There are many standards for High Speed Steel (HSS) grades. We make the comparison table based on Chinese grades to try to tell the counterparts of a HSS grade you know in other standards.
High Speed Steel (HSS) is a kind of steel containing some other elements: carbon, tungsten, molybdenum, chromium, vanadium, and/or cobalt. After heat treatments, it will have high hardness even at high temperatures. When the cutting temperature exceeds 600°C, the hardness of HSS will not decrease apparently. The cutting speed of cutting tools made of HSS can exceed 60 meters per minute, thus High Speed Steel gets its name.