Brinell Hardness of Tin ?

[GLL]

My Cabine Tree tester indicates certified 99.99% Tin BHN at 9.

Cast Bullet Association Alloy Calculator indicates Tin BHN=30 !

Los Angeles Silhouette Club chart shows Tin BHN= 7

Midway sells Tin but indicates BHN=Not Available !

At least one other source I know indicates it is 30 !

Anyone else want to give their measurements ??? Using an alloy calculator is great fun when are you not sure of the actual hardness of the components ! :) :)

I just looked up Sn in the Handbook of Chemisry and Physics BHN= 2.9 ! Two other sources show BHN=3.9 & 15 !

Jerry

[AZ-Stew]

GLL,

I tested some this weekend with my Lee hardness tester and it ran off the bottom of Lee's scale, which is, I believe, BHN 8. I also have some pure lead, which is supposed to be about BHN 5, and it ran even farther off the bottom of the scale, so Tin is somewhere between really soft wheel weights and pure lead. My Lee pegged my wheel weight alloy at slightly over BHN 13, which is near the high end of what's mentioned in most references on the subject.

While we're on the subject, does anyone have a chart for the Lee hardness tester that extends both ends of the scale?

Regards,

Stew

[montana_charlie]

This says 51...but then, they also say that lead is 38.3.
http://en.wikipedia.org/wiki/Hardnesses_of_the_elements_(data_page)#Brinell_har dness


I'm confused...!?!
CM

[largecaliberman]

GLL,

Regardless of what other sources say. I use a hardness tester from Leeprecision.com and just use that as a guideline for the purpose of making boolits.

[rhead]

The 30 and 38 are probably blend values. It is not unusual for an alloy to be harder than either of the components. The blend value would be accurate only for one alloy. The 30could be right for blending with pure lead and the 38 could be right for blending with lead antimony. The 8 is probably the hardness of the pure metal.

[GLL]

rhead:

Thanks.

If that is the case the Cast Bullet Association Alloy Calculator is useless !

I just tested it with various lead/tin ratios and indeed it is not at all internally consistent ! :(

So much for science ! I will go back to trial and error "alchemy techniques" and test each hardness as I produce my alloys ! :) :)

As largecaliberman indicates, I will use my own numbers and see what works. It does seem someone would have worked this out by now though.

Jerry

[Harry O]

One of the problems with grabbing numbers off the Internet, you don't really know what everything surrounding it is. There are at least 3 different Brinell scales that I know of and you will get a different number for each of them when you test the same stuff. And, there are a bunch of other hardness scales out there.

I just got done testing some cut up chunks of Midway certified tin on the Lee and the SAECO tester. They gave far different results, but for good reasons (I think).

Keep in mind that I do NOT have tin bullets to test. I have some small 1/2oz and 1oz chunks that I cut out of the bar I got from Midway. I did file enough of a flat to test. The SAECO came up with a number 10 (which is somewhere around Bhn 22 or so). Then I tested it with the Lee. It showed VERY soft, softer than most of my lead at Bhn 5. One or the other has to be wrong-------right?

Actually, they are probably both right. The SAECO has a very narrow, deep pin. The Lee has a wide, shallow semi-circle. Since I cut the tin bars with large wire cutters, the surfaces I tested were all work softened. The SAECO would go deeper and get into the harder stuff than the Lee would.

Anyway, most hardness tests are just to get melts that are close to the same so they will act the same when under pressure. And, what was said above (that you cannot tell anything about what the hardness will be from the two metals you started with) is true. I know there are charts somewhere that narrow it down somewhat, but I have not bothered to dig for them. Also keep in mind that most information on the strength of lead-tin mixtures is NOT for bullets. It is for soldering. That means any numbers they give are for shear, not compression or tension.

It gets pretty complicated pretty quick.

[GLL]

I think the problem as Harry O is indicating may be differnt types of Brinell value because when people report BHN they are using different units of force in the numerator of the equation (rather than Newtons). This results in varying BHN values for the same material. What is most interesting to me though is that TIN seems to be the one metal (or alloy) where there is so much variation in reported Brinell values . There seems to be a rather small range of values for lead, antimony, WW, linotype, Lyman #2, 10/1. 20/1, etc.

When using Alloy calculators there is a big difference between Tin @ 5 and Tin @ 30 and I would hope the software program would be internally consistent. All of the BHN Tin values I searched were referring to bullet metal alloys. You would hope the reporters were using the same scale for lead, tin, and antimony ! ;)

Jerry

[AZ-Stew]

GLL,

Let me add some info to what I posted earlier.

