A PROCESS FOR MANUFACTURING A FRAME FOR COLOR PICTURE TUBES

Abstract: The alloyzation reaction of steel and zinc is performed with only heat in calcinating, baking, sealing and exhausting of gas of a frame of a machine part for a color picture tube to form tau and delta phases and form a film of alloy. The film of alloy plays a role of the oxidized film to be capable of omitting the oxidizing process, and to prevent the corrosion and the oxidation to start before a thermal treatment, by the zinc layer.

Description: A PROCESS FOR MANUFACTURING A FRAME FOR COLOR PICTURE TUBES BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a frame for a color picture tube, more specifically, to a frame for a color picture tube which an oxidized film is formed therein by plating zinc on a steel for a frame, one of the machine parts in the color picture tube without an oxidizing process to overcome problems occurring by an oxidizing process and to manufacture by a simpler process. 2. Description of the Related Arts After a shadow mask for color picture tubes (CPT) is assembled with a screen in a panel leaving a space between them, it is annealed for further processes, processing and forming processes. The mask is finally formed by a press and foreign substances such as oil, contaminants and fingerprints are removed by a next step, a degreasing process. The degreasing process is to remove oil and foreign substances used in the process for forming by using original trichloroethylene solution. The formed shadow mask is fixed on a frame by welding to maintain the form thereof. For the frame to play a role of fixing the shadow mask, no changes of the form or outer size of the frame must be observed after calcinating for stability of an assembly against heat. The frame is assembled through springs which are attached by welding on the side faces of the frame. The frame and the degreased mask are electrically welded to produce a mask assembly and oxidized to prevent rust from forming. The oxidizing process is the process which forms an oxidized film of iron oxide (Fβ3θ 4 ) on the surface of the mask, to prevent from possible oxidation and diffused reflection such as thermal decalescence and exposure light beam. An oxidizing process is carried out according to the following oxidation reaction. oxidation Fe + CO 2 — FeO + CO T (1) reduction 3FeO + CO 2 -→ Fe 3 O 4 + CO Fe + H 2 O - → FeO + H 2 T (2) 3FeO + H 2 O - → Fe 3 O 4 + H 2 3Fe + 4C0 2 - Fe 3 O 4 + 4CO t (3) 3Fe + 4H 2 O - Fe 3 0 + 4H 2 The oxidizing process proceeds by reactions (1) and (2) above 570 °C and reaction (3) below 570 °C . The steel for a frame has the possibility of forming rust by an oxidation before an oxidizing process and an oxidized film produced with iron oxide (Fe 3 0 4 and FeO) is brittle and weak to clog holes of the film. Therefore, the surface of the frame has rust to produce foreign materials before an oxidizing process and a total process is more complicated by an addition of an oxidizing process. SUMMARY OF THE INVENTION Accordingly, the present invention is intended to overcome the above- described disadvantage of the conventional arts and to provide a process for a frame for a color picture tube which corrosion and oxidation of a steel break out before an oxidizing process of a frame to prevent producing foreign materials and to delete oxidizing process for a simple process. An embodiment of the present invention provides A process for a frame for a color picture tube comprising forming of steel for a frame after plating zinc on said steel using an oil, degreasing the oil, and calcinating, baking, sealing and exhausting of gas. A thermal process of calcinating, baking, sealing and exhausting of gas is preferred to carried out to react alloyzation of the steel and the zinc. The plating zinc is preferred to carry out electrically. Another embodiment of the present invention of a color picture tube using a frame formed τ and δ phases by alloyzation reaction of the zinc and the steel. The alloyzation reaction of zinc and steel is preferred to carry out with only heat in calcinating, baking, sealing and exhausting of gas without oxidizing process. Japanese Patent 89-1522044 discloses a process for a color picture tube solving the above problem of the conventional arts. After Ni and Cr are plated on the shadowmask, the frame and the inner shield with the thickness of 0.5 μ to 1.0 μ , the shadowmask and the frame are welded to produce a maskframe, and the frame and a holder are attached, and the maskframe and a panel are assembled. Then, the fluorescent screen is formed, the oxidized film of metal components is formed through sealing, exhausting and aging processes. Therefore, the surface of the metal formed by thermal process without oxidizing process is thinner and harder than the conventional oxidized film. BRIEF DESCRIPTION OF THE DRAWINGS The above object and other advantages of the present invention will become more apparent by describing in detail the preferred attached drawings in which: FIG. 1 is a cross section of the film produced by an oxidizing process of the frame according to the conventional process. FIG. 2 is a cross section of a steel alloy according to an embodiment of the present invention. FIG. 3 is a cross section of a steel film for the frame according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS Although the invention has been described with reference to a preferred embodiment it is to be understood that the invention is not limited to the preferred embodiment as herein described. EXAMPLE A cold rolled steel sheet was plated electrically and plated with zinc thereon. The steel sheet was mold processed in the press by calcinating, baking, sealing and exhausted in nitrogen air to produce a fixed a frame for a color picture tube. COMPARATIVE EXAMPLE A cold rolled steel sheet was oxidized at high temperature in methane gas and air atmosphere and was calcinated, baked, sealed, exhausted of gas and mold processed in the press to produce a frame for a color picture tube with fixed size. The alloyzation reaction of the zinc is reacted with only heat in calcinating, baking, sealing and exhausting of gas in an nitrogen gas atmosphere without an oxidizing process. The film of an alloy was formed by the formation of τ and δ phases. Therefore, the present invention prevents from producing the foreign substances from the rust on the frame before an oxidizing process and clogging holes by parts of the oxidized film. The omission of an oxidizing process brings about an economical effect.

Claims: What is claimed is: 1. A process for a frame for a color picture tube comprising the steps of: forming steel for a frame after plating zinc on said steel using an oil; degreasing said oil; and calcinating, baking, sealing and exhausting of gas. 2. The process for a frame for a color picture tube according to claim 1 , wherein a thermal process of said calcinating, baking, sealing and exhausting of gas is carried out to react alloyzation of said steel and said zinc. 3. The process for a frame for a color picture tube according to claim 1 , wherein said plating is performed electrically. 4. A color picture tube using a frame formed τ and δ phases by an alloyzation reaction of a zinc and steel. 5. The color picture tube according to claim 4, wherein said alloyzation reaction of said zinc and said steel is performed with only heat in calcinating, baking, sealing and exhausting of gas without oxidizing process.

Inventors: KOO HAENG MIN, PARK JUNG DAE, KOO, HAENG, MIN, PARK, JUNG, DAE
Applicants: KOO HAENG MIN, PARK JUNG DAE, SAMSUNG DISPLAY DEVICES CO LTD, KOO, HAENG, MIN, PARK, JUNG, DAE, SAMSUNG DISPLAY DEVICES CO., LTD.
Application year: 1997
Main classification: C23C26
IPC codes: C23C26, C25D5, H01J9, H01J29, H01J31