Rojo Pedro

Temper colors and steel

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Do different steel types show the same colors when tempered at the same temprature?

I ask because my first (bed frame) and second (coil spring) knife shaped objects came out dark straw and the third (leaf spring) came out pea cocky purple. 

All were quenched in oil and tempered at 425 for two hours in my toaster oven. 

Disclaimer. I know next to nothing and my methods are sketchy. Just curious. Thanks

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The colors are from the build up of layers of oxides, and each alloy builds them differently so yes they colors will differ as well

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Steve, with all due respect, ive never seen anything from tool steel manufacturers that, all things being equal, other than type of steel, that temper, forging, and the colors we see in the forge dont represent absolute temps.  Frank Turley, Francis Whitaker, my experience,Carpenter tech and Uddeholm steel are my references for this.  To be clear, what you see is what you get.

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Tempering is really a diffusive process much like quenching and trying to sustain a temp to fully austenize a part of steel prior to quenching, only at really low temps for tempering it alot longer to acheive this.

What really matters is getting the steel to an even heat throughout and then the time counted after that temp for the grains to expand, the surface tempering isnt that important unless its case hardened. So unless youre using an extreme heat and watching the colors crawl as a tempering method it really doesnt matter. (The traditional method)

Another important thing is if the steel ever reached room temp or if it was kept above 300 f and tempered immediately, this matters because room temp martensite slowly dissipates tempering immediately helps retain the martensite or other... Desired phase states If you ever get into those...

Something to concider is that differerent alloyed metals will retain heat differently, chromium content will oxidise faster but if its purple it reached that temp.

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On 1/31/2019 at 8:30 AM, Sly said:

What really matters is getting the steel to an even heat throughout and then the time counted after that temp

I would say held at that temp for the proper time. And you are correct, Getting an even heat is critical. 

Most important, I believe that given a competent smith, and a competent knife maker and using the same type of steel, the smith with coal forge and knife maker with the best state of the art HT equipment, that when field tested, under normal usage, bla, bla, they will get dull with relatively the same amount of usage, and each will be sharpened in the same relative time. 

So my conclusion is that the best way to HT is the one that fascinates you the most. For me thats the traditional way backed by a laymans learning and library concerning contemporary methods and techniques. And I can see and respect that you are just as smitten by the high tech approach.  ;)  

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As someone who tempered blades over and in a fire for years as well as used boiling oil and borrowing a heat treat oven or even just using a toaster oven i would have to agree on that.

While our world is filled with monkey see monkey imitate and everyone is so proud of the methods they use to acomplish their goals the science of the doing is what really attributes to success or failure, the implements are just toys and ego.

Admittedly using a solid fuel forge requires skill and experience especially if its water quenched and flame tempered, compared to stock removal heat treat with a 1000$ oven and expensive oil and then tempering with that oven on forum info requires no experience or aquired talent what so ever in comparison.

Or the guy who pays for it the answer is all the same, do you hold a good tool at the end of your effort was the fruits of your labor successful and are you happy with the time and money spent, buyer or maker.

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11 hours ago, Sly said:

Or the guy who pays for it the answer is all the same,

Naa, you knife guys are in an economically competitive world. And not much room between makers to show your clientèle you are The Man! So, snow them with technogeek and it works every time.  ;)  :)   :)

 

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Ah but see you mistake me im a blade smith not a cut away guy, my love is for the fire and swinging the hammer and not the grinding part. 

Only people i disdain are the kids on reddit who say swinging anything bigger then a 2lb will hurt your body. Or someone who makes a sword without distal and longital tapers.

As for how you temper or quench steel its just a means to an end, as long as its austenized properly and the requirements are met does it matter?

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7 hours ago, Irondragon Forge & Clay said:

Or as I always say "If you can't convince em, confuse em".:P

Dazzle them with brilliance or baffle them with BS, is a golden oldie.

But does pretentious BS ever work? -_-

Frosty The Lucky.

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7 hours ago, Frosty said:

But does pretentious BS ever work

One word: Fluffy... Toned down now on his updated website, but still...

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lol I remember Fluffy,  a complete idiot with his "cold forging truck springs into swords so as to not upset the high tech heat treat the auto makers do, which is better than any smith could."  blah blah blah .... forgetting the micro fractures and that springs want dif HT than blades anyway, hard to believe he is still in business. maybe form all his law suits? lol

for those in the dark,  we dont use his real name because he is sue happy over his claims, to anyone that complains about him

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Was he the guy making "unbreakable" swords that only weighed 2 to 3 times what battles swords weighed for about 1000 years in Europe and Japan?

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9 minutes ago, Glenn said:

As he is not available to offer his opinion, let us move on.

Sorry Glen, just responding to the question from Frosty.

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Let's pause for a moment to consider that there's a big difference between "proven science" and "manufacturing decisions".

