Carbon steels are steels with carbon content up to 2.1% by weight.
Spring steel is a name given to a wide range of steels used widely in the manufacture of springs, prominently in automotive and industrial suspension applications. These steels are generally low-alloy, medium-carbon steel or high-carbon steel with a very high yield strength. This allows objects made of spring steel to return to their original shape despite significant deflection or twisting.
304 Stainless Steel
304 Stainless Steel contains both chromium (usually 18%) and nickel (usually 8%) metals as the main non-iron constituents. It is an austenite steel. It is not very electrically or thermally conductive and is non-magnetic. It has a higher corrosion resistance than regular steel and is widely used because of the ease in which it is formed into various shapes.
316 stainless steel
SAE 316 stainless steel, is a molybdenum-alloyed steel and is the second most common austenite stainless steel (after grade 304). It is the preferred steel for use in marine environments. Marine grade stainless alloys typically contain molybdenum to resist the corrosive effects of NaCl or salt in seawater. Concentrations of salt in seawater can vary, and splash zones can cause concentrations to increase dramatically from the spray and evaporation. because of its greater resistance to pitting corrosion than other grades of steel without molybdenum.