US3795961A - Thermal and abrasion resistant sintered alloy - Google Patents

Thermal and abrasion resistant sintered alloy Download PDF

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US3795961A
US3795961A US00286399A US3795961DA US3795961A US 3795961 A US3795961 A US 3795961A US 00286399 A US00286399 A US 00286399A US 3795961D A US3795961D A US 3795961DA US 3795961 A US3795961 A US 3795961A
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alloy
sintered
thermal
sintered alloy
abrasion resistant
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K Takahashi
M Hasegawa
K Nara
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Nippon Piston Ring Co Ltd
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Nippon Piston Ring Co Ltd
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C33/00—Making ferrous alloys
    • C22C33/02—Making ferrous alloys by powder metallurgy
    • C22C33/0242—Making ferrous alloys by powder metallurgy using the impregnating technique
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C33/00—Making ferrous alloys
    • C22C33/02—Making ferrous alloys by powder metallurgy
    • C22C33/0257—Making ferrous alloys by powder metallurgy characterised by the range of the alloying elements
    • C22C33/0278—Making ferrous alloys by powder metallurgy characterised by the range of the alloying elements with at least one alloying element having a minimum content above 5%
    • C22C33/0285—Making ferrous alloys by powder metallurgy characterised by the range of the alloying elements with at least one alloying element having a minimum content above 5% with Cr, Co, or Ni having a minimum content higher than 5%

