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Forge Welding and Grain Size Effects on Toughness

Posted by me2 
me2
Forge Welding and Grain Size Effects on Toughness
June 30, 2017 06:28AM
[knifedogs.com]

I find it hard to understand why this thread hasn't received more attention. Very nice work on forge welds in stainless Damascus with AEB-L and 3xx series steel.

I'll have to post the one on grain size from my phone. I can't access the site here.
Re: Forge Welding and Grain Size Effects on Toughness
June 30, 2017 07:06AM
me2,
Interesting!

"I am still discussing issues of steels and performance at this stage."
--Cliff Stamp

"Cause geometry cuts, .....steel determines the level and the duration"
--Roman Landes

"But in general, I'm all about high performance, Ergos, safety. That's why I've been accused of 'designing in the dark' "
--Sal Glesser
me2
Re: Forge Welding and Grain Size Effects on Toughness
June 30, 2017 08:26AM
The only thing missing is the carbon migration from the AEB-L to the 304 (I think). I'm not sure it would be homogeneous, even after hours near melting. Something about nickel preventing carbon migration, but that might be through solid nickel layers in steel/nickel Damascus. If the carbon did migrate and even out, the max hardness would be relatively low I'd think, since AEB-L doesn't have much to spare, and I'm not sure putting more carbon in 304 would make it harden from quenching, since carbon is an austenite stabilizer like nickel. But it depends on the ration of 304 to AEB-L.

The other is some good information on grain size and it's effects on toughness, coupled with the effects of aluminum in steel, and he basically comes to the same conclusion Alvin did in hardening plain carbon and low alloy steels, going over 350 to 400 doesn't help you. He recommends 180 C tempering for carbon and low alloy steels.
Re: Forge Welding and Grain Size Effects on Toughness
June 30, 2017 08:32AM
Chris,
Is there any issues with the steels being different HRC's?

"I am still discussing issues of steels and performance at this stage."
--Cliff Stamp

"Cause geometry cuts, .....steel determines the level and the duration"
--Roman Landes

"But in general, I'm all about high performance, Ergos, safety. That's why I've been accused of 'designing in the dark' "
--Sal Glesser
me2
Re: Forge Welding and Grain Size Effects on Toughness
June 30, 2017 09:10AM
I don't think so. That's after forging/welding. After hardening it might be an issue in thin edges. It friends on how much there is, though it looks close to 50 50.
me2
Re: Forge Welding and Grain Size Effects on Toughness
June 30, 2017 09:12AM
[www.bladeforums.com]

This is the other thread on grain size.
Re: Forge Welding and Grain Size Effects on Toughness
August 05, 2017 02:39AM
Quote
me2
The only thing missing is the carbon migration from the AEB-L to the 304 (I think).
I'm not sure it would be homogeneous, even after hours near melting.

If forged correctly, it should have even smaller grain size.
Thats the whole point of forging apart from shaping even for stainless smiling smiley
Many hits in short time, temperature control, fast heating, generally
working fast, forge evenly at all areas as possible..

Quote
me2
Something about nickel preventing carbon migration, but that might be through solid nickel layers in steel/nickel Damascus. If the carbon did migrate and even out, the max hardness would be relatively low I'd think, since AEB-L doesn't have much to spare, and I'm not sure putting more carbon in 304 would make it harden from quenching, since carbon is an austenite stabilizer like nickel. But it depends on the ration of 304 to AEB-L.

Compared to the plenty of Cr and Ni in 304 considering still low C even after migration
That would not be significant. Never seen C to be used to stabilize austeninte in a little
amounts. Huge amounts in the complex alloy will simply cause difficulties for austenite
to transform into martensite completely during the quench but It isnt why I would consider
it to be a stabilizer f.e.: like Ni or Cr..

Under certain conditions it will stabilize austenite but it is a different attribute
if it contributes to its existence if we quench it as in this case..

If 304 will get closely under 0,2 wt%C It will harden and is no longer 304 grinning smiley.
Most areas close to weld will harden and contain martensite and mid section
of 304 layers will stay austenintic - probably.
In this case of migration you still have 0.45C left in AEB-L areas close to welds
that can give some 56HRC and then mid section of its layers can have some 62HRC..
Interesting to think of this happening.. Hypothetically )

www.instagram.com/jscuttingtools



Edited 1 time(s). Last edit at 08/05/2017 02:47AM by JSCT.
Re: Forge Welding and Grain Size Effects on Toughness
August 07, 2017 09:22AM
Quote
me2
[knifedogs.com]
I find it hard to understand why this thread hasn't received more attention. Very nice work on forge welds in stainless Damascus with AEB-L and 3xx series steel.
I'll have to post the one on grain size from my phone. I can't access the site here.
nice work. on a KD sub-forum I don't look at often. one on grain size is again not on a sub-forum I look at.
Is there a chart that will convert 1 to 10 grain size to microns? an example, properly HT'd O1 will have a grain size of 9.5, what would that be in microns?



