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Thanks, I did wonder and thought it was too good to be true
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Piston Ring Materials
- Thread starter ac16
- Start date
Thanks, I did wonder and thought it was too good to be true
- Joined
- Nov 13, 2012
- Messages
- 165
Re: Piston Ring Materials - More Data
Tom G is right in that pipe fittings are available as "mallaeable" iron which is white iron castings that have been heat treated to make them somewhat mallaeable.
These are probably not a good choice for piston rings. (For reference, the standard for malleable iron fittings are ASME/ANSI B16.3)
Traditional cast iron fittings are also available. These are "as cast" from gray cast iron.
They might be a cheap source of round and hollow cast iron if you can find a fitting size that matches your requirements.
Here in the US, gray iron, screwed fittings are produced according to ASME/ANSI B16.4 (dimensions) and ASTM A126 (gray cast iron). These are often used with water systems and steam condensate systems. They used to be used a lot with fire protection sprinkler systems.
There is another standard for gray iron screwed fittings designed for drainage systems under ASME/ANSI 16.12. These fittings are low pressure, but have heavy walls designed to deal with long-term corrosion in drainage systems.
In the US, there is an easy way to tell the difference between B16.3 (malleable) and B16.4 (gray iron) fittings.
The B16.4 gray iron fittings are rated at 125 psi with a heavier grade at 250 psi.
The B16.3 malleable fittings have ratings of 150 psi with a heavier grade rated 300 psi.
So, if you are buying from a supplier, the supplier will know what standard and pressure rating is being supplied.
If you are digging fittings from a scrap heap, you have to compare the dimensions - B16.3 and B16.4 fittings have different ODs on the hubs. You need a catalog page or a standards table to compere the dimensions. If you hold a cast iron elbow next to a malleable elbow, the difference is very obvious.
There is another standard for gray cast iron pipe flanges. This is ASME/ANSI B16.1. These are not as common as they once were, but an interesting fitting might be a threaded to flange fitting. This is a 4-hole flange with threads on the ID. These are most common in pipe sizes of 2" and up, but the standard defines flanges all the way down to 1/2 inch. McMaster-Carr still sells them in the US. Take a look at page 12 in this pdf link for gray iron flange dimensions.
http://www.smithcooper.com/Illustrative Catalogs/2010-07/SCI FLANGED 0710.pdf
I think Rob, the originator, is located in Australia.
I am not up to speed with down-under piping standards.
I suspect a call to a local Australian piping supplier explaining what you want to do, and asking for the local version of ASTM A126 and ASME/ANSI B16.4 fittings will lead you to the local version of gray cast iron fittings. Then you would have access to new as well as scrap fittings as a gray cast iron source.
I'm not sure how one would go about turning a piston ring from a piece of cast iron.
If you think you want to try it, I suspect one of the experienced lathe operators on this site would have a recommendation.
Best regards,
Terry S.
Minnesota, USA
Tom G is right in that pipe fittings are available as "mallaeable" iron which is white iron castings that have been heat treated to make them somewhat mallaeable.
These are probably not a good choice for piston rings. (For reference, the standard for malleable iron fittings are ASME/ANSI B16.3)
Traditional cast iron fittings are also available. These are "as cast" from gray cast iron.
They might be a cheap source of round and hollow cast iron if you can find a fitting size that matches your requirements.
Here in the US, gray iron, screwed fittings are produced according to ASME/ANSI B16.4 (dimensions) and ASTM A126 (gray cast iron). These are often used with water systems and steam condensate systems. They used to be used a lot with fire protection sprinkler systems.
There is another standard for gray iron screwed fittings designed for drainage systems under ASME/ANSI 16.12. These fittings are low pressure, but have heavy walls designed to deal with long-term corrosion in drainage systems.
In the US, there is an easy way to tell the difference between B16.3 (malleable) and B16.4 (gray iron) fittings.
The B16.4 gray iron fittings are rated at 125 psi with a heavier grade at 250 psi.
The B16.3 malleable fittings have ratings of 150 psi with a heavier grade rated 300 psi.
So, if you are buying from a supplier, the supplier will know what standard and pressure rating is being supplied.
If you are digging fittings from a scrap heap, you have to compare the dimensions - B16.3 and B16.4 fittings have different ODs on the hubs. You need a catalog page or a standards table to compere the dimensions. If you hold a cast iron elbow next to a malleable elbow, the difference is very obvious.
There is another standard for gray cast iron pipe flanges. This is ASME/ANSI B16.1. These are not as common as they once were, but an interesting fitting might be a threaded to flange fitting. This is a 4-hole flange with threads on the ID. These are most common in pipe sizes of 2" and up, but the standard defines flanges all the way down to 1/2 inch. McMaster-Carr still sells them in the US. Take a look at page 12 in this pdf link for gray iron flange dimensions.
http://www.smithcooper.com/Illustrative Catalogs/2010-07/SCI FLANGED 0710.pdf
I think Rob, the originator, is located in Australia.
I am not up to speed with down-under piping standards.
I suspect a call to a local Australian piping supplier explaining what you want to do, and asking for the local version of ASTM A126 and ASME/ANSI B16.4 fittings will lead you to the local version of gray cast iron fittings. Then you would have access to new as well as scrap fittings as a gray cast iron source.
I'm not sure how one would go about turning a piston ring from a piece of cast iron.
If you think you want to try it, I suspect one of the experienced lathe operators on this site would have a recommendation.
Best regards,
Terry S.
Minnesota, USA
You may even be able to use a teflon coating on the iron rings. I'm not too hip to steam but I use Rem Drilube on my rifles and machine guns and it seems to last quite a while before I need to reapply it. I figure if it can stand up to the compression and heat generated by some of these machine guns, it shouldn't be a huge issue in a steam cylinder.