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  • FIG. 2 A H I OEXAMPLE OF THIS INVENTION CONVENTIONAL SINTERED E FERRO-ALLOY z x CONVENTIONAL CAsT ALLOY o 0.2 a O.
  • a publicly known metal such as chromium, cobalt, tungsten, etc. has not only a large abrasion resistance but also is prominent in its characteristics at elevated temperatures and is applied in various fields.
  • a metal has many problems to be solved when it is used as sintered parts for a machine. That is, such a metal has a high melting point so that the sintering temperature is, of necessity, required to be elevated, and the sintering time has to be extended, and, therefore, it is naturally disadvantageous in cost.
  • the present invention provides a sintered alloy having large thermal resistance and abrasion resistance suitable for use as a sliding element such as, for example, a valve sheet in which high thermal resistance and high abrasion resistance are required. That is, the present invention comprises a sintered thermal and abrasion resistant alloy comprising a molded and sintered powdery composition consisting of by weight 0.6 to 2% of carbon, 0.4 to 4% of nickel, 0.5 to 5% of molybdenum, 6 to l 1% of cobalt and the balance iron.
  • FIG. 1 is a graph showing the abrasion resistance of sintered alloys of the Examples and of a conventional cast iron and a sintered iron alloy when evaluated in a valve sheet abrasion test machine;
  • FIG. 2 is a graph showing the hardness at elevated temperatures of sintered alloys of the Examples'and of a conventional cast iron and a sintered iron alloy.
  • the alloy of the present invention when the carbon content is less than 0.6%, by weight, the alloy becomes a ferrite-excessive structure so that a high hardness cannot be expected while, when the carbon content is more than 2%, the alloy changes to a cementite-excessive structure which is high in britteleness.
  • Nickel strengthens the base structure of the alloy and improves the thermal resistance and abrasion resistance, however, the effect is small with a nickel content of less than 1%, while, when it becomes more than 4%, the base structure locally changes to martensite so that the hardness increases unnecessarily.
  • Molybdenum increases the tenacity of alloy as well as the impact strength and endurance limit, and, on the other hand, improves the heat treatment property and stabilizes the structure after sintering, however, there is little effect with less than 0.5% of molybdenum and even if more than 5% is present, no effect corresponding to the increase is obtained.
  • Cobalt is selected for substantially improving the thermal resistance and the abrasion resistance at elevated temperatures and has been established to be 6 to 11% on the basis of a synergistic effect with the other elements.
  • the sintered alloy of the present invention from a viewpoint of providing the material with a high density and improving the lubricating property, it is very advantageous to impregnate molten lead into the alloy after the alloy is molded and sintered.
  • the amount of lead impregnated has been experimentally confirmed to be preferably within the range of 0.05 to 5%. That is, with less than 0.05% the effect of impregnation is not remarkable and the impregnation of more than 5% of lead involves a problem in strength from the relation with the density of material before impregnation.
  • EXAMPLE 1 1.2% of graphite powder (325 mesh), 2% of carbonyl nickel powder (-250 mesh), 2% (as molybdenum) of ferromolyb-denum powder (1 50 mesh), 10% of cobalt powder (-150 mesh) and 1.0% of zinc stearate as a lubricant were added to reduced iron powder (l00 mesh) as iron powder.
  • the mixture was molded under a pressure of 4.5 ton/cm and sintered at 1,120 to 1,l C for 30 to 60 minutes in an atmosphere of decomposed ammonium gas.
  • the sintered material so obtained had a density of 6.6 g/cm and a Rockwell B scale hardness of 92.
  • FIG. 1 The results of the abrasion test on this sintered material using a valve sheet abrasion testing machine (rotation number 3,000 rpm, spring pressure 35 Kg, valve velocity at the time of valve closing 0.5 m/sec., width of valve 1 mm, test repeating number 8 X 10 material SUI-I 31B) are shown in FIG. 1, and the results of the measurement of hardness at elevated temperatures are shown in FIG. 2.
  • EXAMPLE 2 A sintered material comprising 0.68% of carbon, 0.71% of nickel, 0.66% of molybdenum, 6.92% of cobalt and the balance iron was made under the same conditions as described in Example 1, and impregnated with molten lead.
  • the sintered material so obtained had a density of 6.4 g/cm and a Rockwell B scale hardness of 90.
  • the lead content was 0.07%.
  • EXAMPLE 3 A sintered material comprising 1.83% of carbon, 3.88% of nickel, 4.79% of molybdenum, 10.62% of cobalt and the balance iron was made under the same conditions as described in Example 1 and impregnated with lead.
  • the sintered material so obtained had a density of 6.7 g/cm and a hardness on the Rockwell B scale of 94.
  • the lead content was 4.7%.
  • Ferro alloy Carbon 1%, chromium 3%, the balance II'OI'I.
  • Cast iron Carbon 3.02%, silicon 2.01%, manganese 0.48%, chromium 0.81%, the balance iron.
  • a thermal and abrasion resistant sintered alloy consisting essentially of a molded and sintered composition comprising from 0.6 to 2% of carbon, from 0.5
  • the sintered alloy of claim 1 exhibiting a hardness from 6 to l 1% of cobalt, by weight, the balance being (HV) on the order of 500 over the temperature range "On.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Powder Metallurgy (AREA)

Abstract

An alloy prepared by molding a powdery composition comprising 0.6 to 2% of carbon, 0.5 to 4% of nickel, 0.5 to 5% of molybdenum and 6 to 11% of cobalt, by weight, and the balance being iron, and then sintering the molded composition, has large thermal resistance and abrasion resistance.

