BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a lubricated steel sheet, more

specifically, to a lubricated steel sheet which is coated with zinc and resin,

which is used for a panel assembly for a color braun tube, i.e., a frame or an inner shield of machine parts for color picture tubes to make unnecessary

degreasing and oxidizing processes and to reduce the time of the process and

to solve environmental pollution problems by not using a degreasing solution.

2. Description of the Related Arts

After a shadow mask for a 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 an assembly to be stable against heat. The

frame is assembled through springs which are attached by welding on the sides

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(Fe ₃ O ) on the surface of the mask to prevent from possible oxidation and

diffused reflection such as thermal decalescence and exposure light beam.

A machine part of a thin metal tube, i.e., an inner shield is attached in

the color picture tube to control the mobility of electron beams by an earth

magnetism and to decrease the influence of the earth magnetism. The beam

mobility of a 16 inch color picture tube is 60 μ without an inner shield and 25

μ with an inner shield.

The mask assembly on which the machine parts such as the frame and the

inner shield are attached by spring frame welding and mask frame welding, is

assembled with the panel and calcinating is performed. When the mask-panel

assembly is calcinated at a temperature of 450 ^° C for 2 hours, the stress of the

mask and the panel is stabilized so as not to affect the metal and the glass from

heat. The panel-mask is separated after cooling. To remove the pollutants

on the panel such as dust and grease, the assembly is washed with acid

solution and rinsed with deionized water.

Trichloroethylene degreasing solution used in the degreasing process

in the above process is colorless and has an odor of chloroform. The liquid

phase thereof is harmless, however, the gas state thereof has toxicity. The

allowable concentration thereof is 100 ppm. It is anesthetic, nonflammable

and insoluble in water. Polyvinyl chloride gloves and protection glasses must

be worn because of the danger of trichloroethylene contacting the skin or eyes

of human beings and trichloroethylene has the possibility of igniting with oxygen

or air by high energy source. In addition, drowsiness headaches, dizziness,

unconsciousness or fatal symptoms can occur when a high concentration of

trichloroethylene vapor is inhaled. Therefore, an ventilation apparatus is

necessary since trichloroethylene is heavier than air and does not disperse

rapidly in a closed container or non ventilated room.

SUMMARY OF THE INVENTION

Accordingly, the present invention is intended to overcome the above-

described disadvantage of conventional arts and to provide the process for the

machine part which reduce loss of the process by deleting the degreasing and

oxidizing process and solve the environmental problem by not using the

degreasing solution.

An embodiment of the present invention provides a process for a

machine part for a color picture tube assembly comprising the steps of coating

resin on a steel of machine parts, forming the steel coated with said resin,

oxidizing, calcinating and baking the steel.

The process further comprises the step of plating with chromate on the

steel before coating.

Another embodiment of the present invention provides a machine part

for a color picture tube assembly comprising of steel and a resin layer coated

on the steel.

the maching part for a color picture tube is preferred to further comprise

a chromate layer between the steel and resin layer.

Another embodiment of the present invention provides a process for a

machine part for a color picture tube assembly comprising the steps of plating

zinc on steel of machine parts, coating resin on the steel plated with zinc,

forming the steel coated with the zinc and resin and calcinating and baking the

steel.

The process is preferred to further comprise the step of plating with

chromate on the steel after Plating zinc on the steel.

Another embodiment of the present invention provides a machine part

for a color picture tube assembly comprising of steel, a zinc layer plated on the

steel and a resin layer coated on the zinc layer.

The machine part for a color picture tube is preferred to further

comprise a chromate layer between the zinc layer and resin layer.

Another embodiment of the present invention provides a lubricated

steel sheet comprising of steel and a resin layer coated on the steel.

The lubericated steel sheet is preferred to further comprise a chromate

layer between the steel and resin layer.

The lubricated steel sheet is preferred to use for manufacturing of a

frame or inner shield for color picture tubes.

Japanese Patent 89-1522044 discloses a process for a color picture

tube solving the problem of the trichloroethylene solution. After Ni and Cr are

plated on the shadowmask, frame and 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

component is formed through sealing, exhaust and aging processes.

Therefore, the surface of the metal formed by a thermal process without an

oxidizing process is thinner and harder than a conventional oxidized film.

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

Zinc and chromate was coated on a steel sheet and then resin was

coated thereon. The steel sheet was mold processed in the press by

calcinating in nitrogen air and baking to produce a fixed frame and inner shield.

COMPARATIVE EXAMPLE

A cold rolled steel sheet was oxidized at a high temperature in methane

gas and air atmosphere and was calcinated, baked and mold processed in the

press to produce a frame and inner shield for color picture tubes with a fixed

size.

The mechanical properties of a steel sheet coated resin is excellent

than that of the conventional steel sheet when they are used as a machine part.

The steel sheet coated resin makes the total process simpler because omission

of degreasing and oxidizing process.