CA1047804A - Metal powder compositions - Google Patents
Metal powder compositionsInfo
- Publication number
- CA1047804A CA1047804A CA264,728A CA264728A CA1047804A CA 1047804 A CA1047804 A CA 1047804A CA 264728 A CA264728 A CA 264728A CA 1047804 A CA1047804 A CA 1047804A
- Authority
- CA
- Canada
- Prior art keywords
- nickel
- manganese
- mixture
- weight
- sieve
- Prior art date
- 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
Links
Classifications
-
- 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
- C22C33/0264—Making ferrous alloys by powder metallurgy characterised by the range of the alloying elements the maximum content of each alloying element not exceeding 5%
-
- 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
- C22C33/0207—Using a mixture of prealloyed powders or a master alloy
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Powder Metallurgy (AREA)
Abstract
METAL POWDER COMPOSITIONS (CASE A) ABSTRACT OF THE DISCLOSURE
Mixtures of metal powders from which ferrous metal alloy articles can be made by the process of powder metallurgy and consisting of, by weight, nickel 0.5 to 4%, manganese 0.5 to 6%, copper (if present) up to 5%, boron (if present) up to 0.4%, carbon 0.05 to 1.5 and the balance iron are modified to result in articles of improved wear resistance by adding the nickel and manganese content of the mixture solely in the form of a binary alloy having a nickel to manganese ratio by weight of 15:85 to 65:35.
Mixtures of metal powders from which ferrous metal alloy articles can be made by the process of powder metallurgy and consisting of, by weight, nickel 0.5 to 4%, manganese 0.5 to 6%, copper (if present) up to 5%, boron (if present) up to 0.4%, carbon 0.05 to 1.5 and the balance iron are modified to result in articles of improved wear resistance by adding the nickel and manganese content of the mixture solely in the form of a binary alloy having a nickel to manganese ratio by weight of 15:85 to 65:35.
Description
` 10~7~Q4 The present invention relates to improvements in the composition of metal powders from which ferrous alloy articles can be made using powder metallurgy technique~. In particular, -the invention provides a metal powder of this kind which provides articles having improved wear-resistance, -U. K Patent Specification No, 975, 322 disclose~ and claims a mixture of metal powders from which ferrou~ alloy articles catl be made by the process of powder metallurgy, the mixture con~i~ting of the following in porcentagos by weight:-Nickel 0, 5 to 6%
Copper 0, 5 to 5%
Manganes o - 0. 5 to 4~10 ~: Boron 0. 01 to 0,4%
: ~ Carbon (graphite) 0, 05 to 1. S~to 15 : ~ Iron ant usual ; ~ - impurities Balance to 100%
", ~
- The a~dition of manganese as an elemental powder in sait :
; mixture has the disad~rantage that manganese is readily oxidized and the ro~ultant oxide layer formed vn the mangane~e particles ,. ~ ,, ~ ~ is difficult to reduce, Tho boron content of the said mixture wa~
,, ~ .. -. :.
- requirod in ordor to reduce the oxide ~ince the presence of oxide :
: inhibits alloying and diffu~ion and causes a variation in the : properties, e~pecially for wear re~istance, of article~ made from ~ ; the powder mixture, However, the presence of the boron failed ; 25 ~to sati~factorily overcome this problem when articles of consistently - high wear~resi~tance were required, : ~ . ,
Copper 0, 5 to 5%
Manganes o - 0. 5 to 4~10 ~: Boron 0. 01 to 0,4%
: ~ Carbon (graphite) 0, 05 to 1. S~to 15 : ~ Iron ant usual ; ~ - impurities Balance to 100%
", ~
- The a~dition of manganese as an elemental powder in sait :
; mixture has the disad~rantage that manganese is readily oxidized and the ro~ultant oxide layer formed vn the mangane~e particles ,. ~ ,, ~ ~ is difficult to reduce, Tho boron content of the said mixture wa~
,, ~ .. -. :.
