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Heat Treat Information, data, FAQ

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Heat Treat Information, data, FAQ


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Heat Treating 1095

Reference data: ASM Book: Practical Heat Treating by Boyer

Written by Tracy Mickley

www.USAknifemaker.com

1095 is a high carbon steel with .95% carbon (the 95 in 1095) and is proven, good quality knife steel with good edge retention. 1095 is considered slightly “fussier” about heat treating than say 1080 or 5160. This isn’t a deal break at all and really can be mostly ignored. Follow the recipe below and you shouldn’t have any problem.

 

Normalizing: Normalize by bringing to 1575F, soak for 5 minutes and allowing to cool in still air. Normalizing steel allows the crystalline structure to be reset and resets the carbides back to uniformity. Steel doesn’t like uneven structure. If the carbides have gotten all bunched up and oversized from forging, the steel won’t hold an edge as it potentially could. Bar stock from the mill probably shouldn’t have to be Normalized, especially if it has been annealed. Material that has been forged could probably benefit. Basically, heat it in your forge or oven and let it air cool. Done.

 

Annealing: Anneal by heating to 1475F and cool at a rate no faster than 50F per hour. Generally, most guys heat to temperature in their forge as the last heat of the day, turn off the forge and let the steel cool in the forge overnight. If you have other work you want done, I use a half size trash can full of vermiculite. I heat a couple large bars of scrap steel to add mass/heat. I heat the steel to temperature and put it all in the vermiculite to cool down slowing using the vermiculite as an insulator. Cooling slower in the forge works better but cooking in the vermiculite works fairly well also. Some guys use lime instead of vermiculite.

 

Hardening: Heat to 1475F or past non-magnetic which is around 1425F. Generally, in a forge, this means heating it until a magnet doesn’t stick and then “just a little more” to get the extra heat into the steel past non-magnetic. A few minutes at this temperature will not grow grain but does allow the carbon to get “into solution”. Overheating steel into the 1550F 1600F range and beyond and soaking it will grow grain. Simple, heat it to non-magnetic, give it another minute or so to heat a bit more, quench. You will see somewhere, a lot of places in fact, that the steel really needs to be cooled off at a high rate, like 1 to 2 seconds and that is absolutely true. That doesn’t mean you only have 1 second to get from your heat source to your quench. Moving a blazing hot piece of steel from heat to oil is where a lot of fires get started. A guy knocks over the oil, drops the red hot steel into the oil and instant fire! The steel will retain heat and survive a few seconds in the air as you move from heat to quench. Do this safely and be prepared for a flare up of fire and a large amount of smoke. Always be prepared for a fire.

 

Tempering: If you did everything right quenching, your steel is around 66RC and fragile as glass. If you drop it now, it will shatter. You want to temper it as soon as it gets to room temperature. I have a left a piece of steel overnight untempered and found it cracked the next day from the stress hardening puts into the steel. It’s rare but it happens. Temper twice at 2 hours each allowing the steel to cool back to room temperature between cycles.

 

  • 450F yields approximately 62RC
  • 500F yields approximately 59-60RC which is where most will want this steel.
  • 600F yields approximately 58RC

Cryo Treatment: Cryo treatment, soaking steel after hardening but before tempering at temperatures at least minus -90F (dry ice range) to minus -290F (liquid nitrogen range) for eight hours.  Most high carbon steels are generally not cryo treated as the benefit to carbon steels is usually not as significant as it is with the newer super stainless steels. Many people will say a properly heat treated steel should not need any cryo treatment as it only “makes up for a poor heat treat” This sounds good but isn’t necessarily true. Cryo treatment is an industry recognized practice in heat treating and simply wouldn’t exist as an unnecessary expense if wasn’t a legitimate extension of the heat treat, quench and temper process. Big business doesn’t waste money on steps on heat treating it doesn’t need to do. Having said all that, most don’t cryo treat carbon steels but you can if you want. Soak it in liquid nitrogen overnight or even a cooler full of dry ice. You will read about guys using acetone in dry ice. Acetone is crazy flammable. Avoid it please. Use Kerosene or even diesel fuel if you feel you need a liquid medium but just putting your blade under a block of dry is all you need to do. Some guys do one low temper heat at at 300F to 350F sometimes called a “snap temper” to take some of the stress out of a hardened blade before cryo. This lowers the chance of cracking the blade. I have never had one crack from cryo treating a blade after quenching but that just means I have been lucky. Eventually I will, it is just a matter of time.

