Sharkfood

1095 heat treat problem

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Ok, first off I’m a rookie so I could very well be doing something dumb.  

I have a blade that was forged from a piece of stock 1095 bar that I purchased.  It’s been ground to shape but is still about 1/8 inch all over.  I’m trying to heat treat it but when I quench in heated canola oil the left side of the blade is hardened but the right side digs the file.  I’m stumped.  I may have been placing the steel into the forge mostly on the same side.  Could that be it?  Any suggestions?

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After doing sone reading on this forum I think I know my problem.  I’ve created 3 blades using two different steels and all result in one side of the blade hardened after the heat treat but not the other.  I’m pretty sure I’m forging at way too high a heat.  I was getting the blades up to light red/ yellow during the forge and mostly lying them on the same side in the forge during heating.  I think I’m burning the carbon out of that one side.  

Until now I’ve only been playing with mild steel projects like Xmas ornaments, hooks and fire pokers so the forge temp didn’t seem to matter.  

Now I’m reading to heat to or below magnetic for blade forging then just past magnetic to heat treat after a few thermal cycles from just below magnetic then air cooled.  Do I generally have it correct?

Thanks. 

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Like Steve said, not all steels forge the same. Something else to consider. Did you grind to 1/8 inch then quench? Generally I like to leave mine a little heavy to allow grinding off any decarburization that may occur when quenching.

For 1095 that you asked about specifically, the recommended forging temperature is between about 1700F and 2100F. Your normalizing temperature (the part where you heat it and then let it cool in air slowly) is about 1575F then down to room temperature. When you are ready to do your quench, your austenitizing temperature is 1475F. Thicker sections can be water quenched, but for under 1/4 inch thick an oil quench is a safer route.

As far as burning the carbon out by placing it on one side repeatedly, that depends a bit on the type of forge you have and how much heat is in it. If you have a gas forge that the burner comes in at an angle and the whole forge is heated up properly and the same temperature, you should be fine. If you have a straight flame on a forge that isn't up to heat and you are using just the flame to heat the steel, then it could be a problem. With no details on your forge, we can't make a good assumption though.

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Thanks for the detailed reply.  

My forge is made from a 5-gallon air compressor tank with a single propane burner at an angle.  It certainly has hot spots though.  I have been using direct flame to heat the metal quicker (didn’t know any better I guess).  I think that’s probably the issue.  I’ll heat slower and more consistently next time.   

I was using a stock piece of 3/16 thick 1095 and forging the blade and leaving that thickness for quenching.  

Thanks a lot for the advice!

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You may want to check your internal space of your forge compared to what your burner is rated at. As a general rule of thumb, a 3/4 inch burner correctly tuned should be good for 300-350 cubic inches of open space in a forge.

If everything is good there, then you need to let your forge come up to temperature. It wastes a little gas and time waiting, but it provides much better results as you get a more even heat in your work.

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If its O.K., secondary questions:  

1.  Are there low cost thermometers for forges?

2.  Is it common practice to modify the flame in propane furnaces to have a reducing mixture?

3.  Is anyone using a thermostat to adjust the flame in propane fired furnaces?

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Low cost as in less than US$1000 or as in less than US$50?

Depends on the user and what they are using it for.  I run reducing for knifesmithing.

My house has a propane fired furnace that is controlled by a thermostat. Heat treating furnaces are often thermostat controlled. I don't recall anyone controlling a forge that way on the hobby side. Wouldn't be surprised if Johnson sold one  with such controls at a cost only a couple of times more than I paid for my current vehicle...

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Thanks folks.. I did figure out my problem.  It was all about the quench oil.  I was trying to quench 1095 with canola and it just wasn't working.   The hardening on one side was a red-herring and it was just the way the file happened to be skating made it seem like it was hard.  After moving to Parks #50, it all went well and I have hard blades.

@eutrophicated1  For forge temp gauges, I did fine this one on amazon and it works quite well.  I use it to test the temp when I'm going through normalizing cycles and then for the final heat treat.  

https://www.amazon.com/gp/product/B079HHSHLQ/ref=ppx_yo_dt_b_asin_title_o08__o00_s00?ie=UTF8&psc=1

 

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Thanks, Sharkfood, thanks, Thomas.  This thread hit me in my ignorance wheelhouse, and I appreciate the very specific information.

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A very good reference to that thermometer, Sharkfood;  can it really "look thru" the furnace opening to a spot inside?  Wondering how the lasers work;  think I'll call Amazon, and ask one of their experts...  or not.  Maybe its just my OCD wondering...  I might try building a natural gas forge for my shop next year.  Welding machine first, then grinder, etc :lol:

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The thermometer won’t tell you internal temp, only surface.  It’s still a great tool.

I started by teaching myself stick welding so I could build a forge out of an air compressor tank.  Then I bought a crappy 3x36 belt grinder which I regret now I’m building a 2x72.  Also building and a bottle-jack press so Ivan reduce the hammering time.  Having a blast!

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Right, regarding the hammer time.  I'm too old to start swinging more than a 2 pound'r much.  I've seen several bottle-jack press builds, been wondering if I should go air-over hydraulic, or straight hydraulic pump.  Didn't even bother to check the prices yet.

I'll start with stock-reduction bladesmithing first, maybe some 1080 steel.  See how that goes, then maybe build an electric heat-treat oven with PID.  

I actually made steel in my youth,  the open-hearth furnaces in East Chicago, Indiana.  Some 12 hour bottle-top stainless heats,  then some zip-zip 3hr. mild steel heats, different furnace.  250-400 tons per heat.  Beeeeeg ladles.  Had to shovel & wheelbarrow 1200lbs of manganese, 600lbs of molybdenum, 500lbs of chromium, 400lbs of magnesium, etc etc per furnace load.  Then tap the furnace with an oxygen hose threaded onto 12feet of 3/4" pipe.  Then throw up to 20 50lb bags of coke into the trough leading to the ladle.  Did you know that molten steel pouring down a trough is translucent?  You can see into it, when you're wearing those dark purple glasses.

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Ha, yeah I'm no spring chicken either...  turning 50 next year.  I've already blown out my elbow trying too hard with a 4-pound.  

I've watched press builds with hydraulic rams but just the hydraulic motors plus rams are $300-400 and that's for cheap ones that probably won't travel very fast.  For now I thought I'd start with the bottle jack.  The whole build is costing me $50.  

Sounds like you've had some fun jobs in the past!  

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