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Scott H 
AMC Apprentice 
Joined: Oct/04/2008 Location: Montana, USA Status: Offline Points: 32 |
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 Posted: Nov/29/2008 at 4:57am |
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The principle is pretty well established and I do not need to defend it. You are, as I theorized earlier reading waaaaaay too much into my prior comment. 4340 is a low alloy steel.
http://www.unified-eng.com/scitech/hardness/hardness.html http://www.tpub.com/content/aviationandaccessories/TM-43-0106/css/TM-43-0106_298.htm http://www.calce.umd.edu/general/Facilities/Hardness_ad_.htm#rf27%22 http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm?csnumber=18084 http://www.efunda.com/units/hardness/convert_hardness.cfm?cat=Steel&HD=Approx.%20TS 4340 http://www.tpub.com/content/aviationandaccessories/TM-43-0106/css/TM-43-0106_65.htm C1040-1045 http://www.tpub.com/content/aviationandaccessories/TM-43-0106/css/TM-43-0106_57.htm Edited by Scott H - Nov/29/2008 at 5:31am |
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Steve_P
AMC Addicted 
Charter Member Joined: Jun/28/2007 Status: Offline Points: 3808 |
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Posted: Dec/01/2008 at 8:07am |
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here's data from the heat treat props of steel that shows 4340 is stronger than 1040 at similar hardness. WHich is why it is specified when high strength is necessary.
bhn= brinell hardness, sy= yield strength, su= ultimate strength
1040: 352 bhn, Sy= 92 ksi, Su=122 ksi
1040: 514 bhn, Sy= 96 ksi, Su=130 ksi
not a huge change in strength between the two hardnesses which vary considerably
4340: 280 bhn, Sy= 124 ksi, Su= 140 ksi
4340: 360 bhn, Sy= 156 ksi, Su= 170 ksi
4340: 486 bhn, Sy= 230 ksi, Su= 250 ksi
4340: 520 bhn, Sy= 243 ksi, Su= 272 ksi
so, you can compare the data and see that 4340 is stronger, even at a lower hardness
Edited by Steve_P - Dec/01/2008 at 8:10am |
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Scott H
AMC Apprentice
Joined: Oct/04/2008 Location: Montana, USA Status: Offline Points: 32 |
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Posted: Dec/05/2008 at 1:30am |
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Steve_P,
I am truly amazed at how much heat, and how little light this thread has generated to date. It has gained a life of its own! Once again, studiously ignored is my prior comment -- “I wasn't suggesting interchangeability between the two alloys. There are quite a few other mechanical properties that separate the two in real world performance and durability.” Please review the following, it is a free website. The data generously provided by Dr. Kopeliovich is very much in agreement with the body of data on the ASM website, which is not free. You will see that it follows the conversion charts I provided in my prior post rather closely. Not surprisingly, the properties vs hardness data differs from yours. Perhaps this is why ASM and ISO still make the charts available and most metallurgy text books still contain them in the reference tables. http://www.substech.com/dokuwiki/doku.php?id=carbon_steel_sae_1020 http://www.substech.com/dokuwiki/doku.php?id=carbon_steel_sae_1045 http://www.substech.com/dokuwiki/doku.php?id=alloy_steel_sae_4130 http://www.substech.com/dokuwiki/doku.php?id=alloy_steel_sae_4340 I came to this site because I am a AMC enthusiast, not to endlessly wrestle with you over facts that are so easily verifiable. Nor was I seeking metallurgy lessons from you. It was my major, and I have managed to feed my family with it since 1976. I do thank you for directing me to “Machinery's Handbook”. Ordinarily it would have been the last resource that would have occurred to me when searching for metal data. Since this is my final visit and post to your forum, I would like to point out that flame-baiting and trolling isn't really an attractive quality. But then, its your forum and you are a moderator. I am not wasting my time here any longer. Best wishes to you all. Scott H |
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amx39068
Supporter of TheAMCForum 
Joined: Feb/21/2008 Location: Arizona Status: Offline Points: 11576 |
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Posted: Dec/05/2008 at 3:59pm |
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I realize that the forum moderators are free to do as they wish but this is a good example of the type of needless negative nonsense that has plagued the AMC hobby for years. Scott is one of many AMCers, myself included, who have many been given crap about things when more often than not the harrasing response is both uncalled and in some cases even inaccurate.
