6G Pipe Welding ~ Tulsa Welding School

hello everybody i'm doug watkins today we're going to be doing a demonstration on 6g pipe welding uh combo welding combo as in two processes we're going to use gtaw which is tig we're going to use smaw which is stick and that's where you get the term combo because it's two processes so to start with we're going to do prep our pipe which is very important and so the the number one thing to start with is your ppe always wear two forms of eye protection in your gloves so we'll get started with that now we're ready to start with our preparation which is very important and the first important thing is to wear your ppe which you always have some gloves two forms of eye protection you can grind your pipe with a sandpaper grinding disc only but i prefer to use a hard carb rundom or composite disc to grind with and clean inside and outside okay notice that i have these two vast grips here it is very helpful to have a holding device if you have those to do that because it keeps the pipe from sliding around so now we're going to clean the inside with a carburetor stone [Applause] okay now notice that the id which is the inside diameter of the pipe is shiny which is known as bright metal when you have oxidation in carbon steel it is rust and and tig uh does not penetrate rust in other words rust will turn your ark away so you're gonna get what's called bright metal shine okay now the next thing i want to shine up the bevel with this sandpaper disc because it puts a very fine finish on it so what we have here is completed prep of our five inch pipe and notice how shiny it is when we started this looks shiny and it was gray but honestly it's not shiny it has fire scale from the plasma cutting it so now we ground all that off we have what's called bright metal and in in tig welding you use a knife bevel the reason why it's called a knife bevel because it is actually sharp on the edges and the reason why it's sharp on the edges is because tig is not a penetrating arc and to consume that bevel and put a positive root on the inside you need to have a sharp where you can consume that bevel so that completes the prep and you may think sometimes well it took too long to prep being too picky about that but the thing is when you prep your pipe properly it gives you a win-win situation to start and it's to your advantage to get the very best in prep so what we have i use a 532 spacer for this process with this rod with a 1 8 rod so i put the 532 spacer here and then i set my pipe on it where it goes where it's lined up properly where the id which is the inside diameter is flush with each other and is straight up and down and lined up with no mismatch which would be called side to side so our prep is complete now we're going to get ready to set up our welding machine all right now we have machine setup and when you have a dc welding machine any dc machine you can do tig welding so ordinarily people that are used to stick welding you put your electrode holder on the plus sign but this is opposite in tig welding we use straight polarity so what we're going to do is we have our our ground our grounding cable goes on the plus side okay and then now we have our cable that's going to go to our power block and i'll show you the power block in just a moment and it goes on the minus side so what we have is our electrode holder which we do you you can use in this process hooked into the mine the negative terminal and we're going to hook it on our power block and what our power block is is a means to collect connect our electrical current to our tig rig i'll show you that in just a second and it's an argon hose that goes to our our tig rig screw it in there you can hand tighten it it's a 7 16 nut you can put a little bit of snug to it if you want to but as long as it's ham tight you're good and this cable has a copper wound cable in it that goes to your tig torch and your tig torch consists of a means of having your tungsten in here to make an arc you turn this on an argon comes out which is the shielding gas tig uh welding does not have coated flux coated electrodes because the argon comes out and makes a inert atmosphere where there's no oxygen in it and the way the the argon gets to this we have what's called a flow meter usually they can be on your argon bottle or they can be plumbed in as they are in this case we have an argon flow meter we turn the argon on and turn it on here as we see this this ball comes up in this uh flow meter which means that we have argon flow coming out of this torch you can feel it and we have about 30 cfh is what we have on there and that's suitable for argon tig welding so now also on our machine we you have process switches on here this machine has is able to uh gtall which what we're doing tig welding smaw stick welding and you can wire weld but we're going to put in the process of gtaw because that's what we're going to use and then we're going to turn the machine on and for this process that i'm using for this thickness of pipe and i'm using 1 8 wire what i like is 105 amps and you can use different amperages but approximately 105 is what i like you can use you can use less than that you can use more than that but in a beginning uh stage this is a good usable amperage because it's forgiving in your travel and time that you use your feed your wire and use your hands to do that so now we're ready to put we'll i use four tacks and we're ready to tack our pipe and then we'll put it in position to get ready to wet okay now we have our machine set up complete our machine is on