steel worm gear coating

[spears]

I have a skewed worm assembly for medium power transmission and indoor use. I have choosen 1045 steel for the helical worm gear and will probably use 1045 for the worm as well. However I have seen similar gear setups with a gold or bronze coating on the steel. I presume this is for friction, hardness, or corrosion. Does anyone have information on these coating or which would work well?

THanks Spears

 

[Acajun]

What you see as a bronze coating is actually a bronze wheel. The reason bronze is used is to reduce friction between the worm and the wheel. Unlike helical bevel gear sets which operate with a rolling action, worm gear sets operate with a sliding action that causes friction. Efficiency ranges for worm units can range between 40% and 90% whereas helical bevel efficiencies can range between 94% and 99%. Also, steel on steel has a higher fricton factor than steel on bronze and wouldn't last very long in a worm wheel set configuration.

Hope this helped

Jp

 

[powertrans]

You may have been looking at a Titanium Nitride coating, commonly used on cutting tools, but also used on other wear items. It is a thin, hard coating, that may help reduce friction and wear between two steel parts rubbing, such as in the worm and gear pair you describe.