Charpy V-Notch tests, and the meaning ...

[JTMcC]

Makes it less confusing.

Or more confusing.
Different brands of the same wire can have a lot of variety in user friendlyness. And personal preference is a large part of it.
There are a lot of wires out there that fall under the same E classification but that run different.
So a guy saying he really likes a particular wire, say UltraCore 71C, isn't the same as saying he likes every wire (even from the same manufacturer) of the same class.
There's quite a bit of differing opinion and preference amoung the T-1 gas shielded and T-8 self shielded wires. Some love one, others don't but really like another.
They aren't all the same old thing regardless of their numbers, you have to try them to see what you'd rather run.
JTMcC

[Donald Branscom]

Looks like your 12VS is going to get a workout UltraCore 71C is some sweet wire. It runs on 100% CO2. The wire itself is black, and perforated, no snips needed. The 15# spool fits in the feeder, because the spool has a recess for the retainer. It's certified FEMA 353 and AWS D1.8 Seismic.

Dave

The Ultracore 71C is a trade name, Lincoln Electric Co.
The AWS number is E71T-1C-H8 .045 Makes it less confusing.

[Dualie]

I witnessed batch lot charpy V notch testing at Lincoln in ohio. its a very interesting process to watch.

They were doing a batch lot of NR-233 @ -30 Deg.

They have something like 30 seconds to remove the ground and prepared sample from the freezer chuck it in the test rig and complete the test.

if i recall the test samples were 1/4" X 1/4" square about 3" long with a V ground 1/8" into the sample.

The techs doing the work say that on rare occasions they do have samples that will dead stop the test rig. which is really bad for the strain gages and equipment.

This was aprox 8 years ago and my memory isn't the best.

[wronghand]

Slightly off-topic here but you're looking for general guidlines, I thought I would throw a few more out there:

For FCAW 10x wire dia. is max weave

For SMAW use about 5-6x electrode dia.

For any application, do not exceed 2x parent material thickness-- a lot of structural welds are actually only 75% of material thickness

ie. when joining 2- 1/2" plates in a fillet weld, don't exceed 3/8" in the throat of the weld.

If the joint dictates making a weldment that will be considerably larger than the thickness of the parent metal, it's likely a good idea to run stringers rather than a large weave to limit heat input on the parent metal.

Cheers,

WH

[Sberry]

Yes, how much is excessive?

[Sandy]

FCAW weld width is typically 10x outside diameter of the wire. It will be on a properly completed WPS. So common 0.045" and 0.052" wire gives you a 1/2" final FCAW weld width if you stay within the WPS. The manufacturer of the wire sometimes has limits aswell.

IMO it's got more to do with heat input into the base metal than the ability the filler in making a clean weld.

Hey thanks, you've helped me here. I was just looking for something I could use personally as a general guideline for what is more or less acceptable and what might be considered excessive.

[Hillbilly69]

Welding Parameters

FCAW weld width is typically 10x outside diameter of the wire. It will be on a properly completed WPS. So common 0.045" and 0.052" wire gives you a 1/2" final FCAW weld width if you stay within the WPS. The manufacturer of the wire sometimes has limits aswell.

IMO it's got more to do with heat input into the base metal than the ability the filler in making a clean weld.

[JSFAB]

I'm glad I started this topic, and I'm glad a few guys that know more about it chimed in.

Hey, Sonora, how about the Reader's Digest version?????

[Sandy]

............................The problem is more common to wire due to the fact that it is highly efficient thus heat input can be easily exceeded. How many times have you seen a FCAW weld wider than 10x filler diam? Almost always. ...........

Just a question,,,, is this ten times the wires listed diameter which includes the filled core??

Thanks in advance.

[Hillbilly69]

Charpy Impact

This topic is a mystery to a lot of people.

Charpy's are just impact toughness at a relative temperature -usually cold temperatures.

The test can be run at different temperatures - as cold as like -60F.
Probably not that low for Califrornia seismic requirements but used in other industries like Natural Gas & Military Shipyard work. Your building code will probably reference testing at one of the temperatures listed in ASTM.

A lot of structural steel, plate, filler wire, welding rods do come prequalified with Charpy tests (You can ask for them when you order your steel or welding rod - It's on the Material Test Reports MTR's from the steel mills). If it doesn't arrive prequilified it can be tested. Rolling direction of the plate is critical when conducting and or qualifying your Plate and/or Welding Procedure Specification WPS.

The problem comes in the companies Weld Procedures Specifications WPS. For doing this work you are supposed to use qualified procedures (Some companies buy these from AWS or they come up with there own). This is where things go wrong welding interpasss temperatures are not usually followed and it destroys the Charpy properties of both the filler and the base metals. The problem is more common to wire due to the fact that it is highly efficient thus heat input can be easily exceeded. How many times have you seen a FCAW weld wider than 10x filler diam? Almost always.

Companies and Supervisors don't need to understand the physics behind the test that's not important. They need to understand the proper use of the companies Weld Procedures Specifications and why the limits are set on the welding parameters. The final and most important issue is training welders - this is difficult because production has always been the priority not quality.

[Sonora Iron]

if anybody has any better explanations, please post up.

[fjk]

There seems to be a lot of misunderstandings here, and most people have absolutely no idea ......

Essentially, a Charpy test measures the "toughness" of a weld.

...

A long time ago I worked in a metallurgical r&d lab ... that's how
I remember it...
The only thing I'd alter is that the Charpy test is not
limited to just welds.

Thanks for posting it

frank

[kcstott]

Yeah I about to charge the company a rental rate
The LWS here supplies to fab shops mostly. Not iron workers so getting a dual shield wire is a day or two out.

[davedarragh]

CalTrans California's transportation Dept. Was forced to grind out and reweld all welds on the rebar on seismic retrofitted bridges. All due to poor craftsmanship.

And thanks for the explaination.
The reason I asked Is one I haven't done enough wire feed welding to know one wire from the next. And two Selecting a wire for this job I found wires that meet impact requirements and wires that are not required to meet impact requirements. And I wanted to know what the difference was.
Now I Know.
Thanks JS, JT, and Dave.

Looks like your 12VS is going to get a workout UltraCore 71C is some sweet wire. It runs on 100% CO2. The wire itself is black, and perforated, no snips needed. The 15# spool fits in the feeder, because the spool has a recess for the retainer. It's certified FEMA 353 and AWS D1.8 Seismic.

Dave

[kcstott]

CalTrans California's transportation Dept. Was forced to grind out and reweld all welds on the rebar on seismic retrofitted bridges. All due to poor craftsmanship.

And thanks for the explaination.
The reason I asked Is one I haven't done enough wire feed welding to know one wire from the next. And two Selecting a wire for this job I found wires that meet impact requirements and wires that are not required to meet impact requirements. And I wanted to know what the difference was.
Now I Know.
Thanks JS, JT, and Dave.