Steel Mixtures

There are dozens of other metals you could add to the alloy for various effects and an infinite range of strength characteristics. Cobalt, Beryllium, Titanium & Vanadium come to mind off the top of my head. There's also the ultimate alloy ingredients, Kryptonite and Unobtainium. Enjoy, Bugs

Actually, it's the plain carbon steel that is brittle at low temps, adding some molybdenum does wonders for low temp strength.

You might want to read up > Hi, I'm a fantasy and science fiction writer, and was recommended to

Also search on "brittle to ductile transition temperature"

Ned Simmons

there is criminal substitution or a great deal of incompetence on the part of the buyer.

Incompetence. But the buyer in this case was the maker of the alloy, and it isn't a modern story. The story is set in a in a milieu where people would be working out the basic alloying characteristics, and the snaps and shackles were on a test platform.

Bill

Thanks for the lead. I've been to several of those articles. It's a land in which I need a native guide. As random luck would have it, I had already seen some of them while I was flailing around the internet trying to do this research on my own. What a tyro like me needs is a simple article with a chart that shows test results. Something that would, say, show Charpy test results for test pieces with a percentage of a single alloying material changed.

Or, alternatively, answer this: if Molybdenum is the right metal to lower the temperature point of material failure, should I just assume that adding, say 1% more to the next batch will lower it's brittle temperature without adversely affecting the overall strength. Where overall strength is measured by shackles that can hold up a beer tent's lines in hurricane force winds.

I know I don't know the terminology well enough to ask this clearly. My language probably causes pain in anybody knowledgeable enough to answer the question.

Bill

Ya shoulda used stainless.

jw

Google-groups Ed Huntress and send him an email. He's forgotten more than most of us have ever known about steel alloys. He used to hang out here.

I am not an expert by any means, but googled and found this.

Metallurgical Factors Affecting Transition Temperature

Changes in transition temperature of over 55=B0C (100=B0F) can be produced by changes in the chemical composition or microstructure of mild steel. The largest changes in transition temperature result from changes in the amount of carbon and manganese. This transition temperature is lowered about 5.5=B0C (10=B0F) for each increase of 0.1 percent manganese. Increasing the carbon content also has a pronounced effect on the maximum energy and the shape of the energy transition-tempera lure curves.

The Mn/C ratio should be at least 3/1 for satisfactory notch toughness. A maximum decrease of about 55=B0C (100=B0F) in transition temperature appears possible by going to higher Mn/C ratios.

Note this article is talking Manganese not Moly to lower the transition temperature. Also note if you do some googling that the transition temperature for mild steel is much higher than -40 F. One of the causes of the Titanic disaster was that the rivets were made of steel which failed at approximently plus 32 degrees F . Not minus 32 F. Similar failure occurred during WWII.

The high strength Kryptonite bike lock will shatter when cooled with a can of stuff used for cooling electronics ( troubleshooting ) and hit with a hammer.

You can make a alloy with a lot of manganese which has high wear qualities. I think it is also high strength, so I don't think that adding too much manganese is a problem.

Dan

According to Bill Swears :

You've gotten quite a few followups, and what looks like some pretty good information.

I am pleased to see a SF writer actually researching what he writes. Please post here to let us know when the story reaches print, where, and under what title.

Is this the name under which you write? I must admit to not having encountered it -- but if you are publishing mostly in magazines, I probably would not for quite a while.

Best of luck, DoN.

I am so easily confused. I just looked at the MSDS for Hobart welding rods and it says that 6013 and 7018 contain 1 to 5 % Manganese.

Dan

How about purifying the steel rather than alloying it? Perhaps the snaps and shackles had too much carbon. Mild steel bolts and things don't seem to snap at -40 here in MN.

Perhaps one of the lurking metallurgists could suggest an additive or process that would remove carbon as CO or CO2 in the wizard's lair.

Welds are more prone to failure at low temperatures, but you wouldn't have any welds on snaps or shackles.

Chris

I am hoping for that lurking metalurgist to pop in.

Bill

Bill Swears wrote in news:11kg88gp23ubae6 @corp.supernews.com:

Try posting to sci.engr.metallurgy, they seem to be a pretty helpful bunch.

Somebody told me in email that my name came up. My narcissistic gene got the best of me.

Sorry, I've never studied cold behavior of steel in any detail. I was always interested in the hot side. I know as much about it as the average hack.

However, here's a good article that should serve the purpose. It's layman-friendly, but gives enough info for a serious writer who wants some background. Hint: Manganese is the big player. But for old alloys, nickel might be the alloying ingredient that you'd want to put in play in a historical story:

Ed Huntress

(If I still have the "3" in my return address, remove it before sending me e-mail.)

It is nice to hear your (online) "voice".

This place went to total ratshit for a while, but lately it has been looking up. Maybe hang around for a bit? How's it going, anyway?

Regards,

Adam Smith, Midland, ON