PPRuNe Forums - View Single Post - Most demanding loads on aircraft landing gear
Old 26th Jul 2016, 03:16
  #17 (permalink)  
riff_raff
 
Join Date: Sep 2007
Location: USA
Posts: 601
pulse1-

I don't think the chrome plated surfaces you saw were heated to 500degC. The MLG components (hydraulic struts, axles, etc) base metal thin dense chrome plating is applied to is usually heat treated to very high strength levels. Exposure to temperatures of 500degC would significantly alter the base metal properties, and I don't think the component would be salvageable.

There are only a few surfaces of a commercial aircraft MLG that are plated with thin dense chrome. These are typically surfaces subject to sliding contact with seals or bushings, to reduce friction, minimize wear, and prevent corrosion. Often shaft surfaces in contact with bearing races are plated with thin dense chrome to inhibit fretting. And sometimes the plating is used to refurbish shaft surfaces that have been scratched or abraded.

The blue hue you saw on the MLG component plated surfaces may have been due to one of the processes involved in the refurbishment procedure. One of the first things done after dis-assembly is to strip/clean the part surfaces, and then perform NDI to check for structural damage. If any chrome plated surfaces require repair, the first step is to electro-chemically strip the old plating.

There is high demand for refurbished commercial aircraft landing gear assemblies. So as long as the components are safe/serviceable/salvageable, they will be refurbished and put back into service.

Here is a good article describing the landing gear overhaul process:
http://www.avitrader.com/wp-content/...O_2011-091.pdf
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