In a color picture tube including a screen and an inline gun for generating and directing three inline electron beams along separate paths toward the screen, the gun includes a plurality of cathodes (34) and at least six electrodes (36,38,40,42,44,46) longitudinally spaced from the cathodes. The first (36), second (38) and fourth (42) electrodes from the cathodes are of materials having lower coefficients of thermal expansion than the coefficients of thermal expansion of the materials of the other electrodes. As a result the time to settle to steady-state static convergence during warm-up of the tube is reduced.