Working in his laboratory to develop new corrosion-resistant metals for auto parts, Haynes discovered that mixing tungsten with chromium, steel and iron resulted in the formation of strong and lightweight alloys that were impervious to corrosion, and could endure high temperatures. In 1912, he formed Haynes Stellite Company to produce one of the new alloys, and received lucrative contracts during World War I, making Haynes a millionaire in 1916. He sold his patent for stainless steel to the American Stainless Steel Company in exchange for enough stock to gain a seat at the company's board of directors, a position he held for 12 years. He merged the Haynes Stellite company with Union Carbide in 1920. After passing through different owners, the company was renamed and is now called Haynes International. Haynes returned his focus to his automotive company, but in the economic recession of the 1920s the business went bankrupt and was liquidated.