Would a Chrome-Vanadium Steel Wrench be Tempered?

[Crunch]

Hello, all,

I was reading a post on a welding forum where a guy needed to make a custom wrench for a specific application, so he ended up welding a socket onto the end of a combination wrench.

In his photo, you could see the Heat Affected Zone near the weld (on the right-hand side of the wrench in the photo), which made me wonder whether the heat would have removed the hardening/tempering of the steel in the HAZ, and made the steel there weaker, by annealing or normalizing it. (I'm not sure you'll be able to view the photo without registering at the other forum, so I've attached it below in the belief that its creator would not mind me doing so.)

I have chrome-vanadium steel wrenches at home that feel like they've been heated/quenched/tempered, because they seem to have a "springy" quality, but it may be that they feel that way simply because of the characteristics of the alloy steel they were made from, rather than because they were hardened and tempered.

So: Does anyone know whether wrenches made of chrome-vanadium steel are typically hardened and tempered?
If so, does that mean welding on them would "weaken" the steel by normalizing/annealing it?
If so, should the welder have re-hardened and re-tempered the wrench after welding it?
If so, does anyone have any idea of what temperature would be appropriate to temper the steel after quenching it?

Thanks in advance for any replies.

P.S. For the purposes of this discussion, please ignore the issues of cracking caused by carbon migration in the weld puddle and finished weldment, preheat and postheat to avoid cracking, and the use of specialized fillers such as ER310 (25% Cr - 20% Ni) to improve ductility and reduce the chances of cracking in the weldment.

[Steve Sells]

Yes the welding messed up the starting HT. It may work fine. but we can safely assume its softer, but it may not be a problem. Also never a good idea to weld chrome plating.

[swedefiddle]

Good Morning,

I look at it that if it got the job done it is worthwhile. I have 'created' many new tools during my time as a Mechanic, all for one specific operation. If I was selling them to someone else, I would be concerned about the proper heat treating. Knowing that they are modified, I accept that they may be a little weak. No problem.

Neil

[ThomasPowers]

As long as they bend and not break then they probability pass the usability test.

[Crunch]

Thanks, guys. I guess my question was more academic than practical...more "were they tempered originally" than "should I re-temper them after modifying them."

[ThomasPowers]

Yes; in general wrenches are drop forged from a medium carbon steel and heat treated to be tough rather than brittle. *Old* ones are more of a "everything goes" type of deal...

[Frosty]

If there's enough vanadium in the alloy it could have become more hard, even brittle in the HAZ. I don't recall what the % was where Vanadium became a significant time&heat factor, it's been a long time since that hard facing class.

Frosty the Lucky.

[Crunch]

If there's enough vanadium in the alloy it could have become more hard, even brittle in the HAZ.

Interesting...I hadn't even considered the possibility of it getting harder, only softer. But I guess if the unheated parts of the wrench acted as a heat sink to "quench" the HAZ after welding, that makes sense.

Thanks again for the replies.

[Billman1956]

I believe it is air hardening material probably become harder and may need to be tempered back. 

[ThomasPowers]

Few wrenches should be air hardening as they need to be tough and not brittle.

[BillyBones]

I have a wrench that broke on me about 10 yrs ago. I grabbed the cutting torch and brazed, yes brazed with a brazing rod, and have been using it since.