How to easily tell difference between 4140 and 12L14

[seal killer]

All--

I bought some hex 4140 and 12L14. Same size. The only marking was a slight bit of red paint on the end of one of the pieces. Does the red paint mean anything? Or, do I resort to the spark test to figure out which is which? (I've never performed the spark test.)

Thanks.

--Bill

[warmstrong1955]

The colors won't help, unless you know where it came from. I have 4140 from various vendors, and paint color among the bunch includes none, blue, red, and black. There's no standard...the various companies & suppliers vary. I've learned to mark everything....in several places with a sharpie, or tags.

Best to have a couple known pieces to compare to for spark testing.
4140 will have more sparks, longer sparks, and more yellow in color than 12L14. The 4140 sparks will branch out more. Low carbon steels have whiter sparks, less branches.

Maybe Ken knows a good URL to look at some pics?

Bill
.

[atomarc]

I seem to remember a rather crude way to figure this out...maybe smack both pieces together, the softer of the two will mark, that being the 12L14. hit each piece with the edge of a file or something quite hard. The softer material will indent more than the harder one.

Stuart

[jpfalt]

Machine a couple of small pieces. The 12L14 will cut remarkably easier.

[seal killer]

Bill and Stuart and jpfalt--

Thanks for the help. I'll start with the spark test. I have a supply of other 4140 and 12L14 with which to compare.

--Other Bill

[tornitore45]

http://www.scrapmetaljunkie.com/241/the ... g-metals-2

Color pictures of various spark tests.
I have a copy of this next to the grinder, however is not as easy to tell the difference as it may seems.
Looks like it takes years of experience and having seen many different specimen to develop the clinical eye required.

[seal killer]

Mauro--

Thanks for the link. I'll try the spark test. If it takes more than the experience I have (crackling wood fires), I will stick it in the mill and take a cut. I know I will be able to tell the difference then.

--Bill

[paulz]

You'll know which is which when the cutter makes it's first chips. I love 12L14.

[rudd]

Look at them both cross-eyed. The 12L14 will immediately be covered in rust.

[GlennW]

^^^ Exactly!

[atomarc]

It truly does machine wonderfully but for most of my applications it's too wimpy. It wears poorly, doesn't have a whole bunch of strength and of course..rusts quite quickly! I wonder why that is.

Stuart