Stainless steel can be either magnetic or non-magnetic, depending on its composition.
Austenitic Stainless Steel: This group, which includes grades like 304 and 316, is non-magnetic. Ferritic Stainless Steel: Ferritic stainless steels, such as 430, are typically magnetic.
Martensitic Stainless Steel: Martensitic stainless steels, like 410 and 420, are also typically magnetic.
It’s important to note that there are exceptions and variations within each of these groups, and some stainless steel grades may have slightly different magnetic properties based on their specific alloying elements and heat treatment
Here’s where buying stainless steel rods and bars - or any stainless product, for that matter - can get really confusing. The ‘grade’ of a stainless alloy product denotes precisely what its intended application or environmental resistance will be, and this is dictated by both the specific chemical/elemental makeup of the alloy in question, as well as any finishing or treatment process it has undergone after casting.
As you can probably imagine given the range of options already outlined in this guide, this leaves us with a bewildering number of potential grades of stainless steel (over 150, in fact, although only around 15 of these are especially common in everyday construction use). Worse still, there isn’t even one universal method for grading stainless steels - while there is often a large degree of crossover, specific grading scales do technically vary from country to country!
Stainless steel grading systems are intended to give users an indication of both the subtype of alloy used, and the range of applications a product is therefore suited to. You’ll typically see them written as numbers, occasionally numbers and letters, with a few common examples being: