The hardest steel does not make a mark.

这种钢最为坚固 不会何痕迹。

Little wheels of extremely hard steel are also used for cutting glass, and this they do fairly well, though not nearly so well as diamonds.

人们还使用极为坚硬钢轮对玻璃进行切割, 这种方法虽然比不上使用那样理想, 但效果还算不错。

Our best steel chisels are made on the same plan: at the cutting edge they have a thin plate of hard steel, which is supported or backed up by a thicker plate of softer steel.

刀口由坚硬薄钢片制成, 后面再附上一块更厚软铁。