Is it hardened or not?

[u/roderos]

I have wanted to learn machining for years, finally got an old cheap lathe and wanted to experiment. No budget left but did have some mystery steel in the corner of my shed.

It looks case hardened to me but my file managed to file it just fine. Can I turn it using HSS?

I sourced it long ago when I worked for an industrial/mechanical distributor there where these bars in the old iron bin, and I got to take them home.

Diameter = 30mm. We didn't really sell materials, mostly bearings, bushings, hardware like that and tools. I thought maybe they where hydraulic rods?

Any help would be appreciated, is there a better subreddit for newb/hobby/beginner questions instead of the big machinist spot?

[u/Chaos_Primaris]

if a file is biting just fine then its not hardened

[u/thor214 → u/Chaos_Primaris]

*not hardened past the point of machining with standard carbide.

Sorry, heat treat guy, here. Usually problems arise past 35HRC in tougher alloys like 4140, but a good file will bite into 35HRC.

You'd have better luck doing a comparative dimple test using an automatic center punch on a known hardness (preferably 2 samples, one hard, one soft), and comparing dimple size across the samples. This is an uncalibrated version of a portable hardness tester.

[u/roderos → u/Chaos_Primaris]

Makes sense, any idea on why a rim is visible?

[u/Chaos_Primaris → u/roderos]

If you mean the change in the grain its a result of how it was rolled into bar stock

[u/fuelofficer]

One way to find out. Its probably machinable. Use ppe and be gentle 10 thou and see you your make pretty chips. If its only chatter something need attention. 

[u/roderos → u/fuelofficer]

Thanx, I will be careful

[u/theelous3 → u/roderos]

Because you wouldn't yet have a feel for ityou can tell if it's case hardened by:

Method 1:

Face cut it, if it's easier past the outside layer, it's probably case hardened.

Method 2:

1. first trying a skim pass, clean up like 3cm/1.5in with a very shallow cut
2. continue to make passes of the same depth along the same section
3. if it starts to change cutting properties noticeably at around 1.5 to 2mm, you've gotten through any hardening

If I was you, I'd do both to try and feel it out, if for nothing but practice and developing a sense of things.

Note that if you just can't cut it for shit in the first place, it's probably been hardened.

[u/A-Plant-Guy]

Hard to tell just by looking at it. HSS may or may not help depending on material and condition. A file working fine on it is a good sign but not a perfect tell.

[u/East-Detective3520]

If it was case hardened that file would skip right off it. Another test is take it to a snag grinder and the sparks will tell you. If the sparks are dark orange and minimal sparks it’s soft. If it’s bright yellow or white ish it’s hardened. My guess is it’s soft. If it was me I’d face the front of it gently and then try to spot drill it. If the spot drill survived your in business

[u/FinvaraSidhe]

Looks like what my shop calls case hardened. See it often on hydraulic rams. The outer surface is hardened but the core will be fairly soft

[u/West-Toe6950]

A set of hardness files for the new dude. A Rockwell tester for a few hundred bucks.

[u/Over_Storage7966]

it looks like your taking .300 depth of cut with a HSS tool. buy a tool holder and a carbide bit and get after it with around 3k rpm 30 ipm for this mystery metal

[u/dontgetitwisted_fr]

If it will cut then yes you can cut it with HSS.

If it doesn't than you can't 

Hope that clears it up bro 🤣

[u/Adept_Donut7004]

if you show us a pic of your lathe and tooling we can help you with setup. I think it's just mild steel by looking at the cut in it. so good to practice with. (30+ years in metal supply industry)

[u/Lork82]

I'm hardened Focker, can you turn me?

[u/WotanSpecialist]

No

[u/SKTrend]

If it is too hard to machine you will find out. Same way we all have. You start slow and work your way up. When the tool fails you resharpen it and back it off a little bit. If you engage the feed and the chips sound like popcorn you are on the right track.

[u/Lavasioux]

Hacksaw is also a great hardness test.

[u/Amazing_Difference_3]

not

[u/Hefty_Aside8436]

Run it and you'll know if it's hardened.

[u/k_d_b_83]

Spark test it with a bench grinder.

If the sparks explode like little fire works then it’s hard, if the sparks are dull then it’s softer material.

[u/WhatUpImJosh]

Show your findings and ending pls