I did my testing with the Lee using the techniques listed in the instruction sheet. Lee warns not to test on the base of a bullet because it will test softer than the sides or nose. Not wanting to destroy one of my newly-cast bullets by filing a flat on the side so that it could be tested in Lee's cradle-like shell holder where the bullet is supposed to be rested, on its side, while testing, I cut my own shell holder on my lathe. It has a flat top, as opposed to the v-block top of the Lee shell holder (test stage). This allows me to test a variety of stuff that's already flat without me having to file a flat on the material to be tested. I'm also concerned that testing on a disturbed surface (filed, in this case) may affect the result, either from the mechanical action of the filing or from filing deeply enough into the bullet that the metal at that location may be softer than it is at the surface that contacted the mould.

I took one of my newly cast SWC pistol bullets and tested, per the instruction sheet, taking data from the nose and base, which I was able to do because of my flat testing stage. As Lee indicated, the bullet nose was harder than the base. I took several measurements. In addition, with my new flat-top stage, I was able to do some tests on my sprue metal on the side of the sprue that's in contact with the sprue plate. It has large flat areas around the sprue cones and after a number of tests across all the flat areas available on the sprue I found that the hardness closely matches the hardness of the bullet nose. The nice thing about using the sprue is that it has really big, smooth, flat areas where the indentation edges are clearly visible with no lumps, bumps, grooves or ridges to confuse the viewer. It's easy to get a clean measurement.

The tin and lead I tested were ingots cast in Lee and Lyman (respectively) ingot moulds. Lee's instructions indicate that these should be tested on surfaces that were in contact with the ingot mould, rather than on the top side. That's how my measurements were made. In hindsight, I guess I should have tested the top sides of both to get an idea of the difference in measurement I could expect. I'll have to run one of these tests later for my own benefit.

I believe Harry O is correct in saying that his measurements may be affected by the work softening of the cut surface he was using as a test surface. I also believe he's right about there being more than one Brinell scale, though I haven't been able to find them listed on the Internet. I didn't have much time to research this issue today.

Here's another resource for you:
http://www.lasc.us/CastBulletNotes.htm

Interesting stuff, especially the Fryxell article links.

Regards,

Stew

[Lloyd Smale]

pure tin bullet go about 10 for me but then hows a guy to know its actually pure tin.

[Harry O]

The real place to learn about different hardness tests is the Machinist's Handbook. I don't have one here, but this is what the books I do have say about it.

Brinell Hardness. The standard size is a 10mm ball with 3000kg of force. There are at least two other ball sizes (for soft and hard metals) and different force levels. They are NOT named differently. You have to know exactly what was used in order to compare anything with anything else.

Rockwell Test. There are the "B" and "C" scales that are commonly used (I don't know what happened to "A"). These are usually used in harder materials than Brinell tests.

Vickers Test. This is a real old one and I have never actually seen it. It came from back when the sun never set on the British empire.

There are a bunch of other small time tests for specific items that I won't get into.

Keep in mind that a hardness test implies many things, but it does not give ANY specific basic design values for any of them. It can give you a rough idea of the materials yield strength, ultimate strength, or wear resistance, etc., but not exactly. It is mainly used to NON-destructively compare one part that you know works with another one that you don't know will work. It is quick, easy, and non-destructive, but it is NOT exact. Coverting from one hardness scale to another just brings in another variable. That is why I think it is useless to try to compare Lee with SAECO. Stick with one and stay with it.

[montana_charlie]

While we're on the subject, does anyone have a chart for the Lee hardness tester that extends both ends of the scale?
I have one, but it's too big to upload as a post attachment. PM me your email address and I will send you a copy.
CM

[montana_charlie]

Brinell Hardness. The standard size is a 10mm ball with 3000kg of force. There are at least two other ball sizes (for soft and hard metals) and different force levels. They are NOT named differently. You have to know exactly what was used in order to compare anything with anything else.
I was Googling this subject, yesterday, because of this thread.
I finally gave up in disgust, but did learn a few things.

- The other two 'forces' used in Brinell hardness tests are 1500 kg and 500 kg...the 500 being used for 'soft' substances.

- Regardless of which hardness testing method is used (Brinell, Vickers, Rockwell, etc.) the resulting value may be expressed in 'SI units'.
Apparently, that is the case in the hardness numbers I posted earlier for tin (51) and lead (38.4). In each of those cases, the number was followed by 'MPa' which identifies the value as being in SI units. ('GPa' is another SI unit used to express hardness values.)

If I remember correctly, 'SI' stands for 'Standard International'. It appears that (along with everything else) hardness values are being 'globalized' into something the world at large can understand...and to hell with bullet casters. It may be that 'BHN' is the dinosaur, and 'SI' is the meteor that will make it extinct.