- requirod in ordor to reduce the oxide ~ince the presence of oxide :
: inhibits alloying and diffu~ion and causes a variation in the : properties, e~pecially for wear re~istance, of article~ made from ~ ; the powder mixture, However, the presence of the boron failed ; 25 ~to sati~factorily overcome this problem when articles of consistently - high wear~resi~tance were required, : ~ . ,
-2~
, . . " . . .... .. .. .. . . . . . . ..
,: . . .~ , .. , : , .
,-,, - . . , , , ,: -10478~
It has now been found that the problem~ associated with the pre~ence of manganese oxide in said mixture can be overcome and articles of improved wear-resi~tance obtained by adding the nickel and mangane~e content of the mixture 501ely in the form 5 of a binary alloy having a nickel to mangane~e ratio by weight in the range 15: 85 to 65: 35. The u~o of ~uch a binary alloy .
permits of variations in the composition of the powder mixture, including the omi~sion of boron, : According to the pre~ent invention, there is provided a mixture of metal powders from which ferrous alloy articles may be made by the process of powder metallurgy, the mixture , . .
consiqting of the following~ercentages by weigh~- :
Nickel 0, 5 to 4%
Manganese 0. 5 to 6%
~ Carbon (graphite) O. OS to 1. 5%
Copper, if present Up to 5%
Boron, if presont Up to 0, 4~o Iron and usual impurities Balanco to lOO~o wherein the nickel and manganese aro addod in the form of a - powdored binary alloy having a nickel to mangane~e ratio by - - weight in tbe range 15: 85 to 65: 3S, :
Advantageously, the mixture of the invention containY, : ~:
: ~ . - nickel, manganose and carbon in the following percontages by weight:- ~ -~,-: ~ ' , ' " ' - -.: ~ : :' ..
.~, .
., . , ~ , .,' -.
.. . .
,, - .
. . .
.,~ , ,.
' - .
~ .
... . :
1~478U4 Nickel l, 4 to 2. 8%
Manganese 2,1 to 3. 9~0 Carbon 0~ 5 to 1. 25%
It i8 preferred that, for maximum wear-resistance said elements should be present in the following percentages by weight:-Nickel 1. 9 to 2. 85to Manganese 3. 0 to 3. 9%
Carbon O. 5 to 1. 25%especially 0.65 to 1.0%
An advantage of the use Of a nickel-manganese binary - alloy as aforesaid is that alloys within the range specified are present in the liquid phase at a temperature of around 1150 C, which is a commonly used sintering temperature, and therefore readily diffuse through the sintered composition. It i9 preferred to use a nickel-manganese alloy with a nickel to manganese ratio , in the range of 20: 80 to 55: 45, which alloys are present in the; liquid phase at a temperature of 1100 C, and most preferably a -: :
continuous solubility alloy with a nickel to manganese ratio of ~-about 40: 60 is used, which alloy has a melting point of about 1025 C.
Z0 It should be understood that notwithstanding the foregoing, higher ~-sintering temperatures of up to 1350 C may be used in order to achieve higher diffusion rates.
: .
Preferably, the particle size of the binary alloy is such that all the alloy particles pass through a 200 mesh B. S, S, ~ieve.
2S lt is egpecially preferred that the components of the mixture except ~ -for the iron powder all pass through a 300 mesh B. S. S, sieve.
, ' ~ .
~4-. ~ . . .
- ' ~ , ' ~: : '. . ' .,, , 16~478~4 ~ ~
In the case of the iron powder, preferably all particle~
pas 8 through a 100 me~h B. S, S, sieve with 7 S% pas sing through a 200 mesh B. S. S, sieve and 50~o pa~sing through a 300 mesh , B, S. S. sieve.
I~ Ca~ an A~ described and claimed in our co-pending U. I~. Patent ~6~, 73~
Application No. 16670/7', it i9 especially preferred that at least 80~o of the binary alloy particles will pass through a ~25 mesh B.S.S. sieve. As explained in that Specification, thi~ selection of particle size ensure~ that the sintered product has a high retained austenite content. It has been shown that the wear-resi~tance .
of article~ made from metal powders is directly proportional to the retained austenite content and this can be explained by the fact that austenite breaks down on the application of onergy to form martensite and hence produces an incr ease in hardness.
is ~ Tho carbon is preferably added a~ fine graphite powdermlcron~sed graphite") and ie preferably added in the ~range of 0. 4 5 to 1. 5% by w oight.
