Heat Treating Results...

Believe it or not we bought one of these, BTW this guy is on crack asking that much. MSC sells one for $1600.

http://www.ebay.com/itm/Wilson-3JR-...488?pt=LH_DefaultDomain_0&hash=item3380733ee8

For only $100.00! We immediately purchased a 50 to 60 standard and new penetrator for more than that. The machine shop was in receivership and we dove in and scooped what we could get. Left lots of stuff behind as we ran out of money.
Pierre
 
All,

Here's a pretty good read on hardness testing 101: http://www.hegewald-peschke.com/info-bereich/guidelines-to-hardness-testing.html The only thing not covered is electronic/ultrasonic methods.

I've found some pretty good Rockwell units (new production) similar to what Pierre showed in the $700 range and I'm waiting to see if one in-particular does Brinell too. It's unlikely I'll look to eBay as, I have no desire to deal with damaged or kludged-up penetrators -and gosh knows what else goes wrong with them. In half the photos, you can see they're missing some parts. And like Pierre mentioned, people seem to want more for used ones than what new ones are going for.

I'm also digging-up info about the hand-held electronic units but haven't gotten too far with that. Any words of wisdom there?

Today, I worked on the box and started to read the instruction manual on the controller. -Poorly translated. The controller has adjustable parameters on convergence which I'd like to tweak. I also saw some strange behavior when trying to step-down the temperature. Wanted to recreate the situation today but, just ran out of gas and did other reading instead.

Ray
 
All,

Here are some planned test results on heat treating. The texts I'm learning from really stress proper procedure and I decided to verify if the authors are being overly cautious (with good intentions) or if it really makes a difference. Aside from passing along what I'm learning, there's a motvation in me to post this... Specifically, I occasionally hear folks here planning to heat treat a part -and sometimes the intended part is something criticical like a bucket pin or home-made parts for a hoist etc... Worse yet, sometimes the material is not precisely known.

Summary: Propoer procedure makes a difference -and a lot moreso than I imagined!

Three varying length slugs of 1045 were heat treated with an intended Rockwell of 32-C. The slugs were 1.5" diameter with lengths of 1/2", 1" and 1.5" and were fully normalized using proper technique.

Without getting into the details of the procedure, the piece shown should have had a uniform case hardening with about 0.050" depth. Since it's the smallest piece, it should have cooked the fastest and most uniformly. So... I decided to heat the piece at the low end of 1525 and started the clock as soon as the oven reached that temperature (about 1 hour) and cooked it for 30 minutes. In reality, it should have been allowed to stabilize for about 10 minutes before starting the clock and ideal temperature should have been 1550.

After the part was heat treated, the tempering process was done properly and according to the cook book.

Here's what it looks like. The piece was face turned in 0.010" increments and on the 2nd pass the soft chewy center was visible. It didn't even harden down to the desired depth. -And by the way, you've probably seen how cold-rolled steel shows this same pattern and it's proof positive that stresses are present in non-normalized material. The Rockwell tested-out at 27-C but, at the current time, the test apparatus is not verified. I'm using a rebound type and also evaluating some brinell testers. -But before making any serious investments, want to learn more about the merits of each technique.

I heat treated some of the othe parts in proper fashion and they pretty-much produced the desired results. BTW: by peeking at the color of red inside the oven, I sure has hell (pun intended) can't tell the difference in color between 1525 and 1550. Even following the cook-book, I did not achieve uniformity in the other pieces that were done properly. It was pretty close -but no cigar... Need to read/learn/experiment more... I think it's a quenching problems but at this time do not have enough knowledge to analyze the symptoms. I'm pretty sure I'll get a handle on this in the next week or so.

BTW:... somewhere along the line, I'll include some comments about the PID controller. Seems to have some glitches -not the end of the world but minor annoyances.

Ray


View attachment 53417

i do a lot of heat treating of the knives I make. I think you should increase your soak time in the oven to insure you get the entire piece to the proper tempature. It may also be that you did not quench the part quick enough or the tempature of the quench oil was not warm enough or if using brine there are lots of things that can happen depending on the steel. Using salts to heat treat is a better way to control all the factors but it should only be done with great care and never by a novice without experienced supervision. Very serious injury can result. Be sure to normalize the piece 3 times to remove stress in metal to reduce war page and cracks. Heat uniformly and quench properly in warm quench oil. Once at room tempature put in oven and draw to desired tempature. A last note if you are unsure of initial hardening heat check the steel with a magnet. It will be non magnetic at its criticle state. Hope this helps
 
OK... moving right along here...


