1095 warping

[Scott Davidson]

Why are my blades wanting to warp ? When i make blades from 1095 , they will slightly bend to one side , why ? My process is as follows : cut and profile , surface grind- gently, i don't grind it hard or try to take off too much. I then will hollow or flat grind , and heat to 1500 degrees and hold for about 15-20 minutes and drop into fast quench oil. This is where it warps , before i draw back the blades . Is it because of dropping it in the oil ? I have used 3/32 , 1/8 , 3/16 and 1/4 inch thick metal. I do check when i am grinding , the blades are ground straight and the same thickness on both sides . What do ya'll think is happenin . Scott

 

[murphda2]

I'm a dummy when it comes to HT, but I'm gonna say it's the dropping part. Try holding the blade by the tang and submerging the blade into your quenchant tip edge first and then agitate slowly in a cutting motion to increase the flow of oil around the blade and reduce the formation of an air pocket. Just my $0.02. I have only HT two 1095 blades and they were pretty small, but this is how I was told to do it.

 

[LRB]

I would recommend a point down quench, move it fore and aft as soon as it's in. Do this maybe 20/30 seconds depending on size, remove and using gloves, hand straighten if it's warped. You have a window of 2 or 3 minutes to straighten, then it will get too brittle.
There is no need to soak 1095 more than 5 minutes at quench temp. When grinding, go back and forth from side to side and try to keep the grinding even as you take it down. uneven grinding pressures will cause warp. A few passes one side, then a few passes other side. I would also recommend a triple normalizing before the hardening process. 1st heat 1525°, 2nd heat around 1475° 3rd around 1425/50°. This will reduce stresses, and reduce grain size. 1095 is not normally sold as spheroidized annealed, so the normalizing will benefit the grain size and structure.

 

[mike miller]

I would also take it to red hot ,let cool and repeat twice before you bring it up to the quenching temp. you may be putting some stress in the steel while grinding and normalizing it will help remove it.

 

[murphda2]

I knew someone smarter than me would chime in. I forgot all about normalizing. Feel free to chastise me later Rusty (I promise it is in my notes).

 

[bubba-san]

I agree with murph , its the dropping , because the bottom of container is cooler . Try this Heat your blade however you heat it, to a bright orange . Then use magnet to see when blade becomes fully non-magnetic , put back in forge for a few more passes , then Quench , I never lay a blade on its side when quenching it will warp almost everytime . I would not stir the quench with your knife ,use a stick or something. Also 15 -20 minutes soak after reaching 1500 degress ! I believe thats too hot . Another good thing to do is heat a piece of metal nice and hot , put it in quench , this warms up the oil . Hot knife and cold quench can also do some funny things. 1095 is a fast quench steel . 4- 10 seconds in quench is fine .

 

[Kevin R. Cashen]

Don't be surprised if you still get warps because it is one of the most complex and ubiquitous issues we deal with, the reasons why steel wants to move are countless. But I am in total agreement that the most glaring issue mentioned would be the "drop" into the oil. One of the most critical factors in proper quenching is even cooling with the same heat extraction occurring on all sides of the part. Allowing the blade to lay on the bottom or sides is almost a certain way to warp it. This also holds true normalizing, annealing or any other heat treatment, it is a big no-no to just toss a part on the floor or any other surface during normalizing. Many of us have little metal racks that hold the blades up in the air for this and also tempering operations.

 

[stabber]

Are you warming up the oil prior to the Quenching ? It should be around 140 degrees

 

[Robert Dark]

Scott,

1095 can be frustrating. Earlier this week, I had a blade about 11" long that was as straight as a string. When I put her into the forge for the first normalizing heat, she made a hard left turn.

I suspect it was stresses caused by uneven grinding. Once I straightened it out, it stayed straight.

Normalizing is a key factor in accomplishing several things, including stress relief. Also, as others have said, don't just throw the blade in the coolant. It doesn't like that and will fight you every time.

