Need advice on these welds

[clevinski]

Appreciate any advice on these welds

Hi...

I'm going to weld a frame out of 1/8 inch (3 mm) mild steel angle, and was welding some scraps to get the settings right. I clamped the material flat to my 1/4 inch (6 mm) thick welding table surface and grounded it well. I was using .030 inch / 0.8 mm wire in a Clarke 180EN. The results are below.

I don't have much experience with welding thicker stock with the 180EN where I should be able to get full penetration, but half these welds were done on 3-max and the others on 2-max, which should be the highest (180 amp) and 2nd highest (150 amp) settings. I expected to see substantial distortion on the back of the piece if I'm achieving full penetration, as I do with thinner stock.

Viewed from left to right, the settings were as follows.

3-max speed=3.0
3-max speed=4.0
3-max speed=5.0
2-max speed=5.0
2-max speed=4.0
2-max speed=6.0
3-max speed=5.0

As you can see from the bottom views, only the two end welds came all the way through, and that is probably because they were at the edge of the piece.

So, my questions...

1. Is the 6 mm tabletop acting as a heat sink and affecting the weld?
2. Should I expect to see the same type of distortion on the back side with 3 mm angle that I would with thinner stock?
3. Shouldn't these settings both be too high for this material and be too hot?
4. What should I do differently to achieve better penetration?

Many thanks for any advice...

 

[dannyweld]

hi, those welds look fine, can't you weld both sides and then grind, when mig welding black steel your better of grinding away black scale before you weld anyway as far as penetration goes.

 

[shenion]

You might need a bit more wire speed. Hard to say as each Clarke seems to be different. My 130EN was using a wire speed of 6 to 7 on its max setting with 0.030 wire. Never could do full penetration on 1/8" steel with it unless i led a 1/16" gap. Then it did it easily.

Using 0.035 wire, i could easily blow holes in 3/16" steel using my big Miller. With 0.030, 1/8" seem to reach a plateau that then need much higher voltage and wire speed.

The welds look fine, leave a small gap or weld both sides if you need full penetration.

 

[clevinski]

Dannyweld, it's standard mild steel, not black steel. (The photos of the back do make it look black, though...) I've added a clarification in the post.

Scott, I guess what's bugging me is that 180 amps and .030" wire, based on everything I've read, should be more than enough to achieve full penetration! It's not that what I'm welding is super-sensitive, it's just that I want to do it right, which means full penetration. I'll try turning up the wire speed further and see if that helps, but at 6.0, the arc already sounds "frantic" rather than your basic frying bacon.

 

[malcolm]

Your table will have been acting as a heat sink, making the work 9mm rather than 3mm. With the additional thickness a lot of heat will have been sucked away resulting in much less penetration than you would otherwise expect. Try supporting the work off the table.

The welds themselves look wide and formless. Movement too slow most likely that's you compensating for the lack of heat and allowing too much filler wire to build up in a big wide pool.

 

[clevinski]

Malcolm, I'll try getting the work off the table and speeding up. Thanks for the advice!

 

[snowcat]

you should penetrate through the joint rather than worry about achieving full pen every time, on thick sections this is improbable, and cause as many problems as no pen, undercut being one, heat distortion another, and damage and cracking in the HAZ....

cutting through some joints and examining the weld would be a better indicator.....

 

[zardoz]

The only way to see if pen' has gone through is to saw through the welds, file and emery them smooth, and acid etch them, so that the melted metal depth and melted wire can each be clearly seen.

As to a 6mm (mild steel?) table being a heat sink, i wouldnt think so to any great extent. Remember inanimate objects only get so cold and have no wind chill factor etc. Even in the unlikely event of your welding bench being in the open. Im sure its getting very chilly this time of year in New Jersey.

If anyone has any figures on diferent metals being used as heatsinks i'd love to see them. Im sure we all did a similar science experiment at school. With different metal bars being heated by a bunsen burner, and seeing how long it took to reach a certain distance before a blob of wax holding a toothpick/matchstick, would fall off.

 

[clevinski]

Hmmmm... Snowcat, you can't see it in the photo, but there is some undercutting on the leftmost weld.

Zardoz, I can cut through the weld and file/emery them smooth, but I need to acid etch them to see the penetration? I can't imaging that this is a very common thing for home hobbyist-types to do. Is there no other way to determine penetration?

Regarding the table acting as a heat sink, I think your point is that the thermal conductivity of the steel table is not high enough to get very much heat away from the weld quickly. But Malcolm's comment makes sense; since the parts were tightly clamped flat to the table, wouldn't it be like welding 9 mm steel?

