GB1580686A - Sintered piston rings sealing rings and processes for their manufacture - Google Patents

Sintered piston rings sealing rings and processes for their manufacture Download PDF

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Publication number
GB1580686A
GB1580686A GB1376A GB1376A GB1580686A GB 1580686 A GB1580686 A GB 1580686A GB 1376 A GB1376 A GB 1376A GB 1376 A GB1376 A GB 1376A GB 1580686 A GB1580686 A GB 1580686A
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United Kingdom
Prior art keywords
copper
ring
sintered
piston
rings
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
GB1376A
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Federal Mogul Coventry Ltd
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Brico Engineering Ltd
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Filing date
Publication date
Application filed by Brico Engineering Ltd filed Critical Brico Engineering Ltd
Priority to GB1376A priority Critical patent/GB1580686A/en
Publication of GB1580686A publication Critical patent/GB1580686A/en
Expired legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16J—PISTONS; CYLINDERS; SEALINGS
    • F16J9/00—Piston-rings, e.g. non-metallic piston-rings, seats therefor; Ring sealings of similar construction
    • F16J9/26—Piston-rings, e.g. non-metallic piston-rings, seats therefor; Ring sealings of similar construction characterised by the use of particular materials
    • 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
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16J—PISTONS; CYLINDERS; SEALINGS
    • F16J15/00—Sealings
    • F16J15/16—Sealings between relatively-moving surfaces
    • F16J15/34—Sealings between relatively-moving surfaces with slip-ring pressed against a more or less radial face on one member
    • F16J15/3496—Sealings between relatively-moving surfaces with slip-ring pressed against a more or less radial face on one member use of special materials