our argon is on we have our our clean coupons they're bright metal shiny we have a 532 spacer in here and we put our pipe on top of the other one and look inside there and make sure that it is even no mismatch side to side so now we are ready to tie okay our prep is complete now we're ready to tack and there's a wide range of hoods that you can use i just use a fiber metal hood with a number 10 fixed lens in there you can use whatever you prefer but this is what i like so now we talked about gas tungsten inert welding which is gtaw which is tig welding we have a number 17 torch and he uses argon we talked about how to turn argon hook it up earlier every time you weld you turn this argon on right here and you just turn it on one turn you don't have to turn it on several turns to make it work so and we use our tungsten very sharp when you use a tungsten sharp your your arc is directed where you put it and if you have a dull tungsten it it goes out several different directions and it's not concentrated and we want to concentrate our arc exactly where we want it so it's very sharp both ends you put it in your gas lens get your stick out right turn your back cap and get it tight so now we're ready to tack and you've probably heard tack welding if you don't know what it is it is a process but it's not a complete weld it's a short uh weld that fixes our pipe in the position that we need it so now we're ready to tack and on carbon steel what we're using today is er 70s6 rod's welding tig wire as we call it is usually stamped and it has a number in there and that way you verify the material that you're using er 70 s6 e stands for electrode r stands for rod 70 is your tensile strength that you use s is for silica which is a coating on here that keeps the rod from uh rusting and six is a composition of your minerals in this rod so now we are ready to weld so we'll turn our machine on and and we'll put attack what we have here is we have a coupon that's ready to weld we're ready to tack it the tack holds the pipe in position to get it in place where we're going to weld it so what i do we use lift arc tig which means you make contact with the metal with the tungsten and then you lift it back up like like a 16th of an inch and you wait and get a molten puddle of liquid metal and then when you do you introduce this wire and this wire melts from this arc and you transfer it to this top side back to the bottom side and you make molten metal in here and you travel and you put a molten metal uh puddle in there that fuses both sides together and then you quit the arc breaks and your pipe is fused together at least one little small part to start with so we did get our first tack in here the first tack secures your pipe in the position where you're going to hold it too well and we do have our 532 spacer rod in here but what you want to do you do not want to make your second tack with it in there because it'll be locked in place so we're going to pull that spacer and when you tack metal metal shrinks down smaller and it'll squeeze onto your spacer bar and sometimes you got to pull it out of there with pliers but what we have is a gout that is that's uniform except it's squeezed down on our tack side and it's bigger on the untacked side so we will squeeze it together and tack this side so we'll push down on it a little bit just bring it down and we're ready to tack so now that we have two good tacks in here to secure our pipe in place where it goes every time i break arc with my wire you see this end where it's melted over the end that's actually trash you want you don't want that trash when you initiate a new puddle so i always clip it off because you got a clean start you don't want to introduce trash into your new puddle that you're going to make so now we're ready to turn this and and put we i like four tanks because that way our gout stays uniform so now we're ready to put our third tack in here right here so now that we have our tax on tax and four places on the pipe we're going to feather these out which means we're going to thin out the ends of them that way when you weld into them and out of them this thick metal is consumed by your new arc and that way you can't tell the difference in the start and the stock so i'm going to grind the ends of these so now as you can tell these ends the starts and stops of these welds are thinned out it's like a ramp it's like a starting ramp to consume the metal and melt right into it so now we're ready to weld these quarters i will tack it up in a 45 degree angle which is the 6g position and we'll be ready to put the root in there uh so now that we have our pipe tacked up in the 45 degree angle we're ready to put our root in there and finish it i have four good tacks so the pipe is secured with a good uh uniform gap what i'll do is i'll weld a quarter like this bottom quarter here and then i'll switch over to this top quarter here the reason why you do that is for the pipe to have the same uh thermal draw so it does not dog leg and bend it'll be uniform and then we'll go back and finish this cord in the top quarter and it'll be uniform and it will not bend so we're ready to do that now so the the root pass is complete and when you after you do that you want to wire will it because when you melt metal even though you have an inert atmosphere when metal melts and the coating on the wire you will have a thin film on there and you want clean bright metal to start your next pass so what we're ready for now we're ready for our hot pass and i like to put the hot pass on there at about 140 amps so we're