Welding Tips and Tricks

Let me try this again, I've got to do a welding cert for my work. It's 1/2 plate vert and overhead. I've done the plates once and they didn't pass the bend test. I welded them too cold. I've done welding certs with the air force a 1" tube on a 45 angle. I'm useing a miller matic350 p .035 wire, co2 argon mix. I see from the company I submitted the test to that I was not running hot enouugh. I ran my test plates at 19 ipm and 220 on the wire. The examiner says 27-33 and 450-650 fpm. At that heat range and feed I have way too much sagging. So apparently I need to strike an arc and haul butt? Also I'm useing er70-6 wire. Apparently there are different dahses of numbers so should I be useing something else like ER70-2 or ER70-?.

So my questions are should I speed up my travel?

Is my wire ok? Will it hold up to a U-Bend?

With 27-33 Volts and 450-650 inches per minute wire speed for an .035 solid wire, this sounds like it's intended to be a spray-arc weld. You say you're using ar/CO2. What mix? 75/25 won't do spray arc. 98/2 will, and there are other mixes that will do the job, with varying properties.

The original parameters you tried, 19 V and and 220 IPM are short-circuit MIG numbers, and appropriate only for the root pass in 1/2". In short-curcuit mode, everything after the root I do at 22.8 V and about 350 ipm.

The WPS should specify the gas. If they didn't give you a WPS, ask the examiner, and also ask the boss why the hell you don't have a WPS for the weld. Unless you're expected to develop a WPS for the weld.

If you're developing a WPS for this weld, it's a different animal altogether, and I can make several other recommendations.

In short, if you are certifying or qualifying your skills (there's a difference), there is a "Welding Process Specification" (WPS) that will tell you everything that is allowed... What wire, what gas, what voltage range, what wire speed range. How much bevel, land, and root gap. It's spelled out somewhere, and you should no more take a test without it than weld a customer's product without it.

Steve S

This helps, I was set up for faulure with the equipment I have. My next question is "what is spray arc"?

I'm expecting other hands to chime in, but, in short, "spray arc" creates a plasma between the tip and the work, and deposits metal in a fine spray of particles. The metal leaving the welding tip almost vaporizes and is deposited by arc force.

I have no real experience with spray-arc, and can't be of much help. I will dig for some resources for you though.

Steve S

I do notice, in both your attempts to ask this question, and both my attempts to try to answer, you ignore the "WPS".

You won't tell me if you have one; You won't tell me what it says.

Steve S

Damn I hate to sound ignorant what is WPS?

Do you read the replies?

Really?

Did you read my entire first reply?

"What's a WPS?"

"Welding process specification". It's in there! In black and white!

Take your Adderol and read it again.

Steve S

RR41mag.

A shop will take responsibility for the welds its makes.

One of the ways to ensure that the welds are acceptable is have the welders follow a procedure which gives detailed information how to weld that joint. The detailed procedure is called a wps - welding procedure specification.

But a wps is not simply written up. Instead, it is based upon how a special test weld was performed and later tested. So a shop will prepare a joint and weld it. All the information concerning the base metals, the filler metals, the volts and wire speed during the various passes, the welding techniques, etc. etc.; is jotted down during the welding of the joint. This information is important. Next, the welded joint is sent away for visual inspection, nondestructive testing (radiography, and/or ultrasonics, magnetic particle and/or liquid penetrant) and destructive testing (bends, pulls, impacts, etc.).

If all the results are acceptable, then based upon the test results and the information taken during the actual welding of the joint, a procedure is written out. This procedure is the wps. This wps will be given to the welders to follow in their production.

Alexa

RR41mag.

One of those informations on the wps will be the amount of preheating of the plates before welding is started. Not all wps require preheating.

But the low alloy steel, Aisi 4130, usually requires preheating if the plate thicknesses are at least 1/2" thick. The thicker the plates, the more important the preheating. In the case of 4130, we do not want the weld to cool too quickly. If the 4130 weld cools too quickly, the hardness (thus the brittleness) will increase.

If you look at that symbol 4130, you will notice the 30. That thirty means that there is approximately three-tenths of one percent (0.30 %) of carbon in the metal. That is enough carbon to make the weld zone prone to hardening, if cooled too quickly. The slight additions of chrome (1%), manganese (0.50 %) and molybdenum (0.20 %) in the 4130 mix, also slightly make it more prone to hardening.

Tanks.
Alexa

RR41mag.

As mentioned above, a shop needs to document all the information taken during the welding of that special test joint, and to document the results of the testing of the completed weld. The attached link shows an example of a form that is often used to register all that welding and testing data. The form would be called a Procedure Qualification Record or PQR.
http://files.asme.org/asmeorg/Codes/Pub ... /14033.pdf

======
Instead below, is an example of a blank WPS, which gives instructions to the welder how to weld a joint. The WPS is quite similar to the PQR above. It should be, because the WPS is based upon the data documented in the PQR.
http://files.asme.org/asmeorg/Codes/Pub ... /14260.pdf

======

Note that there are many informations within the WPS. Some of the same questions you asked are also on the WPS.