In the science of metallurgy, there are things that work and things that don't. Atoms of iron, carbon, chromium, nickel, etc will behave in certain ways under certain conditions with different results. Heating to a specific temperature, holding for a certain length of time, cooling at a certain rate, reheating to a certain temperature, lowering to a certain (very, very cold) temperature at a certain rate -- all of these things will have specific and predictable effects, depending on the order in which they are done and the state of the steel before each procedure (for example, tempering before hardening is a waste of time, and annealing after tempering will ruin your previous heat treatment). It doesn't matter whether or not you think they will have such effects: they will.

Now, manufacturing decisions are where judgment starts coming into the picture. Any piece we make is going to have an ideal set of properties, some of which are critical and some of which are not. The decision of which properties are critical and which aren't is central to the choice of steel, whether to forge or do stock removal (or a combination), how to heat treat, and so on. Budgetary considerations come into play: Can I afford this kind of steel or this piece of equipment? Logistical concerns also become relevant: Can I accomplish procedure X with the equipment I have on hand? Do I have the skill and experience necessary to properly heat-treat [notoriously finicky steel X], or will a properly executed blade in [more forgiving steel Y] have properties I consider acceptable? 

It's also worth noting that many of these manufacturing decisions involve a cost/benefit analysis. For example, a certain steel may be perfectly acceptable with a standard heat-treatment, but benefits in certain ways from an additional cryogenic treatment. Is the additional benefit worth the additional manufacturing cost in time and material? Can that additional cost be recouped through a higher price to the customer?

The point is not whether or not fancy heat treatments or temperature-controlled ovens work. They do. The question is not whether or not you can produce a durable and completely acceptable knife with a more low-tech approach. You can. The question is What you want to accomplish, how you choose to accomplish it, and (assuming you're selling your work) is there someone willing to pay a price that adequately reflects everything (by which I also mean your aesthetic sense and knifemaking skills) that went into it?

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Sorry, it was more rhetorical than a serious question. Success depends on picking the right market.

51 minutes ago, JHCC said:

Let's pause for a moment to consider that there's a big difference between "proven science" and "manufacturing decisions".

Here's a real topic! Where in the decision making process SHOULD philosophical preference come in? I believe ethics should be high on the list but you see some that are purely philosophical. Say "traditional methods."

What defines "traditional blacksmithing?" What's the market and how do you sell your time and the labor necessary?  Seriously, how do you define and sell YOUR definition of Traditional methods? For the most part I see folks choosing a tech level rather than traditional but that's my opinion. I'll work to whatever the customer believes is "traditional" IF they're willing to pay shop rate to have me or minions wade bare footed around in peat bogs to find bog iron. THEN refine it into usable iron and make their products? Making charcoal and lunch for the minions figures in too. 

How do you sell THAT? :huh:

My opinion has the tradition of the blacksmith sitting in an air conditioned control booth sipping a Jolt Cola and monitoring everything on screens. Or walking the floor supervising operations. s/he ain't swinging a hammer in dim light, not if it's modern day traditional.

Thoughts?

Frosty The Lucky.

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I've always been amazed at how many completely a-historical  things many "traditional" smiths claim are mandatory. 

Yes there is a market for "from the ground up" items; but it's very limited and pretty much NEVER was done that way---after all currency bars show that iron was a trade good from the very early iron age rather than a DIY material.  Single authorship does not seem to have been a common ideal historically---even in shops where only 1 person signed the work, a dozen may have worked on it.

(Now the exception that proves the rule:  there is evidence that a few remote farmsteads in northern europe during the early medieval period did both smelting and forging of their own iron as they had to be pretty much self sufficient.)

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I suppose it would be a skillset to be able to make and forge from scratch using the most primative of tools to replicate steel and then the tools from that steel. 

Buuuut most of the time its a historical cult you walk into and they often get xxxxx about things like using propane or electricty powered anything delcaring theres a skillset that needs to be practiced.

I think i put it before as; its just a source of ego, it doesnt change the science of the metallurgy, sure theres a skill but its just an ends to a mean.

Every metalworking group and forum has its niches and its ways and doesnt cater well to people who do things differently, this forum is better then some but still got some of the same mentality, people do things differently in each group, and theres always a troll out there whos been doing things so long and not open minded to the methods of others. *cough* above.

I suppose lets use an example though, a person buys premade damascus rounds and uses a power hammer to make barstock, then laminates it to 1095 using a power hammer and then grinds in the bevels and the tip, puts a cheap hamon on it and calls it a san mai katana.. The japanese never made san mai they made hon san mai which has a soft core and a edge steel, to be san mai by definition it would have to have soft side plates to absorb shock and add back in toughness to the edge steel. Does it really matter? No damascus isnt really wootz steel but the term gets used enough that its now the new definition

Buuuut does it stop the brand from saying hand forged? If it was forged the pattern would be deformed so you can obviously tell the bevels were not forged. But you will still say: hand forged because thats what the martial artists want, its a selling title tag for your google foo.

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How do you differentiate between a Japanese master swordsmith who has 3 acolytes swinging sledgehammers and someone using a powerhammer?

Feels like this thread may be  heading down the "workmanship of risk" vs "workmanship of certainty" rabbit hole.....

Now mislabeling or misattributing your work is just a simple ethics issue...

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