Hardness test question

[*Paladin*]

Well, tonight I did a half-azzed hardness test on 4 samples from my stash, all ingots and all over a month old. I used an automatic punch on the following, and came up with the following measurements with my digital calipers, measuring dimples edge to edge:

Clip on WW- .072"
SO WW's- .106"
Lino- .063"
Range Lead- .082"

Anybody use an auto punch or anyone venture to take a stab at the hardness of each based on the above numbers? I know this isn't the right way to measure hardness, but I don't have a hardness tester yet and I'm curious.

One thing I found interesting is how hard the range lead was. I figured it would measure closer to pure, and I was surprised to find the lino and clip on WW's so close in hardness...

[KYCaster]

It's hard to get good hardness readings on ingots...too much variation in cooling and shrinkage to be repeatable.

You'd be better off casting some boolits and checking them after they age for a week or so.

Jerry

[bumpo628]

I made you a graph.
If you get some more data, it will be more accurate.

It estimates the range lead to be only 9.7 or so.

Using the following hardness values:
SO WW = 6
CO WW = 12
Lino = 19

30040

[*Paladin*]

Thanks guys! Yeah, I plan to cast some to test the boolits rather than ingots, but I only have 2 different alloys currently casted into boolits and they are 50/50 and straight WW. This was kind of a goofing off in the garage experiment until I get a tester. I doubt the punch is repeatable enough to be considered accurate, but I will say I tried 3 strikes on each of the samples and came up with the same measurements, so it's consistent to this point.

I really need to get a tester tho, because it drives me nuts not having one. I'm kind of hessitant to really start experimenting with different alloys until I have one.

[montana_charlie]

I really need to get a tester tho, because it drives me nuts not having one.
Make one...
http://castboolits.gunloads.com/showthread.php?t=107948

[KYCaster]

I really need to get a tester tho, because it drives me nuts not having one. I'm kind of hessitant to really start experimenting with different alloys until I have one.



Having one will drive you nuts too!! [smilie=b:

Jerry

[montana_charlie]

Having one will drive you nuts too!!
...if you believe that you can only get good readings from bullets...and not from ingots...

[KYCaster]

...if you believe that you can only get good readings from bullets...and not from ingots...


What are you trying to tell me Charlie?

Teach me something here....I'm willing to learn.

Jerry

[montana_charlie]

Not trying to teach you anything...just intimating that I think you're wrong.

If taking a reading on a bullet is the only way to get a 'good' Brinell reading, you would have to believe that the only way to get a good Rockwell reading is from a knife blade, or something equally 'special'.

When I check lead ingots for hardness, they read as reliably as bullets, blobs, and odd sized pieces from the scrap yard.

CM

[KYCaster]

Not trying to teach you anything...just intimating that I think you're wrong.

If taking a reading on a bullet is the only way to get a 'good' Brinell reading, you would have to believe that the only way to get a good Rockwell reading is from a knife blade, or something equally 'special'.

When I check lead ingots for hardness, they read as reliably as bullets, blobs, and odd sized pieces from the scrap yard.

CM


On a typical 1 lb. ingot of WW poured into a Lyman ingot mold, I can get a half dozen different hardness readings depending on exactly where on the ingot I choose to do the test. If I reuse the same ingot mold over and over during a smelting session, the first cast in a cold mold will have a different hardness than subsequent casts in the hotter mold.

Can you get consistent readings on ingots? Sure you can...I didn't say you can't, I said its hard to. If I were as careful with temps and casting rates when making ingots as I am when casting boolits then repeatable tests would be much easier...but I'm not that careful....maybe you are, I don't know.

In order to get consistent, repeatable, BELIEVABLE results, we need to eliminate the variables. That's what we try to do when casting boolits, eliminate the variables....makes repeatable results much easier.

Like Dolly says, "Its enough to drive you crazy if you let it." :drinks:

Jerry

BTW...I spent about 14 years working in a foundry. Part of my job was doing hardness tests on our products and on repair parts from the machine shop. I've tested aluminum, brass, zinc, titanium, various iron and steel alloys, stainless and hard surfacing alloys...cast, forged, rolled, machined, sintered and case hardened.

I also prepared samples for microscopic analysis of grain structures, including case to core transition, weld filler to base metal and hard surface to substrate bond.

I think I have a handle on the process. :wink:

[cajun shooter]

KY Caster, I am sure with your time in a foundry that you have the knowledge. I have seen people test ingots on top and I was always told to never test the top of any ingot but only the surfaces that touch the mould. I use a Cabin Tree tester and receive the same readings from all ingots that were smelted at the same time. I have never heard of not being able to test ingots until now. That is how I sort my ingots and store them. When I cast with these tested ingots I receive the same readings as I had with the ingots used. You are now telling me that after all these years since about 1970 that I am doing it wrong. What is your post based on and why is it wrong to do it my way? Paladin you would serve yourself well by buying a Cabin Tree and while at it purchase the model that also test run out if you shoot rifle. Both bullets and loaded ammo may be tested.

