 Crack, or normal casting? |
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| 74ravenna |
 Sep 24 2016, 10:04 AM
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Member  Group: Members Posts: 471 Joined: 19-October 14 From: nh Member No.: 18,032 Region Association: North East States 
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Is this a superficial blem in the casting?
Once magnified it appears to be but I just want to get some knowledgeable folks opinion. TIA Steve  |
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| veekry9 |
Sep 26 2016, 12:49 AM
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OldMember Group: Retired Members Posts: 3,068 Joined: 17-June 13 From: TO Member No.: 16,025 Region Association: Canada |
 Yep,that is why we had the specialized fire extinguishers and 'smothering powder' while machining the metals. As I recall,one 'prototype aircraft titanium splice plate' was ruined because the finish chips sparked up,he didn't get it out quick enough. Started out as a 6' x 6' x 2" thk plate,real pricey piece of scrap,the chips were recycled,of course. Somewhere out there is a treatise on the physics of why the shrink risers appear,and the crystalline solidification of light metals. The temperature gradient while cooling is from the outside in,as the effect is seen in micrographs of etched castings. A close inspection of the results of modern casting techniques show a reduction of the surface upsets,by a more refined control of cooling the castings. https://www.google.ca/search?q=cfd+metal+ca...bIfW72dKk0ZM%3A This may be of interest,to do a minimum of chassis calculation: https://www.youtube.com/user/expertansys/videos / |
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Posts in this topic
74ravenna Crack Sep 24 2016, 10:04 AM
stugray casting imperfections.
They are covered in them. Sep 24 2016, 10:08 AM The Cabinetmaker What is that we are looking at? Sep 24 2016, 10:08 AM
dangrouche
What is that we are looking at?
looks like under... Sep 24 2016, 05:16 PM injunmort is that the cylinder spigot? Sep 24 2016, 05:24 PM earossi Appears to be a surface crack in the spigot on a c... Sep 24 2016, 07:15 PM stugray
Appears to be a surface crack in the spigot on a ... Sep 25 2016, 01:28 AM veekry9 Shrinkage of diecast surfaces,a subject of depth a... Sep 25 2016, 02:09 AM 74ravenna Its the top of the engine where the cylinder head ... Sep 25 2016, 04:51 AM rgalla9146
Its the top of the engine where the cylinder head... Sep 25 2016, 05:50 AM earossi
Its the top of the engine where the cylinder hea... Sep 25 2016, 06:27 AM veekry9 Not a crack,it's a 'shrink riser'.
The... Sep 25 2016, 06:48 AM 74ravenna
Not a crack,it's a 'shrink riser'.
Th... Sep 25 2016, 07:03 AM 76-914 I think it happens on all Aluminum engines. The Su... Sep 25 2016, 07:16 AM Mikey914 Only one way to tell for sure. File the imperfecti... Sep 25 2016, 09:47 AM bretth I read about using a torch to briefly heat up a su... Sep 25 2016, 10:53 AM Mikey914 Wouldn't personally use a torch on this, too m... Sep 25 2016, 02:17 PM earossi Hitting magnesium with a torch will ignite it; so,... Sep 25 2016, 02:38 PM veekry9 AiYnDskFxTo
Burning metal! :blink:
VW/Porsch... Sep 25 2016, 09:56 PM earossi
AiYnDskFxTo
Burning metal! :blink:
VW/Porsc... Sep 25 2016, 11:35 PM ThePaintedMan
Without this turning ugly, I suggest that you Go... Sep 26 2016, 07:16 AM Beach914 Magnesium solids will not normally combust when ex... Sep 26 2016, 07:50 AM mbseto In college chemistry, we had a stash of magnesium ... Sep 26 2016, 08:08 AM Mikey914 You can light them with a flare, so it takes a goo... Sep 26 2016, 10:55 AM veekry9 George,you have attributed those words to me,a res... Sep 28 2016, 01:39 AM bretth I didn't think someone would take a torch to a... Sep 28 2016, 04:30 AM |
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