Is it REALLY 4130 chromoly?

[JR]

When a vendor advertises his product as being made of 4130 chromoly, how can we be really sure?

We have a lot of steel laying around the shop, must of it chromoly but some of it is cold rolled steel. How can we be REALLY sure?

These threaded inserts from KARTEK are supposed to be 4130 but the truth is, I'm trusting people less and less these days. Seems like an easy way to rip off a customer if they were so inclined.

Is there a way to verify for sure without a metallurgy test?

I didn't do a search, maybe it's been covered before.

[mobil1syn]

whats wrong they .00001 out of round?

[Pook]

Spark test can tell you if it has more carbon than the other piece.

Its how I try and tell if a piece of scrap cut off is good enough to use to make a tool from for blacksmithing. But if its an important hard to make tool, I just buy new known material, since sometimes when you go to temper it thinking its one kind and turns out to be something else...it cracks. Sucks wasting hours of work.

[JR]

Originally Posted by mobil1syn

whats wrong they .00001 out of round?

[JR]

Originally Posted by Pook

Spark test can tell you if it has more carbon than the other piece.

I can't see the difference?

[onetoncv]

I know when we machine 4140 heat treated to rockwell 42 thru hardend its a little different than dom the chips are slightly different , Try a spark test on each though sometimes the sparks tail will be different . Jess

[Pook]

http://www.fpga-faq.org/sb-metal_hol...%20Testing.pdf

[Pook]

You could also do a file test... but that really would depend on what state the 4130 is in if you'd notice any difference in hardness.

[Corey Young]

How about a Rockwell hardness tester? Cold rolled will be around 0-4c and non heat treated 4130 will be around 18c. Am I close?

[onetoncv]

I'd say the rockwell on 4130 n should be around 30 - the cold roll 20 or so - there's a decent difference in hardness - Jess

[JR]

I just did a spark test. Must be doing it wrong. Can't tell the difference.


Anyway, I'm not sure I want to grind small, expensive, precision "chromoly" parts.

[Blase]

Rockwell hardness test can tell you which is harder but IMO that is about it. It will not tell you if one is 4130 and one is heat treated 1018,1026,8620,4140 Etc. The range would narrow down or eliminate some grades if high enough but that is all.

Only thing I can think of would be to find a nickel recyling yard. Most Nickel recyling yards will have a "gun"(some hand held) that will tell them a ROUGH chemistry of the steel from an "x-ray". THIS BY NO MEANS AS ACCURATE AS A METALLURGY TEST but should be more accurate than a spark test or hardness test.

My local guy uses it to tell the difference between 625, 718, 825 and 925 Inconel machine shavings. So it can tell you chemistry pretty close but it would be up to you to know the difference between 4140 and 4130.

Jr I think the only TRUE way to know would be to do a metallurgy test. As i'm sure you already know even 4130 chromoly will have a wide range of properties if heat treated at different times and temps.

[JeffHPK5]

Spectrometer...anything else is a guess

[Goat]

Spark test is the cheapest...the other affordable alternative is an acid spot test. It's an ND test and looks for concentrations of Molybdenum.

One drop of testing solution on the piece, deposit onto filter paper and look for it to change to purple.

[onetoncv]

the top pic is slightly duller - more carbon -if it was short and curvy it would be cast- Jess

[SCRAMBLR]

Take it to a local scrap yeard most have the tool that can scan it and tell. Might charge a couple dollars but worth it for the piece of mind.

[MotoDave]

If its really critical that the part be 4130, ask for a material certification sheet when you buy the part. Don't be surprised if they tell you there is a bump in cost, or to be told its not available, I doubt very many fabrication shops track material certs.

[Pook]

Look at your first pic... see how the sparks starburst.

[laproscopic]

i purchased a bunch of link tabs from kartek. supposedly chromo. $10 per piece. look the same as cheaper stuff

I dont know if the kartek stuff is chromo or not but their stuff sure is machined well. for instance, i bought a bunch of their weld washers-they are polished finish. their tube adapters are similar. their tube clamps are perfect. and they get me the part in 3 days every time. if they dont have it in stock, they say so.

i baught a pile of 5/8 weld washers from ballistic and they look like shit-machined with an ax.

[MT4Runner]

Originally Posted by MotoDave

If its really critical that the part be 4130, ask for a material certification sheet when you buy the part. Don't be surprised if they tell you there is a bump in cost, or to be told its not available, I doubt very many fabrication shops track material certs.

Easy to get the mill cert when or right after their supplier's truck arrives. Should't cost a dime more if it's available.

Very, very difficult to know what's sitting in the bin if it's got 6 months of dust on it.

[RedBullJeep]

For a company like Kartec, they have too much on the line to get nailed by an employee blabbing. In most cases, it's just a matter of trust.

[MNtal]

Originally Posted by Pook

http://www.fpga-faq.org/sb-metal_hol...%20Testing.pdf

Thank you for posting that...

Originally Posted by onetoncv

the top pic is slightly duller - more carbon -if it was short and curvy it would be cast- Jess

I'm with Jess you can see the more amber color with a distinct star burst at the end of the spark...

Edit: You can also see the spark is straighter (longer) coming off the mild steel.
The 4130 fans out in a shorter span.

Originally Posted by SCRAMBLR

Take it to a local scrap yeard most have the tool that can scan it and tell. Might charge a couple dollars but worth it for the piece of mind.

Good solid piece of advice...

[onetoncv]

By the way Pook I saved that info you posted to my desk top -Great info buddy- Jess

[JR]

Originally Posted by Pook

Look at your first pic... see how the sparks starburst.

I was grinding a piece of stock in one hand and taking a picture with the other.
My main concern was not to run my hand into the grinder.
The sparks all depended on how much pressure was applied, and it was not probably the same. So, the pics are a little misleading.

I looked at the sparks in real life and could not tell a discernible difference and that was comparing one to the other. If I picked up a piece without a comparison, there would be absolutely no way I could tell.

I like something like an acid test. Stopping work to drive some where and have something checked is just not practical.

Those tube ends are going on links that will be heat treated. It would be nice if they really are 4130.

[BossBuilt]

Originally Posted by JR

I just did a spark test. Must be doing it wrong. Can't tell the difference.


Anyway, I'm not sure I want to grind small, expensive, precision "chromoly" parts.

Your shutter speed is faster on the first pic so it must have brighter sparks, unless you monkeyed with the camera. *Note the sand belt.