After learning that, I went looking for a chart, or calculator, to convert SI units into BHN. That search was the source of my disgust...
CM

[Finn45]

I could be wrong, but since those tables are presented in pressure unit MN/m^2, they should be multiplied by approximately 0.10197, which is 1N (Newton) in 1kg-force (or kiloponds). This should put those numbers to basic Brinell scale based on kg-force.

Relation between MN/m^2, MPa, GPa goes something like... ehh, umm.... Basic unit N/m^2 (Newtons per square meter) is Pascal (Pa). MN/m^2 is 1000 000 N/m^2 ie. 1000 000 Pascals ie. MegaPascal (MPa). GPa is GigaPascal 1000 000 000 Pascals...

You have heard also other pressure unit, bar; 1bar is 100kPa ie. 100 kiloPascals ie. 100 000 Pascals. Clear as a mud?

Vickers hardness system is close to Brinell, also in values. Intender is different, pyramid shaped but not very sharp so it goes close to Brinell's ball system. Vickers values can be shown in old units as Brinell, or MPa (MN/m^2) or GPa (GN/m^2)...

Ideally, used force doesn't change the hardness values, because indentation mark changes accordingly, softer materials just needs less force and harder ones higher. Also ball size can be different, because unit is force per surface area. Homemade hardness testers (everybody have tried those) can use for example 1/4" steel bearing and weight of the user... Key is the indentation, which should be reliably measurable. My first home tester consist of a bucket full of rocks (weighed) and reloading press as a weight multiplier (calculated force via linkage system). 1/4" ball was okay for hard boolits, but soft lead needed bigger one.

Then I bought a Saeco from beagle.

http://www.webelements.com/webelements/elements/media/nearingzero/Pb.gif

[AZ-Stew]

Brinell hardness is (as has probably been stated earlier) measured by indenting the test sample using a 10mm ball and applying either 500Kg force or 3000Kg force, then measuring the indentation left in the test sample. there are two ASTM (American Society for Testing and Materials) test methods: E10 (area), E103 (depth). The two force values do not exactly correlate where their values overlap on the same material, therfore there may be different values of Brinell hardness assigned to a material, depending on the force applied.

Another test also uses an indenter, but rather than using a single force value and then measuring a varying area or depth of indent, the indent size is controlled to a single value and the varying applied force (depending on material hardness) is measured. This value is listed in Mega Pascals (MPa), a metric (SI) unit of force. Theoretically, this will give more clearly defined measurements between materials of similar hardness because the scale is expanded. This represents yet a third "Brinell" hardness number that may be assigned to a material that is unlike either of the others. In any case, the number will be higher than ones developed from the methods used in the first paragraph, for instance the "51" value for tin is in MPa of force, not the traditional numbers we associate with indent area and applied force, which should be in the range of 8 - 10.

I haven't been able to find a chart that allows one to see how these numbers relate to each other. All I've been able to find is charts that relate Brinell numbers to Rockwell, Vickers and a couple of others. Generally, these charts begin at hardness values far above the range we're interested in.

All this aside, and after all the reading and research I and others have done on the subject in the last few days, I'm getting really fond of my Lee tester. Its numbers relate very closely to the values listed in all the books and magazine articles I've read on bullet casting. Lee's tool is based on the formula that can be found at: http://www.answers.com/topic/brinell-scale. He reduced the size of the ball and proportionately lowered the force that presses it into the test sample. A chart is supplied that correlates indentation diameter (and, therefore, area) with the appropriate Brinell number. Any other scale of values, whether accurate within its own realm or not, only confuses the issue.

More info can be found at:
http://www.calce.umd.edu/general/Facilities/Hardness_ad_.htm

I got most of this info from the two URLs listed, the remainder from one of the engineers at a Brinell hardness test device manufacturer.

Regards,

Stew

[Harry O]

It is always good to get everything into the same units, but there will NEVER be an exact conversion from one kind of hardness test or another. The reason is that they have different shape points. That means how the material they are testing will react differently. There are rough correlations in a number of places, but they will never be exact. They cannot be. In addition, as was said above, almost all of the tests really get going at hardnesses way above what we are interested in. We are down at the lower fringe where there are wider swings (or less repeatability).

I used a portable hardness tester a number of years ago when I had to have quick results in the field without ruining anything (like cutting out a chunk of tension flange in order to get more accurate destructive tests). It was easy for me to sort out 80ksi steel from 100ksi steel. It was like falling off a log telling the difference between 100ksi steel and 240ksi steel. Actually, the 240ksi steel was a mistake -- the alloys added into it did not get mixed in well. Great strength in places, but NO ductility. It broke the first time it was used. So the little hardness tester was used to sort out the good ones from the bad ones without destroying them all.

