Hi Ajay Any hardfacing deposit with hardness more than @ 52 HRC is bound to show cracks. They are called as Stress relief cracks and are mandatory after hardfacing. You cannot avoid them. As you are depositing Tungsten carbide the hardness will be definately more than 63 HRC. You have not mentioned the thickness of hardfacing deposit you are welding. As per my past experience Tungsten carbide can be deposited only upto max. 1 layer @3mm. Else the deposit becomes too brittle and chunks out. You have not mentioned your final hardness requirement. As per that you can give a barrier layer of E309L. If your application needs a crack free deposit then you have to go for Thermal Arc Spray or PTA process. Regards Prem S Nautiyal Mobile +91 9004063879 / 9769316004
--- On Mon, 11/14/11, pgoswami <pgoswami@quickclic.net> wrote:
From: pgoswami <pgoswami@quickclic.net>
Subject: [MW:12966] RE: 12956] Cracking problem during Hardfacing (FCAW)
To: materials-welding@googlegroups.com
Date: Monday, November 14, 2011, 8:47 AM
Hi Ajay, Deposition of tungsten carbide is very hard with little or no ductility. It's advisable to know what's is the matrix (microstructure) and preferably the chemical composition of the deposit. If a hard alloy in the form of hard facing is deposited by arc welding process then it may crack on shrinkage ,if the there's not enough ductility to accommodate the shrinkage stress/es. If the deposit required is more than one layer ,use of a barrier layer of austenitic alloy ( E=ER-309 or Inconel 82(ER-NiCr-3) or Inconel 182 (E-NiCrFe-3) could be useful. You may check with the consumable manufacturer with the problem and see what's their response. More feedback of your end on this subject would be appreciated. The following AWS article provides good information on effects of various alloying elements on hardfacing deposits/microstructures. Thanks. Pradip Goswami,P.Eng.IWE Welding & Metallurgical Specialist & Consultant Ontario,Canada. - http://www.aws.org/wj/supplement/wj0710-133.pdf
Hello Friends, We are conducting trials for Tungsten carbide Hardfacing on F-22 material (2.1/4Cr - 1 Mo). we are facing problem of transverse hairline cracks on weldbead. need your help to overcome this problem. Process: FCAW Filler wire Dia: 1.2mm Cuerrent used: during trial we changed current from 87Amps to 140Amps. different runs were taken but all cracked Volts: 16 to 19.5V Wire feed: 2.8 to 5m/min Travel speed: 235 to 600mm/min Preheat: 120 to 260DegC Shielding: Argon With these parameters, we achieved satisfactory weld bead appearance though. Please let me know if i am missing any factor which is vital for the success of the process. also need you guidance on the parameters i tried.Hope to see your suggestions soon Please let me know if anyother info is needed. Thank you. Regards, Ajay -- To post to this group, send email to materials-welding@googlegroups.com To unsubscribe from this group, send email to materials-welding+unsubscribe@googlegroups.com For more options, visit this group's bolg at http://materials-welding.blogspot.com/The views expressed/exchnaged in this group are members personel views and meant for educational purposes only, Users must take their own decisions w.r.t. applicable code/standard/contract documents. -- To post to this group, send email to materials-welding@googlegroups.com To unsubscribe from this group, send email to materials-welding+unsubscribe@googlegroups.com For more options, visit this group's bolg at http://materials-welding.blogspot.com/The views expressed/exchnaged in this group are members personel views and meant for educational purposes only, Users must take their own decisions w.r.t. applicable code/standard/contract documents.
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http://materials-welding.blogspot.com/ The views expressed/exchnaged in this group are members personel views and meant for educational purposes only, Users must take their own decisions w.r.t. applicable code/standard/contract documents.
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