Bfe30-1-1 Copper-nickel Alloy Tube Heated Mold Continuous Casting

BFe30-1-1 cupronickel tube is an excellent material to resist sea water corrosion. But current casting and processing technique show disadvantages that results in a yield rate of only 25-35%, and serious waste of materials and energy.Heated-mould continuous casting (OCC, Ohno continuous casting) is a near net shape manufacturing process and gives high quality. The study of heated-mould continuous casting of BFe30-l-l cupronickel tube can develop a manufacturing mode including near net shape casting tube, cold drawing and finished product. That would provide a way for material processing.04 N 08 BFe30-1-1 cupronickel rod has been cast by OCC process. The relation of solidification characteristics and casting parameters were studied by use of the ANSYS software, which has very strong function in temperature field analysis. The result show that adjusting the casting parameters, such as mould temperature> cooling distance, casting speed and metal head, etc, can control the length and location of solid+liquid(S +L) zone.Smooth surface casting without hot tear can be obtained when the S +L zone is shortened to 8mm and moved to the outside of the mold exit about 0.5mm, because friction between dendrite and mould decreases. With this process, 010X2 BFe30-l-l cupronickel tube is cast successfully. The microstructure of casting by OCC process is unidirectionally arranged dendrite.The 04 cupronickel rod of smooth surface is obtained with mould temperature of 1230 癈 .cooling distance of 8mm,casting speed of 30mm/min and metal head of 30mm. The dendrite space of the 04 rod is 30~45u m. The 08 cupronickel rod of smooth surface is obtained with otherwise the same conditions except the metal head of 18mm. The dendritespace of the 08 rod is 45 ~ 60 U m. The typical tensile strength and elongation of the rod are 345~355 MPa and 70% respectively. The o 0.2 is ranged from 119.2~ 130.1 MPa. The 010X2cupronickel tube of smooth surface is obtained with mould temperature of 1200 癈,cooling distance of 8mm,casting speed of 30mm/min and metal head of 30mm. The dendrite space of the 010X2 tube is 30~50u m.The solidification rate of the OCC casting is greater than that of the ordinary casting because the OCC casting has a much thinner thickness. So the microsegregation degree decreases greatly. The decrease of microsegregation degree of NK Fe and Mn in 04 rod is 45%, 86% and 87% less than the 0130 ordinary casting respectively. As for the 08 rod, the decrease of Ni, Fe and Mn is 30%, 65% and 55% respectively.Carbon content in this experiment increases greatly to 0.15wt% because of the use of graphite crucible, graphite trough and graphite mould. The average corrosion rate of 08 rod On longitudinal section by OCC process is 1.24X10"3g/(cm 2 * year), superior to the ordinary 0130 casting(3.062 X 10"3g/(cra 2 * year)). But On cross section, its average corrosion rate is 3.24 X 10"3g/(cm 2 * year), inferior to the ordinary 0130 casting.Generally, Heated-mold continuous casting of BFe30-l-l cupronickel tube is feasible. The targets of improving casting quality and manufacturing tube have been achieved, and industrialized production experiment can be further conducted.