This is one of the reasons why welding people want to know so much information concerning the troubleshooting or planning of a weld. The more procedural information we have, it is easier to comment.

Hopefully this was not too boring.
Tanks.
Alexa

I have a WPS but i had to fill it out myself. They then made corrections and sent it back to me. The difference was the the amperage and wire were bumped up. When I try welding to their specks the weld litterally falls off when welding in the overhead position. That tells me I'm not going fast enough. But when I go faster I know I don't get penetration.

rr41mag wrote:I have a WPS but i had to fill it out myself. They then made corrections and sent it back to me. The difference was the the amperage and wire were bumped up. When I try welding to their specks the weld litterally falls off when welding in the overhead position. That tells me I'm not going fast enough. But when I go faster I know I don't get penetration.

=====

RR41mag.

When you wrote 'they' I assume you are talking about your employer's supervision.
So they want you to weld at a stated range of wire speed (change in sync with the amperage).
With that wire speed (amps), you will have to fine tune your voltage (temporarily set the voltage too high resulting in a unstable/wild arc, and then taper it back until the arc is controllable, this should give you a good fusion).

If the supervision wants you to run at the higher amperage range for that wire, then your 'gun moving technique' may need to change too.
My guess, if you move too slow in the overhead position, while running at the top range of the amperage for that wire, the puddle may drop out, so you will need to move along quicker, utilizing straight passes (without weaving).
You may help to keep your torch angle as straight as possible.
Also keep track of your stick-out (puddle to contact tip distance) ... this may need to be shortened.

Keep track of your parameters that you are using, from weld to weld during this qualification process.
The supervision might be using you to optimize the procedure.

Keep us informed.
Tanks.
Alexa

now this sounds like what I've been wanting to know. I just found out I can go to the test faculity. I would much rather do that then keep mailing these coupons off.

New here, but not to gmaw. Spray arc can only be done vertically with a pulse being used. You can run it flat and horizontal without pulse. Try 18 volts and 250-300 on your fill and cap. 15-16 volts and 180-220 on your root. Hope your downhilling the root. Uphill is a little tougher. Uphill your fill and cap. It will bend!

I noticed the sheet of recommendations had something about "pulse" (it wasn't a WPS) I started reading the machine settings owners manual. After running a few beads really hot 30/440. I switched the machine over to pulse. It welds alot better now but I cut one of the coupons and I'm not getting penetration. Like I said I've never been formally trained on mig welding. The Air Force concentrated on tig, stick and oxy/ace. I really appreciate all the help so far. I doubled up on my adderal today to help me get through the stress of welding these coupons.

rr41mag wrote:I doubled up on my adderal today to help me get through the stress of welding these coupons.

That statement helps me understand you better.

I'll be looking back through your posts, and at your future posts, with that thought in mind.

I have some experience.

Steve S

30/440 is most definitely a spray transfer setting. Should be very quiet at that setting. If its not turn your wire down a little at a time until it is quiet. Keep about a 3/4" stickout( wire sticking out of the nozzle). 98/2 argon like he said. Most machines have a preset for the pulses per minute. I know your not doing an open butt so give yourself a 3/16 gap before you tack your backing on for good penetration.

Almost every job has a wps. Companies have to prequalify a welding procedure before it can be used for construction. Once it's qualified the welder has to stay in those parameters for liability insurance reasons. Theses guys know their stuff and steering you right. Good luck man and lay off the shaky pills its just a weld haha

Ok I got my plates. I've got the machine set at pulse (which is cool with the tester) 50 and 300? I've started taking extra adderal too. The beads look great

Ready to run my plates today. I spent all day yesterday sanding cleaning etc. I took extra adderal this morning and am ready.

Well don't leave us hanging. Any luck?

Let me see if I can load pictures, What do yall think? the left is verticle, the right is overhead.

Terrible picture sorry bout that

I guess I'll be turning them in tomorrw. It will take about 4 to 5 days to get the results. I want to thank all yall for being patient with me and helping me out. Like I said I've never been formally trained on mig and yall help tremendously. Lets see if I put that good help to use. By the way I'm still taking double doses of my adderal. If I don't pass this test they are probably going to let me go. It's a great job too. I love going to work.

Visually, I think you're fine.

Despite the looser weave on the overhead, when I put this in my photo viewer and zoomed, I don't see any undercut, which is the big weakness in cap passes for the bend tests these will see.

As long as you're confident in the root, and the cleaning between passes, I think you have a solid shot at passing this.

Let us know how it goes!

Steve S

Also,

Don't hang your hat on one job.

EVERY job is a better job... an opportunity to learn something new.

Steve S