Engineers and Welders help needed

OpenToSuggestions · 11 Mar 2009 at 21:42

I am doing a lab at uni on welding for a manufacturing engineering degree.

I cannot for the life of me find out the speed of which to butt-weld two plates together. I have had a good google and looked in many books but not found much of use!

Any ideas (or know of any websites) on the welding speeds of Manual Metal Arc (MMA) welding??

I know it is just the simple speed = dist/time equation andI know the length of the plates but that is all.

jr1104 · 11 Mar 2009 at 21:50

I'm not quite sure what you mean by welding speed? If you want an actual quantitative value, then I've never heard of doing that before (although that might just be my education).

OpenToSuggestions · 11 Mar 2009 at 22:19

I mean the speed the welder should do the butt-joint (ignoring the layers he has to do due to edge preparation).

Say the joint to be welded is 20cm, should he do it in 20secs or something. Are there recommended speeds at which you should weld (obviously 1m/s is way too fast for MMA!)

Siders77 · 11 Mar 2009 at 22:20

As above I don't see what you mean by speed of welding, if it's what I think you mean (How fast to move the torch etc) then I don't think there's any set speed, it all depends how the welding plant is set up.

I.E- Some people have it set hotter than others so move the torch faster, or some people have it set cooler and move slower.

I might be barking up the wrong tree here but I didn't really understand what you meant by speed of welding

OpenToSuggestions · 11 Mar 2009 at 22:21

Siders77 said:
How fast to move the torch etc

Thats what I mean

jr1104 · 11 Mar 2009 at 22:27

If you mean how fast to move the torch, it's just a matter of getting a feel for it. There is no set speed, just start the weld and then keep it going, slowing down if you are not getting enough penetration, and speeding up if you find yourself going through. The aim is to stay at a constant speed, but it takes some practice, so just keep doing lots of butt welds, that's how I learnt.

Remember that the angle of the rod also has a large affect on the weld, and sometimes people tend to decrease the angle of the rod when they speed up, and that results in poor contact and a lot of spitting. Try and keep it at 45 degrees, and keep your speed steady.

djbenjo · 11 Mar 2009 at 22:32

There's no set speed. It all depends on the type of material, the thickness, the rods (type and gauge), what your juice is set at. Are you welding this yourself or is it a theory?

If doing it yourself, all I can say is practice, practice, practice and more practice. Then practice some more. Welding is all about hands on experience.

Using the correct rods and juice is half the battle though tbh

TaKeN · 11 Mar 2009 at 22:36

djbenjo said:
There's no set speed. It all depends on the type of material, the thickness, the rods (type and gauge), what your juice is set at. Are you welding this yourself or is it a theory?

If doing it yourself, all I can say is practice, practice, practice and more practice. Then practice some more. Welding is all about hands on experience.

Using the correct rods and juice is half the battle though tbh

I was about to post that!

You need to work out the thickness of the plate your welding, thickness of the wire your welding with, then you've got the various power settings and wire speeds..

Hmm, the mig forum is probably your best bet OP!

OpenToSuggestions · 11 Mar 2009 at 22:38

The lab guy is going it as my (and the groups) welding is crap! (I am even worse at Tig and Mig!).

If the speed is too slow then penetration is too deep and wide weld bead.
If the speed is too fast then penetration is too shallow and thin weld bead.

Can anyone verify the above too sentences are correct? (as that is what I think).

Of the text books I have looked at they recommend an angle of about 20degrees for the electrode in MMA (so 70degrees between weld direction and electrode).

The currents for the chosen electrodes are just recommended ranges so we are just going to go in the middle of these ranges.

jr1104 · 12 Mar 2009 at 08:23

What you have said there is correct. As everyone has said the best thing to do is practice. Watching someone else do it will only show you how to do it, you won't actually be able to put it into practice yourself. It took me a month of just doing butt and then fillet welds until I had full confidence in welding.

Geek · 12 Mar 2009 at 10:23

It will depend on the thickness of the material, the frequency of the machine and the width/type of welding flux you are using.

PhillyDee · 12 Mar 2009 at 11:06

Try and contact a fabrication plant. They will have guidelines for pricing jobs up based on those facts. Usually places like that do have approximate times for estimating job times/prices. Just ring them up and explain what you are doing and why.

OpenToSuggestions · 12 Mar 2009 at 13:43

jr1104 said:
What you have said there is correct. As everyone has said the best thing to do is practice. Watching someone else do it will only show you how to do it, you won't actually be able to put it into practice yourself. It took me a month of just doing butt and then fillet welds until I had full confidence in welding.

I don't particularly enjoy welding. Especially Mig where I cannot feel the trigger through the thick gloves! I don't want to fry my eyes or anything via a mistake.

TaKeN · 13 Mar 2009 at 23:25

mglover070588 said:
I don't particularly enjoy welding. Especially Mig where I cannot feel the trigger through the thick gloves! I don't want to fry my eyes or anything via a mistake.

Sod the gloves!

I used to wear gloves when welding, I only wear the one now when picking up the hot piece I've welded with..

It will give you bad sunburn if you weld for a long time, I've yet to suffer this

For christs sake though.. do not let any part of your body touch the metal

thats my arm

moremoney · 14 Mar 2009 at 02:22

Are you asking for the theoretical answer which there is,or the practical answer.
There is a very precise way of welding which i only know from my bro,because he was a welder.
Imagine welding a sub, you don't guess the thickness of the weld do you, you work it all out.
So what is the formula.

Does the speed also depend on what you are welding.

Lumeycom · 14 Mar 2009 at 02:56

mglover070588 said:
I don't particularly enjoy welding. Especially Mig where I cannot feel the trigger through the thick gloves! I don't want to fry my eyes or anything via a mistake.

Use TIG gloves, they dont last too long with the heat of mig but you get a decent feel through them. I cant weld with thick gloves on so this is my best solution to avoid the evil sunburn

OpenToSuggestions · 16 Mar 2009 at 00:08

I can fully appreciate why it takes a long time to become a good welder.

It is tricky and has the potential for some nasty injuries too.