Abbreviated HSS. A kind of tool steel, invented in the early 20th century, which retains its hardness and temper at high temperatures (at which previous kinds of tool steel would soften), thus allowing cutters made from it to be employed at higher cutting speeds than were previously practical
Alloy of steel introduced in 1900. It doubled or trebled the capacities of machine shops by permitting the operation of machine tools at twice or three times the speeds possible with carbon steel (which loses its cutting edge when the temperature produced by the friction of the cutting action is above about 400°F, or 210°C). A common type of high-speed steel contains 18% tungsten, 4% chromium, 1% vanadium, and only 0.5-0.8% carbon. See also heat treating, stainless steel