At a guess I would say it started to be come common with the advent of the industrial revolution, with the switch over to first crucible steels then Bessemer steels , giving more consistent formulation, as well as the addition of Manganese in most grades of steel.

MP

The problem with finding answers to this type of question, is the knowledge was around long before anyone recorded it. If someone figured out that using oil gave better results then water for a specific steel, he certainly didn't go around telling anyone. It wasn't until something because common knowledge, that history starts to record it's use. Also, since using a oil quench would have been something the working class did, those that recorded information and history, would not have found it worthy of note.

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The problem with finding answers to this type of question, is the knowledge was around long before anyone recorded it. If someone figured out that using oil gave better results then water for a specific steel, he certainly didn't go around telling anyone. It wasn't until something because common knowledge, that history starts to record it's use. Also, since using a oil quench would have been something the working class did, those that recorded information and history, would not have found it worthy of note.

actually given the fact that it was not nobles who created the business like the steel industry but instead it was working-class people like Andrew Carnegie, Thomas Edison, even Joesfe Rockafeller all really rages to ritches stories. its likely the invention of O1 that really oil use became common.

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actually given the fact that it was not nobles who created the business like the steel industry but instead it was working-class people like Andrew Carnegie, Thomas Edison, even Joesfe Rockafeller all really rages to ritches stories. its likely the invention of O1 that really oil use became common.

Quite the contrary I think. Oil as a quenchant is probably ancient in origin, just not the kind of oil we use today. Whale oil was incredibly important to the rise of the industrial revolution and whale oil was a commodity over 1000 years ago. The idea that nobody ever tried to use it as a quenching medium is probably because of exactly what Gerald mentions. When you consider the importance of making a high quality steel in the ancient world, you have to consider the fact that this was primarily a weapons technology. When you discovered something that made your weaponry superior to anyone else's, or gave you a more consistent process, you didn't tell anyone about it. You certainly didn't write it down anywhere. This was coveted knowledge and not to be shared openly by any means. I think O1 and other specifically oil hardening steels were developed because oil as a medium was already in common use. The steel was likely developed with the quenchant qualities in mind, not the other way around.

whale oil was pretty commonly used as quench oil as late as the 40s-50s. Pretty sure it is mentioned in Practical blacksmithing (orginlaly written 1890s) and I know it is in my oldest copy of machinery handbook (1912) I would not be surprised if oil was mentioned in De Re Metalica (1556) as well. I seem to remember tallow mentioned but it has been years since I read it. I know of a heat treating shop that was still using whale oil for some jobs as late as the 1990s.

MP

Kevin Stinson quote:

"so there was no way to know if your alternative works until you have a way to accurately judge hardness and that was not until the industrial revolution"

I disagree somewhat with this assumption. While the quantification of hardness was not numeric with one of the various scales that we have today, hardness could be judged. We do it all the time when we test the hardened cutting edge by attempting to file it. They had files. Yes, hand cut, but files. If it cut the material, the file was sufficiently hard regardless of the Rockwell. This principle (sufficiency)was followed in many places and in many processes.

I will add as a point to ponder: Oil or water does not chemically alter the metal's make up. It's heat extraction. Will the quench medium extract the heat sufficiently to allow the temperature change necessary for that steel to harden? The necessity to alter and tune the quenchant's character is evident when water is salted to form brine and in the preheating of quenching oil. I realize this simple fact is elementary to most of us bladesmiths so bear with me.

Those of us who regularly work with ancient steels tend to refer to things as pre-Bessemer or Post-Bessemer as it is a significant dividing line in working with steel. Having to tell a medieval sword collector that one of their babies appears to have post-Bessemer characteristics is unpleasant all the way around. The number of people who are not aware of the profound differences between modern alloys and ancient steel is evident in the number of times I have had people take the position that all this metallurgical nonsense and proper quench oils isn’t necessary because our ancestors made the best blades ever and they didn’t bother with any of it. 1. They made some pretty awful blades too, 2. They didn’t work with the same materials, not even remotely the same. It takes me back to one of my favorite sayings- alloying changed everything.