Austempering: This is a process of hardening steel into Bainite, something we knife guys generally don’t use. We are after Martinsite steel.

 

Heat Treating 1080 or 1084

Reference data: ASM Book: Practical Heat Treating by Boyer

Written by Tracy Mickley

www.USAknifemaker.com

 

1080 or 1084 is a high carbon steel with .80% carbon (the 80 in 1080) and is proven, good quality knife steel with good edge retention. 1080/1084 is slow close together the industry specifications overlap to the degree that 1084 could be closer to the 1080 and vice versa when tested. You will hear about 1084fg which has a bit of vanadium added to reduce grain size. I have never hear anyone testing for a difference in performance between 1080 and 1084 and it is generally assumed they perform so similarly they are practically the same steel despite slightly different specifications. We will just call it 1080 to keep it simple.

Normalizing: Normalize by bringing to 1600F, soak for 4 minutes and allowing to cool in still air. Normalizing steel allows the crystalline structure to be reset and redistributes the carbides back to uniformity in the structure of the metal. Steel doesn’t like uneven structure. If the carbides have gotten all bunched up and oversized from forging, the steel won’t hold an edge as it potentially could. Bar stock from the mill probably shouldn’t have to be Normalized, especially if it has been annealed. Material that has been forged could probably benefit. Basically, heat it in your forge or oven and let it air cool. Done.

Annealing: Anneal by heating to 1500F and cool at a rate no faster than 50F per hour. Generally, most guys heat to temperature in their forge as the last heat of the day, turn off the forge and let the steel cool in the forge overnight. If you have other work you want done, I use a half size trash can full of vermiculite. I heat a couple large bars of scrap steel to add mass/heat. I heat the steel to temperature and put it all in the vermiculite to cool down slowing using the vermiculite as an insulator. Cooling slower in the forge works better but cooking in the vermiculite works fairly well also. Some guys use lime instead of vermiculite.

Hardening: Heat to 1500F or past non-magnetic which is around 1425F. Generally, in a forge, this means heating it until a magnet doesn’t stick and then “just a little more” to get the extra heat into the steel past non-magnetic. A few minutes at this temperature will not grow grain but does allow the carbon to get “into solution”. Overheating steel into the 1550F 1600F range and beyond and soaking it will grow grain. Simple, heat it to non-magnetic, give it another minute or so to heat a bit more, quench. You will see somewhere, a lot of places in fact, that the steel really needs to be cooled off at a high rate, like 1 to 2 seconds and that is absolutely true. That doesn’t mean you only have 1 second to get from your heat source to your quench. Moving a blazing hot piece of steel from heat to oil is where a lot of fires get started. A guy knocks over the oil, drops the red hot steel into the oil and instant fire! The steel will retain heat and survive a few seconds in the air as you move from heat to quench. Do this safely and be prepared for a flare up of fire and a large amount of smoke. Always be prepared for a fire.

 

Tempering: If you did everything right quenching, your steel is around 65RC and fragile as glass. If you drop it now, it will shatter. You want to temper it as soon as it gets to room temperature. I have a left a piece of steel overnight untempered and found it cracked the next day from the stress hardening puts into the steel. It’s rare but it happens. Temper twice at 2 hours each allowing the steel to cool back to room temperature between cycles.

  • 400F yields approximately 62RC
  • 500F yields approximately 59-60RC which is where most will want this steel.
  • 600F yields approximately 57RC

 

 Cryo Treatment: Cryo treatment, soaking steel after hardening but before tempering at temperatures at least minus -90F (dry ice range) to minus -290F (liquid nitrogen range) for eight hours.  Most high carbon steels are generally not cryo treated as the benefit to carbon steels is usually not as significant as it is with the newer super stainless steels. Many people will say a properly heat treated steel should not need any cryo treatment as it only “makes up for a poor heat treat” This sounds good but isn’t necessarily true. Cryo treatment is an industry recognized practice in heat treating and simply wouldn’t exist as an unnecessary expense if wasn’t a legitimate extension of the heat treat, quench and temper process. Big business doesn’t waste money on steps on heat treating it doesn’t need to do. Having said all that, most don’t cryo treat carbon steels but you can if you want. Soak it in liquid nitrogen overnight or even a cooler full of dry ice. You will read about guys using acetone in dry ice. Acetone is crazy flammable. Avoid it please. Use Kerosene or even diesel fuel if you feel you need a liquid medium but just putting your blade under a block of dry is all you need to do. Some guys do one low temper heat at at 300F to 350F sometimes called a “snap temper” to take some of the stress out of a hardened blade before cryo. This lowers the chance of cracking the blade. I have never had one crack from cryo treating a blade after quenching but that just means I have been lucky. Eventually I will, it is just a matter of time.