Tho iron i~ preferably added as a soft powder. A small proportion of the iron content may be replaced by the ~ame weight ~ of one or more other elements which do not adversely affect the tonsilo strength and ductility of the articles produced from the powters. The amount of iron 80 replaced does not exceed 5%
. ': ' : ~ :
of the total weight of the mixture. The following is a li~t of -: - :: , . ~ ::
- element~ which may be added, the figures in bracket~ indicating : ~ . - . ~
tho upper limit:- ~
. ~. :
,: :
.: " ' : ~
.,~ , . ...
: ' ' . , ,. . . .
. .
1~4~78~
Al (1%), B (0, 3%), Cr (5~0), Mg (1%), Nb and/or Ta (4~o), P (O, 3%), Si (1%), Ti (1%), W (4%), V (0. 3%), Zr (0, 6Clo), Se (0, 6%), and Pb (0, 5), Copper may be added to the compo~ition and when 80 added is present in the range up to 5% by weight, The addition of copper has a beneficial effect on the strength of the sintered metal powder composition, but has little or no effect upon its wear-ro~i~tant characteristics, which characteristics are an important feature of the metal powder composition, The copper is prefcrably added a~ an elemental powder with a particle size preferably such that all of the powder will pass through a 100 mesh B. S. S. sieve.
.
, It is an advantage of the metal powder compo~ition according to the present invention that it is not e~sential to add boron, which acts as a flux, although this element can be added if 80 desired, ~ The boron, when added, may constitute up to 0,4% by weight of , . .
~; ; the composition, It may be introduced as ~o-called amorphous boron or in the form of one or more key alloys ~for example ferro-. boron) or in the form of one or more chemical compounds of boron : ~uch as metallic borates (for example cupric borate), The powder mixture of the pre~ent invention can be used to ~: . makc ferrous alloy articles u~ing conventional powder metallurgy - : technl~ues, Thus, after weighing out the ingredients of the metal - powder composition, the ingredients are thoroughly mixed to produce a homogenoous mixture and lubricants such a~ paraffin wax, : .
stearates or other lubricants well known in the art. may be incorporated in the desirablo proportion~, The resultant mixture is then ': - :
.
. . : . :
1~478(~4 compacted in a die under a pressure of at least fifteen tons per square inch, the c~mpact so formed ejected from the die and sintered in a protective atmosphere, preferably cracked ammonia and propane, at a temperature between 1100 C and 1350 C
for at least five minutes.
The following Examples are given to illustrate the invention, but are not intended to impose any restrictions upon the scope of the invention. All percentages given are calculated on a weight basis, and temperatures are in C.
A metal powder composition was obtained by thoroughly mixing together 4, O~o of a binary nickel manganese alloy having a nickel to manganese ratio of 40: 60, 1. O~o of elemental copper powder, 0, 8% of micronised graphite, and the balance to 100% of soft iron. The particle size of the soft iron powder was such that all of it passed through a 100 mesh B, S, S, sieve, 75% passed a 200 mesh B. S. S. sieve and 50% passed a 300 mesh B. S, S, sieve.
All the remaining ingredients were of particle aize which pas~ed through a 300 mesh B. S. S. sieve, 0. 7% of zinc stearate was added as a lubricant to the mixture.
Test pieces in the form of 1.125 inch diameter blanks were manufactured from the powder by compacting to a green density of 6, 8i gm/ cc and sintering at 1140 C for 30 minutes in a cracked ammonia and propane atmosphere, The resultant sintered blanks had an average skin hardness of the order of 210 (HV5Kg) and a mean austenite content of about 9 with a standard deviation in ' ....
