JPS64462B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for forming a thermal spray coating on the inner surface of a thin metal cylinder.

[Prior art]

Conventionally, when spraying metal or ceramics onto a metal plate, the surface of the base material to be sprayed is cleaned, then blasted with grit to roughen the surface, and the anchoring effect between the sprayed material and the base material The adhesion of the thermal spray coating is increased, and if even higher adhesion is required, the material is preheated and the base treated.

[Problem that the invention seeks to solve]

However, when applying a thermal spray coating to the inner surface of a thin cylindrical body with a thickness of 1 mm or less, such as an inner stator wear-resistant material, it is necessary to perform preheating treatment and surface roughening treatment to prevent distortion caused by the thermal spraying heat. The occurrence is large and causes not only warping of the cylindrical body itself, but also burnout of the base material, making it impossible to obtain a thermal sprayed coating in a sound state.

The purpose of the present invention is to provide a method that enables the formation of a sound thermal sprayed coating on a metal thin cylinder, prevents deformation of the metal thin cylinder itself, and obtains a thermal sprayed coating that has a good surface condition and good adhesion to the substrate. It is about providing.

[Means for solving problems]

The object of the present invention is to roughen the surface as a pretreatment for thermal spraying by a mild blasting process, and during thermal spraying, rotate the cylindrical body around the cylindrical axis while applying a cooling fluid from the outside of the cylindrical body, This is accomplished by applying thermal spray material to the cooling location from a thermal spray device traveling within the cylinder along the axis of the cylinder.

In the surface roughening by blasting in the present invention, when the thickness of the thin plate is 1 mm or less, the surface roughness of the base material is
Experiments have confirmed that Rz 20mm or less is good.

The blasting conditions for this are:
The above roughness is obtained when processing with a #60 abrasive material at intervals of 100-150 mm under a blasting pressure of 3 Kg/cm ² .

The accompanying drawings show an example of an apparatus used to thermally spray the roughened inner surface of a cylindrical body in accordance with the present invention.

In the figure, a cylindrical body 1 with a roughened surface is fixed to a chuck 3 via a protective sleeve 2 of a large rotating device, and a sleeve 4 for preventing intrusion of cooling water is fitted into the opening at the other end. A cooling pipe 5 having a water jet nozzle 6 opening downwardly over the entire length of the cylinder 1 is arranged above the cylinder 1 attached to the rotating device. Reference numeral 7 denotes a plasma spraying apparatus that is supported by a traveling arm (not shown), has a spraying material powder supply pipe 8, and sprays spraying material from an upwardly oriented spraying nozzle 9. The thermal spraying device 7 is configured to move parallel to the axis a of the rotating cylindrical body 1 so that the spraying distance to the inner surface of the cylindrical body 1 is always constant.

The cylindrical body 1 as the object to be thermally sprayed is rotated by the rotating device, and with cooling water spouted from the water jet nozzle 6 onto the upper surface of the cylindrical body 1, the plasma spraying device 7 is started to spray the cylindrical body 1. While moving along the axis, the spray material is sprayed toward a cooling position.
In the thermal spraying process, the amount of material supplied per time is reduced, and the thermal spraying is performed a plurality of times while the plasma spraying device 7 is reciprocated to form the thermal spray coating layer 10.

When applying the thermal spraying method of the present invention, there are no restrictions on the base material and the thermal spraying material, and any thermal spraying material such as metal aluminum, alumina, zirconia, etc. can be used as the thermal spraying material.

〔Example〕

The inner surface of a cylindrical thin steel plate of 80 mmφ x 250 mm length x 0.4 mm thickness was blasted with #60 abrasive material under a blasting pressure of 3 kg/cm ² using a nozzle exclusively for the inner diameter, resulting in a surface roughness of 15 μm. The surface was roughened. Then,
As shown in the figure, this roughened steel plate cylindrical body 1 is fixed to a rotating chuck 3 via a chucking protection sleeve 2, and a cooling water intrusion prevention sleeve 4 is fitted to the other end, and the rotation speed is 200 rpm. While rotating and applying cooling water from the outside surface, plasma spraying was performed using an extension gun while feeding Cr ₂ O ₃ powder with a particle size of 15 to 45 μm at a rate of 15 g/min under conditions of 500 Amp and 75 V. .

The feed speed of plasma spraying was 640 m/min, and 3 passes were performed, and the Cr ₂ O ₃ was uniformly coated with a thickness of 45 μm throughout.
A coating was obtained. There was no warping or deformation of the cylindrical steel plate after thermal spraying, and the adhesion strength of the Cr ₂ O ₃ coating was extremely excellent.

〔Effect of the invention〕

By the thermal spraying method of the present invention, it is possible to obtain a thermal sprayed coating that does not bend or distort the base material itself even on an extremely thin metal cylinder, and has excellent adhesion and surface condition. We were able to realize the formation of a thermal spray coating on the inner surface of a thin cylindrical body.

[Brief explanation of the drawing]

The drawings are diagrams showing an embodiment of the thermal spraying method of the present invention. 1: cylindrical body, 2: protective sleeve, 3: chuck, 4: cooling water intrusion prevention sleeve, 5: cooling pipe, 6: water jet nozzle, 7: plasma spraying device,
8: Thermal spray material powder supply pipe, 9: Thermal spray nozzle, 1
0: thermal spray coating layer.

[Claims]

1. In a treatment method for forming a phosphate chemical coating on the surface of copper and copper alloys, persulfuric acid, persulfates, perboric acid,
One or two oxidizing agents from the group of permanganates, dichromates, peracetic acid and hydrogen peroxide
A method for phosphate chemical conversion treatment of copper and copper alloy surfaces, characterized by containing 0.1 to 10% by weight of active oxygen.