Description

United States Patent Takahashi et al.
THERMAL AND ABRASION RESISTANT SINTERED ALLOY Inventors: Kentaro Takahashi, Ohmiya;
Minoru Hasegawa, Saitama; Kaoru Nara, Kawaguchi, all of Japan Nippon Piston Ring Co., Ltd., Tokyo, Japan Filed: Sept. 5, 1972 Appl. No.: 286,399
Assignee:
Foreign Application Priority Data Sept. 2, 1971 Japan 46-66978 U.S. Cl 29/182, 29/182.l, 75/123 J,
75/123 K, 75/125 Int. Cl 1322f 1/00 .Field of Search 75/125, 123 J, 123 K, 200;
29/182.l, 182; l9l/59.1
[ 51 Mar. 12, 1974 [56] References Cited UNITED STATES PATENTS 3,471,343 10/1969 3,495,957 2/[970 2,662,0[0 l2/I953 2,562,543 7/l95l Gippert 75/l23 K Primary Examiner-Carl D. Quarforth Assistant Examiner-B. Hunt Attorney, Agent, or FirmSughrue, Rothwell, Mion, Zinn & Macpeak 3 Claims, 2 Drawing Figures PAIENTEU 3.795.961
A H I OEXAMPLE OF THIS INVENTION CONVENTIONAL SINTERED E FERRO-ALLOY z x CONVENTIONAL CAsT ALLOY o 0.2 a O.|5- x I 5 OI OO5- g x a I X o NI %\QAISALIOO 200 300 400 500 (C) TRANSFORMATION TEMP FIG. 2
0 EXAMPLE OF THIS INVENTION CONVENTIONAL sINTEREO FERRO-ALLOY 600- x CONVENTIONAL CAST ALLOY s s A g 0 o E4OO- v 0 I-IARONEss I ALIOO 2OO 3C0 4OO 5OO COO TRANSFORMATION TEMP.
THERMAL AND ABRASION RESISTANT SINTEREI) ALLOY BACKGROUND OF THE INVENTION A publicly known metal such as chromium, cobalt, tungsten, etc. has not only a large abrasion resistance but also is prominent in its characteristics at elevated temperatures and is applied in various fields. However, such a metal has many problems to be solved when it is used as sintered parts for a machine. That is, such a metal has a high melting point so that the sintering temperature is, of necessity, required to be elevated, and the sintering time has to be extended, and, therefore, it is naturally disadvantageous in cost.
SUMMARY OF THE INVENTION The present invention provides a sintered alloy having large thermal resistance and abrasion resistance suitable for use as a sliding element such as, for example, a valve sheet in which high thermal resistance and high abrasion resistance are required. That is, the present invention comprises a sintered thermal and abrasion resistant alloy comprising a molded and sintered powdery composition consisting of by weight 0.6 to 2% of carbon, 0.4 to 4% of nickel, 0.5 to 5% of molybdenum, 6 to l 1% of cobalt and the balance iron.
BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a graph showing the abrasion resistance of sintered alloys of the Examples and of a conventional cast iron and a sintered iron alloy when evaluated in a valve sheet abrasion test machine; and
FIG. 2 is a graph showing the hardness at elevated temperatures of sintered alloys of the Examples'and of a conventional cast iron and a sintered iron alloy.
DETAILED DESCRIPTION OF THE INVENTION In the sintered alloy of the present invention, when the carbon content is less than 0.6%, by weight, the alloy becomes a ferrite-excessive structure so that a high hardness cannot be expected while, when the carbon content is more than 2%, the alloy changes to a cementite-excessive structure which is high in britteleness.
Nickel strengthens the base structure of the alloy and improves the thermal resistance and abrasion resistance, however, the effect is small with a nickel content of less than 1%, while, when it becomes more than 4%, the base structure locally changes to martensite so that the hardness increases unnecessarily.
Molybdenum increases the tenacity of alloy as well as the impact strength and endurance limit, and, on the other hand, improves the heat treatment property and stabilizes the structure after sintering, however, there is little effect with less than 0.5% of molybdenum and even if more than 5% is present, no effect corresponding to the increase is obtained.
Cobalt is selected for substantially improving the thermal resistance and the abrasion resistance at elevated temperatures and has been established to be 6 to 11% on the basis of a synergistic effect with the other elements.
In the sintered alloy of the present invention, from a viewpoint of providing the material with a high density and improving the lubricating property, it is very advantageous to impregnate molten lead into the alloy after the alloy is molded and sintered.
In this case, the amount of lead impregnated has been experimentally confirmed to be preferably within the range of 0.05 to 5%. That is, with less than 0.05% the effect of impregnation is not remarkable and the impregnation of more than 5% of lead involves a problem in strength from the relation with the density of material before impregnation.
The present invention will be further illustrated by the following Examples by which the present invention is not intended to be limited. All percents are by weight.
EXAMPLE 1 1.2% of graphite powder (325 mesh), 2% of carbonyl nickel powder (-250 mesh), 2% (as molybdenum) of ferromolyb-denum powder (1 50 mesh), 10% of cobalt powder (-150 mesh) and 1.0% of zinc stearate as a lubricant were added to reduced iron powder (l00 mesh) as iron powder. The mixture was molded under a pressure of 4.5 ton/cm and sintered at 1,120 to 1,l C for 30 to 60 minutes in an atmosphere of decomposed ammonium gas. The sintered material so obtained had a density of 6.6 g/cm and a Rockwell B scale hardness of 92.
The results of the abrasion test on this sintered material using a valve sheet abrasion testing machine (rotation number 3,000 rpm, spring pressure 35 Kg, valve velocity at the time of valve closing 0.5 m/sec., width of valve 1 mm, test repeating number 8 X 10 material SUI-I 31B) are shown in FIG. 1, and the results of the measurement of hardness at elevated temperatures are shown in FIG. 2.
EXAMPLE 2 A sintered material comprising 0.68% of carbon, 0.71% of nickel, 0.66% of molybdenum, 6.92% of cobalt and the balance iron was made under the same conditions as described in Example 1, and impregnated with molten lead. The sintered material so obtained had a density of 6.4 g/cm and a Rockwell B scale hardness of 90. The lead content was 0.07%.
EXAMPLE 3 A sintered material comprising 1.83% of carbon, 3.88% of nickel, 4.79% of molybdenum, 10.62% of cobalt and the balance iron was made under the same conditions as described in Example 1 and impregnated with lead. The sintered material so obtained had a density of 6.7 g/cm and a hardness on the Rockwell B scale of 94. The lead content was 4.7%.
Next, the abrasion test results using a valve sheet test machine on Examples 1, 2 and 3 are shown in FIG. 1 and the test results of hardness at elevated temperatures are shown in FIG. 2. For comparison these tests were run on a conventionally known cast iron and conventional sintered ferro alloy. In this case, the compositions of the cast iron and ferro alloy are as follows:
Ferro alloy: Carbon 1%, chromium 3%, the balance II'OI'I.
Cast iron: Carbon 3.02%, silicon 2.01%, manganese 0.48%, chromium 0.81%, the balance iron.
What is claimed is:
1. A thermal and abrasion resistant sintered alloy consisting essentially of a molded and sintered composition comprising from 0.6 to 2% of carbon, from 0.5
3 ,795 ,96 l 3 4 to 4% of nickel, from 0.5 to 5% of molybdenum and 3. The sintered alloy of claim 1 exhibiting a hardness from 6 to l 1% of cobalt, by weight, the balance being (HV) on the order of 500 over the temperature range "On.
2. The sintered alloy of claim 1 consisting of the recited components. 5
of from normal temperature to about 500 C.

