JPS61246301A - Production of corrosion-and wear-resistant sliding material - Google Patents

Abstract

PURPOSE:To produce a sliding material having the resistance to wear and corrosion by impregnating a water soluble chromium compd. into the pores of a green compact of an alloy steel, sintering the green compact and converting the chromium compd. to chromic oxide (VI). CONSTITUTION:The powder of the alloy steel such as stainless steel is pressed to prepare the green compact having the pores sized about 1-10mu. The water soluble chromium compd. (chromic phosphate, etc.) is impregnated into the part of the green compact to be used as a sliding surface and is held for about 10min in a high-pressure chamber in which about 9.5kg/cm<2> pressure is maintained. The compact impregnated with the chromium compd. soln. is held for about 30min at about 400 deg.C to reduce the chromium compd. to the hard chromium oxide (VI). The compact is further sintered in the high vacuum or reducing gaseous atmosphere at the temp. lower than the m.p. of the respective materials to intensity the mechanical strength of the compact.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method of manufacturing a sliding member having corrosion resistance and wear resistance.

BACKGROUND OF THE INVENTION Stainless steel is generally known as a material with corrosion resistance and wear resistance.

The problem that the invention attempts to solve is that the above-mentioned stainless steel has poor mechanical properties such as hardness, tensile strength, and elongation, so there have been few examples of its application as a sliding member.

Means and Effects for Solving the Problems The present invention has been made in view of the above, and involves impregnating the pores of a powder compact of alloy steel such as stainless steel with a water-soluble chromium compound, and then applying pressure. The powder compact is sintered and the chromium compound is changed to chromium oxide (W).

Example Embodiments of the invention are described below.

A powder compact having pores of 1 to 10 μm in size is made by pressing powder such as stainless steel. A water-soluble chromium compound is added to the part used as the sliding surface of this molded body.
For example, it is immersed in chromium oxide (M), chromium phosphate, chromium acetate, etc., and kept in a high-pressure chamber K at a pressure of 9.5 mm for 10 minutes. The next formed body is taken out from the chromium compound solution. In this state, the pores of the molded body are impregnated with a chromium compound solution. This molded body is sintered in a vacuum at 400° C. for 30 minutes, and then in a high vacuum or a reducing gas atmosphere at a temperature lower than the melting point of each material. During the initial heat treatment at 400°C, the chromium compound in the pores is reduced to hard chromium (VI) oxide, reinforcing the mechanical strength of the final molded product.

Process example (1) (1) Chromium-coated iron powder is press-molded.

(II) The press-molded product is immersed in an aqueous chromium oxide (M) solution and pressurized at a pressure of 5.0 to 9.5 for about 10 minutes.

(10 The molded product is taken out from the chromium oxide (M) aqueous solution at normal pressure.

4V) The molded product is placed in a sintering furnace and subjected to heat treatment as shown in FIG.

■ Take out the molded product from the sintering furnace and process the above (11) → 01
Perform step 0.

(VD The molded product is placed in a sintering furnace and subjected to heat treatment as shown in FIG. 2.

■! i) Repeat the above step (V)-+IVD 4 to 9 times.

&+iD Impregnation process completed.

Process Example (2) (1) A SUS 410 sintered material is immersed in a chromium oxide (V[) aqueous solution at room temperature and pressure for 10 minutes.

(11) The sintered material is taken out of the chromium oxide (Vl) aqueous solution and subjected to heat treatment as shown in FIG.

(iii) Repeat the steps (1)→(11) above five times.

FIG. 4 is an enlarged sectional view of a press-molded 13Cr powder. In the figure, 1 is a molded body base, and 2 is a hole. In addition, the upper and lower rows in Figure 5 are photographs showing surface analysis of Cr and 0 elements by EPMA at the same part as shown in Figure 4 above, and it is clear that the elements are located in the white parts. shows. The pores 1 shown in FIG. 4 are shown in the Cr analysis photograph in the upper part of FIG. 5, and it can be seen that they are Cr voids as they are.

FIG. 6 shows an enlarged cross-section of the press-molded I 3 Cr powder shown in FIG. 4, which has been impregnated with chromium oxide (M) in the step of process example (2). As shown in this figure, the holes 2 shown in FIG. 4 are filled with a chromium compound solution by an impregnation process.

The photograph in the upper row of FIG. 7 is a photograph of the Cr element surface analysis by BPMA of the same portion as shown in FIG. 6 above. In this photograph, KCr is concentrated in the pattern (impregnated area) shown in FIG. 6 above.

The photo at the bottom is a 0 element analysis photo, and you can see that 0 is similarly concentrated in the pattern. Crabs are the elements in which Cr and O are found filling the pores.

Effects of the Invention According to the present invention, it is possible to compensate for the weaknesses of stainless steel, that is, poor mechanical properties such as hardness, tensile strength, and elongation, thereby expanding the range of applications for sliding members. Furthermore, the mechanical properties of materials other than stainless steel can be improved.

[Brief explanation of drawings]

1 and 2 lines 4v and (V
) Heat treatment diagram in the process, Figure 3 is 01 of the second process example.
) Heat treatment diagram in the process, Figure 4 is an enlarged cross-sectional view of the compression molded body, Figure 5 is a surface analysis photograph of Cr and O elements in the area shown in Figure 4 by EPMA¥C, Figure 6 is the diagram of the compression molded body FIG. 7 is an enlarged cross-sectional view of the material impregnated with chromium oxide (VI), and FIG. 7 is a photograph of the area shown in FIG. 6 taken by EPMAK and analyzed for Cr and O elements.

Claims (1)

[Claims] A water-soluble chromium compound is impregnated into the pores of a powder compact made of alloy steel such as stainless steel, and then the powder compact is sintered, and the chromium compound is converted to chromium (VI) oxide. A method for manufacturing corrosion-resistant and wear-resistant sliding materials.