Spark testing 6

[Dave0001]

I am looking for detailed information on spark testing and identification of material from the sparks. I am especially interested in colour pictures, any suggestions.

 

[unclesyd]

Are you interesed in sparks off a grinding wheel for metal indtification?

 

[swall]

Metals Handbook, Desk Edition (ASM) has a small section on spark testing. Also, some of the handbooks you can get from steel service centers have spark testing sketches.

 

[unclesyd]

Here are two that I had ran across and noted. Check with your local scrap yard and see if they have a chart and see where they got it. There is information on websites concerning blacksmithing and knife making.

Go to Virtual Classroom and checkout Spark Chart

http://www.ohiosteel.org/

Tool Steel

http://www.cknife.com/sparks.htm

There is also a book "Rapid Spot Testing of Alloys" which I believe is published by ASM. Check the website and get the isbn no. and see if you can find a secondhand book.

I have colored wall chart but the company that put it out doesn't exist anymore. The one, different, where I worked has been replaced with a motivational poster.

If you are going to be using the spark test the best thing is to get you some samples, 3/4" rod works well, of the materials of interest and make a comparison each time you test. Always use a clean wheel.

 

[metman]

Follow unclesyd's advice of comparative testing with known samples.

Carpenter Steel Company published a book (do not know it it is sill in print). The Title is Tool Steel Simplified. It has the best charts I have seen.

 

[TheProfessor]

Dave,
Colour pictures are not the answer, as colour is not what you are looking for in spark testing. It is structure:
the lace and arrows and fineness of the spark pattern. The primary element you'll sort for is carbon. The rest of the metals are much harder to see, if at all. Low carbon steels have almost all straight sparks; high carbon is almost all lacy bursts.

As unclesyd says, keep the wheel clean. As swall says, the ASM metals handbook has info - better still find a very old edition. Spark testing has fallen from grace in the computer-in-your-hand era. But it has its place yet.

Wear protective goggles or shields. Keep the light low. Use a gentle touch. The volume of sparks results from how hard you bear down on the wheel - not the chemistry. This is an inexact art and requires practice. But for rapidly sorting between two suitable unknowns, it is priceless.

There are also various 'spot' tests which use chemical reagents. A bit messy, but useful too sometimes.

For plain carbon steels, a good eye can distinguish 20 points. Almost anyone can tell 50 points or carburized from not. Many tool steels have quite unique spark signatures - develop a known sample box and practice, practice, practice.

 

[swall]

And if you see a brilliant white spark stream, you've got titanium!

 

[metman]

You might not be the brightest star in the sky but I think you chose the brightes one off the wheel! Oops that's a stream not a star.