Edited 1 time(s). Last edit at 08/07/2017 09:25AM by oldsailorsknives.
Re: Forge Welding and Grain Size Effects on Toughness
August 07, 2017 03:59PM
Quote
oldsailorsknives
Quote
me2
[knifedogs.com]
I find it hard to understand why this thread hasn't received more attention. Very nice work on forge welds in stainless Damascus with AEB-L and 3xx series steel.
I'll have to post the one on grain size from my phone. I can't access the site here.
nice work. on a KD sub-forum I don't look at often. one on grain size is again not on a sub-forum I look at.
Is there a chart that will convert 1 to 10 grain size to microns? an example, properly HT'd O1 will have a grain size of 9.5, what would that be in microns?

ASTM 9.5 grain is about 14um.
Table on page 5

I think I ve seen some more charts in papers by John D. Verhoeven and Roman Landes
and maybe someone else..

Edit: Please do not forget that grain size is an average value so you can easily find
25um grains in the steel with average grain size of 15um.
Also do not mistaken alloy grain size with size of carbides in the particular alloy
as in fine grained steel they should be smaller than martensite grains..

www.instagram.com/jscuttingtools



Edited 1 time(s). Last edit at 08/07/2017 04:19PM by JSCT.
Re: Forge Welding and Grain Size Effects on Toughness
September 07, 2017 04:28PM
I answered some of my grain questions when reading new book. first was preparing the steel, sanding and grinding to almost perfect flat, then treating with an acid solution for several hours then applying proper dye. then photograph or project the image so it is enlarged 1000x. draw a 5" line and count grains. do ten readings at 10 random points, then average. the best trained techs can do is a result that is +/-1.

scott
[www.etsy.com]
Re: Forge Welding and Grain Size Effects on Toughness
September 11, 2017 12:28PM
Yep, this is how grain size is measured just count them in an area..
Imagine piece of steel lets say cube inch x inch x inch. And imagine the area
magnified at one sight. Imagine u do 100 observations and at random spots
and measure the grain size.. also you practically observe 2 dimensional
picture however grains arent. Another important point is after 100 observations
how big total fraction of material was observed ? Can it quantify reliable prediction ?

www.instagram.com/jscuttingtools
Re: Forge Welding and Grain Size Effects on Toughness
September 11, 2017 08:10PM
and read further and see that with fine grain steels, even with chemical etching, it is difficult to seperate steel grain from carbides. with some work, i could probably do the polishing required, but buying quantities of hydrochloric, picric or nitric acid and ethyl alcohol is a little difficult. I don't have a microscope either. which makes me wonder how folks can take a piece of steel, break it, take a photo of the jagged ends and swear that they have grain size 12-13.
reading more in the book Tool Steels, found some interesting ideas that were written 40 years ago. with low alloy high carbon steels, to include W1, W2, 1095, 80CrV2, O1, 52100, O7, and others, hardening from 1475-1500F, quench then temper at 350F gives a product with finest grain, most resistance to size change, good toughness with hardness over Rc60. still trying to find some of the source articles sited. their was a lot of research done on 52100, W1, O1, and O2 in the '40's and 50's looking for best heat treat when using these steels as high hardness calibration standards and test blocks.

scott
[www.etsy.com]



Edited 1 time(s). Last edit at 09/11/2017 08:14PM by oldsailorsknives.
Re: Forge Welding and Grain Size Effects on Toughness
October 01, 2017 02:49PM
Hey, Scott

Just a little objection:

I am not sure as I dont have exact info on steel production in 40ties and 50ties,
I am almost sure some details have changed in the process.. So the material
has been casted - solidified / hot woked - rolled / forged - (left to cool or not)
then annealed differently And that might give a little different result after identical ht.
Grains and carbides - size, distribution and orientation
could be different.. that would impact mech properties..
However best ht scheme would be still valid just material
properties could be a bit better these days..
It is very dependable as many processes has been technologically
upgraded just to produce more effectively but not so often to a higher standards..

www.instagram.com/jscuttingtools



Edited 1 time(s). Last edit at 10/01/2017 02:54PM by JSCT.
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