Steel type(s) used in mnfr of Hydraulic Cylinder shafts

[Joseph Noci 1Participant @josephnoci1]

Would anyone know what type of steel is typically used for the shaft/piston rod of oil hydraulic cylinders such as used on earth moving machinery?

I need to re-make the spindle for my CNC lathe – the previous attempt used a piece from a caterpillar side shaft and was successful, but the oil seal mechanism I used in the headstock was not.. So a new headstock setup with different bearing oil drainage means a longer spindle is needed.

I cannot find another CAT drive shaft, but can get lots of hydraulic cylinder shafting from the local mining equipment repair shop.

I have cut a 200mm length from a 60mm OD shaft – it has (had) a very thick hard chrome layer, which I took off with a carbide tip in the lathe. Under the chrome, the steel machines very nicely, leaves a smooth, shiny finish, and the swarf comes off blue/straw coloured – either a long curly string at 1000RPM with 'low' feed rate, or short curly chips at high feed rates with the tip chipbreaker doing its job- the high feed rate also creates fine sparks at the cutting edge.

I used a 1mm wide carborundum cutting disc to cut a groove around the shaft periphery in order to get through the chrome before cutting the shaft off in the bandsaw – saw blade in that groove.The disc raised fine very bright white sparks once past the chrome layer.

Any Ideas on the steel type?

Joe

[Joseph Noci 1Participant @josephnoci1]

[bernard towersParticipant @bernardtowers37738]

Not absolutely sure but think it might be EN8 but might be an idea to contact a hydraulic company which could give you contacts to manufacturers.

[HopperParticipant @hopper]

Depends on the manufacturer and application of the hydraulics. Some are medium duty with a mild chrome moly alloy steel, heavier duty ones are often 4140 chro mo, which is good stout stuff. I suppose if you want to be sure of what you have, you would have to purchase some new 4140 bar.

Bit of info from an Australian supplier of readymade chrome plated shafting for making your own rams here, including metalurgy specs: **LINK**

[David George 1Participant @davidgeorge1]

I used to make piston rods for mining roof supports and the ones we made used 80M46 Carbon Steel a medium carbon steel which was machinable, ground nice for pre chroming.

David

[old martParticipant @oldmart]

I would think that the steel you have is suitable for making the spindle, there will be no wear of the surface involved, and all steel alloys have similar stiffness.

[John ReeseParticipant @johnreese12848]

The chrome plating on piston rod material is usually .0005" thick. The induction hardened material can vary in thickness. As I remember it is .03" to .06" thick.

I cut the bar in a horizontal band saw using a bi-metal blade. It is not necessary to grind through plating and hardened surface.

For lathe work I drop the speed while machining off the hardened layer, no other special procedures are needed.

The base material for the rod is usually 1045 but sometimes it will be 4140.

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