Meehanite bar

[Steamingandy]

Has anyone come across this it looks like a stain and won’t machine or polish out it’s cast iron Meehanite bar
So I have turned the other end and the pattern is mirrored exactly 2” down the bar? Must be a production issue otherwise it would be random any ideas

[derekwarner]

Meehanite bar is a general term for continually cast iron, but without a Grade nominated it could vary in both properties and chemistry

British or US nominations of SG Grade 3D cast iron offers excellent machinability and used for general applications ranging from the Steel Industry to model sized bushes.......a German or European nomination Cast Iron Grade GGG offers similar properties to the 3D.....totally different machining qualities to those you nominate ...

Naturally dependent on speeds & feeds etc....grey iron that machines with satin? finish as you describe would suggest as closed grain & with extreme hardness  ...low natural lubricity and will not hold oil on the surface .......drop a bush on the floor  & it may shatter

Could make a good boat anchor 

Derek

[Jo]

Must be a production issue otherwise it would be random any ideas

I would agree. CI is, as Derek has said, "Continually cast", that looks like a problem with what came out as it was cast.

What were you planning to use it for? I would not want to use it for piston rings or an IC engine cylinder

Jo

[Steamingandy]

It’s for a flywheel so not structurally important,I have been able to get rid of the marking but had to go 3mm deeper so looks like I need to get a piece of bar 10mm bigger to get what I want, just seems a waste, going to talk to the supplier on Monday see what they say.

[Alyn Foundry]

It’s for a flywheel so not structurally important,I have been able to get rid of the marking but had to go 3mm deeper so looks like I need to get a piece of bar 10mm bigger to get what I want, just seems a waste, going to talk to the supplier on Monday see what they say.

Wouldn’t a casting be far less wasteful? Is it just a lump or is there any detail to it ?

Cheers Graham.

[jadge]

It's not uncommon and is a consequence of manufacture. It is usually a surface effect. In the UK continuously cast iron is generally GR17, aka Grade 250, unless otherwise stated. It's a grey cast iron and machines very well, giving a smooth and uniform finish.

Tne machined surface finish shown appears poor. So there is either something fundamentally wrong with the material, or the machining technique. Was the tooling HSS or carbide and what were the speeds and feeds?

Andrew

[Steamingandy]

It's not uncommon and is a consequence of manufacture. It is usually a surface effect. In the UK continuously cast iron is generally GR17, aka Grade 250, unless otherwise stated. It's a grey cast iron and machines very well, giving a smooth and uniform finish.

Tne machined surface finish shown appears poor. So there is either something fundamentally wrong with the material, or the machining technique. Was the tooling HSS or carbide and what were the speeds and feeds?

Andrew

If you look closely there is small blow holes at the edge of the stain, that’s down to production not machining, I’ve used carbide tools just as I did with other cast bar never had a problem,
I have asked elsewhere and apparently it can happen if the production is not hot enough and paused to long it affects the grain direction as well causing difficulty with drill wandering, that’s exactly what has happened to me.

[Steamingandy]

It’s for a flywheel so not structurally important,I have been able to get rid of the marking but had to go 3mm deeper so looks like I need to get a piece of bar 10mm bigger to get what I want, just seems a waste, going to talk to the supplier on Monday see what they say.

Wouldn’t a casting be far less wasteful? Is it just a lump or is there any detail to it ?

Cheers Graham.

Agreed a casting would be better but I can’t get what I need.

[Alyn Foundry]

Please tell me what you need?

I might just have it on the shelf….

[Jasonb]

For "disc" type flywheels on marine engines then a bit of bar produces minimal waste. If it is sized just under the nominal bar size then there is less to come off the diameter than there would be with a cast one and unless the recesses either side are large there is not much to machine away.

Reeves and Stuarts also do sell separate disc flywheel castings but often more expensive than a slice off a CI bar. I just made one 39mm dia x 18mm overall length from 40mm nominal bar which would cost £1.74 per 25mm from M-machine, same sort of size casting from reeves £11.68, using solid is certainly not wasteful of money

As I said elsewhere I have also come across the marks you show and have just put it down to an inconsistant pour, maybe at the start or end of the continuous length.

[Steamingandy]

Please tell me what you need?

I might just have it on the shelf….

Thanks I will bear that in mind Alyn