All About Stainless Steel

MIG-welding tips from Lincoln Electric.I’ve been contemplating the idea of welding/fabricating a stainless steel counter top, but I’ve never attempted any welding before, and most people say stainless steel is difficult to work with. Thanks to this PDF, I know everything there is to know about stainless steel finishes, but nothing about working with the material.

Azom, “the premier on-line materials information site, supplier and expert directory” has a guide to stainless steel fabrication with rules for machining, welding, soldering, and brazing the various types of stainless. From the intro:

The common austenitic grades can be folded, bent, cold and hot forged, deep drawn, spun and roll formed. Because of the materials’ high strength and very high work hardening rate all of these operations require more force than for carbon steels, so a heavier machine may be needed, and more allowance may need to be made for spring-back.

Austenitic stainless steels also have very high ductilities, so are in fact capable of being very heavily cold formed, despite their high strengths and high work hardening rates, into items such as deep drawn laundry troughs. Few other metals are capable of achieving this degree of deformation without splitting.

Key-to-Steel has a guide to welding that tells us as much about what stainless is as it does about how to weld it. I didn’t realize that most stainless is made up of iron and chromium. I thought nickel was the goodness in stainless, but it can be found in only certain expensive grades. Nickel is non-magnetic, but chrome and iron are meant for magnets, so that explains something. Along with iron, chrome and nickel, you might find manganese or molybdenum.

MIG-welding tips from Lincoln Electric.In short, there is no one “stainless steel.” And care must be taken to work the material appropriately for its type. So sayeth Key-to-Steel:

The properties are not the same for all stainless steels, but they are the same for those having the same microstructure. Regarding this, stainless steels from the same metallurgical class have the similar welding characteristics and are grouped according to the metallurgical structure with respect to welding.

The three types of stainless, according to Key-to-Steel:

  • Austenitic Type
  • Ferritic Stainless Steels
  • Martensitic Stainless Steels

My question, however, was about welding the stuff, and Lincoln Electric and TWI offer detailed tips on just that.

Finally, sheet metal gauges are a matter of US law. 22 gauge is about 1/32 of an inch, but here’s a table of sheet metal gauges to make sense of the rest.