really would like to get the ceramics to work though. We are a father/son business, and my dad always said that the round button inserts always chattered way more than the other inserts because of the larger radius. Did you have that problem?

    We almost always use carbide wnmg no 2 radius and cnmg no 2 radius for roughing.

    Thanks,

    Chris
    Chris if you have a stout lathe heavier the better you shouldnt have any issues. the smallest machine I used them on was a 1990 hitachi seiki 20sII 8 inch chuck.
    That machine was pushing it it had liner ways and a no gearbox motor . Rarely got chatter but stalled it quite a few times, just work around it.
    box ways is the best. our other machines were big H.E.S. and a few big manual machines.
    surface feed what we ran was around 800-1100. cuts anywhere from .035 -.150 feed rates were .008- .015 sometimes higher
    we primary used 1/2" rounds flat greenleafs the whisker ones, I liked the old black Mitsubishi inserts I cant remember the number on those.
    we also reground our 1/2 rounds on the surface grinders and used carbide shims and we didnt put a land on the regrinds they worked just as well.
    always used flood coolant with 1/2" lines on the tool. we tried them with out coolant but found we could get more tool life with coolant on the regrinds.
    again the key is your entry the part must not have a sharp entry edge, we used SNMG inserts to put angles on all out entry areas. also as all of our parts had holes in them we drilled them 1st so not to have the insert goto center line and break.
    all our parts were garret aviation aka allied signal rotors, housings, seals etc etc.
    for smaller fetures we used the 1/4 " round inserts with the v groove for location. those sucked for regrind and useage as you only were able to rotate once. it was more cost effective to use carbide on those features most of the time.
    if I recall we went through about 50-75 ceramic inserts a week running 2 10 hour shifts on 4 machines. if you dont run your ceramic till it breaks you can get 8-10 edges on the top of the insert and the same on the bottom when you flip it. that obviously depends on your depth of cut. your chips will tell you when its time to rotate them. we had a few guys that were lazy on the 30 min-1.5 hour rough cycle and would not watch the machine breaking the inserts with out rotating it.
    if I recall we would get about 15 mins before we had to rotate the insert running .050-.075 doc. everything that had a contour we roughed in contour form they would keep the inserts from breaking as well.
    if we were just facing or cutting a od we always rad on the end of each pass so not to ruin the inserts. sometimes it was a toss up on those just to use a 5 or 6 series(big ones) snmg at a 45 degree angle to take off stock you could get about .150 .200 DOC. yeah it was slow but we didnt break inserts on break outs.
    if I recall carboly 883 885(cant remember exact grade)? grade was best for our high nickle/cobalt alloys at that times. if we didnt have those it was h13a nothing beat them as we tried all the grades avail. back then and most werent cost justifiable.
    hope that helps as I dont know what they have out now for inserts.

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    My dad had a saying, that if a material has a name, leave it for the next guy.
    Also, if it's real pretty looking in the stock rack, leave it. It's a little like mother nature, the prettiest animals are usually the most lethal.

    OK, humor is over.

    Have you tried Kennametal? They have some inserts that work well on the nasty stuff. Kyon 4000 I think.

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    No I haven't tried kennametal ceramics. I know it sounds silly, but we've been avoiding kennametal ever since they became the biggest sponsor of titan gilroy. I tried the greenleafs because I read online that people had good success with them. For carbide and all other inserts, we use iscar. We find other brands (sandvik) to be more expensive without an increase in performance compared to iscar.

    Delw we are a 2 man shop and my dad likes to be gentle with the machines (usually .003-.008 feedrates) so the machines and tooling last longer and so the machines don't wear out. We would generally avoid doing anything that would stall the spindle and put significant wear and tear on the machine.

    I'd be willing to try ceramics again, but we just had a bad experience with them in that they didn't do what the manufacture said they would do.

    We called iscar for machining the mp35 and they recommended wnmg's with no 2 radius IC806 grade carbide.


