Surface chemistry of cooking
Stainless steel is considered stainless because it has at least 11% chromium by mass. Chromium is a relatively inert metal and does not rust or react as easily as plain carbon steel. This is what makes it an exceptional material for cooking. It is also fairly inexpensive, but does not have a very high thermal conductivity. From a surface standpoint, this is because of the thin layer of chromium oxide that is formed on the surface. This thin layer protects the metal from rusting or corroding. While it is protective, the oxide layer is not very conductive, which makes cooking food less efficient than it could be. For most cooking applications, high thermal conductivity is desirable to create an evenly heated surface on which to cook. In this way, stainless steel is usually not considered high-grade cookware.
Elwood Haynes
He applied for another patent on an alloy he called stainless steel, now known as martensitic stainless steel. The Patent Office rejected his application saying that it was not a new alloy. Haynes conceded their point, but submitted a second application and supplied a sample showing the stainlessness of his alloy when created using his exact proportions of metals, and it was granted. At the urging of his wife, he created the first set of stainless steel silverware for her personal use. The first piece of stainless steel was forged by Homer Dan Farmer in Haynes laboratory. It was a large meat knife and was donated to the Haynes Museum by the family of Dan Heflin, grandson of Homer Dan Farmer. In later years he claimed to have created stainless steel because she did not enjoy polishing their silver tableware. British metallurgist Harry Brearley independently produced an identical alloy around the same time and applied for an American patent and found that one already existed. Brearley had also created other innovations for the metal, but they were of little value without the stainless steel patent. He sought out Haynes and the two decided to pool their findings in a single company to produce the alloy. Haynes sold his stainless steel patent in 1918 to the American Stainless Steel Company, a company Brearley had created with the assistance of investors in Pennsylvania. In exchange he and his estate received royalties on its production until the patent expired in 1930. The stock he received as payment allowed him to gain a seat among the company's board of directors and he installed his son, March, to represent him. The income from the transaction led Haynes to begin the accumulation of a large fortune.