'~ , ,, , , ' `
1~)478~4 content of about Z, 75, This result i8 considerably better than one would have expected frorn the prior art having regard to the fact that ~he composition included no boron as flux, S Four metal powder compositions were prepared each having the same elemental composition of 1, 6~o nickel, 2, 4%
manganese, 1, 25% carbon, 1. 0% copper and the balance iron, In each ca~e the nickel and manganese were added as a binary alloy having a nickel to manganese ratio of 40 to 60, The particle size of the binary alloy differed in each powder as will be explained below, In each case, the carbon was added as microni~ed graphite, the copper as elemlental copper and the iron a,s soft iron, The particle sizes of the graphite, copper and iro!n were as stated in Example 1, The binary alloy in Powder 1 wa~ an atomised nickel manganese powder which would not pass through a 100 mesh B, S. S. sieve. In Powder 2, the binary alloy was a milled powder with a particle size distribution such that 0, 2% of powder would!not pass through a 140 mesh B, S. S. sieve, 5. 2% would not pass through a 200 mesh B, S. S. sieve, 38. 0% would not pass through a 325 me4h B, S, S, sieve, 31, 0~o would not pass through a 400 mesh B,S,S, sieve, and25,6% would pass through a 400 mesh B, S, S. sieve, In the case of Powder 3, the binary alloy was an atomised powder with a particle size distribution such that 0.1% would not pass through a 140 mesh B. S. S. sieve, 0, 2~1o would not pass through a 200 me~h B, S, S, sieve, 10, 3~o would not pass 1~47~304 through a 325 mesh B. S. S sieve, 26, 0% would not pass through a 400 mesh B. S. S. sieve, and 63. 4% would pass through a 400 mesh B. S. S. sieve. Finally, in the case of Powder 4, the binary alloy was an atomised powder which would all pass through a 400 mesh B. S. S. sieve, which powder was obtained from Powder 3 by sieving.
Each of the powders was thoroughly mixed and 0. 7~/0 zinc stearate added to the mixture as a lubricant. 1,125 diameter blanks were made from each of the powders by compacting to a - green density of 6. 8 gm/cc and sintering at 1140 for ~S~minutes in a cracked ammonia and propane atmosphere. The test pieces were then subjected to hardness tests and an assay of the austenite content, The results are set forth in Table 1 below.
Powder No. 1 2 3 4 Average skin hardness (HV5Kg)191. 8 213. 3 229, 3 236. 6 Mean austenite content6. 578. 9615, 5 17.15 Standard deviation in austenite content 2. 63 Z, 712, 73 1. 68 - It will be seen from the results set forth in Table 1 that all of the powders had better properties than would have been predicted from the prior art having regard to the omission of boron from the compositions, However, it is apparent that the particle size of the binary alloy powder has a clear effect upon the hardness and retained austenite content (and hence upon wear-resistance), Powder 3, in which 89. 4% of the binary alloy passed through a 325 me~h B, S. S. sieve, is clearly ~uperior to Powders 1 and 2 but ~4~4 is inferior to Powder 4 which contains a binary alloy powder of which 100% will pass through a 400 mesh B, S, S, ~ieve. Not only i8 the mean austenite content of Powder 4 higher than that of Powder 3, but al~o the standard deviation is lower, that is S there i8 less variation in the value of tho austonito cuntent.
, . . " . . .... .. .. .. . . . . . . ..
,: . . .~ , .. , : , .
,-,, - . . , , , ,: -10478~
It has now been found that the problem~ associated with the pre~ence of manganese oxide in said mixture can be overcome and articles of improved wear-resi~tance obtained by adding the nickel and mangane~e content of the mixture 501ely in the form 5 of a binary alloy having a nickel to mangane~e ratio by weight in the range 15: 85 to 65: 35. The u~o of ~uch a binary alloy .
permits of variations in the composition of the powder mixture, including the omi~sion of boron, : According to the pre~ent invention, there is provided a mixture of metal powders from which ferrous alloy articles may be made by the process of powder metallurgy, the mixture , . .
consiqting of the following~ercentages by weigh~- :
Nickel 0, 5 to 4%
Manganese 0. 5 to 6%
~ Carbon (graphite) O. OS to 1. 5%
Copper, if present Up to 5%
Boron, if presont Up to 0, 4~o Iron and usual impurities Balanco to lOO~o wherein the nickel and manganese aro addod in the form of a - powdored binary alloy having a nickel to mangane~e ratio by - - weight in tbe range 15: 85 to 65: 3S, :
Advantageously, the mixture of the invention containY, : ~:
: ~ . - nickel, manganose and carbon in the following percontages by weight:- ~ -~,-: ~ ' , ' " ' - -.: ~ : :' ..
