Interesting Welding Statement.

[gemini5362]

Originally Posted by Flatheadyoungin

I didn't make it to pipe welding level but my instructor always said something about MIG wasn't approved for pipe.......dunno.....

I broke out the ole' stick the other night and realized just how much I missed it......

I dont know if it is aproved but I do know it is used. Many years ago I went for a job interview. The company was laying 12 inch pipeline on the ocean floor. they would take and 80foot section of pipe clamp it into a machine the machine had three mig welders 120 degrees apart. they would run around the pipe and then it was inspected and if it passed it was sent down into the water and another piece was put in place.

[crbr]

Different results for different requirements. Most codes allow for various degrees of results, along with any applicable site specific procedures.

My limited knowledge of hands-on stems from 25 years of U.S. nuclear power applications under AWS, and various sections of ASME. The API 1104 and B31.1 power piping codes were never allowed (less stringent codes). I was a welding engineer for years in the nuclear world, all beginning with Quality Control responsibilities (AWS CWI). However, neither job consisted of hands-on welding. Always good to hear from the welders. I can quote metallurgy and processes all day long but can barely stick a rod to bare metal.

What I enjoy most for fun is weld symbols on a drawing.... I see a lot of incorrect symbols that folks will just weld away reading an incorrect symbol...

Good thread....

.

[Egon]

Sorry I shouldnt have used the term full penetration it is an issue of lack of fusion. With MIG when you first pull the trigger your depositing material right away, however the substrate isnt fully heated yet and doesnt allow full fusion. Do a sample weld and cut out your start and it will most likely fail. With Stick you strike your arc, pull away slightly and it preheats without deposition allowing full fusion right off the start.

Well said!

Could the size of the machine be a factor also?

[SnowRidge]

Originally Posted by alltoys

.............. Also these procedures were developed by ASME - American Society of Mechanical Engineers, an American Government Agency..........

The ASME is a private organization. It is not an agency of the US government. However, governments, US and otherwise, and governmental agencies sometimes reference ASME codes and standards in their laws and regulations.

[alltoys]

Originally Posted by SnowRidge

The ASME is a private organization. It is not an agency of the US government. However, governments, US and otherwise, and governmental agencies sometimes reference ASME codes and standards in their laws and regulations.

I was waiting for someone to clue into this statement.

ASME is as well connected to the Government as the Food and Drug Administration.

[Sully2]

Its a lot of personal preference!!

"The body is 8' tall and 5' diameter, made from 3/16 hotrolled."
If a weld coupon of that material ..welded with a MIG welder can stand a bend back test and not snap ( which it had better not!!) then why wouldnt it be able to be "rolled and formed" to a much lessor degree?

[Flatheadyoungin]

when you hammerweld, the weld is actually is being forced to move.....since mig is a hard weld, it cracks...

when you bend something, the metal around the weld is what does most of the moving.....so the pressure is spread out...

well, at least in my thinking

Originally Posted by Sully2

Its a lot of personal preference!!

"The body is 8' tall and 5' diameter, made from 3/16 hotrolled."
If a weld coupon of that material ..welded with a MIG welder can stand a bend back test and not snap ( which it had better not!!) then why wouldnt it be able to be "rolled and formed" to a much lessor degree?

[alltoys]

Originally Posted by Flatheadyoungin

when you hammerweld, the weld is actually is being forced to move.....since mig is a hard weld, it cracks...

when you bend something, the metal around the weld is what does most of the moving.....so the pressure is spread out...

well, at least in my thinking

Sully is talking about a bend test. No matter the type of weld if it is bent against the face and or the root without breaking or splitting in the slightest degree the weld passes. Whether it is a MIG weld or not.

Lets get this straight, many things that are used on a daily basis are MIG welded. For instance a Propane Cylinder ( which is a pressure vessel ), your car, and lets not forget the Airplane. Anything automated these days is MIG processed and in production as well.

There are ways around the cold start of a short circuit method of MIG operation.

[wushaw]

Originally Posted by alltoys

Sully is talking about a bend test. No matter the type of weld if it is bent against the face and or the root without breaking or splitting in the slightest degree the weld passes. Whether it is a MIG weld or not.

Lets get this straight, many things that are used on a daily basis are MIG welded. For instance a Propane Cylinder ( which is a pressure vessel ), your car, and lets not forget the Airplane. Anything automated these days is MIG processed and in production as well.

There are ways around the cold start of a short circuit method of MIG operation.

Airplane??? What is mig welded on an airplane and please define which airplane you are refering to.

[Sully2]

Originally Posted by wushaw

Airplane??? What is mig welded on an airplane and please define which airplane you are refering to.

MANY items are Mig and TIG welded on airframes...far too many to attempt to list for sure.

Only airplanes Im semi familiar with are combat aircraft. F16;F14;F15...etc