ready for that now so now we have our hot pass complete on this side and as you notice when we come up here with our metal our metal is a only toe to toe on the root because what it is it's reinforcement for the root it's not meant to be a field pass in other words you don't make metal go all the way here and here that's not the case that's not what you want to do you want to concentrate it right behind that root to reinforce that and once you do that that's a complete hot pass okay so now that we have our hot pass on here what we want to do is what we usually do we wire wheel because cleanliness is the name of the game you want any uh contaminants which is our airborne particles when when the metal cools and the coating on that wire so we'll wire will it it'll be clean and we'll be ready for our field pass with 7018. and so now earlier we we were in gtaw for tig welding we changed our machine swapped our leads over to reverse polarity and we have our stinger on the plus side and we will change our machine to the smaw mode and then we will dial our our amperage so we turn our machine on and i'm going to put it on about 90 amps close enough and so in some people ask how many passes do you put on a pipe to fill it up there's not an answer for that you put enough till you get it full enough flush and then cap it so we're going to put us a stick pass on there a field pass okay what i'm going to do now is i'm going to start the field pass with a 7018 rod and uh often the question that people ask is what pattern do you use or how do you run your rod basically what i do is i start an arc and i proceed to look at the puddle and see how the puddle spreads out and it's called oscillation which you move your rod just a tiny bit side to side and it'll make that puddle spread out a little bit and that's all i use is a little bit of oscillation so we're ready now um so what we have now we have our first field pass with a 7018 on here and it's a single pass right behind the uh hot pass what we want to do after that is we're going to split it up we're going to have a double pass we'll have one right here and one on top it'll be a two bead pass and it'll get us close to flush enough to cap so we're ready for that now so now we have our second field pass on here and it's to to one side of the bevel but notice one thing these are called the shoulders right here on the edge of the bevel and the edge of the bevel here and we do not melt these off this is very close to the edge but you save that that's a a point a viewing point that it's like a the side of the road to keep it between the lines don't melt the shoulders off and you maintain a straight cap so now we're ready for this pass right here and as we talked earlier between each pass we'll wire will it to get any slag anything off of there that we want we want clean metal so we're full we're flush we're about a 16th below flush so i'm going to wire wheel this now and we'll be ready for a three bead cow so we're progressing right along toward the finished pipe um so now we're ready for our three bead cap and as we talked earlier there's one question that people ask a lot where do you run your rod we have a visible shoulder here and we have a visible shoulder here and we'll strike up a arc and we'll run our rod right here and our flux on a rod never gets outside of this shoulder if it gets out of the shoulder your calf is going to be wide you keep your rod up here and your puddle flows over the shoulder and as it flows over the shoulder that's when you move along so you just want to barely cover this shoulder and that's all you want to do and be above flush so we got our first bead on here we'll call it our bottom bead of our three beads we have it on here we laughed over the edge or with the shoulder we don't have any undercut because it's filled all the way so we'll start and run one continuous bead up here to the top our second bead then we'll be ready for a third bead [Music] so we have our our bevel full we have our first two cap beads on here and both of these beads basically filled up the groove but we have a little bit of shoulder showing on top so we're going to run our third bead on here which won't require much you could call it a toe bead uh the definition of the toe on the weld is where the weld metal meets the base metal so we'll put a thin pass right here and then we'll finish this weld out and we do not want any undercut we don't have any undercut on the bottom it's visible that it's pipe all the way and the the main tip that i would have people talk about letting pipe cool or not or whatever but basically if you have the right amperage on your machine and your proper rod angle and you have positive metal puddle as you go up and it follows you that weld metal will fill any uh any areas that you you will not have undercut because you have positive metal so we're going to run this on up and we'll be finished with this side and also i'm only capping this side i staggered these you you if you're even if you're welding both sides you stagger your starts and stops so they're not in one place as to build like up a hunk you'll stagger one two three and that's why they're not in one place so here's the last beam did you look at it all right doug watkins saying bye for today thank you all for watching enjoy doing the demo you

Channel: Tulsa Welding School

Views: 406,290

Keywords: weld, welding, welder, tulsa welding school, welding school, skilled trades, vocational school, vocational training

Id: 8DuN8qzl8ew

Length: 35min 8sec (2108 seconds)

Published: Wed May 19 2021