Shop Press Brinell test

[cascao]

Had someone used a regular shop press plus a bearing ball to conduct a Brinell test?

My goal is identify unknown steels and relate brinell hardness with ultimate strenght.

At 3tons, there much risk of ball bearing exploding?

https://me-mechanicalengineering.com/brinell-hardness-test/

 

[mikey]

Hmmm, a ball in a press ... hope you plan to use Lexan shields between you and the work.

 

[cascao]

Have seen some funny videos about ball bearings exploding.....my plan is cut a section of an old fire extinger I have and use it as a shield.

 

[mikey]

Just be careful, cascao. An off-center object in a press can be expelled forcefully if it slips.

 

[cascao]

Just be careful, cascao. An off-center object in a press can be expelled forcefully if it slips.

Good point. Will do one tip like this

 

[mikey]

Good idea. If you can somehow make it so the ball cannot possibly be ejected, that would be good. Many years ago, I saw the aftermath of a pump that slipped in the press. This thing had to be over 10# and it was ejected through the shop wall and into the side of a truck parked in back of the shop. That left an impression, on the truck and in my mind.

 

[pdentrem]

How are you going to regulate the pressure to make the test repeatable?
Pierre

 

[cascao]

the idea is to use my shop press manometer and conduct the test at 3 tons and see if impressions are similar sizes expected for a known material.

 

[cascao]

I Made the "holder" for 10mm (3/8") ball. The holder let only 3mm (1/8") of the ball exposed.

For sure the holder is a must if you doesn't want to brinell test your press ram.

Tested some 1020, 1045, A36, SCH80 and AL 6061 I have at scrap bin.

My readings ended being a bit off expected numbers. Had a tough time taking precise measurements with a paquimeter.

I Had read that there is a dedicated microscopes for this....maybe a good photo and convert pixel to mm....this will be my next try.

 

[Tony Wells]

Hardness is generally specified at mid radius when checking on a face as you have pictured. It will always be lower in the center and climb a bit as you approach the OD of a round. Using a Brinnell method you must get an accurate pressure, substantial support under the test specimen, and if checking the OD of a round, if it is hot rolled, grind away the decarb layer and use a good sturdy vee block of adequate size.

And yes, there are special microscopes for that purpose.