Shallow hardening steels

[Olorin]

Any chance anyone has a list of shallow hardening steels? I can't seem to find one online. Are there any others besides the 10X series of metal?

 

Thanks!

[swedefiddle]

Good Morning,

A silly question, What are you trying to do?

The hardening process does not penetrate to the core of whatever you are trying to harden, unless it is thin. The hardening process makes maybe .040" hard (1mm), usually not even that deep. The hardening process is controlled by the 'Quench Rate', how many seconds (or parts of a second) per temperature loss (ie. 900 degrees per second??).

Brine hardens the fastest, then water, then oil (there are many different Oils, all with different quench rates), then Air.

Hardening makes something brittle, Tempering makes the brittleness into toughness.

My favorite colour is Blue, with orange slashes and purple speckles. Subject to change!!!

Neil

[Chris Williams]

I've never had a need for a shallow hardening steel, so I haven't taken note of them if I have come across any. When I specify a heat treat, I am aiming for certain minimum properties at the center of the stock or part. Have you considered case hardening? It is specifically intended to provide a hard case on the surface. 

I provided a link describing the Jominy end quench test that shows how "through hardenability" is measured. I recommend that you perform a search for steel with low "through hardenability." 

https://www.industrialheating.com/articles/92224-understanding-the-jominy-end-quench-test

What is "shallow" to you? This information may help others that may know of something that meets your needs. 

[Welshj]

I've never hear of "shallow" hardening steel.

I have however heard of the process of case hardening steel parts. I used to work in a foundry that did just that for the automotive industry. We did roller bearings, clutch pressure plate arms, etc...

You are talking about a process that cannot not reliably be done in a home shop. (In my opinion) Ammonia, nitrogen, and argon gasses , amongst others were pumped into storage tanks which were fed into large furnaces under controlled conditions.

[Steve Sells]

Shallow hardening steels are low alloy having no chrome or other deep hardening materials, and low Mn especially. you may have been better if you had posted this in a knife making section where people are aware of this, many general smiths think its imaginary, try 10XX and W series, as most water hardening steels are such because they are shallow hardening and need the speed of brine to harden at all

[ThomasPowers]

Shallow hardening steels are often used by bladesmiths who want to do a differential hardening to he a hamon line on their blades.

Traditional Tamahagane  steel was/is quite shallow hardening due to the lack of other elements alloying it.  As it was smelted using charcoal, sulfur was not an issue and so the pretty much omni present Manganese added to modern steels to deal with sulfur from the smelting process using coke is not necessary.

The NJ Steel Baron used to have some low Mn 1084 IIRC; I do not know if it would work for your planned use; but you might contact him and discuss it.

[Chris Williams]

Although I am quite aware that different steels must quench at different rates in order to fully transform Austenite into Martensite (as opposed to ferrite/Bainite/perlite with no or limited Martensite as each material and rate may dictate), I must admit that I thought "shallow hardening" was just a physical description rather than technical terminology.  I did, however, find an interesting NIST paper from 1935 that clearly demonstrates otherwise. 

Thank you for providing your input, Steve.

Note: this NIST PDF is ~26MB! Don't download if you have bandwidth or data constraints. 

http://nvlpubs.nist.gov/nistpubs/jres/15/jresv15n4p385_A1b.pdf

[ThomasPowers]

I remember it as rather a common term in old metallurgy works; the ones I tend to buy anyway as I'm cheap and I have an abiding interest in earlier days and earlier ways!  Some days I consider Theophilus' "Divers Arts" to be "cutting edge" and "De Re Metallica" to be Science Fiction!

[Latticino]

Steve and Thomas are on point in their replies, as usual.  In the Heat Treatment class I took with Kevin Cashen he mentioned that shallow hardening steels, in the way he used the term, were for steels where the "nose" on the TTT diagram was far to the left, needing a quench time on the order of 1 second to achieve acceptable transformation.  He recommended use of Parks 50, or equal, for quenching these steels and listed 1070, 1075, 1080, 1084, 1095, W1, and W2 as being common steels needing this quench oil and that 1084, W1 and W2 were specifically shallow hardening.  Of course my notes are a little suspect, as Kevin inundated us with a fire hose of information.

[ThomasPowers]

Generating a variation on my forge welding saying: "Don't look at it Hit It!"  morphing into "Don't look at it Quench It!"  Arranging the forge and the quench tank and doing a dry run to build up speed helps a lot.

[Olorin]

Thanks for all the tips! My questions have been answered! I'll keep an eye out for W1/2 and the 10x series or low Mn/Cr steel. And I'll be sure to post in a more specific area next time, I didn't realize the term "shallow hardening" wasn't universal with blacksmiths, that's good to know!

[Steve Sells]

there are still smiths that think RR spikes are high carbon, when in fact they are just large nails

[Olorin]

Huh, I was kind of on the fence on wether or not rr spikes were high carbon or not, I didn't think so but I had heard otherwise from other people. Also good to know!

[ThomasPowers]

The ones stamped HC are at the border between mild and medium carbon steel; I've read the reports on 1000 year old blades with more carbon than that!