JPS5938305B2 - Manufacturing method of metal corrosion resistant body - Google Patents

Description

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

In general, iron-based metals have surfaces that are 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 a chestnut paste and adheres to the surface of iron-based metals. However, the surface of the metal layer formed from such metallicon contains many pinholes, which has the disadvantage that the corrosion-preventing 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 conducted extensive 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 is 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 the metal base material 1 to make the surface rough. The surface roughening method involves spraying an abrasive onto the surface of the base material 1 to make the surface uneven. Diamond as an abrasive material,
Natural products such as emery, spinel, garnet, 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. In addition, before spraying the abrasive material onto the surface of the base material 1, the surface of the base material 1 is pretreated by degreasing, pickling, water washing, etc. to remove oil, dust, rust, etc. attached to the surface. It is preferable to leave it there. or,
The metal base material 1 is made of cast iron, pig iron, various iron alloys, metals mainly composed of iron, and the like.

The shape of the base material 1 may be tubular as shown in FIG. 1, or plate-like as shown in FIG. 2. In addition,
In the case of FIG. 1, in order to prevent corrosion on the inner surface of a tubular base material 1, a synthetic resin 3 is formed by previously applying a synthetic resin lining to the inner surface or inserting a synthetic resin pipe. Next, a porous metal layer 2 is formed by spraying metal particles of zinc, aluminum, copper, brass, or an appropriate alloy thereof onto the roughened surface of the base material 1.

Zinc, aluminum, or an alloy thereof is preferably used as the metal to be thermally sprayed, and in the case of this alloy, zinc 85
In terms of weight, a material consisting of 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 made smooth by rolling, and the pores are sealed. That is, the porous metal layer 2 formed by the above-described thermal spraying is compressed to increase its density, and voids within the metal layer 2 are eliminated or closed. As the rolling process, swaging process, roll rolling, press process, etc. are used. Further, the surface of the rolled metal layer 2 may be coated with anti-rust coating, or when the base material 1 is tubular, a corrosion-preventing vinyl tape may be wrapped around the surface of the metal layer 2. Next, the implementation of the present invention will be described. [Example] Iron pipe whose inner surface is lined with epoxy resin (outer diameter 2
The surface of the iron pipe (5mm thick, 3m7n) was ground by grid blasting to make the surface of the iron pipe uneven with an average roughness of 30 microns.

Next, zinc wire (purity 99.99%) was placed on the surface of the iron pipe.
was thermally sprayed using gas-sprayed metallicon to a thickness of 150 mm.
A micron layer of zinc was formed. Next, the iron pipe was compressed by 20% of the thickness of the zinc layer using a swaging machine, and the surface of the zinc layer was smoothed and the holes were sealed. The iron pipe thus obtained was tested in salt water spray for 500 hours.
No iron rust other than white rust occurred. [Comparative Example] In the same manner as in the example, a zinc layer was thermally sprayed with metallicon on the surface of an iron pipe, and the iron pipe was not swaged.

In the iron pipe of this comparative example, pale yellow iron rust occurred during the 300-hour salt spray test.

As described in detail above, the present invention rolls the surface of the metal layer formed by metal spraying to smooth it and seal the pores, thereby increasing the density of the metal layer and providing an excellent corrosion-resistant surface. A beautiful corrosion-resistant metal body can be obtained. Moreover, since the surface of the metal base material is roughened by forming irregularities and the metal layer is formed thereon, the base material and the metal layer can be firmly bonded.

In addition, zinc, aluminum, copper,
Since the metal layer is formed by thermally spraying metal made of brass or an appropriate alloy thereof in the form of particles, it is possible to increase the purity of the metal particles to be thermally sprayed and improve the corrosion prevention effect compared to molten plating etc. can.

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-melted 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...Synthetic resin layer.

Claims (1)

[Claims] 1 The surface of a metal base material is roughened by forming irregularities, and a porous metal layer is formed by thermally spraying a metal made of zinc, aluminum, copper, brass, or an appropriate alloy thereof in the form of particles. 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.