Pouring Motor Oil on hot weld.

[NicholasWinkel]

Does it strengthen the metal at all?

[cruizer]

Going to say nope, nice smelly flamy mess though.

You need special oils, and automotive isn't one of them. Bacially used for hardening, thus making the material somewhat brittle, and it won't take a load without cracking.

[captkipp]

motor oil vs. hot weld.

Now there's an idea. I don't know all the dynamics behind this but I bet either way it makes a heck of a mess to clean up. Not to mention the obnoxious smoke and fumes. Good luck with that. I think I'd just stick with water. But if you really need and engineered type of answer, call Miller in the morning and get one of the weld engineers on the horn. They live for questions like this.

[TxDarth]

I think this might be old school....I remember doing that to metal coming out of the forge in high school shop class in maybe 1958...

[con_fuse9]

Heat treating metal is not something you guess at.

Only certain metals harden that way, most will become brittle though. Even black Smiths understood a little about steel and what color meant what temperature and when to quench and for about how long.

99 out of a 100 times you will be making things worse by quenching except maybe stainless steal (apparently you can anneal it that way - I have found no reason to test the theory though).

If you need better properties from steel, pick different steels and give it to someone that knows how to heat treat.

Barring that, go to custom knife show and talk to the black smiths.

[popspipes]

Knife maker

Heat treating metal is not something you guess at.

Only certain metals harden that way, most will become brittle though. Even black Smiths understood a little about steel and what color meant what temperature and when to quench and for about how long.

99 out of a 100 times you will be making things worse by quenching except maybe stainless steal (apparently you can anneal it that way - I have found no reason to test the theory though).

If you need better properties from steel, pick different steels and give it to someone that knows how to heat treat.

Barring that, go to custom knife show and talk to the black smiths.

I was watching a guy make knives in Branson Mo. out of railroad spikes, he quenched them in horse urine of all things, in the process of making the knife, he explained that it had minerals in it that were good for the steel..........

I use a material called Kase-Nit, its a granular type material, heat the part red, dip it in this material and it makes a coating on it, reheat and quench in cold water. This will case harden mild steel, I dont know much about the process other than what I stated, I use it for hardening small dies.

In the past on a more critical part, I sent the parts to a heat treater, I believe they used a Cyanide gas oven in a controlled enviornment.

[Kevin Meier]

Steels with high carbon content can be hardened by heating above their critical temperature and then quenching. Quenching can be done in air, oil, water, brine, and probably some other choices, the exact composition of the steel determines the best quench. The difference between the quenches is really how quickly the steel cools.

For shop tools, oil, water, and air hardening steels are available and can successfully be used in the typical hobby shop. After hardening, the part needs to be carefully tempered. Typically this is done by slowly raising the temperature until a particular color is obtained (light straw is typical).

Heat treating for optimal performance of steels in particular applications keeps a whole industry alive. I looked into the process for heat treating S7 (good for high stress and shock loading) tool steel many years ago. It went something like this: raise to 1200 degrees and hold for one hour per inch of thickness, raise to 1750 degrees within 15 minutes and hold for two hours per inch, quench and then there were more steps after quenching. This was for a "Battlebot" weapon in a hobby shop. I think we hired out the pieces and went with an air-hardening steel.

[Sberry]

Made it my whole career without knowing anything about it,,, ha,,, and know very little about steel in general above mild steel.

[Keith_J]

Won't harden most weldable steels. The transition point is usually well above the "glowing red" stage. Unless you are welding with oxy-fuel, the weld pretty much cools through this stage rapidly because of the high heat in arc processes and the cool metal around.

This is why preheat is used in tool steel alloys and thick sections, to limit the self-quenching effect so the weld isn't brittle. Thermal expansion is the other reason, preheat limits these stress effects.

The thermal expansion isn't linear, the transition point where a steel could be hardened shows a jump in expansion, this is the change in crystalline structure from body-centered cubic to face centered cubic structure. Another way to tell is magnetism. BCC is magnetic, FCC isn't. Which also explains why 300 series stainless expands more when heated even though it is 75% iron by mass. And non-magnetic for the most part.

[Andy]

he quenched them in horse urine of all things

And you thought the motor oil would smell bad!

[popspipes]

And you thought the motor oil would smell bad!

I asked the guy what he was quenching with as he did this often in the process of making the knife, his reply was, take a sniff of the bucket and you will know right away what it is! After talking to him for some time I believe he was truthful, but then again I didnt smell the bucket ha!

[popspipes]

And you thought the motor oil would smell bad!

I asked the guy what he was quenching with as he did this often in the process of making the knife, his reply was, take a sniff of the bucket and you will know right away what it is! After talking to him for some time I believe he was truthful, but then again I didnt smell the bucket ha!

One other thing I noticed was that he kept his nose out of the steam as he was quenching it..........

[dunes]

As stated above, heat treating is a controlled process that can differ depending on the composition of steel (carbon content, alloys, etc.)

On lower carbon/mild steels, Kasenit is basically a process of adding more carbon to the "skin" of the steel. Another method used to be heating the metal in bone (crushed). Since life forms(cattle and horses here) are carbon based, this was a method of adding more carbon to the steel. The old Springfield 1903 rifle receivers were produced using this method.

[PTsideshow]

I will add this as a safety warning about using used motor oil as a finish for forged or other worked steel items.
Back in the olden days, before all the fancy metals were used in the engines and oil was truly an organic product with few additives. used motor oil was used for putting a coating that would be slow to rust. In high school welding and blacksmithing shop classes, we used it because it was cheap and we had a free supply from the auto shop class. The oil didn't have any synthetic additives or synthetic oil mixes in it. Also the metal that would be from wear in the oil from the engines wasn't all this fancy crap (Heavy Metals) that are in engine now for wear etc. Stuff that when heated is nasty to breath, same as welding fumes. Don't do it!
For an oil finish on fireplace tools, dinner triangles, hooks and other smith type utensils. All you need is to heat the metal to around\black heat 450°F or there abouts. you then can wipe it on with a rag, dip the item, pour it on, or use aPIG BRISTLE BRUSH only no cheap plastic brushes as the bristles will melt. As it has been stated keep your head out of the fumes. Use Food grade cooking oils for eating or food utensils, peanut or canola have a high smoke point temp this oil can be "used". Some items will retain the smell of the oil for a while.

A smith used oil from a french frier his stuff smelled like french fries for a while drove some people nuts trying to figure out where the smell was coming from.

There is no need to heat the metal above the black level.

I think the problem comes from "The legends in their own minds" confusing oil hardening tool steel with regular steel. And the if it works for that, it will work for any steel which isn't true. There are certain steps and temps both hardening and then tempering that have to be followed to get the proper results.

I will also add that knife makers have more BS about steel and knife making procedures per minute and per pound than any other trade or activity dealing with metal. Most are based in tradition rather than fact! But that is best left for somebody that cares to argue a never ending discussion.

[1930case]

Also the metal that would be from wear in the oil from the engines wasn't all this fancy crap (Heavy Metals) that are in engine now for wear etc.

Babbitt etc contained lead too. Used oil was never healthy, it's just that "health" wasn't a concern back in the day.