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Hello knife experts.  I have access to some industrial band saw blade material, which my "junkyard steel guide" says might be L6. 

 

btw i searched on L6 and the search engine on this site wouldn't let me search for that!  i don't know why. 

 

Anyway, some sources call for a rather involved 6-7 step heat treat and temper process, holding specific temps for specific times.  i have no equipment to do this.  Can I just grind to shape and leave the hardening/tempering alone?  this is reportedly a very tough steel with some air-hardening tendencies... 

 

thx for any help

Mike

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The error message explains the search issue rather well I thought:

"One or all of your search keywords were below 4 characters or you searched for words which are not allowed, such as 'html', 'img', etc, please increase the length of these search keywords or choose different keywords."

 

I did find some info searching on "L6 heat treating"  (using the quotes)

 

The search limit does make problems for L6, ax, axe, etc.

 

As for heat treating it; what are you trying to accomplish?  Band saw blade heat treat is usually not a great knife blade heat treat as in general only the teeth are made hard and the body is kept much softer to lower breakage.

 

You can always try your own system:   I'd start by quenching from slightly above magnetic in warm vegetable oil, (around 140 degF) and then, if it survives that, testing various draw temps till you get one you like.  Please remember that the hardness/toughness one person likes may not be the same that another person likes.  One person may want a very hard blade to cut abrasive materials, another a springy blade to fillet fish.  One is NOT better than another they are suited to their use case and personal preferences.  (I dislike blades I have to use a diamond hone on, a friend loves blades that can only be sharpened with such...)

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    L-6 Tool Steel Data Sheet



AISI L-6 is a tough, high- strength tool steel suitable for general purpose applications.

Chemical Composition Carbon 0.75% Manganese 0.70% Chromium 0.80% Silicon 0.25% Nickel 0.150% Molybdenum 0.30% Typical Applications Form Rolls   Brake Dies Machine Tool Parts   Chucks Pinions   Shear Blades

 

 

Cold-Work-Tool-Steel-Comparison-Chart.jp

Thermal Treatments

Note: Full hardness will only be attained in sections less than 3" thick

Preheat : 1250/1350F (675/730C), equalize

Austenize : 1500/1550F (815/840C), 15/30 minutes at temperature.

Quench : Oil to 150F (65C). For minimum distortion, parts may be removed from oil at about 400F(205 C), and air-cooled to hand warm. 

Temper : 350/600F (175/315C), hold 2 hours minimum (4 hours preferred) at temperature air cool. Temper twice. 

Cryogenic Treating : Refrigeration treatments may improve long term dimensional stability by transforming retained austenite. Refrigeration treatments should generally be performed after the first temper, and must be followed by a temper.

Hardness and Impact Toughness Data
Oil Quenched from 1500F(810C) 

 

 

Tempering     Toughness Temperature   Hardness Charpy C-Notch Deg. F Deg. C HRC Ft. Lbs. Joules As quenched   64 - – 300 150 64 15 20 400 205 61 43 58 500 260 59 38 52 600 315 57 68 92 700 370 54 - -

 

 

 

 

 

 

Surface Treatments

L-6 can be given standard surface treatments such as hard chrome plating if desired. Nitriding is not generally practical due to a substantial loss of core hardness.

 

 

 

Annealing

A. Heat to 1375/1425F(745/775C), hold two hours, cool slowly, 50F(30C) per hour maximum, to below 1100F(600C), then air cool.
OR
B. Heat to 1375/1425F(745/775C), hold 2 hours, cool to 1200/1250F(650/675C) 6 hours, then air cool.
Typical annealed hardness: 187/235 BHN.

Stress Relieving

Annealed Material: Heat to 1100/1300F(595/705C), hold two hours, cool in still air.
Hardened Material: Heat to 50F(15C) below original tempering temperature, hold two hours, cool in still air.

Welding

Use oil hardening (L-6, O-1) tool steel filler material.

 

 

Annealed Material:Preheat to 400/600F(205/315C). Maintain above 400F(205C) during welding. Reanneal or temper 1250/1300F(675/700C) 6 hours.

 

Hardened Material: Preheat to 50F(15C) below original tempering temperature (300F(150C) minimum). Maintain above 300F(150C) during welding. Cool to 150F(65C) after welding. Retemper twice 25F(15C) below original tempering temperature.

Physical Properties

Modulus of Elasticity

30psix10(6) (207 GPa) Density 0.284 lb/in3 (7860 kg/M3) Thermal Conductivity 20 BTU/hr./ft./F 34 W/m/ °K)
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The regularly scheduled reminder that these charts are usually based on 1" (25mm) sq cross section material and items with knife cross sections do not generally need the same times at temp to be sure the entire piece is up to the same temp.

 

Now where things get difficult is with high alloy materials where the soak times may be engineered to alow re-solutioning of the carbides; but high alloy steels generally require more professional heat treating to get the best from them anyway.

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I should have put some sort of disclaimer on there, as there is also one on the Data sheet that specifies that the info came from compiled info and may not suit all applications. I apologize for the mistake on my part. I believe these sheets come from industrial standpoint and the "15-30 minutes" might have been suggesting to get an even heat on larger material or something along those lines. I'll double check copy and paste info a bit better next time.

-Crazy Ivan

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I can tell you, it's not L-6.  I have never run across any that was nor are there any manufactures that use it.  It could be 15n20, 1070ish or some other blend.  You'll just have to play with it until you find the right formula.  I have obtained from two sources large band saw 10 and 14" tall and who knows how long and it turned out to be almost basic 1070 with a little extra manganese.  Good luck.

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So because you never run across it it can't be L-6?

Seems about the same degree of certainty as the OP assuming it is L6 based on a Junkyard guide.

It is a mystery steel until a spectrograph or specs from the manufacturer define it as otherwise and it should be treated as such.

 

I can tell you, it's not L-6.  I have never run across any that was nor are there any manufactures that use it.  

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Junkyard steel is a best guess based on your knowledge and experience. If you are going to invest several hours or days on a project, get a known metal so you know the heat treating and the performance of the metal your using. If it is a critical application, definitely use a known metal.

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ok well, i ain't got a spectrograph or a uniform automated HT oven or much of anything else except some of the saw blade material.  I'll go with JMCustom's opinion since it meshes with my own ability to harden and heat treat.  if it doesn't work out its no great loss. 

 

thx everybody 

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