Simiar to stainless steel casting, many stainless steel alloys are available for CNC machining. SS 302: This is the austenitic variety of stainless steel and is known for its corrosion resistance and flexibility. The steel can be cold hardened but is easily converted to slow speed. SS 303: This austenitic steel is readily machinable. 303 stainless steel has excellent toughness. However, its resistance and corrosion can sometimes resist because of the sulfur addition.SS 304: This type of steel contains 8% nickel, 18% chromium, and a carbon concentration of 0.07% (usually maximum). 304 stainless steel has excellent corrosion resistance and formability after CNC machining, so it is widely used to manufacture various commercial and household appliances. Different resistance and fusion welding methods can easily weld this steel.SS 316: This type is commonly used in harsh environments. Although 316 and 304 are the same, the only difference between them is the presence of an increased amount of molybdenum. The molybdenum gives 316 excellent heat and corrosion resistance. However, its machining is more complicated than others of all the common stainless steel.SS 17-4 PH: This is a type of martensitic stainless steel that is hardenable by precipitation. These steels have a combination of mechanical properties, such as resistance, corrosion resistance, oxidation resistance, etc. However, the mechanical properties can be further improved by heat treatment. SS 400 series: These steels contain 11 percent chromium and 1 percent manganese. To harden them, they are heat treated. The martensitic crystal form of these stainless steels is due to their high carbon content. Because of this structure, they exhibit high wear resistance and structural integrity after CNC machining. However, they do not exhibit excellent corrosion or rust resistance.