STAINLESS STEEL PROPERTIES

Stainless steel is a great material due to its resistance to corrosion and its durability. While welding stainless steel can be challenging, it is possible to learn with the right knowledge and practice.
Let's explore the facts about welding stainless steel!

Stainless steels are iron base alloys which contain at least 10.5% chromium. Chromium oxide forms on the surface of a stainless steel. This thin but dense film makes stainless steels resistant to corrosion and prevents further oxidation.

Types Of Stainless Steels

Austenitic Stainless Steels
This includes the 200 and 300 series of which type 304 is the most common. 
The primary alloying additions are chromium and nickel. 

Ferritic stainless steels 
These are non-hardenable Fe-Cr alloys. 
Types 405, 409, 430, 422 and 446 are representative of this group. 

Martensitic stainless steels
These are similar in composition to the ferritic group but contain higher carbon and lower chromium which permits hardening by heat treatment. 
Types 403, 410, 416 and 420 are representative of this group. 

Duplex stainless steels 
These are supplied with a microstructure of approximately equal amounts of ferrite and austenite. They contain roughly 24% chromium and 5% nickel. 
Their numbering system is not included in the 200, 300 or 400 groups. 
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Precipitation hardening stainless steels 
Which contain alloying additions such as aluminum which allow them to be hardened by a solution and aging heat treatment. They are further classified into sub groups as martensitic, semiaustenitic and austenitic precipitation hardening stainless steels. 
They are identified as the 600-series of stainless steels (e.g., 630, 631, 660). 

Most stainless steels are considered to have good weldability!

They may be welded by several welding processes such as arc welding,
​ resistance welding, electron and laser beam welding, friction welding and brazing.
Remember: it’s important to keep joint surfaces and any filler metal clean!