The popularity of 304 surgical stainless steel is due to its gleaming appearance which lasts for the life of a product with just an occasional cleaning. Its excellent corrosion resistance is due to an invisible, passive oxide film that forms on the metal's surface in air. 304 Surgical Stainless Steel is sometimes referred to as T304. Hospitals use surgical stainless steel because it can be kept clean and sterile.
More nickel increases luster and the cost.
The other major factor to determine your cookware choices are the number of plys. 5 ply construction includes the following layers from the inside out. Stainless steel 7 ply construction includes the following layers from the inside out. Stainless Steel Carbon Stainless Steel Aluminum Alloy Pure Aluminum Aluminum Alloy Stainless Steel 7 ply is more expensive to manufacture. The aluminum conducts heat well in the inner layers, but is not desirable on the outside because it corrodes and comes off in the food.