... 1.SEAMLESS steel tube, 2. Production based on DIN2391, EN10305-1, EN10305-3 , 3. High precision on the tolerance of tube ... surface and outside surface. We strictly execute precision tube production standard, each production stage can be ... , EN10305-1, EN10305-3.Steel grade: ST35, ST37, ST45, ST52, E235, E355.Tube OD: 5-80mmTube WT: ... is sent together with goods. EN 10305-1 precision seamless steel tube