I made several parts this weekend requiring a TIG weld with ER80S with final finishing later. Weld caps are hard. It make the best HSS cry like a baby and eats carbide inserts faster than stainless steel. The solution? Normalize! Can't show you the part right now, it's still tapering-down in the oven.

While the oven was fired-up last night, I took a shot at carburizing a different finished part made of 1045 (It's 3.25" dia, 1/2" thick). This was a finished part that I'll have to re-finish and do a rockwell test. The part does not need this level of treatment but, it won't hurt and I'm just experimenting. Anyhow, I sealed the part in stainless foil, shot it up with CO2, cooked it at 1565 for 40 minutes and threw it in brine then, tempered it at 400 for 2 hours. This should give a 50 RC.

Hope it comes through in the picture but the finish right now looks like matte black oxide. It's not dirty at all and doen'st rub-off on your fingers. It should clean-up nice. First I'll sandblast it to see what that looks like and maybe hit it with ceramic on the lathe.

Ray
C02Part.jpg

C02Part.jpg
 
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I don't think your case is going to be very deep Ray. The CO2 may help reduce decarburization, but there is not going to be much available carbon to absorb into the surface. I have not tried it myself, but I recall an article in HSM that walked you through the process. IIRC the guy was using a commercial product, but I have heard the old timers used bone meal and oil, packed in a steel container. If I remember, I see if I can find the article when I get home.
 
Yeah, probably right -but it sure looks cool.

One book I have describes many of the modern/useful methods of carburizing and I went into this knowing well I wasn't doing a completely proper job. I was really just normalizing a couple parts and decided to try this at the last minute because the oven was hot. Anyhow, the added CO2 (as you said) probably minimized the decarburization.

I'm still trying to get a handle on quenchant. I increased the salinity and this time, it produced a 1 minute long show of what looked like foaming soda bubbles -but extremely turbulent. Wish I knew what to expect. The book I have that covers 1045 is not "cookbook". It only mentions the possible processes and "what" to do; not, "how to do it" or "what to expect".




I don't think your case is going to be very deep Ray. The CO2 may help reduce decarburization, but there is not going to be much available carbon to absorb into the surface. I have not tried it myself, but I recall an article in HSM that walked you through the process. IIRC the guy was using a commercial product, but I have heard the old timers used bone meal and oil, packed in a steel container. If I remember, I see if I can find the article when I get home.
 
OK, so I tied a "Pack Carburize" technique on a piece of 1045 scrap. It worked very well except that I managed to get surface cracks. The problem with quenchant is resolved and in this case, it worked too well. Oil would have been better in this case. It tests out at 55 RC and is very deep. One side was surface ground and I gave-up at 60 thou since I was only hoping for 50 thou. The other side (shown) was lathed and instantly punished a carbide tip and wouldn't cut.

HT1.JPG

BTW: I made more grinder hubs the other day which are two piece welded. The weld caps usually beat-up carbide so I normalized the piece first and the whole thing (caps and all) cut like butter. Now that they're shaped, I'll bring them up to 30 RC, do the final surfacing, black oxide them and call it a day.

Next project is to take a piece of tool steel and make a B&S taper reamer (can't find one commercially). I'll try to bring that up to 60+ RC. Still deciding if I should practice on a piece of tool steel first.

Ray

HT1.JPG
 
That's pretty awesome Ray. Thanks for keeping us up to date.
 
Thanks for the kind words. Since I have no artistic ability I stick to technical things. The business of heat treating is confusing when you try to glean information in bits and pieces. As I started to do more interesting lathe/mill work, it became apparent you cannot escape some heat treatment processing. Some stuff is just too darn hard to work on unless normalized and then of course, they need to be re-hardened later on. I had other parts changing shape in other places when I milled on them (internall stresses letting go). I tried reading various articles on the "Net" -and ended-up screwing-up parts (fortunately, all things from my personal pet projects).


Anyhow, the 4-5 books I've picked-up in the last several months cost just under 600 bucks with one book in particular costing $350 -and that just covers ferrous metals. And of course, the books that cover Inconel (which is what I'm really after) are even more rare. At the moment, I'm only disussing the things which I'm universally certain about and once I get more practical information, I'll pass it along.

So, you seem interested... Go ahead and ask about the quenchant and what I concocted for pack carburizing.

Ray


That's pretty awesome Ray. Thanks for keeping us up to date.
 
So, you seem interested... Go ahead and ask about the quenchant and what I concocted for pack carburizing.
Ray
Hey Ray, tell us about the quenchant and what you concocted for pack carburizing.
 
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