JPS5941461A - Preparation of corrosion-proof body made of metal - Google Patents

Abstract

PURPOSE:To obtain a corrosion-proof body made of a metal having a smooth surface and excellent in corrosion-proof effect, by a method wherein a metal is applied to the surface of a substrate by flame spraying to form a porous metal layer and the whole is subjected to rolling processing to perform pore sealing. CONSTITUTION:Recessed and protruded parts are formed to the surface of a metal substrate 1 to roughen the same. On this roughened surface, a metal comprising Zn, Al, Cu, brass or a proper alloy is applied in a particulate form by flame spraying to form a porous metal layer 2. The surface of the metal layer 2 is subjected to rolling processing to be smoothed and to perform pore sealing finish. By this method, a corrosion-proof body reduced in the generation of a local battery with respect to the substrate 1 of the metal layer 2 and excellent in electric corrosion-proofness is obtained.

Description

[Detailed description of the invention] The present invention relates to a method for manufacturing a metal corrosion-resistant body.

In general, the surface of iron-based metals is easily rusted and corroded, so in order to prevent rusting and corrosion, corrosion-preventing means, such as metallicon, have been conventionally used. Metallicon is made by thermally spraying other rust-resistant metals into particles to form a porous metal layer that resembles millet paste and adheres to the surface of iron-based metals. However, the surface of the metal layer formed from such metallicon contains a large number of pinholes, so there is a drawback that the corrosion prevention effect cannot be sufficiently exhibited. Furthermore, the surface of the metal layer formed of metallicon is uneven, which has the disadvantage of detracting from its aesthetic appearance.

In view of these conventional drawbacks, the present inventor has completed intensive research and has completed a method for manufacturing a metal corrosion-resistant body that eliminates the above-mentioned drawbacks.

The present invention will be described below with reference to the drawings.

1 and 2 are cross-sectional views showing examples of corrosion-resistant bodies manufactured according to the present invention, in which (1) shows a metal base material;
(2) is a metal layer, and (3) is a synthetic resin layer.

In the present invention, first, irregularities are formed on the surface of a metal base material (1) to make the surface rough. The method of roughening is to spray an abrasive material onto the surface of the base material (41) to make the surface uneven.As the abrasive material, natural products such as diamond, emery, spinel, garnet, etc.
Alumina, silicon carbide, boron carbide, cast iron particles can be used. Among these, it is preferred to use cast iron particles or grids. The unevenness formed by these abrasive materials preferably has a height difference of about 30 to 70 microns at most between the peak and valley of the protrusion in the cross section. Also, before spraying the abrasive on the surface of the base material (1), the surface of the base material (1) is pretreated by degreasing, pickling, water washing, etc.
It is preferable to remove oil, scum, shavings, etc. adhering to the surface.

Further, the metal base material +1) is made of cast iron, pig iron, various iron alloys, gold 14 mainly made of iron, and the like. The base material (1
The shape of 1 may be tubular as shown in FIG.
It may be made into a plate shape as shown in FIG.

In the case of FIG. 1, in order to protect the inner surface of the tubular base material ftl from corrosion, synthetic itMlI! is applied to the inner surface in advance. A synthetic resin layer In) is formed by applying quenching or inserting a synthetic resin (In).

Next, a porous metal layer (2) is formed by thermally spraying a metal made of zinc, aluminum, copper, brass, or an appropriate alloy thereof in the form of particles onto the roughened surface of the base material (11). As the metal, zinc, aluminum, or an alloy thereof is preferably used, and in the case of this alloy, an alloy containing 85% by weight of zinc and 15% by weight of aluminum is preferably used.

The thickness of the porous metal layer (2) formed by this thermal spraying is usually about 75 to 500 microns.

Next, the surface of the metal layer (2) is rolled to make it smooth and finish the pores. That is, the porous metal layer (2) formed by the above thermal spraying is compressed to increase its density, and the voids in the metal layer +21 are eliminated or closed. As the rolling process, swage process, roll rolling, press process, etc. are used.

Further, the surface of the rolled metal layer (2) may be coated with anti-rust coating, and if the base material (1) is tubular, the metal layer 121 may be coated with anti-rust coating.
Corrosion-preventing vinyl tape may be wrapped around the surface.

Next, examples of the present invention will be described.

〔Example〕

Epoxy tree inside i10! The surface of an 11ft lined iron pipe (outer diameter 25m, thickness 3M) was ground using a grid grinder, and the iron-lined surface was ground to an average roughness of 3mm.
It was made into an uneven shape of 0 micron. Next, a zinc wire (purity 99.99%) was sprayed onto the surface of the iron pipe using a gas-sprayed metallicon to form a zinc layer with a thickness of 150 microns. Next, the iron tube was subjected to a swaging process 4a to compress the thickness of the zinc layer by 20% to smooth the surface of the zinc layer and finish the pores.

The iron heave obtained at this temperature is salt water fountain i11KM50
At 0 hours, no iron #I was generated other than white rust.

[Comparative example]

As in the example, a zinc layer was formed on the surface of the iron pipe by spraying metallicon, and the iron pipe was not swaged.

In the iron pipe of this comparative example, pale yellow #tI4 was generated during the 300-hour salt water jet W test.

As described in detail above, the present A invention smooths the surface of the metal layer formed by metal spraying by rolling and seals the pores, so the density of the metal layer is high and the corrosion prevention effect is excellent. A corrosion-resistant metal body with a beautiful surface can be obtained.

In addition, since the surface of the metal base material is roughened by forming irregularities, and the metal layer is formed on top of it, the base material and the metal layer are bonded to a strength of 1i! i
! Can be glued to.

In addition, zinc, aluminum, copper,
Since the metal layer is formed by thermally spraying a metal made of brass or an appropriate alloy thereof in the form of particles, the purity of the metal particles to be thermally sprayed can be increased and the corrosion prevention effect can be improved compared to hot-dip plating. That is, it is possible to obtain a corrosion-resistant body with less occurrence of local batteries on the base material of the metal layer and excellent electrical corrosion resistance.

Furthermore, since the metal layer is formed on the surface of the metal base material by metal spraying and the surface of the metal layer is rolled by swaging or the like, the corrosion-resistant body can be manufactured easily and continuously. Therefore, corrosion-proofing can be easily applied to conventional corrosion-resistant pipes, such as thin-walled pipes that were too hot to be hot-dip plated, and large-diameter pipes that were difficult to plate continuously.

[Brief explanation of the drawing]

1 and 2 are cross-sectional views showing examples of corrosion-resistant bodies manufactured according to the present invention. (1)...Metal base material, (2)...Metal layer, (
3)...Ge, resin layer.

Claims (1)

[Claims] 1) The surface of a metal base material is roughened by forming irregularities, and a porous gold layer is formed by spraying metal particles of zinc, aluminum, copper, brass, or an appropriate alloy thereof onto the surface. 1. A method for producing a metal corrosion-resistant body, which comprises forming a metal layer, and rolling the surface of the metal layer to make it smooth and finish the pores.