Carburisation was a complicated process when minimising warping/deforming on a new track plate.
The standard 20,5" wide track was a well-understood process and produced a track plate that was of a standard quality.
However, making the plate 24" wide instead of the 20,5" produced a major headache! The MkV tank was supposed to have the wider plate, but warpage during the carburisation process brought about a long delay until a satisfactory track could be produced, so much so that the MkV had initially to be fitted with the standard 20,5" tracks.
So itās possible the Germans were using the same process at Kruppā¦ hence their unintended multi-plate result with the A7v.
No. 4 is brilliant! Quintessential prove. Canāt say the same about rest of all
This suggest the tracks would only be black before the tank had been driven. As soon as the tank has been driven a few miles on softer ground the outer track surface should be worn to a steel color, and then it would start to tarnish. The inner track surface should also be worn by contact with metal road wheel, idler and drive sprockets, for no WWI tank had rubber tires on road wheels, so the black film should also rapidly wear away on the inside.
Mud turns into grinding paste, so that black paint coating wouldnāt last too long on any part of the tracks. But the inner areas would be mostly a dark mud colour with the mud darkened by all the grease used in thereā¦
I might suggest researching the common heat-treating processes used at the time on suspension and drive train components manufactured for the railroad and agricultural tractor industries. There would have been quite a difference between the processes used to harden armor plate (pioneered by the ship building industry for naval vessels) and the processes used to harden the wear surfaces of steel wheeled locomotives, railroad cars, all-metal tractor tires and the nascent caterpillar tracks used on other agricultural traction machines.
The answer to how WWI tank tracks were manufactured most likely lies in the same general processes used to manufacture other caterpillar-type tractor tracks and not in some arcane, yet theoretically possible, process that would not have been economically viable for parts that were almost certainly considered āconsumableā and easily replaced when worn beyond serviceability.
caterpillar tracks were a relatively recent innovation during WWI, the volume of tracks manufactured before they were applied to tanks was probably low. i suspect different manufacturers of tracks during the warwere still trying out different track design and construction methods. It looks to me like the track links on the Mk 1 and FT-17 were made from several pieces, each stamped from heavy gauge sheet steel, riveted together.
Indeed - all the British tanks from MkI to MkV, and Whippet, used the same basic design. Two cast side pieces were rivetted to a stamped steel plate, and hinged to the next link by a pin. The pins sat in holes that were greased, and rode on a series of wheels whose axles were also greased. The links may or may not have been painted black at the factory, but it wouldnāt take long for the mud and the grease to strip away any coating! If left standing long enough theyād develop surface rust, at least on the outer surface of the plate. I wonder what the figures for track service life were?
Compared to the service life of the tank itself?
Indeed! Life for a WWI tank was nasty, brutish, and short.
Life for everything in WWI was nasty, brutish, and short!
Ken
Not for the politicians and bankers back home.