Unfortunately, a lot of people either look at hardness tests as totally worthless OR more accurate than they really are. They are good stuff, but very limited. The biggest limitation is: don't try to cross from one to another and compare results.

[Finn45]

Just one more clarification, Pascal Pa, kPa, MPa, GPa are units of pressure, not force. Pressure is force per surface area; just like PSI is pounds per square inch and Pascal is Newtons per square meter. Newton is unit of force.

Handy calculator for home made testers:
http://www.gordonengland.co.uk/hardness/brinell.htm

Here's calculator for Vickers, MPa and GPa; it works for Brinell as well because Vickers system is also kilogram-force per surface area...:
http://www.gordonengland.co.uk/hardness/hvconv.htm

I'm not saying that Vickers can be converted to Brinell directly, they are close, but only close and closer on the lower scale than higher scale.

Lots of clear info on that site btw.

[AZ-Stew]

Finn45,

Force vs Pressure. Ya got me!

Regards,

Stew

P.S. for all: Here are a couple of photos of the flat testing stage I made for my Lee hardness tester. See post #9 of this thread. The V-block stage that came with the Lee is on the left, Mine is on the right. The flat stage allows me to measure hardness at the bullet nose, at the base and on any other flat surface, such as sprues. Note the tester dents in the sprue shown in the photo on the right. I'm going to try to make a small "ingot" mould from a short piece of aluminum channel extrusion. This should let me do alloy batch testing without using any bullets.

Stew

[John Boy]

Pour a thin rod of the metal. When it cools, bend it. If it crinkles - it's Sn

[randyrat]

Here is what I kinda go by: From the Los angeles silhouette club -"cast bullet page" http://www.lasc.us/CastBulletNotes.htm

Alloy BHN
Lead


5
WW (stick on) ...............6
Tin ..........................7
1 to 40 tin lead...............8
1 to 30 tin lead............9
1 to 20 tin lead................10
1 to 10 tin lead............11
WW (clip on) ...................12
Lead Shot*...................13
Lyman # 2.........................15
Water quenched WW .....18
Linotype ............................18 - 19
Monotype................25 - 27
Oven heat treated WW .......30 - 32
Antimony ...................50
I think it is all over the place I got +- in the range with the Lee tester. I have been all over the place by testing wrong when I first tried a tester. I think you have to be very consistent in the method and only use it for comparison

[uncrichie]

I know this thread is 6 years old but the science should still be the same. Can someone please tell me how 20-1 (20 lead to 1 tin) alloy can have a B hardness of 10 if the B of lead is 5 and the B of tin is 7 and there is 20 times more lead than tin in 20-1? I just don't get the math or physics here? How does a byproduct of 20 x B5 to 1 x B7 get to equal a Brinnel of 10.

Thanks, Kurt



Here is what I kinda go by: From the Los angeles silhouette club -"cast bullet page" http://www.lasc.us/CastBulletNotes.htm

Alloy BHN
Lead


5
WW (stick on) ...............6
Tin ..........................7
1 to 40 tin lead...............8
1 to 30 tin lead............9
1 to 20 tin lead................10
1 to 10 tin lead............11
WW (clip on) ...................12
Lead Shot*...................13
Lyman # 2.........................15
Water quenched WW .....18
Linotype ............................18 - 19
Monotype................25 - 27
Oven heat treated WW .......30 - 32
Antimony ...................50
I think it is all over the place I got +- in the range with the Lee tester. I have been all over the place by testing wrong when I first tried a tester. I think you have to be very consistent in the method and only use it for comparison

[JonB_in_Glencoe]

I know this thread is 6 years old but the science should still be the same. Can someone please tell me how 20-1 (20 lead to 1 tin) alloy can have a B hardness of 10 if the B of lead is 5 and the B of tin is 7 and there is 20 times more lead than tin in 20-1? I just don't get the math or physics here? How does a byproduct of 20 x B5 to 1 x B7 get to equal a Brinnel of 10.

Thanks, Kurt


Read the 5th paragraph.
http://www.lasc.us/Fryxell_Book_Chapter_3_alloySelectionMetallurgy.ht m
the last line of the 5th paragraph
"It is important to recognize that tin is well-mixed in the matrix and it hardens lead by making the matrix itself harder. "

:coffeecom

[uncrichie]

Thanks JonB. I just couldn't understand that the resultant alloy could actually be harder in brinell than the two combined metals used. There certainly is a lot more to this than just adding/subtracting numbers. Thanks again.

Kurt