×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Contact US

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

repair of crack in steel pipe that conttains oil.

repair of crack in steel pipe that conttains oil.

repair of crack in steel pipe that conttains oil.

(OP)
I was once told by someone that I now feel lacks much credibility that when you are welding on a pipe that has any oil in it, that when yoou attempt to weld up the crack that any oil in the pipe will be drawn too and will contaminate the weld.  this is wrong, isn't it?  Won't the oil actually be pushed away bfrom the weld until after the weld has been cooling down for some time.  Then after cooling for awhile the oil will be drawn to the weld.  The oil will in no way contaminate your weld though, right?  You can just inert the pipe and weld it, right?

RE: repair of crack in steel pipe that conttains oil.

You are both correct!! The heat of the welding does tend to drive the oil away from the area of the weld but welding anything which has been contaminated with oil presents difficulties. My own experience is with gearbox housings. It is impossible to clean the cracked area sufficiently well to remove all the oil and the weld is generally of poor quality ( lots of porosity) however if the first weld bead is ground out and then the part rewelded the second weld is usually much better and if the process is repeated several times, welding/grinding, welding/grinding etc. a reasonable weld can be produced.

RE: repair of crack in steel pipe that conttains oil.

If it is possible to tig it thats what i would i would try.

I repair thin wall tubing quite frequently that has had oil,
Alcohol and Nitromethane in it and have had no problems by slowly preheating the start zone before adding filler rod.

This works on mat. up to .125

Jeff

RE: repair of crack in steel pipe that conttains oil.

(OP)
Carberize,
I appreciate your help, hoowever I ddon't really feel that gearbox housings have the same characteristics as steel pipe.  I would guess that your gearbox housings are either cast aluminum, cast iron, or cast steel.  The emphasis of course being on the "cast."  Although I may be mistaken, I would expect a gearbox housing crack would contain many more fissures and inclusions so any oil would be very difficult to remove. If you aare dealing with cast iron, it almost seems to absorb oil like a sponge, whicch I guess is why oil makes it much harder  once oiled it becomes considerably more difficult to machine.  If  your housing is aluminum... we already know that aluminum needs to be immaculately clean to weld.  Cast steel is somthing that I've had little experience with, but I still wouldn't expect it to have as clean a crack  as steel pipe.  If I am wrong please do not hesitate to correct me, Becaause most of my statements came from within rather than a text book, and I'm not a mettallurgist, see I can't even spell it correctly.

RE: repair of crack in steel pipe that conttains oil.

I have had similar experience with cast iron housings and those fabricated from welded steel plate. As I said in my earlier post - it is possible to get a decent weld but it sometimes takes several reworks to get there

RE: repair of crack in steel pipe that conttains oil.

We have repaired steel tanks holding oil and diesel and found great success with pre-heating the area around the repair prior to welding. This tends to bake out any contaminates and at least in our applications, eliminated porosity and defective welds.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login



News


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close