protection of thermal spray coating

[sarathmeetme]

I am working in a oilfield drilling jar servicing firm. I have watched that thermal sprayed coating of the male spline mandrel is protected by an oil soaked cloth while dispatching the tool. besides to prevent the chance of mechanical damage, is there can be another reason for this (like corrosion)?.....This drilling jar is to be used is rigs ie. in very adverse conditions....

 

[tbuelna]

Do you know what the thermal sprayed coating on the external spline is composed of?

A sliding spline joint external member that has a coating of lubricant would collect debris on its surface, and this debris would cause abrasive wear at the spline contact when the the joint is cycled. Placing an oil-soaked cloth over the exposed section of the external spline is an effective way to keep debris off of it. An oil-soaked fabric is a common type of air filter element (ever see a K&N air filter?). The oil causes dust and debris to stick to the fabric, and it will not shake loose when the fabric cover is removed.