Applying GTAW inert gas (MIG) process for Stainless Steel and Duplex Steel

[Thuhuongengineer]

Currently my company is using GTAW/SMAW process for Stainless steel and duplex steel but now we want to increase labour productivity. We intend apply GMAW inert gas (MIG) process for Stainless Steel and Duplex Steel.
I dont know the feasible,qualiy and efect. Pls advice to me.

 

[stanweld]

GMAW has long been used for welding austenitic Stainless and Duplex stainless steels.

 

[Thuhuongengineer]

Could you pls give me more information about weling Duplex and SS by GMAW process.
Welding consumable?
Welding machine?
Which defect often occur?
Can you supply WPS sample for this process?

 

[fegenbush]

Thuhuongengineer,

Stanweld is correct. GMAW can be very productive with stainless and duplex. However, beware the gas suppliers trying to sell you the latest (expensive) proprietary gas blend. You may be able to achieve acceptable results with economically priced shielding gasses.

 

[weldtek]

Thu..
Your line of questioning is far too broad. We have no idea if your welding 16 gauge duct work or 3" thick vessels. Why don't you start by speaking with one or more equipment sales representatives. Get some ideas on the types of power sources and wire feeders available and focus on those most suitable for the work you have in mind.

 

[XL83NL]

Purchase a copy of API TR 938 C, as it will help you understanding some basics in DSS use for the oil refining industry.
It may give you a little kick start. After reading it, please rephrase your question to more detail ...

 

[drumsdw]

I agree with weldtek, depending on your material thickness and type of work, you could use a number of different fabrication techniques when it comes to welding process.

1. Is the welding single-sided open root welding?
2. Depending on the grade of DSS and process type, I use a different gas mix to ensure proper phase ballance.
a)2205- AR+1-2% AR or CO2 (depending on the base metals being joined, low grade 304 stainless w/Ar+2% CO2 may cause increased weld metal carbon content.
b)2507- I use GMAW-P with a 4-part gas mix AR+30He+1-2N²+1-2%CO2, and this gas mix gives excellent mechanical properties and toughness with very good phase balance.(I am required to use this gas mix by customer, I achieve good results GMAW-P with the above gas mix which costs less)

I currently utilize GMAW-P for welding DSS of grades 2205 and 2507 to them selves and to other higher Ni-Fe-Cr alloys. API technical manual 938-C gives information on welding duplex stainless steels and sample requirements for testing procedures. The welding consumables should be of the same composition currently used when using GTAW. A CV machine will need to be used, there are alot of machines to choose from. I currently use The Lincoln S500 powerwave with RapidX program wave forms.