Bruce Edney | 30/01/2016 03:53:54 |
![]() 167 forum posts 53 photos | Hi folks I have a ring of cast iron about 155mm ID 210mm OD and will be 12mm thick. If I heat it to say 300 deg C can some tell me approx what size the ID would increase to? Thanks Bruce |
pgk pgk | 30/01/2016 07:11:21 |
2661 forum posts 294 photos | I think that it's as simple as looking at the missing central disc i.e cast iron 155mm long. coeff expansion I found was 0.0000112 / degC so from say 20C to 300C for 155mm = 155 x 289 x coeff = 0.48608 for a new id of 155.48608. |
Roger Head | 30/01/2016 07:32:24 |
209 forum posts 7 photos | pgk pgk is correct, 'cept for the typo 155 x 280 x coeff = 0.48608 for a new id of 155.48608. There are slight variations quoted for different types of CI, and the CTE changes with temperature, but the effects are small and would only change the ID by one or two thou. The following horrible link brings up pages 295-298 of the Iron Castings Handbook which shows the effect. https://www.google.com.au/url?sa=t&rct=j&q=&esrc=s&source=web&cd=10&ved=0ahUKEwjLyqaV-9DKAhXDKWMKHVXTB2kQFghKMAk&url=http%3A%2F%2Ffiles.engineering.com%2Fdownload.aspx%3Ffolder%3Db1e13803-7e48-479f-ae19-67666ee8c97b%26file%3DIron_Castings_Handbook_4th_Edition_-_Thermal_Expansion.pdf&usg=AFQjCNFrTGDj2Ee1KzAXqlWC-xbRgmYQIg&sig2=ZTACQ5c2_EgulHd2JODncA&bvm=bv.113034660,d.cGc&cad=rja Roger |
Bruce Edney | 30/01/2016 08:03:14 |
![]() 167 forum posts 53 photos | Thanks guys Looks like I have to do a bit more machining Bruce |
pgk pgk | 30/01/2016 08:10:17 |
2661 forum posts 294 photos | If they gave out degrees in typo I'd have a first.. thanks for the correction. |
Michael Gilligan | 30/01/2016 08:43:50 |
![]() 23121 forum posts 1360 photos | Roger, I present your 'horrible link' in friendlier forms, for those of a nervous disposition: Thanks for finding it. MichaelG. |
Roger Head | 30/01/2016 11:15:44 |
209 forum posts 7 photos | Yeah, thanks Michael. I know, I should have done that. Interesting to see Fig 2 in that reference and read of Ni-Resist. I used Invar in some laser opto-mechanics in the past (20 years ago), but I was never aware of a casting alloy. I wonder what's available now... Roger
|
Please login to post a reply.
Want the latest issue of Model Engineer or Model Engineers' Workshop? Use our magazine locator links to find your nearest stockist!
Sign up to our newsletter and get a free digital issue.
You can unsubscribe at anytime. View our privacy policy at www.mortons.co.uk/privacy
You can contact us by phone, mail or email about the magazines including becoming a contributor, submitting reader's letters or making queries about articles. You can also get in touch about this website, advertising or other general issues.
Click THIS LINK for full contact details.
For subscription issues please see THIS LINK.