 

Austempering: This is a process of hardening steel into Bainite, something we knife guys generally don’t use. We are after Martinsite steel.

 

Poor Man’s heat treating of 1095 – 1080 - 1084

 

Written by Tracy Mickley, owner of:

Midwest Knifemakers Supply, LLC at www.USAKnifemaker.com

Knife Dogs Knife Forum at www.KnifeDogs.com

 

This is remarkably easy and can be done a dozen different ways. A simple propane torch, magnet and bucket of oil or even water will get the job done. The more precise you are about heat treating your steel, the better result you will have. Use the internet to research different ways to heat treat. Visit most any of the knife making forums and search for heat treating for 1095 1084 or 1080. They are all so close the only difference will be slightly different temperatures and resulting hardness.

 

Normalize:

Normalizing steel resets the steel crystalline structure and will redistribute the carbides to a uniform size across the metal structure. Uneven crystalline structure creates stress and weakness. Uneven carbide size and distribution lowers the cutting performance. Normalizing is such an easy step it is worth doing. Heat to 1550F to 1600F depending on the steel.  Allow to cool slowly in still air. Done. Generally, steel that comes in bar form from a mill is often annealed and probably doesn’t need to be normalized. It still wouldn’t hurt to do it. Read on for how to do this poor man’s style if you don’t have a forge or heat treat furnace (oven).  

 

Annealing:

To anneal, heat to 1475F to 1500F, cool very slowly by leaving in a furnace (heat treat oven) to return to room temperature. Your rate of cooking should be 50F per hour at most. I heat mine to temperature and then it in a bucket of vermiculite to cool slowly. Some guys use a tub of lime. I put in some scrap steel I have heated up to help add heat mass and slow down the cooling rate.

 

Hardening:

Heat to 1475F to 1500F (steel type depending) until the metal is just past non-magnetic. Non-magnetic is around 1425F. A propane (or MAPP gas) torch played evenly along the blade will get the job done. Try to get the heat color evenly across the blade. You don’t need to harden the entire knife blank. Just the blade is good enough. Don’t worry about hardening the handle. It will never cut anything and it will be more than hard enough for use as a handle. Still, you can if you want to.

Alternatively, you can make a poor man’s forge in charcoal BBQ grill using a hair dryer to fan the charcoals hot enough. This is amazingly easy. Pile up some charcoal in your BBQ and get them going good. Aim your hair dryer at the charcoal and turn it on. See how hot the coals get from the blower on the hair dryer. Some guys will take a pipe and put one buried in the charcoal and duct tape the other end to their hair dryer. This forces air up through the charcoal and is pretty close to genuine blacksmith forge.

Put your knife in the pile of charcoal and heat it up. It won’t take very long at all. These steels doesn’t need a long soak time. A couple minutes is enough. In practice, you heat the blade and keep touching a magnet to the blade. When the magnet doesn’t stick any more, give it a minute more of heat and then quickly plunge the blade into your quench oil. Fire will flare up where the hot blade meets the surface of the oil. Be ready for that. You should slowly agitate the blade up and down or side to side along the thin edge. This helps remove any insulating air or gas bubbles. Do not agitate side to side as the soft metal can actually warp from the fluid being cooler on side versus the other. Agitate so the fluid moves evenly over both sides of the blade. The blade is very brittle at this point. If you drop it on hard surface, it will crack or may shatter like glass. When it reaches 100F or less, start your temper cycles to reduce the stress. Handle your blade carefully at this stage or you may end up with a cracked or broken blade. It will help if you pre-heat the oil to around 100F. This can be done by heating up some junk steel and sticking it in the oil a couple times.

