久久天码专区国产精品_日韩一级 片内射视频播放蘑菇_国产在线国语对白_亚洲6080yy久久无码国产_99r少妇极品熟妇人妻无码_美女视频一区二区三区在线观看_国产v片在线播放_欧美小屁孩cao大人网站_动漫高清无遮挡免费观看_国产一级牲交大片

In addition to special material requirements, seamless pipes for ships are required to have a smooth inner and outer surfaces, small errors in outer (inner) diameters, and uniform wall thickness. It has the characteristics of dense metallographic structure, good mechanical properties, good resistance to seawater corrosion, and long service life. The company's factory certifications from classification societies such as American Bureau of Shipping (ABS), Lloyd's Register of Shipping (LR) of the United Kingdom, Germanischer Lloyd (GL), Bureau Veritas (BV) of France, Det Norske Veritas (DNV) of Norway, Registro Italiano Navale (RINA) of Italy, and China Classification Society (CCS), as well as ASME material certification, ADWO material certification, and Russian (GOST) material certification are under review.