SS316 pump for handling Hydrogen Flouride wearing out

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Dear FriendsHave attached photos of the application areas.We have a SS 316 pump which is handling Hydrogen flouride, high corrosive it wears out very frequently, what welding solution would you suggest.?Also we have a ss 316 rotary vaccum dryer which scrubs pottasium flouride powder , these blades wear out due to abrasion . what remedial solution would you suggest here.Look forward for a long term solution.RegardsSanjay Attached Images
Reply:contact your pump manufacturer and see if they can produce the pump internals out of Hastalloy or Monel.  These alloys MAY give you some added durability, albeit at much greater cost.Another option might be finding out if you can have the pump internals coated in Teflon.  Teflone(PTFE) has excellent resistance to HF.  However, the operating temperture of the pump and internal clearances may not allow for retrofitting the pump internals; if it's possible at all.Your pump supplier or manufacturer is the best resource for solutions to this problem.  HF service is going to be a very difficult application for any pump.Your KF vacuum dryer is also a difficult application.  KF in combination with water or water vapor can form a caustic solution that may be aggravate any abrasive damage occurring.  I can't offer a specific solution because errosive corrosion, stress corrosion cracking, or simple abrasive wear might all be occurring.  My advice is to take a failed part to a metallurgical lab and have them evaluate the root cause of the failure.  Again an organic coating may help mitigate any chemical attack of the parts prolong their life.  Or a surface hardening may help.  It could also speed failure if the parts are being chemically attacked in addition to suffering from abrasive wear.  You need a clear understanding of what's happening into the parts in the dryer in order to come up with a solid fix.  Just guessing is likely to cost you even more time and money.  Good luckBenson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector
Reply:Thanks  A_DAB_will_do  Really appreciate it.Can you eleborate more on teflon coatings , what type of teflon , can a very thin layer be deopisted. etc..regardsSanjay
Reply:Read these two documents:http://www.nickelinstitute.org/Techn...dFlourine.aspxhttp://www.nickelinstitute.org/Techn...ne_10074_.aspx"USMCPOP" First-born son: KIA  Iraq 1/26/05Syncrowave 250 w/ Coolmate 3Dialarc 250, Idealarc 250SP-175 +Firepower TIG 160S (gave the TA 161 STL to the son)Lincwelder AC180C (1952)Victor & Smith O/A torchesMiller spot welder
Reply:Those are good references Oldendum.  Thanks for sharing.  I've not seen those papers before. Originally Posted by OldendumRead these two documents:http://www.nickelinstitute.org/Techn...dFlourine.aspxhttp://www.nickelinstitute.org/Techn...ne_10074_.aspx