.~, .
., . , ~ , .,' -.
.. . .
,, - .
. . .
.,~ , ,.
' - .
~ .
... . :
1~478U4 Nickel l, 4 to 2. 8%
Manganese 2,1 to 3. 9~0 Carbon 0~ 5 to 1. 25%
It i8 preferred that, for maximum wear-resistance said elements should be present in the following percentages by weight:-Nickel 1. 9 to 2. 85to Manganese 3. 0 to 3. 9%
Carbon O. 5 to 1. 25%especially 0.65 to 1.0%
An advantage of the use Of a nickel-manganese binary - alloy as aforesaid is that alloys within the range specified are present in the liquid phase at a temperature of around 1150 C, which is a commonly used sintering temperature, and therefore readily diffuse through the sintered composition. It i9 preferred to use a nickel-manganese alloy with a nickel to manganese ratio , in the range of 20: 80 to 55: 45, which alloys are present in the; liquid phase at a temperature of 1100 C, and most preferably a -: :
continuous solubility alloy with a nickel to manganese ratio of ~-about 40: 60 is used, which alloy has a melting point of about 1025 C.
Z0 It should be understood that notwithstanding the foregoing, higher ~-sintering temperatures of up to 1350 C may be used in order to achieve higher diffusion rates.
: .
Preferably, the particle size of the binary alloy is such that all the alloy particles pass through a 200 mesh B. S, S, ~ieve.
2S lt is egpecially preferred that the components of the mixture except ~ -for the iron powder all pass through a 300 mesh B. S. S, sieve.
, ' ~ .
~4-. ~ . . .
- ' ~ , ' ~: : '. . ' .,, , 16~478~4 ~ ~
In the case of the iron powder, preferably all particle~
pas 8 through a 100 me~h B. S, S, sieve with 7 S% pas sing through a 200 mesh B. S. S, sieve and 50~o pa~sing through a 300 mesh , B, S. S. sieve.
I~ Ca~ an A~ described and claimed in our co-pending U. I~. Patent ~6~, 73~
Application No. 16670/7', it i9 especially preferred that at least 80~o of the binary alloy particles will pass through a ~25 mesh B.S.S. sieve. As explained in that Specification, thi~ selection of particle size ensure~ that the sintered product has a high retained austenite content. It has been shown that the wear-resi~tance .
of article~ made from metal powders is directly proportional to the retained austenite content and this can be explained by the fact that austenite breaks down on the application of onergy to form martensite and hence produces an incr ease in hardness.
is ~ Tho carbon is preferably added a~ fine graphite powdermlcron~sed graphite") and ie preferably added in the ~range of 0. 4 5 to 1. 5% by w oight.
Tho iron i~ preferably added as a soft powder. A small proportion of the iron content may be replaced by the ~ame weight ~ of one or more other elements which do not adversely affect the tonsilo strength and ductility of the articles produced from the powters. The amount of iron 80 replaced does not exceed 5%
. ': ' : ~ :
of the total weight of the mixture. The following is a li~t of -: - :: , . ~ ::
- element~ which may be added, the figures in bracket~ indicating : ~ . - . ~
tho upper limit:- ~
. ~. :
,: :
.: " ' : ~
.,~ , . ...
: ' ' . , ,. . . .
. .
