Definition of Tool steel?

[KYBOY]

Just curious what you think..I have seen the term tool steel used a lot just because someone makes a tool with it..Its my understanding from the AISI readings(and ASM international) that tools teels have clearly definded peramiters that have to be meet to be classified as a tool steel..Several people that I have talked to in the steel industry have told me the same thing...Whats your take?

[SmoothBore]

For practical purposes, ... the nuances in chemical content of high carbon steels, is of virtually no significance, in regard to it's suitability for hand forged items.

 

The variations in the suitability of these steels for ANY particular purpose, ... is directly related to the amount of control you can exercise over the process.

 

An open hearth forge, ... and hand forging practices, do not begin to approach that level of sophistication.

[KYBOY]

Im relly refering to the requirments of the steel itself not the finished item(or really a forged item at all, just in general)..Why is W1 not 1095 or vise versa? Why isnt 1045 classified as a tool steel yet we all use it for tools? if there is practically no difference then why is their much stricter requiments in smelting tool steels vs plain carbon steels..Now of course Im not talking about the difference in M42 and 1060 or D6 and 1075..Then of course their is a lot of difference if we bring heat treating into the mix..Most tool steels dont do well with the old "get it hot and dunk into something wet" practice..Even with the simplest of tool steels(like the W series) its best to soak at austenitizing temp for 5-10 minutes( or 20 minutes for O series) before hardening.

[MOblacksmith0530]

The original term "tool steel" is probably a couple of centuries old. It was either crucible steel or blister steel with enough carbon that it could be used for machine tool in cutting. Such as with a lathe or shaper that kind of thing as well as gravers for the engraving trades etc. To my mind the medioun carbor to high carbon steels as well as the alloy steels are all "tool steels" I doo not get tied up in the specific chemistry for the definition of tool steels. I do care when I am contemplating the forging and heat treatment process.  And yes I have had tools fail from a poor heat treat that is the nature of the game. Sometimes I know what went wrong other times I don't. If you get too tied up in definitions I think you will be giving yourself headaches that are not necessary. Heck I have quenched s7 in water and everyone knows you can't do that. But for a very small punch it made it really hard and it did it's job admirably for the few holes it had to do then it was made into something else later. I have a astm steel guide that I refer to to try and determine what the best process will be in my limited shop and go from there even though it is not perfect and a proper heat treat facility would do a better job.I know if I am forging a lathe tool I am going to try and use a very high carbon straight carbon steel if at all possible and air hardening if I can get it. I also try to limit the time in the forge at the soaking heats since it is hard to stay at the lower end of the critical range even with the forge turned down. I can do the hardening process multiple times to convert more of the structure to convert.

Just be aware of the possibility of tool failure and be careful.

 

My .02

[KYBOY]

Thats why Im so picky about the difference in heat treating simple steels and tool steels..Failures..If someone pays us for a tool made from W2, O1 or L6 and its heat treated simply its either gonna fail or its not going to live up to its potential.Thats not what people pay for.

 You see the biggest part of our business is heat treated tools..We have to be "picky" about what we do..Our business relies heavily on properly heat treated steels..We cant use O1 and heat treat it like 1075. If we send out a turning tool or a carving tool with a substandard steel or heat treat these people will figure it out real fast..Then your reputation takes the hit..So we are super picky about heat treating..Temp controlled heat treat and specially forumlated quench oils like Parks 50 and so on.

[KYBOY]

I also want to add that Im not a steel snob..When we need a hand tool for the shop we'll often just grab any old hardenable steel and make it..I just think that when someone wants a tool made from a certain grade of steel then thats what it should be..Also that it should be treated as such. I had the misfortune of telling a guy why his chisels wouldent hold an edge like the A2 chisels he had used..Even though the guy said he made them from "tool steel"..Well needless to say that leaf spring is not "tool steel".Big difference in the edge retention of 5160'ish and A2...

[Mainely,Bob]

For me personally; Tool Steel = the steel I feel is most appropriate for the tool I intend to make.
Beyond that there are far too many variables to chase what with O,W,A, HSS, particle steels, pattern welded and carbides being involved.