Folks who have never worked with an ancient steel type, i.e. non alloyed iron carbon system, may have no idea how incredibly shallow hardening they are. To put it bluntly, with the exception of a few specialized circumstances, oil is just not fast enough, even a modern seven second oil will struggle with any significant cross section. If truly hardened steel is your goal there was no reason to bother with anything other than water until the advent of alloying that could suppress pearlite formation, with Mn being one of the first and most common. That is not to say that oil was never used, but the question we really need to ask is- was oil used in a way that would have been satisfactory to our modern ideas of heat treatment? I could see it being used to create very fine non-martensitic structures, as many ancient blades were not hardened in the same way that we would call “hardened.” But many indeed were martensitic in nature, and I have little doubt that those were quenched in water.

I cannot recall if there is any mention of quenchants in De Re Metallica, it is mostly devoted to the mining and production of metals. I don’t have time to re-read it now, but a quick look through my copy, and a scan of the index, shows nothing. Distortion and cracking issues in parts drove much of the development of deeper hardening alloys in the early 20th century so it is hard to say in a “chicken or egg” context but I would say the development of deeper hardening alloys drove the exploration of better oil based quenchants.

I may have been thinking of De la pirotechnia been a LONG time since I read either.

Kevin said: Folks who have never worked with an ancient steel type, i.e. non alloyed iron carbon system, may have no idea how incredibly shallow hardening they are. To put it bluntly, with the exception of a few specialized circumstances, oil is just not fast enough, even a modern seven second oil will struggle with any significant cross section.

I seem to remember reading somewhere that even our modern versions of "simple steels" (1070. 1095, etc.) only harden to a depth of about 3mm from the face or edges. So yes, in sections that exceed say, 5 or 6mm, you do not get through hardening. It has occurred to me that this might be something very desirable in larger blades. Is it possible that this was an objective trait sought after by smiths who only had these shallow hardening steels? Could the use of oil rather than water or brine have allowed them to create a more desirable blade condition in pre-Bessemer times?

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Kevin said: Folks who have never worked with an ancient steel type, i.e. non alloyed iron carbon system, may have no idea how incredibly shallow hardening they are. To put it bluntly, with the exception of a few specialized circumstances, oil is just not fast enough, even a modern seven second oil will struggle with any significant cross section.

I seem to remember reading somewhere that even our modern versions of "simple steels" (1070. 1095, etc.) only harden to a depth of about 3mm from the face or edges. So yes, in sections that exceed say, 5 or 6mm, you do not get through hardening. It has occurred to me that this might be something very desirable in larger blades. Is it possible that this was an objective trait sought after by smiths who only had these shallow hardening steels? Could the use of oil rather than water or brine have allowed them to create a more desirable blade condition in pre-Bessemer times?

With 1095 4mm to 5mm sections will start showing pearlite colonies in the center with most oils. I have pushed it to slightly over 6.5 to 7 mm with ideal conditions and a fast (7 second) oil. Bloomery product will vary but you would be very lucky to avoid pearlite in sections greater than 2.5mm with a carefully engineered seven second oil.

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With 1095 4mm to 5mm sections will start showing pearlite colonies in the center with most oils. I have pushed it to slightly over 6.5 to 7 mm with ideal conditions and a fast (7 second) oil. Bloomery product will vary but you would be very lucky to avoid pearlite in sections greater than 2.5mm with a carefully engineered seven second oil.

Would that be a desirable trait in large blade, like broadsword sized? In other words, would a pre-Bessemer smith, working with bloomery steels and iron, have preferred the oil quench (let's assume whale oil because it was readily available) over water, specifically for its ability to form an adequately hardened exterior over a softer core? Especially if it was less prone to cracking in the quench?

By experience with bloom has been it has about half the depth of hardening of 1095 or even less in some cases. I seem to remember a reference to some fine springs for locks being quenched in tallow , that might be what I was remembering.

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actually given the fact that it was not nobles who created the business like the steel industry but instead it was working-class people like Andrew Carnegie, Thomas Edison, even Joesfe Rockafeller all really rages to ritches stories. its likely the invention of O1 that really oil use became common.

You mean someone like Benjamin Huntsman?