 

Temper:

Heat up the blade for two cycles of two hours each. Many use their kitchen oven for this. Put the blade in the center of the oven away from the elements. Make sure all the oil is cleaned from the blade or your house will smell like oily smoke and your knife making career may be cut short by the boss of the kitchen.  Consider picking up a cheap table top oven at the thrift store if you are going to make more knives. The temperatures for house hold or small table top ovens are often wildly inaccurate. Use an oven thermometer to get close to your target oven temperature. Allow the blade to return to room temperature between temper cycles. There is enough difference in temper temperatures here that you want to check out the specific steel for the proper temperature to achieve a desired hardness. Most custom knives tend to be hardened to 59RC for a good compromise between edge retention, toughness and sharpening ease. A harder blade, say 61 to 62RC will generally cut longer between sharpening sessions. It will also generally chip easier along the cutting edge. It will also take longer to sharpen. A softer blade, say 57RC, will chip less, be easier to sharpen and will bend quite a bit more before snapping. The edge will not stay sharp as long.

More on Quenching:

Quenching oil is very sophisticated in design and application. If you can afford it, buy some and use it. In place of that, use low viscosity motor oil or even canola, vegetable or peanut oil. It will work. It won’t be perfect and veteran knife makers will tell you to use dedicated heat treat quench oil to get better results. I recommend that also. I also know most any oil will work “good enough” for our purposes here. You can even use water and something called “interrupted quench” but let’s leave that for another time.

Watch out for fire flaring up during quenching! There will be fire and smelly, heavy smoke. Be ready and be safe. Do not breathe in the fumes. Wear eye protection. Wear heavy leather gloves and apron.  Have a fire extinguisher nearby. Many shops have been lost to fire by someone knocking over burning quench oil. A surface fire on quench oil is not the end of the world. Simply put a lid on your quench oil container to smother it and put out the fire. You should end up around 65RC in hardness. Visit Youtube.com  and search for “quench knife” to see dozens of short videos on what to expect. This isn’t that hard but you do need to respect the hazards.

 

Blade Bending:

Chances are your blade will be perfectly straight from quenching. Once in a while, they warp a little. Check it during quench before it cools down to less than 200F by looking down the spine. If you see a warp, now is the time to bend it slightly back to being straight and it should take.

Have fun. Be safe…

 

Heat Treating Stainless Blade Steels at Ranger Original Handcrafted Knives
Special Thanks to Rob Ridley of Ranger Original for this Information

We have had a number of people ask us for our “secrets” about heat treating knife blades. While we appreciate the compliment, there really are no secrets – and what works for us may not be your favoured solutions. Here are our recipes. You may copy them, publish them or use them as you please. We have drawn from various sources, including Crucible data sheets, other steel suppliers and postings on Blade Forums as well as a good dose of personal experience.

All of our stainless blades get double wrapped in high temperature, 309SS foil envelopes – with double folded seams pressed down firmly. Always put them in the envelope the same way – so you can put them in spine down and pull them out by the handle, instead of the tip.  We use brown paper (no idea why brown – just what we use) in pieces about 2 x 2 inches. 2 pieces for an average hunter and four for a big bowie. The trick is to use enough paper to eat up the Oxygen in the envelope – without blowing up the envelope like a balloon.

154CM, CPM154, ATS34

All three of these, heat treat the same. After a full speed ramp up to temperature, they soak 45 minutes to an hour in the Evenheat Oven at 1950F degrees. Then they get placed – still in the foil – spine down – then flat - on a 1” aluminum plate. The second aluminum plate is placed on top and pressure is applied. We used to use weights for the pressure, but now we use clamps. You are looking for good firm contact. If you are thinking hydraulics you are thinking WAY too much pressure. After 2 minutes (or less) they will be hand cool, and ready to remove from the foil for cryogenics. They don’t have to go straight into cryo, but aim for something less than an hour from plate quenching. We use liquid nitrogen for cryo but dry ice in acetone will also do.  The household freezer is no use at all. They probably only need a couple hours in cryo, but we leave them overnight.

The next morning, they will be in the range of RHC63+. After warming to room temperature, they get tempered. We temper twice at 500F degrees for two hours each time – to get about RHC61. You can experiment for other hardness's but 61 is a very good target for these steels.

CPMS30V

Same wrap – same temperature (1950F) - same soak time – same plate quench – same cryo as 154CM above. This steel gets double tempered at 400F degree for about RHC60

440C

Same wrap – Harden at 1900F degrees and only about 15 minutes at temperature – then plate quench and cryo as above.  Hardness out of cryo will be about 61. Temper (twice for 2 hours) at 275F for RHC60 – 325F for RHC59 – and 375F for  an excellent RHC57-58. 

