Perlitic Cast Iron ?

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robwilk

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I have plans for a Stirling engine that i am having a go at making but the plans say for the displacer bearing use perlitic cast iron what is it and what are its properties ? , Why use it for a bearing ?. The displacer rod is steel. is it something to do with wear.?
Can any body cast some light on this for me.
Thank you.

Rob......
 
Perlitic Cast Iron is made of alternating layers of soft Ferrite and hard iron carbide, It's properties are high strength and wear resistance.

Would not be concerned about those properties for a Stirling engine the main thing is zero, or as close as you can get, friction.
 
The primary requirement on the displacement rod bearing is a good seal. I have always used 660 bronze or plain yellow brass. None of my engines ever get enough hours of use to wear them out.

The piston rod and bearing have to be as close a fit on a polished rod with minimum friction as you can get. Other than that, nothing to it ;D
 
Pearlitic cast iron just means cast iron that has been cooled moderately quickly. Pearlite refers to the material between the graphite flakes (if pearlitic gray iron) or graphite nodules (if pearlitic ductile iron). Pearlite is a lamellar arrangement of alpha iron and iron carbide (cementite - Fe3C). Given theapplication, I'd just get some constinuous cast gray iron bar (e.g., Durabar) and machine away.
 
Thank you for your input it has given me something to think about :bow:

Rob......
 
I notice that a lot of Jan Ridders plans call for this material. I am getting ready to build a 2 Stroke that uses this material for the cylinder and piston. Can someone recommend a good supplier for this stuff so that I know I am buying the right thing? I have looked around the web a lot I'm just not sure exactly where to get it.

Thanks,
Dan
 
Dan . Good Question I have been searching the web my self and have not found a supplier here in the uk for pearlitic cast or for durabar unless i buy it by the ton .

Rob......
 
Here are some cast iron grades. Hope the table works. ???

Tim


G1A
Gray Iron Pearlite & ferrite matrix, flake graphite Moderate strength, increased machinability, excellent damping G2 Class 40
Gray Iron Pearlite matrix, flake graphite Moderate strength, good wear as-cast, excellent damping G2 Heat Treated
Gray Iron Martensitic matrix, flake graphite Best wear in a non-alloyed ferrous metal, moderate strength, tooth sections >.250", good damping Same as above, better wear resistance
G2 Alloyed
Gray iron Pearlite or martensitic matrix, alloyed carbides, flake graphite Improved wear over class 40 grade or quench and tempered class 40 grade; increased wear resistance with higher chrome levels. 65-45-1
Ductile Iron Ferrite with 20% pearlite matrix , nodular graphite Good machinability, size control after heat treatment 80-55-06
Ductile Iron Pearlite with 15% ferrite, nodular graphite Higher strength, higher hardness, increased wear; good heat treat response when flame or induction hardening 100-70-02
Ductile Iron Ferrite with 50% pearlite matrix, nodular graphite Good wear resistance without heat treating Austempered
Ductile Iron Ausferrite matrix with nodular graphite
 

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