Description

(54) SINTERED PISTON RINGS, SEALING RINGS AND PROCESSES FOR THEIR MANUFACTURE (71) We, BRICO ENGINERING LIMITED, a British Company of Holbrook Lane, Coventry CV6 4BG, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to sintered piston rings, sealing rings and processes for their manufacture.
According to the present invention in one aspect, there is provided a piston ring or sealing ring made of sintered metal and having a composition within the range, in percentages by weight: combined carbon 0.5 - 2.0%; copper 0 - 25%; molybdenum 0.2 3.0%; manganese. silicon, sulphur, phosphorus and other trace elements up to 2.0% in total; balance iron.
According to a feature of the invention, one preferred composition is within the range, in percentages by weight: combined carbon 0.5 - 0.9%; copper 2.0 - 6.0%; molybdenum 0.4 0.8%; manganese. silicon, sulphur, phosphorus and other trace elements up to 2.0% in total; balance iron.
According to another feature of the invention, another preferred composition is within the range, in percentages by weight: combined carbon 0.9 - 1.2%; copper 2.0 - 6.0%; molybdenum 0.4 - 0.8C/c; manganese, silicon, sulphur, phosphorus and other trace elements up to 2.ouzo in total; balance iron.
According to the invention in another aspect, a process for the manufacture of piston rings or sealing rings of sintered metal includes the steps of selecting powders to give an article having the composition: combined carbon 0.5 - 2.0%; copper 0 - 106sic; molybdenum 0.2 - 3.0%; manganese. silicon. sulphur, phosphorus and other trace elements up to 2% in total; balance iron; compacting the powder together with a powder lubricant to form compacts, and sintering the compacts at a temperature of at least 1050"C in a protective atmosphere such as to avoid loss of carbon or oxidation of the compacts.
According to a feature of this aspect of the invention, such a process may include the step of filling or partially filling the pores of the sintered compact with copper or with a copper ally to give a copper content up to a maximum of 25% (including the infiltrant).
According to another feature of this aspect. a copper or copper alloy powder is compacted and passed through the sintering furnace in contact with the previously sintered ferrous compact.
By a sealing ring is meant a ring which co-operates with two parts having very limited relative movement between them, such as movement due to relative thermal expansion, or a ring which co-operates with two relatively rotatable parts, in both cases to reduce leakage between the parts, in a comparable manner to the way that a piston ring reduces leakage between relatively reciprocable parts.
According to a feature of this aspect of the invention the process may include the filling or partial filling of the pores of the sintered compact with copper or with a copper alloy to give a maximum copper content of 25% (including that df the skeleton and the infiltrant).
This may be effected by separately compacting a copper or copper alloy powder to form a compact which is then passed through the sintering furnace in contact with the ferrous compact, which optionally may have been previously sintered; alternatively the infiltration and sintering may take place simultaneously. In these cases the sintering temperature must exceed the melting point of the copper (1083"C) or of the copper alloy. This technique is called infiltration and is well known to those in the field of powder metallurgy. The copper content of the resulting article may then be up to 25% by weight of the article.
The sintered article resulting from the above process may be susequently machined to the desired dimensions. Other secondary treatments, including heat-treatment, surface coating or secondary pressing, may be applied to the article. The presence of molybdenum within the limits stated confers enhanced response to heat-treatment by quenching, and added resistance at service temperatures which would otherwise cause tempering and loss of hardness.
A number of specific examples will now be described.
Metal powders essentially of less than 150 microns in size were selected as examples 1-9.
These powders, plus a suitable lubricant, were pressed in a suitable powder metallurgy press with the pressure given in the example, to form different articles as described below, the pressing resulting in compacts having the values of density given in Tables 1A and 1B.
The compacts were then sintered at the temperature given in a protective atmosphere such as to avoid loss of carbon, or oxidation of the compact. Example 1 was sintered in an atmosphere of endothermic gas having a dew point of -10 C, e.g., partially combusted hydrocarbon air mixture (the hydrocarbon may be propane).
Example 2 was sintered in an atmosphere of similar endothermic gas but having a dew point of -15 C.
Example 3 was sintered in a similar atmosphere but having a dew point of -18 C.
It will be understood that the atmosphere must have a high carbon potential so that the atmosphere is in equilibrium with the carbon content of the compact, so that the latter does not decarburize considerably during sintering; for example, using the same endothermic gas but with a dew point of 0 C would give a carbon potential which was too low, resulting in decarburization of the compact.
Instead of endothermic gas, other atmospheres may be used, e.g. cracked ammonia, having a dew point of -35"C. or dry hydrogen, having a dew point of -60 C, (these should be so chosen as to give no significant decarburization of the compact).
The composition of each example is given in Tables 1A and 1B.
TABLE 1A Example 1 2 3 4 Combined carbon 0.7 1.0 1.2 1.5 1.2 Copper 4.0 3.0 5.0 6.0 Molybdenum 0.6 0.7 0.5 1.1 0.43 Manganese, Silicon. Sulphur ) 1.0 2.() 0.3 0.5 ().26 & Phosphorus ) Iron 93.7 93.3 93.0 90.9 80.1 tons/sq. in. 30 35 40 40 4() density gm/cc 6.6 6.7 6.7 6.9 7.5 sintering Temp. "C. 1110 1085 1100 llI() 1105 * Example 5 was obtained by copper infiltration of example 3.
13% Copper was added by infiltration.
TABLE 1B Example 6 7 8 9 Combined carbon 0.5 0.9 0.9 2.0 Copper 0 6.0 10.0 5.0 Molybdenum 0.2 0.8 0.6 3.0 Manganese Silicon, Sulphur ) 0.1 2.0 1.0 0 & Phosphorus ) Iron 99.2 90.3 93.5 92.3 tons/sq. in. 35 30 35 35 density gm/cc 6.7 6.6 6.6 6.7 sintering Temp. "C 1090 1110 1090 1090 Example 1 was pressed to form a sealing ring. The sintered blank was machined to give the finished dimensions. The sealing ring was tested and had a Vickers hardness of 150, a ring tensile strength of 525MN/m2, and an Elasticity number of 118 GN/m Example 2 was pressed to form a automotive piston ring and machined after sintering.
The piston ring had a Vickers hardness HVs of 180, a ring tensile strength of 433 MN/m-, and an Elasticity Number of 125 GN/m2.
Examples 3, 4 and 5 were pressed to form valve seat inserts. After sintering, sharp edges were removed by barrelling and the outside diameter was machined. Example 3 had an average Vickers hardness HV5 of 20, and a 0.1% proof stress in compression of 540 MN/m2.
Example 4 had a Vickers hardness HV5 of 250 and a 0.1% proof stress in compression of 570 MN/m2. Example 5 had a Vickers hardness HVs of 310 and a 0.1% proof stress in compression of 560 MN/m2. Examples 6, 7. 8 and 9 had physical characteristics similar to those of Examples 1, 2, 3 and 4 respectively.
Comparative wear tests were also carried out between example 2 on the one hand, and typical grey cast iron piston ring material on the other. Piston rings made of the respective materials were bench tested for 500 hours in a number of 950 cc 4 cylinder engines.
The average diametral wear of the piston rings in the engines having the material of the composition of example 2 was 0.00052 inches, whereas the average wear of the piston rings in the engines having grey cast iron piston rings was 0.00195 inches at the end of the test.
Thus it will be seen that the sintered piston rings had only about one quarter of the wear of the cast iron piston rings under the same conditions.
WHAT WE CLAIM IS: 1. A piston ring or sealing ring made of sintered metal and having a composition within the range, in percentages by weight:- combined carbon 0.5 - 2.0%; copper 0 - 25%; molybdenum 0.2 - 3.0%; manganese, silicon, sulphur, phosphorus and other trace elements up to 2.0% in total; balance iron.
2. A piston ring or sealing ring as claimed in claim 1 and having a composition within the range, in percentages by weight:- combined carbon 0.5 - 0.9%; copper 2.0 - 6.0% molybdenum 0.4 - 0.8%; manganese, silicon, sulphur, phosphorus and other trace elements up to 2.0ago in total; balance iron.
3. A piston ring or sealing ring as claimed in claim 1 and having a composition within the range. in percentages by weight:- combined carbon 0.9 - 1.2%; copper 2.0 - 6.0CHo molybdenum 0.4 - 0.86sic; manganese. silicon, sulphur. phosphorus and other trace elements up to 2.0% in total; balance iron.
4. A process for the manufacture of piston rings or sealing rings of sintered metal, including the steps of selecting powders to give an article having the composition:combined carbon 0.5 - 2.0% copper 0 - 106/c; molybdenum 0.2 - 3.OC/o; manganese, silicon, sulphur, phosphorus and other trace elements up to 2% in total; balance iron; compacting the powder together with a powder lubricant to form compacts. and sintering the compacts at a temperature of at least 1050"C in a protective atmosphere such as to avoid loss of carbon or oxidation of the compacts.
5. A process as claimed in claim 4 including the step of filling or partially filling the pores of the sintered compact with copper or with a copper alloy to give a copper content up to a maximum of 256sic (including the copper content both of the sintered compact and the infiltrant.
6. A process as claimed in claim 6 in which a copper or copper alloy powder is compacted and passed through the sintering furnace in contact with the previously sintered ferrous compact.
7. A process as claimed in any of claims 4, 5 and 6 in which the protective atmosphere is
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (13)

