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First beads - no penetration!

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First beads - no penetration!

Postby AussieWelder » Mon May 15, 2017 1:50 pm

IMG_4881.JPG
IMG_4881.JPG (71.57 KiB) Viewed 202 times
Hello everyone,

I'm running my first practice beads on 3/8" by 3" hot rolled steel bar. After running a few of these, and trying to get the Miller 140 autoset welder dialed in (amperage and wire feed speed), I have sliced across the work so far. I was chagrined to find no evidence of penetration.

I am using 75/25 gas mix, .030 wire. I cleaned up the surface prior to each bead.

Am I reading this situation correctly? Photos attached. I will continue to try different combinations of settings, but I had hoped to find at least some evidence of penetration here.

I know that the most basic problem here is that I am attempting welds on material that is outside the specs of this welder, but I was hoping that with good technique and settings, I would be able to compensate for at least some of the shortfalls of an underpowered system.
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IMG_4882.JPG (46.99 KiB) Viewed 202 times
Grant
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Re: First beads - no penetration!

Postby cj737 » Mon May 15, 2017 2:18 pm

If the base metal is too thick, you'll never get the penetration needed. If your machine is limited on its capacity,you can preheat the base to aide in penetration. But your issue is more than just too little current, you have some technique errors as well.

Your travel speed is too fast.
Your arc length is probably too long as well.
Your metal doesn't cleaned up at all either. It needs to be bright shiny metal with MIG.
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Question on arc length

Postby AussieWelder » Mon May 15, 2017 2:55 pm

Thanks CJ.

Is the arc length primarily decided by how far your nozzle tip is from the welding surface? Most of the time, I felt that I had it about as close as it could possibly be. I will try some subsequent runs of bead with slower travel speed.

I am still not getting a good look at the puddle as it is being formed. I think this might be a factor that is leading me to run the weld a bit 'blind'. I have my helmet set at 8 (lightest setting) and have also put in an optical 2 x piece.

I appreciate this.

Grant.
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Re: Question on arc length

Postby Farmwelding » Mon May 15, 2017 3:01 pm

AussieWelder wrote:Thanks CJ.

Is the arc length primarily decided by how far your nozzle tip is from the welding surface? Most of the time, I felt that I had it about as close as it could possibly be. I will try some subsequent runs of bead with slower travel speed.

I am still not getting a good look at the puddle as it is being formed. I think this might be a factor that is leading me to run the weld a bit 'blind'. I have my helmet set at 8 (lightest setting) and have also put in an optical 2 x piece.

I appreciate this.

Grant.

Arc length is officially the distance from the end of the contact tip to the base metal. Generally for short circuit mig I use 3/8-1/2¨
A student now but really want to weld everyday. Want to learn everything about everything.
warning!! Bad English may be in post. It's off a phone/autocorrect. I've had teachers with worse spelling!
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Re: Question on arc length

Postby MinnesotaDave » Mon May 15, 2017 3:50 pm

Farmwelding wrote:Arc length is officially the distance from the end of the contact tip to the base metal. Generally for short circuit mig I use 3/8-1/2¨


Respectfully, I disagree.
That's CTWD: contact tip to work distance, people also call it stick out.

Arc length is something different, for example with stick welding or spray transfer - then you have an arc length.

From Miller:
"Wire Stick-out
Stick-out is the length of unmelted electrode extending from the tip of the contact tube, and it does not include arc length. Generally, maintain a stick-out of 3/8 in. and listen for that "sizzling bacon" sound. If the arc sounds irregular, one culprit could be that your stick-out is too long, which is an extremely common error."

Lincoln, more in depth: http://www.lincolnelectric.com/en-us/su ... -ctwd.aspx
Last edited by MinnesotaDave on Mon May 15, 2017 3:54 pm, edited 1 time in total.
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Re: First beads - no penetration!

Postby PeteM » Mon May 15, 2017 3:52 pm

Also, how is your gun angle? It shouldn't be more than a few degrees off of 90, but a lot of new to mig guys will end up tilting the gun way over to kind of see what is going on. That just stacks the metal upon itself with virtually no penetration/fusion. This also messes up the contact tip to work distance.
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Re: Question on arc length

Postby Farmwelding » Mon May 15, 2017 4:39 pm

MinnesotaDave wrote:
Farmwelding wrote:Arc length is officially the distance from the end of the contact tip to the base metal. Generally for short circuit mig I use 3/8-1/2¨


Respectfully, I disagree.
That's CTWD: contact tip to work distance, people also call it stick out.

Arc length is something different, for example with stick welding or spray transfer - then you have an arc length.

From Miller:
"Wire Stick-out
Stick-out is the length of unmelted electrode extending from the tip of the contact tube, and it does not include arc length. Generally, maintain a stick-out of 3/8 in. and listen for that "sizzling bacon" sound. If the arc sounds irregular, one culprit could be that your stick-out is too long, which is an extremely common error."

Lincoln, more in depth: http://www.lincolnelectric.com/en-us/su ... -ctwd.aspx

My apologies. Every one else said arc length so I accidentally put that instead of ctwd. Thanks for pointing it out.
A student now but really want to weld everyday. Want to learn everything about everything.
warning!! Bad English may be in post. It's off a phone/autocorrect. I've had teachers with worse spelling!
Instagram: @farmwelding
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Re: First beads - no penetration!

Postby Otto Nobedder » Mon May 15, 2017 6:46 pm

AussieWelder wrote:
IMG_4881.JPG
Hello everyone,

I'm running my first practice beads on 3/8" by 3" hot rolled steel bar. After running a few of these, and trying to get the Miller 140 autoset welder dialed in (amperage and wire feed speed), I have sliced across the work so far. I was chagrined to find no evidence of penetration.

I am using 75/25 gas mix, .030 wire. I cleaned up the surface prior to each bead.

Am I reading this situation correctly? Photos attached. I will continue to try different combinations of settings, but I had hoped to find at least some evidence of penetration here.

I know that the most basic problem here is that I am attempting welds on material that is outside the specs of this welder, but I was hoping that with good technique and settings, I would be able to compensate for at least some of the shortfalls of an underpowered system.


You say you're cleaning the material each pass. I see no evidence the material is anywhere near clean. Define "cleaning" as you are using it.

That metal should be bright and shiny before you call it clean. Every bit of that (green?) crap should be gone. It seems to appear in the line of "no penetration" in your cut section. Use a grinder with a hard stone, and make some sparks until the metal is silver in color. Until that is done, there's no use working on settings.

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Re: First beads - no penetration!

Postby motox » Tue May 16, 2017 6:03 pm

not that this is the issue but grind a clean spot for your ground and place it as
close possible to the weld area.
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Re: First beads - no penetration!

Postby cj737 » Tue May 16, 2017 9:10 pm

The other thing that strikes me as questionable is the gas flow rate. Do you know what CFH your bottle is flowing?
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