Anyway, I'm going to try again today or tomorrow and change some other factors (work off the table, faster torch movement, faster wire speed, lower temp, gap between parts, etc.) I'll post the results...

 

[jugs]

Your table will have been acting as a heat sink, making the work 9mm rather than 3mm. With the additional thickness a lot of heat will have been sucked away resulting in much less penetration than you would otherwise expect. Try supporting the work off the table.
.

Regarding the table acting as a heat sink, I think your point is that the thermal conductivity of the steel table is not high enough to get very much heat away from the weld quickly. But Malcolm's comment makes sense; since the parts were tightly clamped flat to the table, wouldn't it be like welding 9 mm steel?

As malcolm said, "Your table will have been acting as a heat sink",
Keep work clamped to table when tacking up because you want the heat to disapate quickly to stop distortion.

When you're welding up slip some 1/8" x 1/2" strips under the work, away from the weld area, this will maintain heat in the job. I often use .8mm wire off cuts as spacers, makes a huge difference.

 

[clevinski]

So I clamped a piece in a vise by its edge so that there was nothing to act as a heat sink. What a difference! Several times, I went too slow and actually burned through the stock, even with the heat set on 1-max. Apparently, the heat sink effect was significant.

Jugs, the strips are an excellent idea and I'm going to implement that. The clamping to the table to tack up is also something that will be really useful...

 

[dannyweld]

hi, when i said black i mean hot rolled, which i'm nearly sure by looking at the surface structure. when you talk about full penetration if its all the way through your still going to have to do something on the other side, dress it up at least, whats the finished product, is the strength critical, then you'll have to do some sort of destruction test, if its ornimental, then just stick it together, make it look nice and get onto your next project. if straightness is very important then you will have to tack the job before you do you're runs and keep checking with your square. if your table is metal then it will act as a heat sink to some degree, although if it makes a difference is hard to tell.

 

[clevinski]

Ah, hot rolled. I thought you meant something completely different. Thanks for the clarification. This is a stand for a tool chest and will have a maximum weight of 500 pounds / 225 kg on it. Actually, it'll probably less than that, but safety margin and all...

 

[snowcat]

Hmmmm... Snowcat, you can't see it in the photo, but there is some undercutting on the leftmost weld.

Zardoz, I can cut through the weld and file/emery them smooth, but I need to acid etch them to see the penetration? I can't imaging that this is a very common thing for home hobbyist-types to do. Is there no other way to determine penetration?

..

An etch test is a relatively cheep, I use it quite allot, I take your point on a bit much for a hobbyist to do, but a can of cleaner, dye and developer isn't doing to brake the bank, you could do some coupons (pieces of material) and do some bend tests, this will let you know if the weld has adequately penetrated the joint.....

Don't get too hooked up on this notion of a good joint being a fully penetrated joint, its the all important fusing to the parent material, joint design is the key to controlling penetration on anything other than sheet metal work, certain joints unless welded in specific ways (ie T fillets) will only ever be partially penetrated, Its why leg lengths, toes root opening values and all other wonders are specked, But theres little need to worry about that..

 

[storm monkey]

An etch test is a relatively cheep, I use it quite allot, I take your point on a bit much for a hobbyist to do, but a can of cleaner, dye and developer isn't doing to brake the bank, you could do some coupons (pieces of material) and do some bend tests, this will let you know if the weld has adequately penetrated the joint.....

Don't get too hooked up on this notion of a good joint being a fully penetrated joint, its the all important fusing to the parent material, joint design is the key to controlling penetration on anything other than sheet metal work, certain joints unless welded in specific ways (ie T fillets) will only ever be partially penetrated, Its why leg lengths, toes root opening values and all other wonders are specked, But theres little need to worry about that..

What he said....... Very few of the welds on the CAT diggers I used to design were full pen welds. Mostly large fillets and the odd butt weld. When you are welding a 10mm thick doubler to the side of a structure, then you are only ever realistically going to have an 8mm or so throat size, and 1-2mm pen into the parent plates, depending on weld parameters. Joint design in these applications is more important, and the effects of stress raisers and fatigue effects take over. Often plate thickness is there for stiffness, rather then strength, so a 10mm thick structural section may only need 6mm fillet welds to secure it in place.

As for the joint cutting inspection exercise, this can still be very useful if you have no etch solution. You won't see the extent of the HAZ, or be able to measure penetration, but you will be able to get an idea of how good the fusion is, and, in the case of joints welded both sides (fillet or butt welds) you'll be able to see if you have got filler fully into the joint or not.

Phil

 

[clevinski]

Interesting... I'm going to try cutting a few just for fun and see what I can see...