Heat treat help!

N

Nikk

Joined
Apr 10, 2000
Messages
49
I'm working on a six-inch blade made of 1095. I quenched it in water and it comes up around Rc 55 or a little less measured by graduated files. I tried requenching after annealing with the same result. Also getting bad warpage. I thought 1095 would be a lot harder than 55. What's the problem? Also I tried quenching point down and edge down. Both ways warped a lot. Any suggestions would be appreciated.
 
Did you heat to non-magnetic? Did he heat slowly and evenly?

Other causes of warping are uneven grind, more metal on one side than the other.
 
boy this site used to be easy to get on,now you got to have a education.what happen!!!! royboy
 
I could also recommend switching to an oil quench at about 140 degrees F...Water quenching can be a bit rough on 1095...

Running Dog
 
Running Dog is right, I would go to oil at 140 and don't get too hot. Non-magnetic is all you need. Did you normalize before your quench? LOL
 
I like to use a heavy oil (used 40W) try working out your hardening problems on a scrap piece ( it seperates hardening from grinding problems)

Now lets see if this goes in or disappears like it did last time:(
 
Are you using new or old stock.If it is old stock are you sure that it is 1095 and if it is new I would try another piece of the bar and if it does the same thing I would contact my supplier and Find out if they sent you the correct steel.
Because after a quench it shoukd be so hard that the files will just slip and then after you draw it back you would have to adjust the drawing heat to get the hardness that you are wanting.
I guess I should ask if this rc is after you drew it back or if it is just straight out of the quench ?
Bruce
 
tHANKS FOR the advice everyone. I will try heated oil, as several suggested. I'm using new stock and I'm heating to non-magnetic. I annealed before each quench, so oil seems like the best suggestion. I use 10-40 oil on other steels but I thought the 1000 series were supposed to be water quenched. Another problem is that the blade is pretty thin. Thanks again.

ps. to beknives: I checked the hardness right after the quench. Like you, I was wondering if the steel could be something else. I bought it from Albraco in NYC (cheap). I might try quenching a sample before forging, as suggested above.
 
A water quench should make the steel harder than most any file and on a thin blade I'd be afraid of warping and cracking. If the blade is reeealllly thin, you may have a serious case of decarb going on. Not much help for that. How are you heating the blade up? Electric furnace, coal/gas forge or oxy/acetylene torch? It's always a good idea to leave the blade a little thicker for the quench than the finished dimensions. That way, you will most likely remove all the decarbed steel during final finishing. The edge is most critical. Even on thin blades I try to leave a blunt edge of at least 1/16" for the quench.

As to the oil, I've used 10W30 from oil changes for years with fair results. Organic oils like vegetable oils will generally give a faster quench for the 10XX series steels. The key is to keep the oil thin. That's the reason you should heat it up to around 125 - 150 for the best results. Fry up a big mess of taters using your favorite deep fry oil and try the leftover oil for your quench next time. Makes the shop smell like a fast food joint and isn't carcinogenic like petroleum based oils. Cheap too!
 
I never have warpage after the quench. It all gets solved in the normalizing cycles. If you can normalize the blade 3 times without warpage then there won't be any after the quench either. If you are getting warpage during the normalizing there's no sense in proceding to the quench. Instead, its time to go back to the forge and straighten the blade and then try normalizing again. The blade should go through all 3 normalizing cycles without any warpage, then anneal and then quench. It wont warp no matter how thin. I was having the darndest time with warpage when I started making ultra thin arrowheads. They're very tricky but they taught me to look at my forging closer becuase thats were warpage begins. The uneven stress hammered into the blade. Normalizing exposes it and if you start looking at your hammer marks and the directions of warpage it will give you clues to where you're screwing up. Normalize the fool out of your blades. I know its a lot of thumb twiddling time but it really makes the difference. Here's an article I authored:
http://www.expage.com/heattreat
 
Tim, I think that is a very important bit of information. I hope it stays with me. I have browsed that page in the past and that advice did not sink in.

ghostdog
 
sounds like your heat treating tongs would be just the thing to temper the the fullered area of a double edged blade and a lot more controlable than a torch
 
Nikk,

your bigest problem is your choice of the steel 1095. This steel is notoriously hard to heat treat because of its low manganese content.
Because of the low manganese content of this steel in makes it very hard to get the steel quenched below the nose of the Isothermal Transformation curve. If not cooled below this curve fast enough the steel will form pearlite in addition to martensite. This pearlite will give you a weaker blade.

People tend to think because 1095 has a high carbon content it will yeild a better blade. The plain truth is that in most simple carbon steels .60 carbon is all thats needed to obtain maximum hardness. a better coice for carbon blades would be 1084. It has pleanty of carbon and twice the manganese of 1095. The manganese makes the 1084 a deeper hardening steel and is much more forgiving in the heat treat.
 
Some of the problem may be the way in which you are quenching. Water will boil around the blade and create a steam jacket that will not allow enough water to come into contact with the hot steel, hence a slow quench. Make sure that you have enough water and drive the steel into the water fast enough to keep the steel in contact with cold water not steam. HTH.

G2
 
Brine gives a fast quench, and has worked well for me for 1095. I had very good results with my latest using epsom salts. Bluing salts also work well, from what I've read. Table salt isn't the greatest, and I wouldn't reccomend it. Something else I thought of, how big of a quench tank are you using? If you have a larger volume of water, then it heats it all up slower, circulates more, and will suck away all that heat that much faster.
Just some ideas.
 
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