Robert

 

[bubba-san]

Don't be surprised if you still get warps because it is one of the most complex and ubiquitous issues we deal with, the reasons why steel wants to move are countless. But I am in total agreement that the most glaring issue mentioned would be the "drop" into the oil. One of the most critical factors in proper quenching is even cooling with the same heat extraction occurring on all sides of the part. Allowing the blade to lay on the bottom or sides is almost a certain way to warp it. This also holds true normalizing, annealing or any other heat treatment, it is a big no-no to just toss a part on the floor or any other surface during normalizing. Many of us have little metal racks that hold the blades up in the air for this and also tempering operations.

Hello Kevin , I agree on your theory about dropping , however if it lands on its side on bottom , it will warp. Especially if quench medium temp is not even , unless you can make knife stand on its point ?

 

[Erin Burke]

There are a couple of things that I would mention based on personal experience... some of which may run counter to what others have said.

• I agree with the others... dropping the blade into the quench is not a good idea. You will likely end up with uneven cooling, but you will also end up with a less-than-optimal cooling rate due to a lack of agitation. Some folks have mentioned a point down quench... sounds good to me. I, however, quench horizontally with the edge down, then agitate the blade longitudinally (this is mainly due to the size and shape of my quench tank).
  
• The bending can also be caused by induced stress in the steel prior to HT; either from your grinding OR (I imagine) from the mill where the steel bar-stock was rolled. It sounds like you are creating blades by stock-removal (similar to myself), and that you are not doing any forging. I have had similar problems with some of the 3/16" 1095 bar-stock that I buy. To avoid the warp during quench I will perform several 1200F stress-relief cycles after grinding and prior to final 1490F dip in the oil. Any stress-related warps will generally reveal themselves here and can easily be straighted by hand or in a straightening jig. Usually by the second third stress relief cycle, the warp will be gone, and will not show up uninvited at quench time.
  If you are dealing with forged stock, you may need to run a normalizing cycle as the others have indicated.
  
• As others have said, you may want to pre-heat your oil... but you may not. It depends on the oil. I use Parks 50, and for the longest time I was pre-heating the oil to 130F for quenching. Then one day I happened to look at the label on the Parks 50 pail which indicated the oil should be around room temp (it actually states that the working temp is 50F-120F). With Parks 50, I no longer pre-heat. I recommend that you review the literature on the oil that you are using.

Keep in mind that I am a novice - unlike some of the folks who have already commented - but these are my current practices based on the info and experience that I have today.

Erin

 

[bubba-san]

good post , The reason blades are quenched horizontolly or parallel are for a reason . If you quench a sword tip down it will curve a lot , thusly if you quench paralell it will curve less. A tanto should be quenched tip down . It is a way to control sori , I also would like to add that steel acts much diferently in water than oil. Water quenching usually produces the most visually appealing hamons.

 

[Scott Davidson]

Thanks guys . I do drop it in point first with the cutting edge down . I have been struggling with this , almost to the point of not wanting to use it any more . I just have so much laying around , that it needs to be used . Thanks so much for the help . I will try these pointers and see if this will fix my problems . I was not preheating the oil first , but will now. I will also try to ease the blade into the oil and move fore and aft , only problem i see with this is the fire that will follow shortly after.
Has anyone ever tried to heat to non magnetic with a torch on the cutting edge and set into a shallow pan to try to get a hammond line on 1095. Thanks again , Scott

 

[Erin Burke]

Thanks guys . I do drop it in point first with the cutting edge down . I have been struggling with this , almost to the point of not wanting to use it any more . I just have so much laying around , that it needs to be used . Thanks so much for the help . I will try these pointers and see if this will fix my problems . I was not preheating the oil first , but will now. I will also try to ease the blade into the oil and move fore and aft , only problem i see with this is the fire that will follow shortly after.

Scott... you don't want to "drop" it at all. You will remove the blade from the heat source with your tongs/pliers (I use extra long vise grips from HF) gripping the knife by the tang and then plunge the blade (either horizontally or vertically) into the quench. You never drop the blade into the oil, but use the tongs/pliers to move the blade back-and-forth through the oil (either tip-to-tang or blade-to-spine [never side-to-side]). Does this make sense?

You don't need to "ease" the blade into the oil. You want to plunge it in quickly... especially with 1095.

What type of oil are you using? I never have any flames during quench when I completely submerge the blade in the oil. If you are doing an edge-quench (not one of my favorite things), then you can definitely expect some fire.

