人人干夜夜操 I 婷五月激情 I 欧美日韩另类在线 I 亚洲福利av I 久久久久国产精品人妻aⅴ院 I 午夜av免费观看 I 第一区免费在线观看 I 一级久久久久久久 I 国产欧美一区二区精品婷婷 I 国产一区二区激情视频 I 超碰导航 I 91免费在线观看网站 I 伊人久久婷婷 I 成人精品视频在线播放 I 91插插视频 I 久久久久美女 I 国产精品久久影院 I 好吊操这里只有精品 I 91美女在线免费观看 I 黄色小说视频 I 成人av集中营 I 国语对白真实视频播放 I 可以免费看a的网站 I 伊人久久精品 I 天天综合网入口 I 无码精品人妻一区二区三区漫画 I 久久a视频 I 亚洲啪啪aⅴ一区二区三区9色

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.