Question to the blacksmiths and those with metalurgy understandin

[Stonevievneilson]

I have an old swing saw blade with the numbers C7475 stamped over a 1. This is an old blade that is sharpened and needs set on it to cut. It doesn't have tungsten tips and an be resharpned and re gullited.
So I am wondering it the numbers denote a steel type? Would be nice to have a known steel one that I could possibly heat treat myself for use as knives, strikers etc.
Cheers
Jonno

 

[19 16 6]

Mate ,that blade is a tungsten carbide steel.
The C7 says it is a finish saw so it possibly has many teeth, hey ?
The other numbers are for percentages of Cobalt & Molybdenum.
This steel will not heat treat well in a home forge.
It is best left as a saw blade.
O.

 

[Black Hand]

Could be made into a knife blade by stock-removal but I wouldn't try heat-treating or forging.

 

[crockett]

Get a catalog from Texas Knife makers supply. They will treat air quenchable steels for you.
Making a knife involves your time plus making a guard, handle materials, etc. If you buy quality steel for a few bucks....why waste time with unknown steels?

 

[Stonevievneilson]

Thanks for the replies. The idea of the post was to find if the numbers gave me a known steel.
The blade is about 2' diameter and has a tooth approx every 1 1/2".
As I don't have a swing saw and the teeth require gulleting and sharpening I began to look at the steel as stock.

I have old horse drawn dump rake tynes that I will have a play with. If i can work out a good heat treat for them I have enough for many many knives.
Thanks very much for your replies. This forum has been a Wealth of knowledge for me and I enjoy the learning from your sharing.
Thanks again. Jonno

 

[Zonie]

I don't think the number has much to do with the material. At least, if it was made in America it doesn't.

7475 is a type of aluminum alloy and it would be hard pressed to cut anything tougher than paper.

 

[Free Plunder]

Zonie - Durst I believe those blokes are messaging from "The Land of Oz", blade not likely from hereabouts. FP

 

[44-henry]

I agree that the numbers likely do not have anything to do with the material, it wouldn't make much sense for the maker to list the type of steel used and what you see is more likely some form of identification number.

If old enough it probably is some form of simple high carbon steel. Personally I would purchase new material with known properties as it is really not that expensive for easy to heat treat steels such as 1075, but if you are in the mood to experiment cut off a section and do some test heat treating to see what happens. It might be great stuff, who knows.

 

[19 16 6]

Zonie & Alexander, the letter & numbers do identify the blade steel & its intended purpose.

Jonno those rake tynes should be good.
Most all that old, old steel is forge worked & forge hardened & brine tempered. The temper can also be done in clean oil, not sump oil.
Experimentation will put you in the know as to how to harden & temper for your intended purpose.

Even though Toyota Land Cruiser leaf springs are a modern alloy that is oven hardened, I worked out how to heat treat them for tool making.
O.

 

[jmforge]

You are using the term "temper" incorrectly. what you are talking about it quenching/hardening. Tempering is done afterwards at a much lower temperature.

 

[19 16 6]

You are correct Joe.
Upon rereading that I don't know how that got by me. Thanks.
O.

 

[jmforge]

I wasn't tyringot bust your chops. That is a common error. As forsaw blades,the ones that aren't HSS tend to be either plain carbon steel like 1075 or some kind of simpler nickel bearing steel like 15N20 for big band saws and 8260 or 1075-1080 with 2% nickel for circular saws. Contrary to popular myth, pretty much no saw blades are made from L6 these days. It is too cantankerous to work with. If yours is not HSS, it might worth finding out what it is. Over here, hay rake tines tend to be some type of higher carbon 10xx steel.