Looking for history of 5160 spring steel

[mariusgmioc]

Interesting topic!

Not the answers you seek but more of what you were saying.

In Nepal the leaf springs are the main source of raw steel material for the Kukris...

http://gurkhakukris.com/Content/cms/index.php?id=43

Moreover, as far as I know most modern combat-ready swords (like those made by Hanwei Forge for example) are made of this steel.

[Will M]

Wilkinson sword used steel very similar to 1095. Main sword manufacturers thought this was the best steel to use for swords. If modern makers use some other steels they probably use it due to availability or ease of manufacture as they are now made by stock removal, not forged and shaped..

[Ian]

Will,

I think the main attractions of 5160 are that it is a readily available, durable steel that can be hardened to take a keen edge, and that it is a type of spring steel that can be bent and it will return to its original state (up to a certain limit of course). The small amount of chromium in the alloy seems important in that respect.

The edged weapons and tools in many developing countries are still largely forged by locals from materials on hand, which is why scrap leaf springs are sought out. 5160 does not need to be folded or have an inserted edge because it has desired properties of toughness, edge retention, and springiness without being combined with other metals. For this reason, I know from personal experience that scrap springs have been widely used in the Philippines, Mexico, and Thailand. Interesting to learn from marius that Nepalese kukhri are also made from the same material.

Ian

[mariusgmioc]

Well Ian... yes and no.

While some smiths may use it for its availability, it definitely does not explain why big, major, modern companies use it. Hanwei for example has easy access to other high alloyed steels.

Its exceptional mechanical properties that makes it an almost ideal steel for swords and other bigger blades. From all I know, it has only two minuses:
1. it is rather sensitive to rusting and,
2. it is somehow harder to be worked.

[Edster]

Ian,

Interesting subject. Not sure if this addresses your needs, but I found them informative.

Try this one."Leaf Springs: Their Characteristics & Methods of Specification, 1912. Free Google Book.
https://books.google.com/books?id=6T...spring&f=false

Author says that the modulus of elasticity of all steels are virtually the same. Springs made with carbon steel "ride" the same as those of alloy steel of same dimensions. Alloy improved the resistance to repeated deflections. Other alloy additions modified other desirable qualities in manufacturing & use.

While not specifically addressed in text 5160's alloy composition enhances other qualities of the carbon steel, not springiness.

Steel grade standards developed first for structural steels and then to needs of the train and auto industries for consistency to engineering needs and design qualities.

Sword makers in Sudan & elsewhere transitioned from bloomery irons to a good material, i.e. carbon alloy steels from railroads or lorry springs when they became available after c. 1900. I guess it just happened that what steel that made good vehicle springs also made good swords.

Regards,
Ed

[Chris Evans]

Hi Folks,

An overview of 5160:https://www.azom.com/article.aspx?ArticleID=6743

A good article on how to best heat treat 5160: https://knifesteelnerds.com/2019/04/...at-treat-5160/

And where 5160 sits in terms of toughness among forging cutlery steels: https://knifesteelnerds.com/2020/02/...-knife-steels/

Ian: You could ask Larrin at Knife Steel nerds when 5160 came into generall usage: https://knifesteelnerds.com/


Cheers
Chris

[Ian]

Marius, Ed and Chris.

Thanks for your thoughts and suggestions. Much appreciated. I will report back here if I discover anything useful.

Ian.

[Ian]

Chris,

I sent off an email to Larrin Thomas, as you suggested. What a nice guy! He sent me a prompt reply which is copied below.

Hi Ian,

Finding steel history can be surprisingly difficult, and 5160 is not one I have looked into. I was unable to find the history of 5160. However, I looked some at some of SAE journals from the early 20th century and found a couple things. I found a reference to 5165 steel in the 1913 journal: https://babel.hathitrust.org/cgi/pt?...ew=1up&seq=638

5165 was not present in the 1912 SAE transactions: https://babel.hathitrust.org/cgi/pt?...iew=1up&seq=51

The chromium limits of 5165 were changed in 1919: https://babel.hathitrust.org/cgi/pt?...iew=1up&seq=14

However, 5165 was removed from the SAE specifications in 1922 "as there is apparently no use for it, and 5150 has been added for shafting material and for gear purposes." https://babel.hathitrust.org/cgi/pt?...ew=1up&seq=218

I found an ad from United Steel in 1919 advertising for "spring steel" which had four different brands including "Crucia" a Chrome-Carbon steel. https://babel.hathitrust.org/cgi/pt?...iew=1up&seq=88

So I didn't find 5160 but early versions of the steel date back to at least 1913. Perhaps with this starting point you can find something.

Larrin

And a further follow-up reply ...

Ian,

I found a reference to 5160 in a 1952 book, though it doesn't talk about 5160 as being the most common choice for springs, just one of the choices. https://babel.hathitrust.org/cgi/pt?...ew=1up&seq=483

Larrin

[mariusgmioc]

Very interesting. Thank you!

But actually this steel could have existed much earlier, maybe with small variations, only it was not analysed and documented.

It was only with Industrial Revolution that steels have started to be studied systematically. Prior to that it was only empirical study by trial and error.

After all, every 16th century rapier blade is a spring... but not even its maker knew its composition.

[David R]

Do you have an EN number for it?

[Chris Evans]

Originally Posted by mariusgmioc

Very interesting. Thank you!

But actually this steel could have existed much earlier, maybe with small variations, only it was not analysed and documented.

It was only with Industrial Revolution that steels have started to be studied systematically. Prior to that it was only empirical study by trial and error.

After all, every 16th century rapier blade is a spring... but not even its maker knew its composition.

I very much doubt that the iron ores used to make bloomery iron would have contained the alloying elements required by the 5160 standard.

Cheers
Chris

[Ian]

Originally Posted by mariusgmioc

Very interesting. Thank you!

But actually this steel could have existed much earlier, maybe with small variations, only it was not analysed and documented.

It was only with Industrial Revolution that steels have started to be studied systematically. Prior to that it was only empirical study by trial and error.

After all, every 16th century rapier blade is a spring... but not even its maker knew its composition.

Hi marius:

Yes, I suppose chance may have led to an earlier use of a similar alloy, but 5160 is not just carbon and chromium added to iron. The detailed composition is given above. It seems unlikely that earlier smiths would have stumbled upon this precise formula, but I suppose anything is possible. There are non-destructive methods that can now test for mineral content, so your idea could be readily tested using old, well-dated pieces.

As for carbon steel alone being springy, that is absolutely true. The quality of a blade depends so much on its tempering, and properly quenched carbon steel can certainly exceed the quality of a poorly tempered 5260 blade. The addition of chromium adds durability toughness to the steel, making it less likely to fail under a load.

Ian