1~4~78~
Al (1%), B (0, 3%), Cr (5~0), Mg (1%), Nb and/or Ta (4~o), P (O, 3%), Si (1%), Ti (1%), W (4%), V (0. 3%), Zr (0, 6Clo), Se (0, 6%), and Pb (0, 5), Copper may be added to the compo~ition and when 80 added is present in the range up to 5% by weight, The addition of copper has a beneficial effect on the strength of the sintered metal powder composition, but has little or no effect upon its wear-ro~i~tant characteristics, which characteristics are an important feature of the metal powder composition, The copper is prefcrably added a~ an elemental powder with a particle size preferably such that all of the powder will pass through a 100 mesh B. S. S. sieve.
.
, It is an advantage of the metal powder compo~ition according to the present invention that it is not e~sential to add boron, which acts as a flux, although this element can be added if 80 desired, ~ The boron, when added, may constitute up to 0,4% by weight of , . .
~; ; the composition, It may be introduced as ~o-called amorphous boron or in the form of one or more key alloys ~for example ferro-. boron) or in the form of one or more chemical compounds of boron : ~uch as metallic borates (for example cupric borate), The powder mixture of the pre~ent invention can be used to ~: . makc ferrous alloy articles u~ing conventional powder metallurgy - : technl~ues, Thus, after weighing out the ingredients of the metal - powder composition, the ingredients are thoroughly mixed to produce a homogenoous mixture and lubricants such a~ paraffin wax, : .
stearates or other lubricants well known in the art. may be incorporated in the desirablo proportion~, The resultant mixture is then ': - :
.
. . : . :
1~478(~4 compacted in a die under a pressure of at least fifteen tons per square inch, the c~mpact so formed ejected from the die and sintered in a protective atmosphere, preferably cracked ammonia and propane, at a temperature between 1100 C and 1350 C
for at least five minutes.
The following Examples are given to illustrate the invention, but are not intended to impose any restrictions upon the scope of the invention. All percentages given are calculated on a weight basis, and temperatures are in C.
A metal powder composition was obtained by thoroughly mixing together 4, O~o of a binary nickel manganese alloy having a nickel to manganese ratio of 40: 60, 1. O~o of elemental copper powder, 0, 8% of micronised graphite, and the balance to 100% of soft iron. The particle size of the soft iron powder was such that all of it passed through a 100 mesh B, S, S, sieve, 75% passed a 200 mesh B. S. S. sieve and 50% passed a 300 mesh B. S, S, sieve.
All the remaining ingredients were of particle aize which pas~ed through a 300 mesh B. S. S. sieve, 0. 7% of zinc stearate was added as a lubricant to the mixture.
Test pieces in the form of 1.125 inch diameter blanks were manufactured from the powder by compacting to a green density of 6, 8i gm/ cc and sintering at 1140 C for 30 minutes in a cracked ammonia and propane atmosphere, The resultant sintered blanks had an average skin hardness of the order of 210 (HV5Kg) and a mean austenite content of about 9 with a standard deviation in ' ....
'~ , ,, , , ' `
1~)478~4 content of about Z, 75, This result i8 considerably better than one would have expected frorn the prior art having regard to the fact that ~he composition included no boron as flux, S Four metal powder compositions were prepared each having the same elemental composition of 1, 6~o nickel, 2, 4%
manganese, 1, 25% carbon, 1. 0% copper and the balance iron, In each ca~e the nickel and manganese were added as a binary alloy having a nickel to manganese ratio of 40 to 60, The particle size of the binary alloy differed in each powder as will be explained below, In each case, the carbon was added as microni~ed graphite, the copper as elemlental copper and the iron a,s soft iron, The particle sizes of the graphite, copper and iro!n were as stated in Example 1, The binary alloy in Powder 1 wa~ an atomised nickel manganese powder which would not pass through a 100 mesh B, S. S. sieve. In Powder 2, the binary alloy was a milled powder with a particle size distribution such that 0, 2% of powder would!not pass through a 140 mesh B, S. S. sieve, 5. 2% would not pass through a 200 mesh B, S. S. sieve, 38. 0% would not pass through a 325 me4h B, S, S, sieve, 31, 0~o would not pass through a 400 mesh B,S,S, sieve, and25,6% would pass through a 400 mesh B, S, S. sieve, In the case of Powder 3, the binary alloy was an atomised powder with a particle size distribution such that 0.1% would not pass through a 140 mesh B. S. S. sieve, 0, 2~1o would not pass through a 200 me~h B, S, S, sieve, 10, 3~o would not pass 1~47~304 through a 325 mesh B. S. S sieve, 26, 0% would not pass through a 400 mesh B. S. S. sieve, and 63. 4% would pass through a 400 mesh B. S. S. sieve. Finally, in the case of Powder 4, the binary alloy was an atomised powder which would all pass through a 400 mesh B. S. S. sieve, which powder was obtained from Powder 3 by sieving.