Claims (2)

  1. 2. The sintered alloy of claim 1 consisting of the recited components.
  2. 3. The sintered alloy of claim 1 exhibiting a hardness (HV) on the order of 500 over the temperature range of from normal temperature to about 500* C.
US00286399A 1971-09-02 1972-09-05 Thermal and abrasion resistant sintered alloy Expired - Lifetime US3795961A (en)

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Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3977838A (en) * 1973-06-11 1976-08-31 Toyota Jidosha Kogyo Kabushiki Kaisha Anti-wear ferrous sintered alloy
US3982907A (en) * 1972-03-30 1976-09-28 Nippon Piston Ring Co., Ltd. Heat and wear resistant sintered alloy
US4080205A (en) * 1972-07-13 1978-03-21 Toyota Jidosha Kogyo Kabushiki Kaisha Sintered alloy having wear-resistance at high temperature
US4123265A (en) * 1974-02-21 1978-10-31 Nippon Piston Ring Co., Ltd. Method of producing ferrous sintered alloy of improved wear resistance
WO1990004042A1 (en) * 1988-10-03 1990-04-19 Gaf Chemicals Corporation Iron/cobalt alloy filaments
DE19506340A1 (en) * 1994-02-23 1995-08-24 Nissan Motor Sintered alloy used for sliding element in corrosive environments
US5489324A (en) * 1992-11-27 1996-02-06 Toyota Jidosha Kabushiki Kaisha Fe-based sintered alloy having wear resistance