My advice to anyone wanting to either learn or split hairs is to pick up a copy of the Machinery Handbook.

[SmoothBore]

..If someone pays us for a tool made from W2, O1 or L6 and its heat treated simply its either gonna fail or its not going to live up to its potential.Thats not what people pay for.

 You see the biggest part of our business is heat treated tools..We have to be "picky" about what we do..Our business relies heavily on properly heat treated steels.

 

My mistake.

 

I made the assumption :rolleyes:  that a question in this Forum would just naturally be of a non-commercial nature.

 

 

 

.

[Chuck_Steak]

From an industry perspective, most tool steels have substantial alloy additions to get a desired response to heat treatment or for the mechanical properties (wear resistance, impact toughness, high temperature strength, etc). "Tool steels" are identified by a letter and a number (M2, T15, H13, etc). The major types are described as:

 

M: Molybdenum High-speed steels, 

T: Tungsten high speed steels, 

H: Chromium hot work steels or Tungsten hot work steels

A: Air hardening, Medium Alloy, Cold work steels

D: High Carbon, High chromium, cold work steels

O: Oil-hardening cold work steels

S: Shock Resisting steels

L: Low alloy special purpose tool steels

P: Low carbon mold steels

W: Water hardening tool steels

 

The other type of material is usually defined as "Alloy steel" such as the SAE/AISI 1500, 4100, 4300, 5600, 8600 series. These typically have lower alloy contents than true tool steels, but they are alloyed, typically with chromium, nickel or molybdenum singly or in combination, unlike carbon steels (SAE 1000 Steels).

 

In commercial applications there is a huge performance and price difference between "tool steels" and "alloy steels" and they are really not interchangeable terms.  I understand where the misnomer comes from, but have found it slightly confusing in a post when one refers to "tool steel" and then says the steel came from an axle or leaf spring. Probably because I deal with this jargon on a daily basis. Important for someone that is doing some advanced heat treatment and material selection, but probably not all that important for the backyard smith. 

[KYBOY]

My mistake.

 

I made the assumption :rolleyes:  that a question in this Forum would just naturally be of a non-commercial nature.

 

 

 

.

A lot of guys here are full time blacksmiths and tool makers that rely on commercial sales for thier livelyhood. I apologize if I implied something else..

[ThomasPowers]

Don't see where "Blacksmithing, General Discussion" limits this forum only to non-commercial smiths and a *lot* of us the difference between commercial and non-commercial is if we have someone willing to *pay* for what we are doing! The better you get and the more you know the more likely you are to have that happen.

I used the information I learned here from people who used to make and repoint jackhammer bits to do a job for a neighbor when he broke a bit on a holiday weekend when he had rented a hammer to get a job done. I didn't charge him but he was sure happy to try to pay me for it. (One of his brother in laws hauled the 20' utility poles that support my shop extension's roof and the other used his 4WD forklift to set them for me and neither of them accepted money---"Country Karma in Action!")

[MOblacksmith0530]

My point was that the definition of "tool steel" has changed as science and technology has advanced. If you are making tools for yourself and can stand the occasional failure you need not be as precise. I would not make a tool that I would use in front of the public to demonstrate out of anything I didn't trust. As an example I make hot punches out of sucker rod. This will be a steel somewhere in the low/medium carbon range somewhere between 25 to 45 points carbon. It will either be straight carbon on 41 or 43 series steel. I use it as forged and quench in beeswax between punching. This tool will never get very hard and therefore won't become brittle and shatter.

If I make a tool for a customer I make it out of known steel and (usually straight carbon steel) and heat treat it properly.

I know there are many out here that have access to proper heat treating equipment and they have a level of knowledge miles ahead of my own. But it is not practical to go to that extent for the average small shop and thus we use things for tools that is not made out of "tool" steel by the modern definition.

Learn from everyone and use this knowledge to the best of your abilities and take precautions until you have verified the result yourself. I think we need to take care not to come off as snobs that might discourage people from attempting these things.

Having said all of that I find straight carbon steels to be the easiest to use.

