精品国产一区二区三区在线观看,中文字幕在线观看不卡视频,超碰97在线播放,手机看片福利久久,成人精品毛片va一区二区三区,欧美伊人久久,国产伦精品一区二区三区视频孕妇

　　First trial production for new grade 30MnVS6 was successful at steel making mills recently . This grade is specially used to produce automotive steering ball end with big difficult process. Meanwhile, the Controlling for N and S content is key point.

　　In order to guarantee successful first production, the mill prepared so much in advance with technical center together, such as off-site inspection, expert advice, special raw material preparation, careful plan and field tracing test. This trial production is successful with fully satisfied chemical content control which gained valuable experience for other grade production with N and S content.