**WARNING** start of CLMS field may overlap end of DESC **. TABLE 1B Example 6 7 8 9 Combined carbon 0.5 0.9 0.9 2.0 Copper 0 6.0 10.0 5.0 Molybdenum 0.2 0.8 0.6 3.0 Manganese Silicon, Sulphur ) 0.1 2.0 1.0 0 & Phosphorus ) Iron 99.2 90.3 93.5 92.3 tons/sq. in. 35 30 35 35 density gm/cc 6.7 6.6 6.6 6.7 sintering Temp. "C 1090 1110 1090 1090 Example 1 was pressed to form a sealing ring. The sintered blank was machined to give the finished dimensions. The sealing ring was tested and had a Vickers hardness of 150, a ring tensile strength of 525MN/m2, and an Elasticity number of 118 GN/m Example 2 was pressed to form a automotive piston ring and machined after sintering. The piston ring had a Vickers hardness HVs of 180, a ring tensile strength of 433 MN/m-, and an Elasticity Number of 125 GN/m2. Examples 3, 4 and 5 were pressed to form valve seat inserts. After sintering, sharp edges were removed by barrelling and the outside diameter was machined. Example 3 had an average Vickers hardness HV5 of 20, and a 0.1% proof stress in compression of 540 MN/m2. Example 4 had a Vickers hardness HV5 of 250 and a 0.1% proof stress in compression of 570 MN/m2. Example 5 had a Vickers hardness HVs of 310 and a 0.1% proof stress in compression of 560 MN/m2. Examples 6, 7. 8 and 9 had physical characteristics similar to those of Examples 1, 2, 3 and 4 respectively. Comparative wear tests were also carried out between example 2 on the one hand, and typical grey cast iron piston ring material on the other. Piston rings made of the respective materials were bench tested for 500 hours in a number of 950 cc 4 cylinder engines. The average diametral wear of the piston rings in the engines having the material of the composition of example 2 was 0.00052 inches, whereas the average wear of the piston rings in the engines having grey cast iron piston rings was 0.00195 inches at the end of the test. Thus it will be seen that the sintered piston rings had only about one quarter of the wear of the cast iron piston rings under the same conditions. WHAT WE CLAIM IS:
1. A piston ring or sealing ring made of sintered metal and having a composition within the range, in percentages by weight:- combined carbon 0.5 - 2.0%; copper 0 - 25%; molybdenum 0.2 - 3.0%; manganese, silicon, sulphur, phosphorus and other trace elements up to 2.0% in total; balance iron.
2. A piston ring or sealing ring as claimed in claim 1 and having a composition within the range, in percentages by weight:- combined carbon 0.5 - 0.9%; copper 2.0 - 6.0% molybdenum 0.4 - 0.8%; manganese, silicon, sulphur, phosphorus and other trace elements up to 2.0ago in total; balance iron.
3. A piston ring or sealing ring as claimed in claim 1 and having a composition within the range. in percentages by weight:- combined carbon 0.9 - 1.2%; copper 2.0 - 6.0CHo molybdenum 0.4 - 0.86sic; manganese. silicon, sulphur. phosphorus and other trace elements up to 2.0% in total; balance iron.
4. A process for the manufacture of piston rings or sealing rings of sintered metal, including the steps of selecting powders to give an article having the composition:combined carbon 0.5 - 2.0% copper 0 - 106/c; molybdenum 0.2 - 3.OC/o; manganese, silicon, sulphur, phosphorus and other trace elements up to 2% in total; balance iron; compacting the powder together with a powder lubricant to form compacts. and sintering the compacts at a temperature of at least 1050"C in a protective atmosphere such as to avoid loss of carbon or oxidation of the compacts.
5. A process as claimed in claim 4 including the step of filling or partially filling the pores of the sintered compact with copper or with a copper alloy to give a copper content up to a maximum of 256sic (including the copper content both of the sintered compact and the infiltrant.
6. A process as claimed in claim 6 in which a copper or copper alloy powder is compacted and passed through the sintering furnace in contact with the previously sintered ferrous compact.
7. A process as claimed in any of claims 4, 5 and 6 in which the protective atmosphere is
an atmosphere of endothermic gas having a dew point in the range -10 to -18"C.
8. A process as claimed in claim 7 wherein the combined carbon content is 0.7% and the endothermic gas has a dew point of about -10 C.
9. A process as claimed in claim 7 wherein the combined carbon content is 1.0% and the endothermic gas has a dew point of about -15 C.
10. A process as claimed in claim 7 wherein the combined carbon content is 1.2% and the endothermic gas has a dew point of about -18 C.
11. A process as claimed in any of claims 4, 5 and 6 in which the protective atmosphere is of cracked ammonia or dry hydrogen.
12. A piston ring or sealing ring as claimed in claim 1 and substantialy as hereinbefore described with reference to any of examples 1, 2, 6 and 7.
13. A process for the manufacture of piston rings or sealing rings as claimed in claim 4 and substantially as hereinbefore described with reference to any of examples 1, 2, 6 and 7.
GB1376A 1976-01-02 1976-01-02 Sintered piston rings sealing rings and processes for their manufacture Expired GB1580686A (en)