[basher]

I believe "tool steel" to be akin to "surgical steel" ie a nonsencical generalisation used by manufacturers/sales people to denote a quality steel.
The origins will most likly have been from a time when tool steels ie those used to make lathe , mill and punching tools were probably a lot more limited in scope.
Having the end use of a steel as descriptive name does not make much sence to me as a maker but probably does as a punter.
Bearingsteel, spring steel, high speed steel etc denote all sorts of steel types for the same end use
XXXX even when we know our steel types its not all that definate 1095 or 20c which is a narrower spec swedish 1095 or 1095 with batch chem so you can adjust HT accordingly.

[ThomasPowers]

I feel it's very important not to claim a steel is something unless we *KNOW* it is.

So that leaf spring *may* be 5160---but it may be a different alloy. Far better to say that "this knife was made from a leafspring" than "this knife is made from 5160"---when it may *not*!

Keeping to the straight and narrow when dealing with a customer is just good business practice IMNSHO!

(I know of several alloys that have been used for leafsprings over the years and even *once* ran into a strain hardened low alloy spring that could *not* be quench hardened enough to make a blade!)

[KYBOY]

I feel it's very important not to claim a steel is something unless we *KNOW* it is.

So that leaf spring *may* be 5160---but it may be a different alloy. Far better to say that "this knife was made from a leafspring" than "this knife is made from 5160"---when it may *not*!

Keeping to the straight and narrow when dealing with a customer is just good business practice IMNSHO!

(I know of several alloys that have been used for leafsprings over the years and even *once* ran into a strain hardened low alloy spring that could *not* be quench hardened enough to make a blade!)

I couldent agree more..I still see makers all the time saying that a knife is L6 when they are actually using saw blades..Ive got several spec tests from saw blades saved and not one of them are L6..Just 1075 plus 2% nickle or a uddenholm 15n20 and Ive seen a few that were 8670M(fairly close)..People wonder "whats the difference?" Besides the obvious chemical differences its just not fair to the customer..Of course any of them will make a good knife but people expect to get what they pay for...

 The buying public, espically the cutting tool and knife buying public are a lot more intelligent than they once were..Most of them now know the difference in steels and what to expect..Most have already had half a dozen blades made from "x" steel and know exactly what kind of edge retention to expect from it. The internet has changed the consumer greatly..They are far more educated, the sharing of knowledge and information and wisened them to the voodoo of steel..Not so long ago the maker could tell them what ever and they would take it as the gospel..Not anymore..

 Lisa now lists the heat treat info with most of her knives because customers were asking how it was heat treated before they would buy..That should say a lot.

[MOblacksmith0530]

Thomas and kyboy I agree whole heartedly I make pattern welded blades sometimes and tell the customer they were made out of steels like "X" and why "X" gives that silvery appearance etc and then explain they came from saw blades and files or whatever the base metal was. Accuracy is very important when dealing with the customer. and I would not make a tool for a customer out of mystery steel that I had not proven for the job. If I make an axe out of an old plow I make at least two from that plow and test the properties first to be sure it does as intended. Then the customer will get theirs with the understanding of what it was made of and how it was made. I have found that different plows for example have different alloys. They were the same size but one JD and one Massey for example. It was a lot of fun and a learning experience to see how they acted. If I am making a stock item it will tend to be a known steel from barstock.

I think we can agree that we need to be careful when it goes out to the public and we can be more flexible when it is for our own use, since we understand the possible failures. Having said all that I think I like bashers description the best.

[ThomasPowers]

Things like plows were often optimized on a local level. So a plow made for sandy bottomland soil might be a higher harder steel than one designed for rocky fields; the one designed to resist abrasion more and the other to resist impact. However a lot of this has disappeared in modern times as factories want to make and dealers want to stock a limited range of items.

[tomhw]

For me personally; Tool Steel = the steel I feel is most appropriate for the tool I intend to make.
Beyond that there are far too many variables to chase what with O,W,A, HSS, particle steels, pattern welded and carbides being involved.

My advice to anyone wanting to either learn or split hairs is to pick up a copy of the Machinery Handbook.

