... Cast,High density,Zero defects Shaanxi Tongxin Continuous Cast Tube Tech Co.ltd, an exclusive manufacture in producing ... etc) Advantages of continuous cast iron hollow bar(tube):--Zero Cast Defects--High Density--Superb Wear Resistance--Free ... hollow bars as follow:1.Ductile Cast Iron Tube(ASTM A536 60-40-18,65-45-12,80- ... 8,ball number 400~600/mm22.Grey Cast Iron Tube(ASTM A48 class 30,40,45,50)3. Alloy ...