The short answer is yes, as long as you use the correct heating source, solder, and flux. When soldering stainless steel you should not use normal soldering flux. You will need a high activity acid flux
because of the amount oxides on the surface of stainless steel. Oxides prevent solder from sticking to the surface of the metal. Small wires and some jewelry items can be soldered with an iron but anything large would require a torch. You will need a silver bearing solder
and high activity flux specifically designed for stainless steel. Once you have both of these the process is very similar to regular soldering. Some silver bearing solders contain an acid flux core but sometimes that is not enough flux and you will need to add more flux to the joint when soldering stainless steel.
The type of torch needed would depend on the size of the parts you are soldering. If they are too large to heat up using a soldering iron, you can use a small butane torch like the popular Blazer GB2001
. The next size up would be the Blazer Big Shot
which produces a much larger flame and is good for plumbing and automotive work.
For larger industrial applications you would use a propane, oxy-acetylene, or map gas torch.
The key is using the correct flux for the job. No-clean and Rosin fluxes will not work on stainless steel. Use a high activity acid flux instead.