Questions and Answers provided by Rob Ridley of Ranger Original


Q1:  Does Cryo really make a difference.

A1:  Yes!  It increases initial hardness between 1.5 to 2 points and even though you may temper back to softer levels, the steel has been more completely transformed to a tough and desirable state.


Q2:  Why do you leave blades in the foil to plate quench them.

A2:  The really hot blades never see oxygen this way. That means no scale and very little oxide.  Air quenching the old way meant going back to the grinder to clean up the mess. Blades done our way can be cleaned up with just a buffer.


Q3:  Why do you remove the blades from the envelope before cryo?

A3:  Experience! We like hanging the blades from a coat hanger in the cryo tank. Handle pin holes make that easier. We also found that when a tight foil bag full of liquid nitrogen, hits the warm summer air, bad things can happen. The low tempering temperatures won’t cause you any scale or oxide problems anyway.


Q4:  Can I use my freezer for cryo?

A4:  No. It isn’t nearly cold enough to do any good at all. Dry Ice or Liquid Nitrogen work equally well. Dry ice is easier to handle but only lasts a day or so. Liquid nitrogen in a good dewar will last a month or more depending on use.


Q5:  I heard ATS34 etc can be tempered at a high or low range. Is this true?

A5:  Sort of – but the high range gives you reduced toughness and corrosion resistance. It should be avoided.


Q6: Are there other ways to heat treat these steels?

A6:  Heck yes! Air quenching, Oil quenching, Salt baths, Vacuum furnaces…. But you’ll have to ask someone else about them.  I haven’t seen anything that gives more satisfactory results that the way we use now.


Q7:  Aluminum is expensive! Can I plate quench between thick steel plates.

A7:  Yes – less desirable because it absorbs heat slower – but workable.


Q8:  How do I know if it hardened and tempered properly.

A8:  The correct answer is to use a Rockwell C scale tester and then to do performance testing on your blades. Some claim they can tell hardness pretty close by the way a file skates over the steel. I can’t. We test every blade through here and write the hardness on the blade before shipping it out.  Having said that, we are rarely out by more than 1 Rockwell point from where we aimed.


Q9:  321SS foil is much cheaper. Can I use it instead of the 309SS?

A9:  Depending on who you talk to, the 321 is rated to something between 1800 - 2000 degrees. The risk is that the 321 will either fail, allowing air in, or stick to the blade inside. In practice, we have used it successfully with our own blades without problem. We have seen 321SS stuck to a blade heat treated elsewhere. Because we treat other maker’s blades, we choose to use only 309SS foil. Experiment at your own risk.


Q10:  Does it matter where in the oven I place the blade?

A10:  Yes.  Temperature inside an oven can vary and generally is only measured at one point – where the thermocouple is located. For consistent results, you should keep your blades in a more or less consistent place in the chamber. Hint; Avoid getting closer to heating coils than necessary.


Q11:  How do I know if my oven is accurate for temperature?

A11:  Some will tell you that you can test temperature with ceramic firing cones. We disagree. Cones do not measure temperature. They measure heat work – a combination of time and temperature. Orton makes a product called TempChek which is better but still requires a rather complex cycle for a good result. An electronic probe and thermocouple is the best way to check, though can be expensive. Of course, unless you can calibrate the probe, you still don’t really know do you?

Note: Rob really nailed the question of using a pyrometric cone for temperature measurement. It's apples and oranges. Save the pyrometric cones for the potters.


Q12:  How far can a blade be finished before heat treat?

A12:  Many of our customers finish to 800 grit before heat treat. We ask makers to leave us 20 thou at the edge and point – essentially a finished blade that has not been sharpened. Although we have not had any stress fractures, it is also a good idea to avoid sharp corners where possible and to deburr pinholes and other irregularities.


Safety

Heat treating has obvious hazards. Please wear safety glasses or face shield and decent gloves. The day will come when you drop a hot blade. Make sure the floor around your oven is free from combustibles and please resist the urge to catch the falling blade.

Email rob@rangeroriginal.com with questions.

 

 

ATS 34, 154CM Heat Treat Procedure
Special Thanks to Mick Koval (R.I.P) of Koval Knives for this Information

This is an oil hardening grade of steel which will require oil quenching. The oil should be warm, thin quenching oil that contains a safe flash point. Olive oil has been used as a substitute. As a rule of thumb there should be a gallon of oil for each pound of steel. For warming the oil before quenching you may heat a piece of steel and drop in the oil.

