Research On Cold Rolling Niobium And Titanium Short Slab With Tension

In the nonferrous metal rolling processing, tension will not be usually applied during cold rolling niobium or titanium short slab in China, which result in lower rolling efficency, production, but higher energy consumption. Based on the analysis of metallic characters of niobium and titanium, cold rolling niobium and titanium slab under tension condition was brought forward. The deformation of niobium and titanium slab correlates with their crystal structures, espescially titanium has fewer slip systems, so that slippings are restricted to given directions when it deforms and shows strong aeolotropy. The yield limit and tensile limit of titanium are adjacent, which increase the difficulty of cold deformation. Applying tension to both sides of niobium or titanium short slab when rolling, the plastic deformation and stress conditions are improved, which permits larger pressure and improves efficency. It is also easy to be adopted in practical processing.Based on the Hill isomerism yield principle, the planar deformation plastic mechanical equation was educed, which also validated the effects of tension to cold rolling niobium or titanium short slab.Tension also improves the rolling conditions of niobium or titanium short slabs as verified. A four-high reversing rolling mill from the State Key Laboratory of Rolling and Automation was used to go on the experiment so that the optimizing process was put forward. Under certain tension, the cold rolling efficiency of niobium was improved obviously. After three passes,the deformation rate of titanium slab reachs 62.5 percent and the shape of the strip is perfect. Rolling under tension can also reduce the draught pressure with decreased roller flattening,which is favorable to reduce the thickness of cold rolling niobium or titanium short slabs.The experiment and the theoretical analysis show that tension improves rolling and producing efficiency, reduces the cost of energy, And make it possible to roll with maximum press and perfect strip shape in a single pass. The loading of tension is flexible and simple.So it is a new effective mode of production which should be applied and extended in practical producing.