[montana_charlie]

On a typical 1 lb. ingot of WW poured into a Lyman ingot mold, I can get a half dozen different hardness readings depending on exactly where on the ingot I choose to do the test.
Think of it this way, and see if it makes sense to you...

With WW (or anything other than pure lead) You get the 'true' hardness in a bullet when you let it air cool. If you want to increase the hardness, you change the cooling rate by water dropping the bullet. It's known to happen that way, and it's logical.

When following that logic, the 'true' hardness is the 'softer' hardness.

If testing an ingot gives you different readings in different places, you know it isn't due to metals in the alloy not being thoroughly mixed. Therefore, you have to assume the variation is caused by different cooling rates.

Following the logic says that the 'softest' reading will be the 'true' reading

CM

[KYCaster]

KY Caster, I am sure with your time in a foundry that you have the knowledge. I have seen people test ingots on top and I was always told to never test the top of any ingot but only the surfaces that touch the mould. I use a Cabin Tree tester and receive the same readings from all ingots that were smelted at the same time. I have never heard of not being able to test ingots until now. That is how I sort my ingots and store them. When I cast with these tested ingots I receive the same readings as I had with the ingots used. You are now telling me that after all these years since about 1970 that I am doing it wrong. What is your post based on and why is it wrong to do it my way? Paladin you would serve yourself well by buying a Cabin Tree and while at it purchase the model that also test run out if you shoot rifle. Both bullets and loaded ammo may be tested.


OK, I went back and read my posts and I couldn't find any place where I said, "Cajun Shooter is wrong". I couldn't even find a place where I said, "Testing ingots is wrong".

Paladin said he was surprised by some of the results he got so I made a suggestion that I thought may help him understand his results a little better. Obviously, you don't agree with my opinion...that's OK, I can live with that....given enough time I may recover. ;-)

But there is one question I want to ask...like I told MC, I'm always willing to learn something new. Could you tell me why you "never test the top of any ingot but only the surfaces that touch the mould"?

Jerry (impatiently waiting for an answer)

[KYCaster]

KY Caster, I am sure with your time in a foundry that you have the knowledge. I have seen people test ingots on top and I was always told to never test the top of any ingot but only the surfaces that touch the mould. I use a Cabin Tree tester and receive the same readings from all ingots that were smelted at the same time. I have never heard of not being able to test ingots until now. That is how I sort my ingots and store them. When I cast with these tested ingots I receive the same readings as I had with the ingots used. You are now telling me that after all these years since about 1970 that I am doing it wrong. What is your post based on and why is it wrong to do it my way? Paladin you would serve yourself well by buying a Cabin Tree and while at it purchase the model that also test run out if you shoot rifle. Both bullets and loaded ammo may be tested.


OK, I went back and read my posts and I couldn't find any place where I said, "Cajun Shooter is wrong". I couldn't even find a place where I said, "Testing ingots is wrong".

Paladin said he was surprised by some of the results he got so I made a suggestion that I thought may help him understand his results a little better. Obviously, you don't agree with my opinion...that's OK, I can live with that....given enough time I may recover. ;-)

But there is one question I want to ask...like I told MC, I'm always willing to learn something new. Could you tell me why you "never test the top of any ingot but only the surfaces that touch the mould"?

Jerry (impatiently waiting for an answer)

Well, no reply so I'll try to answer the question myself..........

The reason you shouldn't test hardness on the top of the ingot is because that's where shrinkage shows the most effect. When metal is poured it freezes first where it contacts the mold then freezing progresses toward the center of the ingot where the metal remains hot longer. As the metal freezes and shrinks it pulls metal from the still molten center, leaving a void or area of lower density where freezing occurs last. I think most of us already understand that.

The void is very near the surface that's exposed to air (that's why there's a dimple there), so that makes it hard to get a good hardness test. I think that was my original comment on the subject.


Think of it this way, and see if it makes sense to you...

With WW (or anything other than pure lead) You get the 'true' hardness in a bullet when you let it air cool. If you want to increase the hardness, you change the cooling rate by water dropping the bullet. It's known to happen that way, and it's logical.

When following that logic, the 'true' hardness is the 'softer' hardness.

If testing an ingot gives you different readings in different places, you know it isn't due to metals in the alloy not being thoroughly mixed. Therefore, you have to assume the variation is caused by different cooling rates.

Following the logic says that the 'softest' reading will be the 'true' reading

CM


CM, refer to my reply to Cajun Shooter. If shrinkage weren't a factor then I would agree with your statement, but in reality, the "softest" reading will be in the area that's most affected by shrinkage.

I stand by my first comment. It's hard to get good, consistent hardness readings on ingots. For someone unfamiliar with the testing procedure it is helpful to reduce the number of variables in order to minimize their confusion and shorten the learning curve. I think most casters try for consistency when casting bullets more than when casting ingots, therefore their bullets should present fewer variables.

Jerry