It depends on what type of SS you are using. SS series 300 and 400 is nonmagnetic; whereas, series 100 and 200 can be magnetized in the same way you would carbon steel. Since I was a child I knew to use a magnet to distinguish *good* stainless from *cheap* stainless. It's all about Ni and Cr content. Take a magnet off the refrigerator and go through any drawer of utensils in your kitchen. The good stuff isn't magnetic. The cheap junk is. The only exception is knives. It's hard to put a sharp edge on good stainless, because it doesn't machine smoothly. You can really see this when you turn it on a lathe. Low carbon steel cuts very smoothly and takes a sharp edge easily. It all depends on the grain. Expensive French chef's knives take a keen edge, but rust easily. Everything is a trade-off.

It depends on what type of SS you are using. SS series 300 and 400 is nonmagnetic; whereas, series 100 and 200 can be magnetized in the same way you would carbon steel. Since I was a child I knew to use a magnet to distinguish *good* stainless from *cheap* stainless. It's all about Ni and Cr content. Take a magnet off the refrigerator and go through any drawer of utensils in your kitchen. The good stuff isn't magnetic. The cheap junk is. The only exception is knives. It's hard to put a sharp edge on good stainless, because it doesn't machine smoothly. You can really see this when you turn it on a lathe. Low carbon steel cuts very smoothly and takes a sharp edge easily. It all depends on the grain. Expensive French chef's knives take a keen edge, but rust easily. Everything is a trade-off.

Dudley is right. Austenitic steels are not magnetic but are generally soft (thus not suitable for knives. In contrary, low-cost spoons are easy to twist but are magnetic). Have a look at the diagram of Pryce and Andrews: where is the material you want to magnetize? If a little ferrite is present, it will be possible but the residual magnetization will be rather low.

Alain

I think it can enhance residual magnetization by thermomagnetic treatment (annealing at temperature lower than curie  temperature under applied magnetic field).

it is important to analyze what the stainless steel composition which is referring. There are various types of stainless steel.

The 300 series, austenitic for example, contains chromium and nickel in their chemical composition, are non-magnetic in their annealed condition (soft) and slightly magnetic in encruado state (hard).

Stainless steel 400 series, the ferritic containing only chromium in its chemical composition, which indeed are magnetic.

Stainless steel 304 or 316 take imam? In case of positive response, we conclude that the material is of inferior quality?

Ferritic grades (TP439 or TP444) are magnetic, and austenitic stainless steel (TP304 or TP316) are not magnetic.

However austenitic stainless steels suffer mechanical stress over a forming process undergo a phase transformation that make them partially magnetic.

Talking about stainless steel magnets, these are of poor quality compared to other commercial magnets such as Sm-Co, Nd-Fe-B, hexaferrite magnets and alnico. That is why the production of SS magnets was discontinued on commercial scale, although low carbon steels are soft and have some applications. Harder steel magnets which were used for permanent magnet applications have higher carbon contents, together with other elements such as tungsten and chromium. Cobalt addition increases the coercivity, but SS magnets remain inferior to other commercial magnets. If your SS is a permanent magnet material, then you can crush the as-cast ingots into fine powder, compact it, and sinter. Then you should apply a field which carries the magnet into the saturation state, and remove the applied field. This will produce isotropic magnet. Due to the poor magnetic properties, however, the magnetization of this magnet can be removed by relatively small stray fields. If SS ribbons are fabricated, the use of a bundle of magnetized SS strips or needle-shape pieces can enhance the capacity of the magnet.

Magnets can be also produced by aligning the particles in a field during the compaction process. This will result in better magnetic properties. Bonded magnets can also be produced by mixing with a polymer or rubber, and curing. So, the answer to your question depends on the type of steel you have; if the steel is magnetic, you can magnetize permanently   

If you need conductive magnetic alloy material to test, there are mu-metal and co-netic stress annealed foil and sheet samples in a university lab kit with an online guide to magnetic shielding. Both of these are soft high permeability alloys. If severe welding, forming, or bending is performed in prototyping, then a hydrogen atmospheric annealing must be done after that to achieve the highest performance. Otherwise, you can use perfection annealed mumetal foil or sheet.

universitylabkit.com

CHEMICAL COMPOSITION:

MuMETAL® Chemical Composition % In Weight*

Nickel (Ni) 80-81%

Molybdenum (Mo) 4.5-6%

Silicon (Si) 0.05-0.4%

Manganese (Mn) 0-0.5%

Carbon (C) 0.01%

Iron (Fe) Balance

*Composition may vary by production lot.

TYPICAL MAGNETIC PROPERTIES*

DC µ @ 40 gauss 80,000

DC µ @ 100 gauss 105,000

DC µ maximum 350,000

DC Hc 0.0005 Oe

DC Br (gauss) 4,000

AC 60Hz @ 40 gauss 65,000

*Data are typical of .014" [0.36mm] annealed sample and should be not be construed as maximum or minimum values for specification or final design. Data for each material thickness and/or lot may vary.

MATERIAL PROPERTIES:

TYPICAL ANNEALED PROPERTIES

0.2% Yield Strength 49ksi (338 MPa)

Density 0.316 lb/in³ (8.7 g/cm³)

Tensile Strength 99 ksi (682 MPa)

Electrical Resistivity 60 micro-ohm cm

Elongation 32% in 2" (51 mm)

Grain Size ASTM 7 or finer

Hardness 15T 85  

http://www.universitylabkit.com/

In order to be magnetisable the stainless steel needs to contain the ferromagnetic , BCC or BCT, phases, e.g. ferrite or martensite, and as already pointed out some stainless steels do have them present, so they are magnetisable. That is to be able to magnetise the steel in the first place, however in order for the steel to retain that magnetism when the external field is removed, something needs to prevent the magnetic domains from randomising their magnetic vectors, and thus the steel losing its magnetism. In the world of magnetic materials, this would be whether the material is classed as a hard or a soft magnetic material. In soft magnetic materials efforts are made to exclude anything that would pin the domain walls or restrict their free movement, so we look for an extremely low coercivity. For hard magnetic materials we seek the opposite behaviour. Modern hard magnets are very resistant to demagnetisation. Older magnetic materials gave poorer performance in this respect, and some of the early history of permanent magnets can be found in Macolm McCaig's book, 'Permanent magnets in theory and practice', now a very dated text, but containing some very interesting information. You will see that there was a crude correlation between physical hardness and magnetic hardness and some early attempt to produce permanent magnets employed martensitic structures. So such grades could I suppose in theory make a poor(ish) 'permanent' magnet in today's spectrum of permanent magnets. For how long they could hold their field, and what their coercivity might be, I don't know, but I suspect they will have a relatively poor performance.