Abstract: A steel sheet has composition consisting of 0.003-0.10 wt. % C, not more than 1.0 wt. % Si, 0.05-1.5 wt. % Mn, not more than 0.10 wt. % P, not more than 0.02 wt. % S, 1.5-8.0 wt. % Cr, 0.003-0.10 wt. % Al, at least one of 0.08-0.40 wt. % Ti, 0.08-0.40 wt. % Nb and 0.08-0.40 wt. % V, optionally at least one of Cu up to 2.0 wt. %, Ni up to 2.0 wt. %, 0.01-2.0 wt. % Mo, 0.01-2.0 wt. % W and 0.0003-0.0050 wt. % B and the balance being essentially Fe except inevitable impurities. The steel sheet is good of both a room-temperature strength and a high temperature strength. The new steel sheet is useful as a frame member of a color picture tube for stretching color selecting electrode elements, instead of an expensive ferritic stainless steel.

Abstract: A steel sheet has composition consisting of 0.003-0.10 wt. % C, not more than 1.0 wt. % Si, 0.05-1.5 wt. % Mn, not more than 0.10 wt. % P, not more than 0.02 wt. % S, 1.5-8.0 wt. % Cr, 0.003-0.10 wt. % Al, at least one of 0.08-0.40 wt. % Ti, 0.08-0.40 wt. % Nb and 0.08-0.40 wt. % V, optionally at least one of Cu up to 2.0 wt. %, Ni up to 2.0 wt. %, 0.01-2.0 wt. % Mo, 0.01-2.0 wt. % W and 0.0003-0.0050 wt. % B and the balance being essentially Fe except inevitable impurities. The steel sheet is good of both a room-temperature strength and a high temperature strength. The new steel sheet is useful as a frame member of a color picture tube for stretching color selecting electrode elements, instead of an expensive ferritic stainless steel.

Abstract: A grid apparatus which has a multiplicity of ribbon-shaped grid elements stretched in tension and attached to a frame which comprises a pair of support bars and a pair of resilient support members. Metallic members which have a larger thermal expansion coefficient than the resilient support members are connected to the reverse surfaces of the resilient support members opposite the side to which the grid-elements are attached. In the grid apparatus during heat treatment, thermal creep of the grid elements is prevented so that the tension of the grid elements will remain high when the normal temperature state is resumed. A method of making such grid apparatus includes an additional heat treatment such as a blackening process after the reduction of the tension applied to the grid elements by the resilient support members and the support bars, hence preventing thermal creep of the grid elements to produce a high-reliability with high tension of the grid elements.

Abstract: In a color selective electrode of a cathode ray tube, a number of grid elements are stretched between a pair of arms of a frame, a damper wire is stretched on the grid elements by means of spring elements fixed to a pair of support members of the frame, and each spring element is provided with a locking means for temporarily positioning the damper wire, whereby the damper wire is fixed temporarily to the locking means during the forming of the fluorescent surface on the tube, and restored to a spaced, final position after forming the fluorescent surface.

Abstract: A grid apparatus for use with a color cathode ray tube is described, having a pair of opposing frame members, and a pair of arm portions respectively welded at free ends thereof to the pair of opposing frame members for mechanically connecting the pair of opposing frame members, and for stretching the grid elements with a predetermined tension in cooperation with the pair of opposing frame members, in which each of the pair of arm portions is curved generally as a U-shape in substantially one plane. Both ends of the arm portions are respectively connected to the pair of opposing frame members at positions outside from their Bessel points, and the plane in which each of the pair of arm portions is arranged to respectively widened rearward with an angle from 45.degree. to 65.degree. with respect to a surface perpendicular to an axis of the grid apparatus.