JPH0115580B2 - - Google Patents

Description

[Detailed description of the invention]

This invention has excellent wear resistance, conformability, and corrosion resistance, and is particularly useful for seal rings for submersible pumps that require these characteristics, and for transportation of fuels such as alcohol, alcohol-containing gasoline, and denatured gasoline. Alternatively, Fe is suitable for use as structural members such as rotors and housings in injection pumps, as well as underwater sliding members.
This invention relates to base sintered alloys. Conventionally, in the manufacture of the above types of parts, properties such as corrosion resistance, wear resistance, and conformability are generally required, so materials such as stainless steel that have these properties have been used, but in recent years Currently, these conventional materials are no longer able to provide a sufficiently satisfactory service life as they are forced to be used under more severe conditions. Therefore, from the above-mentioned viewpoint, the present inventors have developed a material with excellent wear resistance, corrosion resistance, and conformability that allows the above-mentioned types of members to be used for a long period of time even under harsh conditions. As a result of research to develop the material, it was found that it contains Cr: 2 to less than 10%, Nb: 1 to 20%, Ni: 1 to 25%, and if necessary, Mo: 0.3 to 10%. , P: 0.1 to 2%, B: 0.01 to 1%, a composition containing one or more of the following, with the remainder consisting of Fe and unavoidable impurities (the above weight % and the below % indicate weight %) ) is an extremely hard intermetallic compound formed by Ni and Nb, and if it contains Mo if necessary, an extremely hard intermetallic compound formed by also adding the Mo component. Because it has a structure in which Cr is uniformly dispersed and precipitated in the base material, it has excellent wear resistance and sliding characteristics (compatibility), and it has also been found that it has excellent corrosion resistance due to the Cr solid solution base material. It is. This invention was made based on the above knowledge, and the reason why the component composition range was limited as described above will be explained below. (a) Cr The Cr component has the effect of imparting corrosion resistance and acid resistance to the alloy as well as reinforcing the matrix, but if its content is less than 2%, the desired effect cannot be obtained; When the amount exceeds 10%, the toughness tends to decrease, so the content was set at 2 to 10%. (b) Nb The Nb component includes Ni and Mo as mentioned above.
combine with to form extremely hard intermetallic compounds,
As this is uniformly precipitated and dispersed in the base material, the wear resistance and sliding properties of the alloy are significantly improved, and it also forms a eutectic with Ni and Mo, resulting in the generation of a liquid phase at a relatively low temperature. Therefore, it has a uniform effect of improving the density of the alloy, but if the content is less than 1%, the desired effect cannot be obtained, while if the content exceeds 20%, The content was set at 1 to 20% because not only does the toughness tend to deteriorate, but also no further improvement effect can be obtained. (c) Ni As mentioned above, Ni forms extremely hard intermetallic compounds to improve wear resistance and sliding properties, and forms eutectic to improve sinterability. When dissolved in solid solution, it has the effect of strengthening the substrate and improving corrosion resistance, but if the content is less than 1%, the desired effect cannot be obtained, while if the content exceeds 25%, the above effect cannot be obtained. As a result, no further improvement effect could be obtained, and considering economic efficiency, the content was reduced to 1.
It was set at ~25%. (d) Mo The Mo component forms intermetallic compounds and composite compounds with Nb and Ni to harden the alloy.
Since it dissolves in solid solution in the base material and has the effect of strengthening it, it is included as necessary when even better wear resistance is required, but if the content is less than 0.3%, the above effect will not be achieved. The desired improvement effect cannot be obtained, and if the content exceeds 10%, the toughness will decrease, so the content should be reduced to 0.3%.
It was set at ~10%. (e) P and B These components not only improve sintering properties and increase the density of the alloy, thereby further improving corrosion resistance, but also have the uniform effect of solid solution in the base material and strengthening it. Therefore, it is included as necessary when these characteristics are particularly required, but each P: 0.1
% and B: less than 0.01, the desired effect cannot be obtained; on the other hand, P: 2% and B:
If each content exceeds 1%, toughness and corrosion resistance will deteriorate, so the respective contents were determined to be P: 0.1 to 2% and B: 0.01 to 1%. Among the inevitable impurities in the Fe-based sintered alloy of this invention, the C component has a stronger reactivity with the above-mentioned Nb than the Ni and Mo components, and therefore preferentially reacts with this Nb to form carbides. The content should not exceed 0.5%, as this may result in the formation of oxides, making it impossible to maintain the excellent properties inherent to this alloy. Next, the Fe-based sintered alloy of the present invention will be explained using Examples in comparison with Comparative Examples. Example Particle size of raw material powder formed by water spray method and containing predetermined amounts of Cr and Nb: -
Various Fe-Cr-Nb alloy powders of 150mesh, Ni powders with average particle size: 3μm, and
Mo powder, Fe-P alloy (containing 27% P) powder and Fe with particle size: -150mesh, respectively
-Prepare B alloy powder (B: 21% content), mix these raw material powders to the composition shown in Table 1, mix for 30 minutes in a minute mixer, and apply to a pressure of 6 ton/cm ^2. The green compact is formed into a powder compact, then heated in a vacuum furnace to a predetermined temperature within the temperature range of 1230 to 1300℃, sintered, rapidly cooled from a predetermined temperature within the temperature range of 950 to 1050℃, and finally By aging treatment at a predetermined temperature within the temperature range of 480 to 540°C for 1.5 hours, sintered alloys 1 to 23 of the present invention and comparative sintered alloys having substantially the same final component composition as the blended composition were obtained. Bonds 1 to 3 were each manufactured. Comparative sintered alloys 1 to 3 all have a composition in which one of the constituent components (indicated with an asterisk in Table 1) falls outside the scope of this invention. It is. Next, the resulting sintered alloys of the present invention 1-
With respect to No. 23 and Comparative Sintered Alloys 1 to 3, the density was measured and a wear resistance test and a corrosion resistance test were conducted. The wear resistance test was conducted using the various sintered alloys listed above.

