JPS61186454A - Fe-base sintered alloy having superior corrosion and wear resistances - Google Patents

Abstract

PURPOSE:To obtain a Fe-base sintered alloy having superior corrosion and wear resistances by blending Fe with specified amounts of Cr, Ni, Mn, P, B and C. CONSTITUTION:The composition of alloy powder is composed of, by weight, 16-26% Cr, 8-16% Ni, 1-5% Mn, 0.05-1.2% P, 0.02-1.2% B, 0.05-0.5% C and the balance Fe with inevitable impurities. The alloy powder is press- compacted to form a green compact, and this green compact is sintered in a reducing atmosphere or in vacuum. The sintered compact is is aged at 500-750 deg.C so as to provide prescribed hardness.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an Fe-based sintered alloy having excellent corrosion resistance and wear resistance.

[Conventional technology]

Traditionally, products with complex shapes, such as compressor nozzles for automobile coolers and mount parts for industrial cameras,
Various types of sintered stainless steel are used to manufacture parts that require excellent corrosion and wear resistance, as they are more cost-effective than machined stainless steel materials that are less rigid. .

[Problem that the invention seeks to solve]

However, although these conventional sintered stainless steels have relatively good corrosion resistance, like general sintered parts, their Vickers hardness is lower due to their lower density than molten materials. It is difficult to obtain a high hardness of 200 or more, and in these applications where wear resistance as well as corrosion resistance is required, the service life has been reached in a relatively short period of time.

On the other hand, attempts have been made to increase the carbon content in order to increase the hardness of the conventional sintered stainless steel, but this leads to a deterioration in corrosion resistance. It is something that cannot be done.

[Means for solving problems]

Therefore, from the above-mentioned viewpoint, the present inventors conducted research to develop a material with corrosion resistance and wear resistance, and as a result, in weight % (hereinafter % indicates weighted %), Cr: 16-26%.

Ni: 8-16%.

Mn: 1-5%.

P: 0.05-1.2%.

3: 0.02-1.2%.

C: 0.05-0.5%.

The Fe-based sintered alloy, which has a composition of
They discovered that aging treatment results in even higher hardness, which results in superior wear resistance and even better corrosion resistance.

This invention was made based on the above knowledge, and the reason why the component composition was limited as described above will be explained below.

(a) Or The Cr component has the effect of increasing the corrosion resistance of the alloy by forming a solid solution in the base material, and also by combining with components such as Mn and P to form hard precipitates, thereby increasing the hardness of the alloy. If the content is less than 16%, the desired effect cannot be obtained, while if the content exceeds 26%, the toughness of the alloy will decrease. Therefore, the content is set at 16 to 26%. Ta.

(b) Ni The Ni component is dissolved in the base material to stabilize the austenite phase of the base material, and facilitates the solid solution of solute components during solution treatment, thereby improving age hardening ability and improving corrosion resistance. However, if the content is less than 8%, the desired effect will not be obtained on the said action, while if the content exceeds 16%, not only will the said action not be further improved. However, the content was determined to be 8 to 16% because the processability of cutting and the like deteriorates.

(C) The Mn lyln component, in coexistence with Ni, has the effect of stabilizing austenite, improving age hardening ability, and improving corrosion resistance, as well as promoting work hardening due to work strain and improving wear resistance. However, if the content is less than 1%, the desired effect of improving the above effect cannot be obtained, while if the content exceeds 5%, the Mn component is a component that easily oxidizes, so it is Since it is oxidized, the oxygen content in the alloy increases, and the toughness decreases, its content is set at 1 to 5%.

(d) P and B These components both form a eutectic with Fe, and only when they coexist do they densify the alloy by the phase opening effect and make it denser. It has the effect of forming hard precipitates and increasing the hardness of the alloy, thereby improving wear resistance.
If P: less than 0,05% and B: less than 0.02%, the desired effect cannot be obtained;
．． If the content exceeds 2%, the amount of hard precipitates becomes too large and the toughness decreases, so the content is adjusted to P: 0.05-1.2%, 3: 0.02- 1.2%
determined respectively.

