Hello All,
We are facing some issues on tungsten carbide coated parts sprayed using HVOF Powder Coating and after grinding the area with diamond wheel, we are observing patches in Liquid Penetrant Test. can you all suggest me that, what's the problem behind this, like its a coating problem or grinding problem. Please do share your thoughts as well, with your answers.
It's not pitting Vadim Sir, as it is not directly visible, the patches only comes after doing the Liquid penetrant Test and i have attached photos for the same.
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RE: HVOF Coating Problems
Hi Ajoy29
As I could see in the picture, the porosity is near the areas when it can be some turbulences in the HVOF flame, and the coating can be affected of this turbulences, if the piece is all as in the picture, try to do the spray in 2 times, masking once a time the zones to be coated, and do some change in the HVOF gun direction, and if the piece is only the cylindrical zone, try to coat it first