straight carbon tool steel(Straight carbon tool steels are still used occasionally in machining, but fast rates of machining cause such a tool to heat so much that it over-tempers itself and softens. 虽然普通碳素工具钢在机加工中仍偶有使用，但车削速度过快会引起这种钢的刀具过热，以致产生过回火而软化。)
plain carbon steel tool(Using such high-speed steel tools, metal parts can be machined many times faster than by the use of plain carbon steel tools. 使用这种高速钢刀具切削金属部件的速度比使用普通碳素钢刀具快许多倍。)
