视频一区在线观看-日本大尺度做爰呻吟-亚洲第一区视频-国产视频大全-枫可怜av-成熟女人毛片www免费版在线-国产福利视频一区二区-日本色图片-六月丁香激情综合-伊人日日夜夜-中文字幕国产高清

        Precision cold drawn pipe is a high-precision steel pipe material with good performance in terms of appearance, size and performance. However, when testing precision cold-drawn tubes, it is found that its hardness does not meet the standard requirements and is on the low side. What is the reason for this?
       During the production process of precision cold-drawn tubes, high-temperature salt bath furnaces are generally used for quenching and heating to achieve the deoxidation effect. However, complete deoxidation cannot be achieved in actual implementation. When it interacts with the carbon on the surface of precision cold-drawn tubes, insufficient hardness will occur.
      In addition, the cooling rate during the quenching process has an important impact onPrecision cold drawn tubeThe hardness should also be very large. Usually, the slower the cooling rate, the more the hardness of the product decreases. In order to avoid the occurrence of this kind of phenomenon, salt bath deoxidation must be strictly carried out, and the cooling temperature and time must be strictly controlled to achieve the best product.