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS51110119A (en) * 1975-03-25 1976-09-29 Nissan Motor NAINENKIKANNOBENZA
JPS51112410A (en) * 1975-03-29 1976-10-04 Nippon Piston Ring Co Ltd Valve seats made of iron-based sintered alloy for internal combustion engines
JPS51117910A (en) * 1975-04-10 1976-10-16 Nippon Piston Ring Co Ltd Iron based sintered alloy piston ring
JPS51135805A (en) * 1975-05-20 1976-11-25 Okamoto Hideo Sleeve and cylinder liner
JPS5277807A (en) * 1976-07-28 1977-06-30 Nippon Piston Ring Co Ltd Sintered ferroalloy for manufacturing valve seat

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2562543A (en) * 1950-01-06 1951-07-31 Allegheny Ludlum Steel Shock resistant alloy steel
US2662010A (en) * 1952-03-29 1953-12-08 Gen Electric Cast tool steel
US3471343A (en) * 1965-05-07 1969-10-07 Max Koehler Process for the production of sinter iron materials
US3495957A (en) * 1965-03-15 1970-02-17 Mitsubishi Metal Corp Lead-impregnated,iron-base,sinteredalloy materials for current-collecting slider shoes

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2562543A (en) * 1950-01-06 1951-07-31 Allegheny Ludlum Steel Shock resistant alloy steel
US2662010A (en) * 1952-03-29 1953-12-08 Gen Electric Cast tool steel
US3495957A (en) * 1965-03-15 1970-02-17 Mitsubishi Metal Corp Lead-impregnated,iron-base,sinteredalloy materials for current-collecting slider shoes
US3471343A (en) * 1965-05-07 1969-10-07 Max Koehler Process for the production of sinter iron materials

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3982907A (en) * 1972-03-30 1976-09-28 Nippon Piston Ring Co., Ltd. Heat and wear resistant sintered alloy
US4080205A (en) * 1972-07-13 1978-03-21 Toyota Jidosha Kogyo Kabushiki Kaisha Sintered alloy having wear-resistance at high temperature
US3977838A (en) * 1973-06-11 1976-08-31 Toyota Jidosha Kogyo Kabushiki Kaisha Anti-wear ferrous sintered alloy
US4123265A (en) * 1974-02-21 1978-10-31 Nippon Piston Ring Co., Ltd. Method of producing ferrous sintered alloy of improved wear resistance
WO1990004042A1 (en) * 1988-10-03 1990-04-19 Gaf Chemicals Corporation Iron/cobalt alloy filaments
US5489324A (en) * 1992-11-27 1996-02-06 Toyota Jidosha Kabushiki Kaisha Fe-based sintered alloy having wear resistance
US5503654A (en) * 1992-11-27 1996-04-02 Toyota Jidosha Kabushiki Kaisha Fe-based alloy powder and adapted for sintering, Fe-based sintered alloy having wear resistance, and process for producing the same
US5512080A (en) * 1992-11-27 1996-04-30 Toyota Jidosha Kabushiki Kaisha Fe-based alloy powder adapted for sintering, Fe-based sintered alloy having wear resistance, and process for producing the same
DE19506340A1 (en) * 1994-02-23 1995-08-24 Nissan Motor Sintered alloy used for sliding element in corrosive environments
DE19506340C2 (en) * 1994-02-23 1999-02-11 Nissan Motor Sintered alloy and method for producing a sintered body therefrom

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JPS4832708A (en) 1973-05-02

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