【table】

[Table] A rotating member having dimensions of diameter: 26mmφ x thickness: 5mm is molded, and this rotating member is molded into a ring member (a mating material) made of JIS/SCM-3 carburized material with Rockwell hardness H _R C: 44. 2% H ₂ O and 10% ethanol in gasoline, surface pressure: 4Kg/cm ² , rotation speed:
Conducted under the conditions of 2100r.pm, test time: 500hr,
After the test, the average depth of wear on the sliding surfaces of the rotating member and ring member was measured. In addition, the corrosion resistance test was conducted by leaving it in an atmosphere of temperature: 30℃ and humidity: 90% for 24 hours, and by immersing it in extremely deteriorated gasoline for 50 hours. Observe the situation and mark ◎ if there is no rust, mark ○ if there is only a little rust, and mark x if it is all over the surface.Also, mark ○ if there is no discoloration in the gasoline immersion test.
The presence of discoloration was evaluated with an x mark. These results are also shown in Table 1. From the results shown in Table 1, the present invention sintered alloy 1
~23 all have excellent abrasion resistance, conformability,
In contrast, Comparative Sintered Alloys 1 to 3 have poor wear resistance, conformability, and corrosion resistance in at least one of the properties. As mentioned above, the Fe-based sintered alloy of this invention is
It has excellent wear resistance, sliding properties, and corrosion resistance, so it is suitable for manufacturing various pump structural parts and various sliding parts that require these properties, as well as turbine disks and clock sides. It exhibits excellent performance when used in

Claims (1)

[Claims] 1 Contains 2 to less than 10% Cr, 1 to 20% Nb, 1 to 25% Ni, and the remainder is Fe and unavoidable impurities (weight %). A corrosion-resistant Fe-based sintered alloy with excellent wear resistance. 2 Contains Cr: 2 to less than 10%, Nb: 1 to 20%, Ni: 1 to 25%, and further contains Mo: 0.3 to 10%, with the remainder consisting of Fe and inevitable impurities ( A corrosion-resistant Fe-based sintered alloy with excellent wear resistance, characterized in that it has a corrosion-resistant Fe-based sintered alloy having a corrosion resistance of at least 1% by weight). 3 Contains Cr: 2 to less than 10%, Nb: 1 to 20%, Ni: 1 to 25%, and further contains one or two of P: 0.1 to 2% and B: 0.01 to 1%. A corrosion-resistant Fe-based sintered alloy with excellent wear resistance, characterized by having a composition (at least % by weight) containing: , and the remainder consisting of Fe and unavoidable impurities. 4 Contains Cr: 2 to less than 10%, Nb: 1 to 20%, Ni: 1 to 25%, and further contains Mo: 0.3 to 10%, P: 0.1 to 2%, and B: 0.01 to 1%. A corrosion-resistant Fe-based sintered alloy with excellent wear resistance, characterized in that it contains one or two of the following, with the remainder consisting of Fe and unavoidable impurities (weight percent).