Study On The New-type Be-Cu Material Roller And Its Applied Performances For The High Speed Twin-roll Casting Of Aluminum Alloys

To produce aluminum strips adopting the technology of twin-roll casting is such kind of near-net forming technology that can combine the solidifying and deforming. Due to the great economic returns and social effect, this technology has become the main way to make aluminum strips. Conventional twin-roll casting technology is hard to produce aluminum alloy strips with high property and surface quality, it has low productivity, limited types of alloy can be formed, and segregation in the surface and the internal part. Adopting the high speed thin gauge twin-roll casting technology can advance the productivity, produce some new aluminum alloy roll-casting products and bring a higher quality, because the productive speed is faster and the thickness is thinner, the solidifying speed of melted aluminum in the roll-casting zone is enhanced and the bigger deforming rate is achieved. Now this kind of technology is considered to be important trend of new aluminum process by the international aluminum process industry.It requires superior conduct heat of the roller than the conventional one to carry out the process and fasten the solidifying of the melt. It is the one of the key technologies of fulfilling the high speed thin gauge twin-roll casting technology for aluminum alloy strips to research the new material roller and its applied performances.The Metallurgy and Machinery Institute of Central South University has researched a new type of roller material—Be-Cu alloy roller material, which set a basis to breakthrough the limitation of the high speed thin gauge twin- roll casting technique. This dissertation has done series of experiments and analyses on the optimizing alloy ingredients and its main performances about the new Be-Cu alloy, trying to provide the bases for manufacturing and using the new roller in high qualities. What this dissertation concerned is as follows:1. Research on the optimizing ingredients of the new Be-Cu alloy. The new Be-Cu alloy material of roll-sleeve has achieved through series of experiments. The mechanics performances of the new alloy material can match that of the alloy tool steel roller, the thermal conductivity is three to four times to that of the alloy tool steel roller.2. Experimental study on the performances of the new Be-Cu roller material in the manufacturing technique. The adaptation of Be-Cu to centrifugal casting technology and its heat treatment performance has been discussed, which has been verified in the process of manufacturing commercial test rollers. The machinability and grindability of the new Be-Cu has been studied. The comparison with relative performances of the current typical alloy tool steel roller is made.3. Research on the working surface integrity of roller for aluminum alloy strips. The notion of the working surface integrity of roller for aluminum alloy strips is raised and the comprehensive explanation has been made. The main factors that affect the working surface integrity of roller is discussed. The mechanism that new Be-Cu alloy roller material can provide roll-sleeve with the superior working surface integrity is studied.4. Research on the heat-resistant damage performance of the new Be-Cu alloy material roller. The mathematical model of roller's temperature field is established. Thought of the approximate analytical solution for roller's temperature field is proposed. The approximate analytical solution for roller's temperature field is derived. The experimental confirmation to the simulation result is carried on. The distribution state of roller's temperature in the high speed thin gauge twin-roll casting is analyzed. Based on the approximate analytical solution of roller's temperature field, the analytical solution of the roller's thermal stress field is derived. The simulation analyses of thermal stress for the new Be-Cu alloy roller in the high speed thin gauge twin-roll casting are carried on.5. Experiments on the new Be-Cu alloy roller in the high speed thin gauge twin-roll casting. After doing the experiments on the high speed thin gauge twin-roll casting with experimental twin-roll caster and the industrial twin-roll caster, the cooling capacity, operational performances and their changes of the new Be-Cu alloy roller, product quality produced by the new roller are detected and analyzed.