two in one welding and boilers

[powerengJP]

Hello all
To set my questions straight, I am studing to be a power eng. i am taking a power eng class 5 course but I have worked in Engineering dept. of a hotel for 2.5 years so I am familiar with what I need to know for the course.



My 1st question is... how the &^%# do you weld stainless steel!!! I am (blowing my own horn) good at mig welding reg steel, my work provides me with a mig and gas and stainless wire and a hand full of guys that say they know how but....
any outside help would be GREAT!

2nd
our steam boiler ( more like kettle 15psi) has a white substance floating in the water. we test the chem daily and the TDS all over the place but lately it has been sitting a 2700. and the other tests are at normal standards

what is the white stuff?

JP

 

[Rich2001]

Your 1st question - How do you weld stainless steel?
Clean, good technique and watch for hot or crater cracks. Generally not more difficult than CS.

Here are some links with more information

http://www.lincolnelectric.com/knowledge/articles/content/stainlesssteel.asp

http://www.weldingengineer.com/Stainless Steel.htm

http://pntbeldyk.wirefire.com

http://home.netcom.com/~dwelding/

http://www.machinist.org/army_welding/Ch6.htm

 

[vesselguy]

PowerengJP,

Since I'm not a Welding Engineer I won't even try to get into details with you on welding S.S.
If you are a qualified welder then you must have course text books that talks about welding S.S. In case you don't then go to this site by the Nickle Development Institute

http://www.nidi.org/pages/home.htm

Look for NiDI Handbook No. 9002, "Welding of Stainless Steels and Other Joining Method". Its a free download. Or just buy the Lincoln Electric "Welding Handbook". It is very cheap for such a quality book.

Hope that helps.

 

[vesselguy]

Looks like they changed the URL. Use this one instead to access Nickle Development Institute

http://www.nidi.org/index.cfm

 

[powerengJP]

thanks Rich2001 and vesselguy
both very valuable tips for welding.

can any one help me with my other question?

 

[pipewelder1999]

1st question
One of the problems with SS welding is the fact that the thermal conductivity of this material is much lower than carbon steel. Interpass temperature is critical. Sometimes you have to let it cool down. If you are using solid wire on welds other than flat it will take MUCH practice.

All welding is best done using stringer beads only. Keep a very tight arc and manipulate the electrode only slightly. If you are welding with SMAW/GMAW/FCAW I suggest using the smallest electrode possible.

I have used some SMAW electrodes that weld as easy as carbon steel however you still have to watch the heat input or the face of the bead will start to hump up.

Rapid cooling between passes with air or damp rags can speed up the cooling and is not detrimental to 300 series SS but can cause excess distortion if your not careful.
2nd
No help. Gerald Austin
Iuka, Mississippi

http://www.weldinginspectionsvcs.com

 

[engatwork]

I like to see stainless TIG welded with gas purge. Not real keen on stick welding with solaflux but sometimes it can't be avoided.

 

[engatwork]

On the boiler water treatment - get a qualified water treatment rep in to help - a company like Betz Dearborn or Nalco will know exactly what to do with a little testing.