A method for preparing metal niobium strip relates to a method for preparing metal niobium strip with high elongation and high grain grade performance by forging rolling process. The preparation process successively includes the following processes :(1) the diameter of 150 ~ 160mm electron beam melting niobium ingot, at 800 ~ 1100℃, with air hammer forging; The processing rate of forging is controlled as 30% ~ 40% for upsetting, 40% ~ 50% for drawing and 50% ~ 70% for beating. (2) rolling the first time of processing rate is ≥ 40%, the second time of processing rate is ≥ 35%, after each time of processing rate is ≥ 15%; The extension direction of billet in rolling process is always the axial direction of the original ingot. (3) Annealing process of 850 ~ 900℃ for 3 ~ 4h. The method of the invention can obtain a long niobium strip of refractory metal with elongation of 30% ~ 41% and grain size of 8.5 ~ 10 with excellent deep drawing performance, and can be used to form electrode heads for CCFL with diameter of 1.6mm and height of 8mm.
According to the method of the invention, the refractory metal niobium strip prepared by the invention has the properties of high elongation and high grain size grade, and the thickness range is 0.1 ~ 0.254mm. By using high temperature forging method, the billet can be dynamically recrystallized and recovered in the forging process through free forging and rapid shape changing method, and the original coarse grain of the billet can be fined finally. The grains in the microstructure of the finished strip were obtained due to the high processing rate at the beginning of the rolling process.
The strip with high elongation and grain size can be obtained by full refinement and heat treatment.The long niobium strip with 30~41% elongation, 8.5~10 grain size and excellent deep drawing performance can be developed into electrode heads for CCFL with diameter of 1.6mm and height of 8mm.
The forging temperature of 150~160mm diameter electron beam melting niobium ingot is 80(between M10(TC; Forging method is air hammer free forging; During forging, the processing rate was controlled to be 30%~40% for upsetting, 40% ~ 50% for drawing length and 50%~70% for flatting. The blank is no longer heated in the furnace during forging.
When rolling, the first pass adopts 240% processing rate, the second pass adopts 235% processing rate, then each pass adopts ^15% processing rate; The extension direction of the billet during rolling is always the axial direction of the original ingot.