    Chris

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    Quote Originally Posted by cgrim3 View Post
    No I haven't tried kennametal ceramics. I know it sounds silly, but we've been avoiding kennametal ever since they became the biggest sponsor of titan gilroy. I tried the greenleafs because I read online that people had good success with them. For carbide and all other inserts, we use iscar. We find other brands (sandvik) to be more expensive without an increase in performance compared to iscar.

    Delw we are a 2 man shop and my dad likes to be gentle with the machines (usually .003-.008 feedrates) so the machines and tooling last longer and so the machines don't wear out. We would generally avoid doing anything that would stall the spindle and put significant wear and tear on the machine.

    I'd be willing to try ceramics again, but we just had a bad experience with them in that they didn't do what the manufacture said they would do.

    We called iscar for machining the mp35 and they recommended wnmg's with no 2 radius IC806 grade carbide.


    Chris
    cant baby nickle and cobalt alloys other wise you just blow inserts. Dont know what kinda machine you have but if it has a 10-12" chuck and not a HASS you should be fine.

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    We don't baby it but we don't kill it either. We find a happy medium. Generally .075" doc, 75-80 sfm, .005 feedrate for inconel 625 forging with wnmg no 2 radius.

    We have stalled the spindle once before in the past when trepanning the stuff.

    Like I said, you don't want to baby it, but you also don't want to kill it.

    Our puma 200 is a 1998. When people come in the shop, they always complement on how good it looks and how good of shape it is in. It still holds +- .0001 to this day. If you take care of your machine, it will take care of you.

    It has an 8" autoblok hydraulic chuck. Really want a 10" but we got the 8"

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    Quote Originally Posted by cgrim3 View Post
    We don't baby it but we don't kill it either. We find a happy medium. Generally .075" doc, 75-80 sfm, .005 feedrate for inconel 625 forging with wnmg no 2 radius.

    We have stalled the spindle once before in the past when trepanning the stuff.

    Like I said, you don't want to baby it, but you also don't want to kill it.

    Our puma 200 is a 1998. When people come in the shop, they always complement on how good it looks and how good of shape it is in. It still holds +- .0001 to this day. If you take care of your machine, it will take care of you.

    It has an 8" autoblok hydraulic chuck. Really want a 10" but we got the 8"
    if your doing alot of roughing (stk removal)on face and O.d. you should really look at SNMGS and a holder that holds them sideways so there 45º or even a cnmg holder that holds them sideways. you can really hog lots of stock off and your spindle load will drop 30-50%. not to mention you can use your used inserts on the CNMG. your machine wont handle the 5 and 6 series inserts so 432's will be fine.
    That puma is Box ways correct? or did they goto liner guides? Box ways are best.
    Also you may be getting chatter if your only holding on normal width jaws. make/buy some wider ones. if your using hard jaws that you dont cut. toss them in the garbage there useless on a cnc holding bigger dia. unless its barfeeding soft metals or alum.

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    Quote Originally Posted by Delw View Post
    That puma is Box ways correct? or did they goto liner guides? Box ways are best.
    Puma series are all box way machines. Lynx series are linear (roller) guide machines.

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    Yeah our machine has box ways. The highest we've gotten on load meter is about 50 - 60% with wnmgs taking about .1 doc on inconel 625 forging.

    I'll make note of those SNMGs. They sound pretty good. I'll have to get a holder for it.

    What brand inserts you guys use? 95% of what we use is iscar but we do have sandvik, seco, kennametal, and pramet lying around.

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    We turn mp35n with super alloy grade inserts. Smallest radius we can get away with. 45 sfm, .050 doc, .006 ipr. It's painfully slow, but it's the only way we can get enough tool life to get through a single part.

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    We are machining the mp 35 today and it is easier than the inconel 625 forging we machine. Using .03 doc, 78 sfm, .005 feedrate. I got the feeds and speeds from a book I purchased. I think its called machining of stainless steel and super alloys.


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