Hardened stainless tubing?

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About a month ago I built some vacuum tubes for a customer that go on a packaging machine for powder mix packets. The customer supplied all the materials was an easy job just drill holes in all ten pieces and weld a nipple onThe supplied tubing was 316 stainless and after about a month of use they are already showing a lot of wear and the customer wants another set made out of harder, more wear resistant material. They asked for 440 ss tubing which I told them I've never heard of tubing in that grade, usually shafts and such are made out of that. So I've been searching for a hardened grade tubing with no luck. The tubing is metric, 12mm ID, 14mm OD. One supplier said i need an A17 or A78 grade??? Wasn't familiar with what they said and may have those numbers wrong but if anyone knows what would be a good fit for this application and where I can contact a supplier I would greatly appreciate any help!Sent from my iPhone using Tapatalk
Reply:They make cold worked tubing that's rral hard, but you can't weld on it, will they allow compression fittings?Experience is something you get right after you need it
Reply:There are the PH stainless steels such as 15-5 or 17-4 that can be hardened.  But does it need to be food grade?
Reply:@ dairywelder - nice work.  Interesting request from your customer.  Believe most of the austenitic stainless steels for dairy/pharmaceuticals that comply with 3A Sanitary Standards (ASTM 270A) are grade 304L and 316L. Here's the  Belgium's Sustainable Stainless approach.  440SS is surgical grade stainless steel.  Magnetic.  Although it can be hardened, the corrosion resistance is subpar in ref to grades 304L/316L.  Haven't had the opportunity to weld any grade 440 tubing, but know that preheat..interpass..and PWHT temps need to be controlled to avoid the formation of brittle martensite. Will check with a metallurgist buddy of mine and see what he says.  BTW, what mixed "powder" is being transported within the tubes you welded?Last edited by ManoKai; 02-21-2016 at 03:33 PM.Reason: layout"Discovery is to see what everybody else has seen, and to think what nobody else has thought" - Albert Szent-Gyorgyi
Reply:It's for a company that makes sports type drinks and these tubes go on a machine that packages the little packs that have powder you mix into a bottle of water. Two sides of the cellophane type wrapper are pulled around both sides of the tube and the powder mix is held inside the tube with a vacuum until the package is sealed and ready to fill. It's the wrapper that is causing the wear on the tubes.Sent from my iPhone using Tapatalk
Reply:Why not make a nylon wear plate for the end where the packing is touching. Cheaper and more practical then replace the metal tubes.
Reply:Hard chrome it.
Reply:440 A,,B and C are knife steels. I don't know why you would  want it in tube or even if it's available. I don't know why you would want to harden it either.
Reply:Just hard chrome the part that's wearing out.  If I had to guess it would be about $400 to the wear end of each tube chromed and ground.  Saves the buying new tubing and saves them a fortune on exotic tubing.
Reply:exactly how is it wearing? what does the part do. I'm doubting that a harder metal is the answer...Welding/Fab Pics: www.UtahWeld.com
Reply:I am going back there on Friday for a tank repair will take pics of wear then... For those of you who have never worked in an industrial/packaging environment just know plastic will cut through steel faster than you would think Sent from my iPhone using Tapatalk
Reply:It won't cut through chrome, though.
Reply:Chrome sounds like a solid idea. Permitting the tube aren't worn too thinIt's simple. get a mud motor. shoot ducks in the face.
Reply:Tell em it's the best solution, your part i$ a wearable tooling item. Too bad you have to make a new $et every month... RyanMiller Multimatic 200 tig/spool gun/wireless remoteMillermatic 350P, Bernard/XR Python gunsMiller Dynasty 350, Coolmate 3.5 & wireless remoteCK WF1 TIG wire feederMiller Spectrum 375 XtremeOptrel e684Miller Digital EliteMiller Weld-Mask
Reply:Originally Posted by xryanTell em it's the best solution, your part i$ a wearable tooling item. Too bad you have to make a new $et every month...