Each of the powders was thoroughly mixed and 0. 7~/0 zinc stearate added to the mixture as a lubricant. 1,125 diameter blanks were made from each of the powders by compacting to a - green density of 6. 8 gm/cc and sintering at 1140 for ~S~minutes in a cracked ammonia and propane atmosphere. The test pieces were then subjected to hardness tests and an assay of the austenite content, The results are set forth in Table 1 below.
Powder No. 1 2 3 4 Average skin hardness (HV5Kg)191. 8 213. 3 229, 3 236. 6 Mean austenite content6. 578. 9615, 5 17.15 Standard deviation in austenite content 2. 63 Z, 712, 73 1. 68 - It will be seen from the results set forth in Table 1 that all of the powders had better properties than would have been predicted from the prior art having regard to the omission of boron from the compositions, However, it is apparent that the particle size of the binary alloy powder has a clear effect upon the hardness and retained austenite content (and hence upon wear-resistance), Powder 3, in which 89. 4% of the binary alloy passed through a 325 me~h B, S. S. sieve, is clearly ~uperior to Powders 1 and 2 but ~4~4 is inferior to Powder 4 which contains a binary alloy powder of which 100% will pass through a 400 mesh B, S, S, ~ieve. Not only i8 the mean austenite content of Powder 4 higher than that of Powder 3, but al~o the standard deviation is lower, that is S there i8 less variation in the value of tho austonito cuntent.
Claims (11)
1. In a mixture of metal powders from which ferrous alloy articles may be made by the process of powder metallurgy, the mixture consisting of the following in percentages by weight:-Nickel 0.5 to 4%
Manganese 0.5 to 6%
Carbon (graphite) 0.05 to 1.5%
Copper, if present Up to 5%
Boron, if present Up to 0.4%
Iron and usual impurities Balance to 100%
the improvement consisting in that the nickel and manganese are in the form of a powdered binary alloy having a nickel to manganese ratio by weight in the range 15:85 to 65:35.
Manganese 0.5 to 6%
Carbon (graphite) 0.05 to 1.5%
Copper, if present Up to 5%
Boron, if present Up to 0.4%
Iron and usual impurities Balance to 100%
the improvement consisting in that the nickel and manganese are in the form of a powdered binary alloy having a nickel to manganese ratio by weight in the range 15:85 to 65:35.
2. The mixture according to Claim 1, wherein the nickel, manganese and carbon are present in the following percentages by weight:-Nickel 1.4 to 2.8%
Manganese 2.1 to 3.9%
Carbon 0.5 to 1.25%
Manganese 2.1 to 3.9%
Carbon 0.5 to 1.25%
3. The mixture according to Claim 2, wherein said elements are present in the following percentages by weight:-Nickel 1.9 to 2.8%
Manganese 3.0 to 3.9%
Carbon 0.5 to 1.25%
Manganese 3.0 to 3.9%
Carbon 0.5 to 1.25%
4. The mixture according to Claim 3, wherein the carbon content is 0.65to 1% by weight.
5. The mixture according to Claim 1 wherein the nickel to manganese ratio in the binary alloy is in the range 20 : 80 to 55 : 45 by weight.
6. The mixture according to Claim 5, wherein the said alloy is a continuous solubility alloy having a nickel to manganese ratio of about 40 : 60 by weight.
7. The mixture according to Claim 1, wherein the particle size of the binary alloy is such that all the alloy powder passes through a 200 mesh B.S.S. sieve.