I agree with that.  I tend toward a rough and ready approach to hardenability in steels.  My shop is not qualified for much more than early 20th century ferrous technology.

[tomhw]

Things like plows were often optimized on a local level. So a plow made for sandy bottomland soil might be a higher harder steel than one designed for rocky fields; the one designed to resist abrasion more and the other to resist impact. However a lot of this has disappeared in modern times as factories want to make and dealers want to stock a limited range of items.

We are in accord.  Hobbyists, purists, and armatures are not in the same order of craftsmen as professionals who seek to provide a service to businesses with specific and particular requirements.

[LastRonin]

From an industry perspective, most tool steels have substantial alloy additions to get a desired response to heat treatment or for the mechanical properties (wear resistance, impact toughness, high temperature strength, etc). "Tool steels" are identified by a letter and a number (M2, T15, H13, etc). The major types are described as:

 

M: Molybdenum High-speed steels, 

T: Tungsten high speed steels, 

H: Chromium hot work steels or Tungsten hot work steels

A: Air hardening, Medium Alloy, Cold work steels

D: High Carbon, High chromium, cold work steels

O: Oil-hardening cold work steels

S: Shock Resisting steels

L: Low alloy special purpose tool steels

P: Low carbon mold steels

W: Water hardening tool steels

 

The other type of material is usually defined as "Alloy steel" such as the SAE/AISI 1500, 4100, 4300, 5600, 8600 series. These typically have lower alloy contents than true tool steels, but they are alloyed, typically with chromium, nickel or molybdenum singly or in combination, unlike carbon steels (SAE 1000 Steels).

 

In commercial applications there is a huge performance and price difference between "tool steels" and "alloy steels" and they are really not interchangeable terms.  I understand where the misnomer comes from, but have found it slightly confusing in a post when one refers to "tool steel" and then says the steel came from an axle or leaf spring. Probably because I deal with this jargon on a daily basis. Important for someone that is doing some advanced heat treatment and material selection, but probably not all that important for the backyard smith. 

What about X series steels, like X70 and X80...?

 

I recently was given about 120# of scrap pieces of X80 steel from a guy at a plant I do some service work for. Most of the pieces are 8" long, 1 1/8" wide and the thickness ranges from 1/2" - 3/4". The plant makes gas-line pipe. I've tried looking up the specs online, but everything I find is too metallurgically-technically jargoned for me to make sense of. Wish they made a 'Laymen's Translator' App for Google.

[Frosty]

Good thread! What we make for ourselves is on us and we can do it how we wish. What we do for others is a different matter. First we have to make things that do what they're intended to do and do it safely. Forget liability and lawyers; do you want to make something that hurts someone? I don't. Then comes the matter of honesty, to call a material something that it isn't is misrepresentation at best, fraud also comes to mind. Saying something like, If I make a tool with it it's tool steel is the kind of semantics that frankly kill information exchange and trust.

 

"Tool steel" is a term that has evolved and will continue to evolve. Even at the turn of the last century tool steel was beginning to mean something other than it did in the mid 19th. Metallurgy was getting more controlled so it was possible to custom make alloys to have specific characteristics and the "jargon" was born. It isn't a matter of secrecy or proprietary anything. Jargon is important for communications and shouldn't be confused as an exclusionist slang even though it's used as such all too often.

 

For a simple but good example the word "bit." If you say, "grab a bit." What you are saying is determined by context. If you're in the kitchen with my Mother, Grandmother or me a bit is less than a dab but more than a pinch. In Dad's shop a bit is the particular cutting tool for the machine he's operating. In the tack room and it's the part of a bridle that fits between the horse's teeth. All of those, every last one is JARGON.

 

The term jargon is sort of a derogatory term for a specialized language necessary to communicate clearly in a specific situation. the term "Tool steel" is a specific term though it is a steel category now rather than a specific steel. Not recognizing just how significant proper identification is relegates a person to doing less than a person can. Trying to fox a customer into believing one material is something higher grade is dishonest and lowers all our reputations.

 

Frankly it doesn't matter what standard you hold yourself to so long as you don't misrepresent yourself to others.

 

Frosty The Lucky.