(12-05-2015, 08:39 PM)andebred Wrote: I'm doing research on Thermal Spray Coating on train axles.
The axles have to be protected against corrosion and impacts from stones and ice.
The surface roughness of the axles are Ra=1.6 [my] and this cannot be changed due to fatigue properties of the axle.
Is it possible to get good adhesion without Grit blasting?
After Grit blasting, what roughness do you get?
thanks for any answers
It is hardly possible to obtain a good coating by means of thermal spraying without sandblasting. However, you can select so a fine grain of blasting agent that has no negative impact on durability.
I recommend the corundum F 090 with grit 125-180 microns. We have samples from the steel 42CrMo4, blasted with this corundum, tested in endurance swing tests and found no difference to the non-blasted samples (both approximately 5,000,000 cycles). Same samples blasted with F 020 (650-1180 microns) were destroyed after approximately 500,000 cycles.