Erin

 

[Scott Davidson]

Great Lakes fast quench. Ok , so submerce the complete knife, just don't let go . I got you .
Yes , with an edge quench you might get a little fire . Thanks Erin , for your help , and the others also thanks .I will give it a try , Scott

 

[Kevin R. Cashen]

Parks AAA fast quench. Ok , so submerce the complete knife, just don't let go . I got you .
Yes , with an edge quench you might get a little fire . Thanks Erin , for your help , and the others also thanks .I will give it a try , Scott

Scott, just two quick things to note, AAA is not a fast quench oil, it is actually a medium speed oil designed more for steels such as O1, 5160, 52100, L6 etc... It may actually be a bit on the slow side for 1095, which is a shallow hardening steel of the type that oils like Parks #50 (a true fast oil) was designed for. Second I know nobody just gives these oils away and you have expressed an interest in edge quenching methods. Edge quenching almost invariably results in flaming of the oil and this will trash your AAA investment in no time. Anything that oxidizes, overheats and leaves AAA or #50 sooted and cloudy from it initial clear amber color is detracting from its effectiveness. I always recommend that if folks really want to go the edge quench route that they use some alternative oil, as many of the benefits of these well formulated quenchants will not even be tapped with those methods.

You have gotten pretty good advice from the guys here- get it under the surface while still holding it with tongs (try not to get the tongs hot to avoid flaming) and you should not have any flare ups. More importantly you need to continue holding the blade in order to properly agitate it through the oil. Continuous movement in a stabbing or cutting motion in the oil is also important to avoid distortion and achieve maximum hardening.

 

[Kevin R. Cashen]

Hello Kevin , I agree on your theory about dropping , however if it lands on its side on bottom , it will warp. Especially if quench medium temp is not even , unless you can make knife stand on its point ?

Hello bubba, I am confused with your post leading me to believe that either I was not clear in my post or I am not reading yours correctly? Are we in agreement or not quite on the same page? I tried to leave no doubt that if a person dropped a blade and allowed it to lay in its side in the quench that it would most likely warp, which seems to be exactly what you believe as well. As I read your post you seem to imply an opposing viewpoint but express the exact same view, making me wonder if I could have expressed myself better.

 

[stabber]

Bubbasan stated a few good points as you did also Kevin. I see no conflict from Bubbasan's suggestions compared to yours. All very helpfull hints.2thumbs

 

[Scott Davidson]

My bad , yes my Parks AAA is for my O1 , with which i have no problems with warping , but the other is from Great Lakes Oils, and is the same as Parks # 50 . You are correct its high enough , about 175.00 for 5 gal shipped to your door . This is all great info . I have a special hoof knife that i make and have no problems with warping. When i cut out a hoof knife , i get enough metal left over to make about 3 nice size knives about 6 1/2 inches long and about 1 inche wide. To me thats enough knives to take a serious look at doing something about , considering the quantity of the hoof knives that i make a year.

Thanks for the help . When iget a chance i will let you folks know how it turned out . Scott

 

[Kevin R. Cashen]

Bubbasan stated a few good points as you did also Kevin. I see no conflict from Bubbasan's suggestions compared to yours. All very helpfull hints.2thumbs

Wow, I am just striking out entirely here, my communication skills are taking a nose dive these days. I had no conflict in my heart at all with my last post, I truly meant to correct anything that I may have miscommunicated since I also see us in total agreement. I think I may have been too heavy handed with my on-line communication over the years due the number of folks who see anything but the friendliest of motives in most of my posts . This whole internet posting really is one of the least effective methods of true communication mankind has ever devised, with no personal contact or vocal inflections single words out of place can entirely reverse intended meanings. Bubba's post conveys all of my feelings perfectly and, as he states, we are in agreement, just the single word "however" reversed things when I read it and had me worried that I had left the impression in my post that laying a blade on the bottom the quench tank was a good idea. I really must stress that my concern was that I had botched my communication in my original post, and was trying to figure out how to word it better. So no need for reconciliatory diplomacy stabber, things are all good, I just wanted to leave the right impression with my often clumsy writing style.