(e) C The C component not only suppresses oxidation due to Mn, which is an easily oxidized alloy component, but also forms carbides to increase the hardness of the alloy.
It has the effect of improving wear resistance, but its content is 0.
If the content is less than 0.5%, the desired effect cannot be obtained; on the other hand, if the content exceeds 0.5%, the amount of Cr carbide formed increases, and conversely, the amount of Cr dissolved in the matrix decreases. Since this reduces the corrosion resistance of the alloy, its content is set at 0.05 to 0.5%.

The alloy of the present invention can be produced by using elemental powders of each component as the raw material powder, or by using Cr, Mn, which are easily oxidized.
, and P, for example, may be used, or an alloy powder having a predetermined final component composition may be used, and these raw material powders may be blended into a predetermined composition. After mixing under normal conditions, it is press-formed into a compact, and then sintered in a reducing atmosphere with a low dew point or in a vacuum to prevent oxidation, and if necessary, after sintering,
Manufactured by heating in a non-oxidizing atmosphere to a temperature of about 1050 to 1150°C, followed by solution treatment of quenching, and then aging treatment at a temperature of about 550 to 750°C to obtain the desired hardness. can do.

〔Example〕

Next, the Fe-based sintered alloy of the present invention will be specifically explained using Examples.

-100 mesh reduced Fe powder as raw material powder, =
100 mesh l: e-18%Or -10%N1-
Fe alloy atomized powder with a composition consisting of 3%1yjn-0,1%C, -200 mesh carbonyl Ni
Powder, -100 mesh Fe-27%0r-0,3%
Fe alloy atomized powder with a composition consisting of C, -1
00 mesh Fe-Mn alloy (containing 5% Mn near)
Atomized powder, -100 mesh Fe-P alloy (P
:23% content) atomized powder, -1oo mesh F
e-8 alloy (B: 20% content) atomized powder, -10
Prepare 0 mesh pulverized Cr powder and -200 mesh graphite powder, blend these raw powders into a predetermined composition, and add zinc stearate as a lubricant at a ratio of 1% to the blended powder. This mixed powder was press-molded into a green compact at a pressure of 5.5 jan/cd, and then this green compact was heated to a temperature of 550°C in a decomposed ammonia gas atmosphere of 1 atm. After removing the lubricant, in a vacuum of 0.05-0.15 tOrr, temperature = 1
Sintering is performed by holding at a predetermined temperature within the range of 140 to 1250°C for a predetermined time within the range of 1 to 2 hours, and then during cooling after sintering, the temperature is maintained at 1130°C for 30 minutes and then cooled. solution treatment, and then in a nitrogen atmosphere of 1 atm.
By performing aging treatment at a predetermined temperature in the range of 0 to 710°C for a predetermined time in the range of 5 to 5 hours, the Fe base of the present invention having the component composition shown in Table 1 is obtained. Sintered alloys 1 to 10 and conventional sintered stainless steel 1.
2 were produced respectively.

Next, the resulting FO-based sintered alloys 1-1 of the present invention
0 and conventional sintered stainless steels 1 and 2, relative density, Vickers hardness load: 5Kg>.

Tensile strength and elongation were measured, and a salt spray test was also conducted to observe the rusting state after 24 hours. These results are shown in Table 1.

〔Effect of the invention〕

As is clear from the results shown in Table 1, the present invention Fe
All of the base sintered alloys 1 to 10 have excellent corrosion resistance, high density, high hardness, and high strength, so they have excellent wear resistance, whereas conventional sintered stainless steel Steel 1 has excellent corrosion resistance but poor wear resistance, and conventional sintered stainless steel 2, which has increased C content to improve wear resistance, has good wear resistance but poor corrosion resistance. It was low.

As mentioned above, the Fe-based sintered alloy of the present invention has excellent corrosion resistance and wear resistance, so it can be used in fields that require these properties, and it is also non-magnetic. Even when used in fields where non-magnetism is required, it stably exhibits excellent performance over a long period of time.

Claims (1)

[Claims] Cr: 16-26%, Ni: 8-16%, Mn: 1-5%, P: 0.05-1.2%, B: 0.02-1.2%, C An Fe-based sintered alloy having excellent corrosion resistance and wear resistance, characterized by having a composition (weight %) of: 0.05 to 0.5%, and the remainder consisting of Fe and unavoidable impurities.