As with all mechanical things, there are many alternatives to what is right or wrong or what is the best alertantive for a given situation. Regardless, insulting people as a result of a difference of opinion particularly when the individual has taken the time to pull together detailed information as Scott did in this thread is both counterprodutive and self defeating in the long run. Hopefully going forward this and other AMC forums will be more focused on being inclusive and welcoming differing points of view rather than turning into a pissing contest over which forum member knows more than the other. Edited by amx39068 - Dec/05/2008 at 4:01pm |
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Dan Curtis-Owner and CEO AZ AMC Restorations; Facebook: https://www.facebook.com/amcmusclecars/ & Curtis Real Estate Development
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Alliups
AMC Addicted
Joined: Mar/25/2008 Location: S.B. county Ca. Status: Offline Points: 1409 |
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Posted: Dec/05/2008 at 5:04pm |
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Edited by Alliups - Dec/31/2008 at 10:55pm |
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amx39068
Supporter of TheAMCForum
Joined: Feb/21/2008 Location: Arizona Status: Offline Points: 11576 |
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Posted: Dec/05/2008 at 8:53pm |
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Disagreeing is both healthy and almost always informative so I am all for a good healthy discussion of even oposing points of view. Contrarily, I see no need and certainly no benefit in giving someone grief simply because they either are less informed than someone else or in some other cases actually know more than the respondent. So how about we all show a little more respect and give those who are looking to learn something a chance to ask questions and get a repsonse that does not include sarcasm and ridicule as well as politley correct the periodic inaccurate response. Too err is human, to forgive (and respond politely :-) is divine.
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Dan Curtis-Owner and CEO AZ AMC Restorations; Facebook: https://www.facebook.com/amcmusclecars/ & Curtis Real Estate Development
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BassBoat
AMC Addicted
Joined: Aug/29/2008 Status: Offline Points: 1719 |
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Posted: Dec/06/2008 at 10:49am |
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GEEZE and I thought the Well at least us unwashed masses won't have to suffer any more enlightenment from some guy in Montana that quotes data from a rod test that he did, but then claims to be a metalurgist who "dismissed its exact composition from his memory -- because it was so mundane and typical of the alloy used for drop forged steel rods" for those of you still reading, he was right, the mundane alloy used in the only rod to survive this (well at least now) famous test was SAE 1042. He still strikes me as somewhat of an ass.
If you click the last two aviation tech pub references scotty posted and read the fine print, you will find that the maximum tensile for 1040 after heat treat is 125ksi, about half what you get from the premium 4300 series nickel chrome molybdenum. Because even low alloy content of those materials makes a difference....
BB Edited by BassBoat - Dec/06/2008 at 10:52am |
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amx39068
Supporter of TheAMCForum
Joined: Feb/21/2008 Location: Arizona Status: Offline Points: 11576 |
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Posted: Dec/06/2008 at 4:40pm |
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Never met the man so can't say for sure. I was more referring to the fact that he spent a lot of time putting togther some information, even if it may have been anecdotal, which hopefully was informative for at least some of the folks so from my perspective his contributions were of value. Alliups, I can't recall anything that you've ever said that was disagreeable to me but thanks for the response. None of us are always right and lord only knows that I, like everyone else I am sure, can make dumb mistakes, say dumb things or even have plain old brain to finger disconnects on the keyboard so hey, live and let live.
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Dan Curtis-Owner and CEO AZ AMC Restorations; Facebook: https://www.facebook.com/amcmusclecars/ & Curtis Real Estate Development
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Alliups
AMC Addicted
Joined: Mar/25/2008 Location: S.B. county Ca. Status: Offline Points: 1409 |
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Posted: Dec/06/2008 at 7:39pm |
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Edited by Alliups - Dec/31/2008 at 10:55pm |
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amx39068
Supporter of TheAMCForum
Joined: Feb/21/2008 Location: Arizona Status: Offline Points: 11576 |
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Posted: Dec/06/2008 at 10:38pm |
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Well at the risk of boring everyone all over again, the reason behind selling some cars, parts and building engines is due to trying to help out a life long AMCer who fell on hard times resulting in our putting deals together using his parts to help him get back on his feet.
Regardless, my responses are based primarily on 35+ years of real life experiences and usually in response to someone's stated needs but they most often do not have a whole lot to do with the parts activities which have only been a factor for the past 6-8 months. I have been contributing the this and other forums for well over 10 years with the vast majority of that time having zero vested interest in the subject matter other than than sharing my experiences.
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Dan Curtis-Owner and CEO AZ AMC Restorations; Facebook: https://www.facebook.com/amcmusclecars/ & Curtis Real Estate Development
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(edited) guys were arrogant....