1. Wrap blades in stainless tool wrap and leave an extra two inches on each end of the package (This will be for handling purposes going into the quench as described below). We suggest a double wrap for this grade. The edges of the foil should be double crimped being careful to avoid having even a pin hole in the wrap.

2. Place in furnace and heat to 1900°F. After reaching this temperature immediately start timing the soak time of 25 to 30 minutes. Evenheats' Set-Pro control can be programmed to automatically soak, for any amount of time desired, once temperature is reached.

3. After the soak time has elapsed, very quickly and carefully pull the package out with tongs, place over the quench tank and snip the end of the package allowing the blades to drop in the oil. You should have a wire basket in the quench tank for raising and lowering the blades rather than have them lie still. Gases are released in the quench and would form a "trap" around the steel unless you keep them moving for a minute or so. IMPORTANT - It is very important that the blades enter the oil quench as quickly as possible after leaving the furnace! Full hardness would not be reached if this step is not followed.

4. After the blades are quenched down to near room temperature (preferably around 125°F) they must re-enter the furnace at 300°F. After they reach 300°F allow them to remain for 2 hours. Evenheats' Set-Pro control can be programmed to automatically soak, for any amount of time desired, once temperature is reached.

5. Remove blades and place them aside for room temperature cooling.

6. After they have cooled to room temperature, place them back in the furnace at 275°F for 2 hours. Remove and check hardness. You should have approx. 60 RC. Evenheats' Set-Pro control can be programmed to automatically soak, for any amount of time desired, once temperature is reached.

7. For extra stability and a point higher hardness you may pack blades in dry ice for one hour.

Note: All the above procedure is based on our own experience realizing there are others using their own trial-error. All equipment must be calibration checked periodically. There are no "short-cuts" for proper heat treating. Always exercise care and precaution.

 

440C Heat Treat Procedure
Special Thanks to Mick Koval (R.I.P) of Koval Knives for this Information

1. Wrap blades in tool wrap. Double crimp all edges of the foil being careful to avoid having even a pin hole in the foil. You may double wrap fro extra assurance of locking out all oxygen. You may wrap the blades with 5-6 stacked side by side or individually wrap and place in an optional furnace rack. This rack will hold the blades in an upright position for minimizing warpage.

2. After placing the blades in the furnace heat to 1850°F. After reaching 1850°F start timing the soak time of 20 to 25 minutes. Evenheats' Set-Pro control can be programmed to automatically soak, for any amount of time desired, once temperature is reached.

3. After the soak time has elapsed, carefully slide the blades on a steel grate or heavy wire mesh for room temperature cooling (This is the air quench). Place aside for cooling. The grate or wire mesh will allow air to circulate under the blades as well as around them for uniform quenching.

4. While the blades are cooling leave the furnace door open and allow it to come down to 220°F. Sometimes the blades willed be cooled before the furnace comes down. In this case keep the blades warm (place near the furnace door) or you may use the kitchen oven for drawing. It is important on all grades that they do not cool much below the 125°F temperature before drawing.

5. After placing the blades in the 220°F temperature they should remain at this heat for 2 hours. Evenheats' Set-Pro control can be programmed to automatically soak, for any amount of time desired, once temperature is reached.

6. Pull the blades out for cooling and place them back at 200°F again for 2 hours. Evenheats' Set-Pro control can be programmed to automatically soak, for any amount of time desired, once temperature is reached.

7. Check harness. You should have approx. 59 RC.

For extra stability you may freeze the blades in dry ice for one hour. This will also increase the hardness a point or two.

Note: All the above procedure is based on our own experience realizing there are others using their own trial-error. All equipment must be calibration checked periodically. There are no "short-cuts" for proper heat treating. Always exercise care and precaution.

 

1084, 1095, AISI 0-1, AISI 0-6 Tool Steel Heat Treat Procedure
Special Thanks to Mick Koval (R.I.P) of Koval Knives for this Information

This is an oil hardening grade of steel which will require oil quenching. The oil should be warm, thin quenching oil that contains a safe flash point. Olive oil has been used as a substitute. As a rule of thumb there should be a gallon of oil for each pound of steel. For warming the oil before quenching you may heat a piece of steel and drop in the oil.

