中国妓女与动ZoZ0z的演员表I911国产精九九 APPI99久久99久久精品免费看蜜桃I真实国产乱子伦一区二区三区I精品熟女I珍藏艳照36PI国产51页ixxx视频在线i97视频在线播放i国产一区日本i久草综合网i6I日本XXXXXX公交车上I久久中文字幕人妻熟avI日韩十八禁I成人九九九I超碰666I青青草763

The first is the requirements for Hardness. For some occasions, the higher the hardness of the material, the better. It is only limited to the hardness requirements of the machined parts. The machined materials cannot be too hard. If they are harder than the machined parts, they cannot be machined.
Secondly, the material should be moderately soft and hard, at least one grade lower than the hardness of the machine parts, and it also depends on the purpose of the processed components and the reasonable selection of materials for the machine parts. In short, precision machining still has certain requirements for materials, and not all materials are suitable for processing, such as materials that are too soft or too hard. The former is not necessary for processing, while the latter cannot.
So, the basic rule is to pay attention to the density of the material before processing. If the density is too high, it is equivalent to a high hardness. If the hardness exceeds the hardness of the machine (lathe tool), it cannot be processed. Not only will it damage the parts, but it will also cause danger, such as the tool flying out and injuring people. So, generally speaking, for mechanical processing, the material material must be lower than the hardness of the machine tool in order to be processed.