**root to hot pass**

By raftergwelding (*****)

Date 11-30-2007 02:29

i run the root in at 40 and the hot pass at 48 works good for me

By Sourdough (****)

Date 11-30-2007 02:47

I appreciate you Shad, but I gotta interject.

Root pass depends on the schedule of your pipe, land thickness, gap, and preheat temp of your work. I won't ever run a root pass, (even 2") at less than 96 amps 1/8, or 135amps for 5/32 rod even on sch 40 2"

There are some companies that wont let you have more than 1/32 height on the inside of your root bead, (inside of the pipe). That means fast and HOT! With a capital H.....

If you are running too cold, you will stick the rod, or pile up on the inside. If you are running too hot, try a forward angle, (drag), and push in moderately to make the puddle chase your arc. If you are just plain too hot you will not be able to maintain coverage on the inside of the pipe and will have to come back and grind, start over on your root - or you will have a burn through on your hot pass, ) fish eye), which will fail on any xray.

By raftergwelding (*****)

Date 11-30-2007 03:02

well i'm use to my dumb ass ways and i set it at 40 with the range selector in 3rd gear on the root and run it up to 48 still in 3rd gear on the hot pass and still cant pass a xray and i never had any formal training of any kind jus got showed the basics and was told to figure the rest out and i can take constructive criticisim so dont fret i aint mad

By 52lincoln (***)

Date 11-30-2007 03:56

Im going to track down some thick walled pipe and start practicing on my welds.I guess i will post some pics as i go.have a friend who is a pipeliner out of Cosicana,he will help me a lil.but he stays hooked up alot. THANKS for your help.

By knslash (*)

Date 11-30-2007 04:52

I concur with Sourdough, the pipe size, schedule, and fit-up must be taken into consideration on the stringer. I personally prefer to run to run a little hotter than others and use rod position to controll burn-in. As for the hot-pass, I've always turned up 10, with good results, I was taught that the hot-pass should be run immediatly after the stringer. Some may not be as picky, but this technique has served me well for many years.

Rafterg- keep practicing you will suceed. Hard to learn on your own, I was lucky and broke out with three top-notch old timers who took me under thier wings. That was 20+ years ago, still use what they taught me every day.

Ray

By samh

Date 11-30-2007 22:19

I was taught to run it as hot as you can. If im running beads with 1/8 on midrange and 50 with sa-200 then i hot pass on midrange and 80 or 90. Better have the bead in there good or it will find the weak spot. But a good hot pass will actually push the bead in a little bit as well as getting rid of the wagon tracks. Run it to hot and you will smoke your rod about half way down. Seen that a bunch. Every ones different but that is what is comfortable for me.

By dbigkahunna (****)

Date 11-30-2007 23:26

This is for Xcountry pipeline DH welding.
You want to run your hot pass at the upper end of the procedure range for travel speed, voltage and amperage.
If there is a heavy grind on the bead, you do not want to punch through. Espically if you are using a 5/32 and are running oh say 240 and 80. One rod should get you to 4 oclock. run slightly past the bottom. On a brother in law weld, one starts at 4 oclock and runs across the bottom and stops. The other starts at 12 and stops at 4. When you change position, you hit the starts and stops with the buffer (Not Grinder) and one side starts at 12 and ends at 4 and the other welds across the bottom. If you have your heat set right, you can see the waggon tracks melt out.
On standard wall pipe 240 and 75 is a good place to start. Go up or down 5. If you see the flux flaming when you get 3/4 of the way down YOUR TOO DURN HOT! On a 2 inch stub, the remainig flux should not change color. IF it does, then the flux is not able to do what it is supposed to. Protect teh weld metal.
BABRT's

By raftergwelding (*****)

Date 12-06-2007 04:28

240 and 80 on 5/32 damn thats hot real hot i run 5/32 on my rig at 190 and 60 - 65 and it's hot for me sumtimes

By dbigkahunna (****)

Date 12-06-2007 13:46

Thats why its called a hot pass. The hot pass is used to remove waggon tracks and turn the bead from convex to concave. Most Xcountry welding procedures allow a travel speed of 12-24 ipm on the hot pass. Most pipeline contractor want the Hot pass finishing up ahead of the bead so the pipelayer can set down and jump ahead to pick up the next joint. On a good pipeline job the hot pass will finish up just as the bead hands are breaking to change rods. That way when the pipe is set on the skids, the bead hands do not have to deal with the pipe jumping as it is being set on the skids. The hot pass pipelayer jumps ahead, picks up the next joint, picks it up and is backing to the pipe clamps when the bead hands finish. THe spacing foreman and his crew goes to the next joint, inserts the spacerTightens the clamp and by that time the bead hands have moved up, the hot pass hands have moved up, the hot pass gets its skim grind and here it goes again.

On 12 inch pipe the time between when the clamps are tightened and the bead is finished is around 2 minutes. If you are running hot pass you have to do all your work in about half that. Plus you have to pick up that little piece of IP the bead hand missed without blowing through and get to the bottom before the pipe hits the skids.

If the bead hands are waiting for the hot pass hands, there will be new hot pass hands before break.

By raftergwelding (*****)

Date 12-06-2007 04:25

I'm trying man I'm trying this cancer thing with my son has me hemmed up when i aint working but i try and get as much as i can in at work. Got a wing you wanna lend me lol

By texasrigwelder (**)

Date 12-07-2007 01:35

shad just stay down on that bead (dont long arc it) and get to stepen and it wont seem as hot just choke that rod down