1. There are two ways of giving 0-1a protective atmosphere before hardening: (A) You may use a non-scaling compound. It works very well for temperatures up to 1650°F. Heat the blades to 500°F, remove from furnace and roll them in a tray of compound. It will adhere to the steel and form an air tight blade. Replace in furnace and continue hardening steps. (B) The other choice is to wrap in tool wrap. When wrapping this grade allow an extra 2 inches on each end for handling purposes. Step 3 will describe further.

2. Place blades in the furnace and stand up on edge, you may use a special furnace rack for this purpose. Heat to 1450°F. As soon as this temperature is reached then begin soak time of 15 to 20 minutes. Evenheats' Set-Pro control can be programmed to automatically soak, for any amount of time desired, once temperature is reached.

3. At this time the blades need to go into the oil very quickly. You should have a wire basket inside the quench tank. If the blades are wrapped in tool wrap, hold one end up and snip the other end of the foil allowing the blades to drop in the basket and into the oil. Raise and lower the basket for a minute or so for good oil circulation (This step is very important).

4. While the blades remain cooling set the furnace at 375°F. After the blades have cooled to approx. 125°F, place them in the furnace (at 375°F). Allow them to remain (draw) for 2 hours. Evenheats' Set-Pro control can be programmed to automatically soak, for any amount of time desired, once temperature is reached.

5. Remove the blades, check for hardness after they are cool enough to handle. You should have approx. 60 to 62 Rc.

Note: All the above procedure is based on our own experience realizing there are others using their own trial-error. All equipment must be calibration checked periodically. There are no "short-cuts" for proper heat treating. Always exercise care and precaution.

 

AISI D-2 Heat Treat Procedure
Special Thanks to Mick Koval (R.I.P) of Koval Knives for this Information

1. Wrap blades in tool wrap. Double crimp all of the folded edges being careful to avoid having even a pin hole in the foil. The blades may be wrapped individually or stacked side by side (stack no more than 5 or 6 per pack for ease of handling). If they are wrapped individually you may consider placing them in an optional furnace rack. This rack will hold the blades in an upright position for minimizing warpage.

2. After placing the blades in the furnace, heat to 1850°F. After reaching 1850°F immediately start timing the soak time of 15-20 minutes. Evenheats' Set-Pro control can be programmed to automatically soak, for any amount of time desired, once temperature is reached.

3. After the soak time has elapsed, carefully slide out of package onto a steel grate or wire mesh (this is the air quench).

4. While blades are cooling allow the furnace to cool down to 950°F.

5. When the package has cooled enough for handling, remove the foil. The blades should be warm (approx. 125°F). At this time place them back in the furnace at the 950°F temperature. After the blades have reached this temperature allow them to remain (draw) for 2 hours. Evenheats' Set-Pro control can be programmed to automatically soak, for any amount of time desired, once temperature is reached.

6. Remove the blades for cooling down to room temperature and place them back in the furnace at 900°F again for 2 hours (this is a double temper we suggest for D-2). Evenheats' Set-Pro control can be programmed to automatically soak, for any amount of time desired, once temperature is reached.

7. After removing and cooled check hardness. You should have a 58 to 60 RC.

For extra stability and 1-1/2 points higher hardness you may pack blades in dry ice for 1 hour.

Note: All the above procedure is based on our own experience realizing there are others using their own trial-error. All equipment must be calibration checked periodically. There are no "short-cuts" for proper heat treating. Always exercise care and precaution.

 

Stainless-Plus Damascus Heat Treat Procedure
Special Thanks to Mick Koval (R.I.P) of Koval Knives for this Information

1. Wrap blades in heat treat foil. Do not put any paper in foil. Preheat furnace to 1900°F. Place blade in furnace and watch controller. When temperature gets back up to 1900°F, let blades soak for 10 minutes (12 minutes for 1/4" blades). Evenheats' Set-Pro control can be programmed to automatically soak, for any amount of time desired, once temperature is reached. Do not soak blades any longer than specified time. The steel will decarburize and you will not know until you etch it. Also, do not exceed 1900°F.

2. Remove blades from furnace and cut foil open. Immediately remove blades and quench in light oil.

3. Place blades in freezer overnight or for 2 hours in dry ice.

4. Temper twice at 350°F for 2 hours. Evenheats' Set-Pro control can be programmed to automatically soak, for any amount of time desired, once temperature is reached.

