Mild or low carbon steel

Memorymaker

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How do you tell the difference between low carbon and high carbon steel. I have a place I can get new metal scraps but they just classify steel as hot rolled, cold rolled and stainless. I want to get them for practice pieces ....... I did get a bunch of hot rolled.

What can be used for practice
 

Crossbolt

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Hi
Apart from sophisticated analysis the only test I'm aware of is the somewhat subjective spark test. The higher the carbon content the "fizzier" or more abundant and "branched" the sparks from grinding.
Jeremy
 

Chujybear

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As above.
Real low carbon radiating sparks like star trek heading into hyper drive (or whatever it's called).
High carbon heavily branched sparks. (Like a bunch of little forked lightning a.
 

Memorymaker

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I guess I asked the question wrong. How do I know when I'm looking at the pieces at the shop which are good practice pieces ........ I have them cut so size is not a factor
 

grumpyphil

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The short answer is you won't. I'm a toolmaker and I can usually look at bar stock on a rack and make a pretty good guess what it is and even though I've been doing this a long time, I'm not always absolutely sure and that that's a rack in a shop I work in. The spark test is good if you have a collection of KNOWN specimens to compare it to.
Better is to buy a couple feet of 2" wide X .25 of 1018 to start. Then get some of the same in 4140 (for instance). Cut some 303 stainless, and then some 400 series. You have now educated yourself and have known specimens to compare to the scrap you are buying. Fill buckets with small pieces
 

oiseau metal arts

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just practice on them all. unless you intend to heat treat them, there shouldn't be much issue. free practice materials if still free. :)
whatever it is it should already be annealed and cutable. if its not..... chuck it and grab the next piece. you could just do a test cut on the edge too.
 

Tim Wells

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Hot rolled is the stuff you get at Home depot, Tractor Supply and Lowes called "weldable steel" and it as well as most cold rolled is mild low carbon steel. Cold rolled is typically more expensive that hot rolled but it won't have that scale all over it that you'll have to remove to make it fit to engrave.
 

Dave London

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Speedymetals.com sells cold rolled cheap and they cut to size for free. I like the 3/16 min thick less vibration YMMV
 

Memorymaker

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Thanks Dave, for the source but I can can get cold rolled from the same place too ....... Also dirt cheap. I'll go back and get some cold rolled this time ...... Thanks
 
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jerrywh

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Heat it red hot and quench it in water. If it is then too hard to file it is tool steel or high carbon. If you can file it after this it is low carbon or mild steel.
 

monk

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take a graver and a file to your source. test on the spot. if it cuts easily, use it. if it resists cutting or marking with a file, no use to practice with it. one soon develops the "eye" needed to sort the useful from the not-so-easy stuff.
 

silverchip

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Usually hot rolled and cold rolled are 1018 mild steel, both should cut easily. If you use hot rolled you can remove the mill scale with a solution of muriatic acid and warm water, a cup of acid in a gallon of hot water. Neutralize it in baking soda water after the scale falls off,dry it off and do your finish work before engraving.
 

BrianPowley

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If they can't tell you what the specific grade is, then it can be a guessing game.
Since the samples are free, take a bucket of them and have at it.
If you can buy some, 4140 is a good steel (not exactly low carbon). 12L14 is stupidly soft and will rust just from breathing on it.
In Stainless Steel, 300 grades are hard and not a good place to start for beginners.400 grades are a lot better for us engravers. 17-4 is a nightmare.
Cold rolled is usually nicer to play with and it has a better surface than hot rolled.
In steel, carbon makes it hard, manganese makes it tough and adds to it's ability to harden, sulphur makes it brittle, aluminum makes it ductile (for stamping purposes).
The chemical specs will drive you nuts because steels are made for particular applications.
Stick with the lower carbon (mild) steels. 0.05 -0.25% carbon content.
Most blued guns are made of low to mid-range carbon steels.
 
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