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Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2176803A (en) * 1985-06-17 1987-01-07 Nippon Piston Ring Co Ltd Iron base wear resistant sintered alloy
GB2189812A (en) * 1986-04-11 1987-11-04 Nippon Piston Ring Co Ltd Assembled cam shaft
GB2215735A (en) * 1988-02-09 1989-09-27 Ovako Steel Ab Steel intended for highly stressed structural members with high demands for ductility and fatigue resistance, and the use thereof
EP0435019A1 (en) * 1989-12-20 1991-07-03 Etablissement Supervis Workpiece, especially cam from sintered powder metal alloy and process for preparing same
US5346529A (en) * 1992-03-23 1994-09-13 Tecsyn Pmp, Inc. Powdered metal mixture composition
EP2870328B1 (en) 2012-07-04 2016-11-16 Bleistahl-Produktions GmbH & Co KG. Highly thermally conductive valve seat ring
CN107520451A (en) * 2017-08-02 2017-12-29 宁波瑞丰汽车零部件有限公司 A kind of shock absorber piston and its preparation technology

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2176803A (en) * 1985-06-17 1987-01-07 Nippon Piston Ring Co Ltd Iron base wear resistant sintered alloy
GB2189812A (en) * 1986-04-11 1987-11-04 Nippon Piston Ring Co Ltd Assembled cam shaft
GB2189812B (en) * 1986-04-11 1989-12-28 Nippon Piston Ring Co Ltd Assembled cam shaft
US5007956A (en) * 1986-04-11 1991-04-16 Nippon Piston Ring Co., Ltd. Assembled cam shaft
GB2215735A (en) * 1988-02-09 1989-09-27 Ovako Steel Ab Steel intended for highly stressed structural members with high demands for ductility and fatigue resistance, and the use thereof
GB2215735B (en) * 1988-02-09 1991-11-27 Ovako Steel Ab Highly stressed steel structural members with high demands for ductility and f atigue resistance and the use thereof
US5122337A (en) * 1988-02-09 1992-06-16 Ovako Steel, Ab Steel intended for highly stressed structural members with high demands for ductility and fatigue resistance
EP0435019A1 (en) * 1989-12-20 1991-07-03 Etablissement Supervis Workpiece, especially cam from sintered powder metal alloy and process for preparing same
US5346529A (en) * 1992-03-23 1994-09-13 Tecsyn Pmp, Inc. Powdered metal mixture composition
US5466414A (en) * 1992-03-23 1995-11-14 Tecsyn, Inc. Process for fabrication of sintered metal components
EP2870328B1 (en) 2012-07-04 2016-11-16 Bleistahl-Produktions GmbH & Co KG. Highly thermally conductive valve seat ring
CN107520451A (en) * 2017-08-02 2017-12-29 宁波瑞丰汽车零部件有限公司 A kind of shock absorber piston and its preparation technology

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PE20 Patent expired after termination of 20 years

Effective date: 19970331