 

Random with CPM420-V and 440-V Heat Treat Procedure
Special Thanks to Mick Koval (R.I.P) of Koval Knives for this Information

The heat treat temperatures for the random with CPM 440-V and 420-V core will be different. Harden at 1950°F and temper at 350°F. This will give you lower hardness readings on the outer steel if you check with a hardness tester, but the center core of the steel will be much harder. This will be on the cutting edge.

Heat Treating & Etching Instructions for Thunderforged™ Damascus 

provided by: Universal Agencies Knife Supplies

Step by Step

1. Heat blade to between 1,400 & 1,500 degrees F.
2. Quench in light oil or brine.
3. Draw temper to desired hardness


Heating the Blade

The blade should be evenly heated to a bright red/dull orange color. This should be achieved between 1,400 & 1,500 degrees F. Be careful not to overheat. Quenching an overheated blade will increase the change of cracking or warping. Another good method it to heat the blade until the magnetic properties are lost. To test that a blade is ready to quench a magnet may be used. Once there is little or no attraction between the blade and magnet the blade will have reached the proper temperature and is ready to quench.

Quenching the Blade

Quenching is performed in either light oil (we recommend olive old with clove quenches well we find), or a standard quenching oil. Or use a brine solution (salt & water). Dissolving salt in boiling water until it no longer dissolves makes a brine solution. The brine quench will make the blade much harder as it will cool the steel much faster than the oil. The oil quench is well suited to a large blade where toughness is more needed whereas the brine quench is more suited to the small skinner and folder blades where holding an edge is important. The blade should be quenched either point first or spine first in order to minimize the chance of cracking or warping. Care must be taken when quenching in brine. The quicker the blade is cooled the more likely it is to crack. A good precaution is to preheat the brine to around 100 degrees F prior to quenching. The oil quench is well suited to a large blade where toughness is more needed whereas the brine quench is more suited to the small skinner and folder blades where holding an edge is important. The blade should be quenched either point first or spine first in order to minimize the chance of cracking or warping.

Drawing the Temper of the Blade

Drawing, or tempering the blade is done by heating the steel in an oven. The blade is placed in a heat treat oven and brought to a specific temperature. It is then allowed to soak at that temperature to assure a full even heat. The specific temperature determines the relative hardness of the blade. Below are listed the approximate Rockwell Hardness achieved at the various temperatures. It should be noted that some parts of all nickel damascus may test somewhat softer due to the nickel content.

1095
Quench 300 350 400 450 500 550 600 650

Hardness 65 64 63 61 59 57 55 54

01
Quench 300 350 400 450 500 550 600 650

Hardness 62 61 59 58 56 55 54 53

Note when heat treating multiple blades keep ample space between each blade for proper air circulation.

Thunderforged™ is a trademark of Universal Agencies, Inc.™ all rights reserved.

©2000 Universal Agencies, Inc. Unauthorized Publication Prohibited

Etching Instructions for Thunderforged™ Damascus

Step by Step

1. Clean blade with acetone. 2. Soak in solution. 3. Rinse in water & soap. 4. Oil.

Detailed Instructions

Clean your blade very well in acetone. At this point make sure you do not touch the blade with your hands, as the oils from your fingers will harm the end result. We recommend that you use tweezers. Once the blade is totally dry you are ready to dip it in to the solution.

Dip the blade point down in to the glass or plastic container that is holding the etching solution. Leave the blade in there for about 15 to 20 minutes. Pull the blade out after 15 minutes & inspect how the etch looks, if you need a higher contrast, again dip the blade back in the etching solution for additional time till you have reached the desired contrast. Do regularly check on your blade while in the solution.

Once you have reached the desired contrast you pull the blade out and immediately rinse it in luke warm water & rub hand soap on it simultaneously. At this time you will notice that a black substance will be coming off, this is the carbon that was removed during the etch. Keep washing the blade until no more black carbon is coming off.

The next step is to oil your blade using good quality gun oil.

Even after you have oiled it, you can go back to step 1 to start all over to reach a higher contrast if desired.

Etching Solution Ingredients

50% PCB Etchant Solution (available at Radio Shack®) & mix with 50% White Vinegar. Use a plastic or glass container to hold this solution DO NOT use a metal container.



Thunderforged™ is a trademark of Universal Agencies, Inc.™ all rights reserved.

 

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