亚洲噜噜在线观看_成人无码区免费AⅤ片WW_久久福利小视频_亚洲 中文字幕 日产_麻豆Aⅴ无码精品一区二区_免费看精品黄色视频_精品人妻大屁股白浆无码下载_亚洲日本熟女中文_中文国产日本在线播放免费_一级 片内射视频播放下载

  Steel ball is the basis of the important parts, especially the precision industrial ball plays a huge role in the development of national economy. In some special conditions, often need special material steel ball, to complete the required to achieve the function of the different environment. In fact, some special material steel ball has been widely used in the national economy each domain, including 9 cr18, 3 cr13 stainless steel, copper, aluminum, steel and titanium alloy agate, glass, ceramic ball, etc. Their popularization and application, not only promoted the development of the steel ball manufacturing, but also promote the technology development of related industries, science and technology progress. Steel ball bearing is the most important part of, also is the rolling element bearing industry to use the most. Its quality directly affects the quality of bearing. Steel ball production process after the steel ball automatic cleaning, since