Metal Spraying of Worn or Damaged Bearing and Seal Diameters
29th July 2008
The eccentric shaft pictured below has been metal sprayed on all of the bearing and seal positions. Final machining has yet to be carried out. Keyways are 'blanked off' with a carbon insert and metal sprayed over the top. The carbon is then removed after final machining.
The bearing diameter on this pinion shaft is very badly corroded. The seal diameter is also showing signs of wear. Both diameters will be undercut to remove wear and any pitting, before being metal sprayed with a 420 stainless steel - a wear and corrosion resistant coating.
In areas such as dusty mine sites where a seal diameter may be subjected to extreme wear from fine particles we recommend a Titanium Dioxide ceramic coating. This coating has a hardness of approx. HRc57, combined with a very low coefficient of friction once the coating is ground.
This transmission shaft has a needle roller bearing running directly on its surface. Normal metal sprayed coatings would not be suitable for this application. In this case a coating was applied and subsequently 'fused' into the parent material and ground to finish. The resultant coating has a hardness of HRC60-62.
At DCL Surface Engineering we can return even the most badly worn and corroded surfaces back to 'as new' condition. This roller journal was initially set up in a lathe and pre-machined. A metal spray Bond Coat was first applied followed by a build up of 2.5mm of stainless steel. The finished machine surface had a bearing re-fitted and returned to service within a 48 hour time frame.