8. The mixture according to Claim 7, wherein all of the components of the mixture other than the iron powder pass through a 300 mesh B.S.S. sieve.
9. The mixture according to Claim 8, wherein the iron is a soft iron having particles all passing through a 100 mesh B.S.S.
sieve with 75% passing through a 200 mesh B.S.S. sieve and 50%
passing through a 300 mesh B.S.S. sieve.
sieve with 75% passing through a 200 mesh B.S.S. sieve and 50%
passing through a 300 mesh B.S.S. sieve.
10. The mixture according to Claim 1, wherein the carbon is present in the form of micronised graphite with the carbon content of the mixture in the range 0.45 to 1.5%.
11. The mixture according to Claim 1, wherein an amount of the iron content not exceeding 5% of the total mixture has been replaced by one or more elements which do not adversely affect the tensile strength and ductility of the resultant articles obtained by powder metallurgy.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB46671/75A GB1541006A (en) | 1975-11-12 | 1975-11-12 | Metal powder compositions |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1047804A true CA1047804A (en) | 1979-02-06 |
Family
ID=10442146
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA264,728A Expired CA1047804A (en) | 1975-11-12 | 1976-11-02 | Metal powder compositions |
Country Status (9)
| Country | Link |
|---|---|
| BE (1) | BE848189A (en) |
| BR (1) | BR7607618A (en) |
| CA (1) | CA1047804A (en) |
| CH (1) | CH617371A5 (en) |
| DE (1) | DE2651251A1 (en) |
| FR (1) | FR2331406A1 (en) |
| GB (1) | GB1541006A (en) |
| IT (1) | IT1066736B (en) |
| ZA (1) | ZA766516B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4170474A (en) * | 1978-10-23 | 1979-10-09 | Pitney-Bowes | Powder metal composition |
| USRE30855E (en) | 1978-10-23 | 1982-01-26 | Pitney Bowes Inc. | Powder metal composition |
| CA1166043A (en) * | 1979-08-20 | 1984-04-24 | Yew-Tsung Chen | Process for producing a powder metal part |
| JPS599152A (en) * | 1982-07-06 | 1984-01-18 | Nissan Motor Co Ltd | Wear-resistant sintered alloy |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1449809A (en) * | 1972-11-27 | 1976-09-15 | Fischmeister H | Forging of metal powders |
-
1975
- 1975-11-12 GB GB46671/75A patent/GB1541006A/en not_active Expired
-
1976
- 1976-10-29 ZA ZA766516A patent/ZA766516B/en unknown
- 1976-11-02 CA CA264,728A patent/CA1047804A/en not_active Expired
- 1976-11-09 FR FR7633682A patent/FR2331406A1/en active Granted
- 1976-11-10 DE DE19762651251 patent/DE2651251A1/en not_active Withdrawn
- 1976-11-10 BE BE172234A patent/BE848189A/en unknown
- 1976-11-10 CH CH1415376A patent/CH617371A5/en not_active IP Right Cessation
- 1976-11-10 IT IT52107/76A patent/IT1066736B/en active
- 1976-11-11 BR BR7607618A patent/BR7607618A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| ZA766516B (en) | 1977-10-26 |
| BR7607618A (en) | 1977-09-27 |
| FR2331406A1 (en) | 1977-06-10 |
| DE2651251A1 (en) | 1977-05-26 |
| BE848189A (en) | 1977-05-10 |
| FR2331406B1 (en) | 1982-01-15 |
| IT1066736B (en) | 1985-03-12 |
| GB1541006A (en) | 1979-02-21 |
| CH617371A5 (en) | 1980-05-30 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5108493A (en) | Steel powder admixture having distinct prealloyed powder of iron alloys | |
| US4913739A (en) | Method for powder metallurgical production of structural parts of great strength and hardness from Si-Mn or Si-Mn-C alloyed steels | |
| EP0813617B1 (en) | Stainless steel powders and articles produced therefrom by powder metallurgy | |
| US4344795A (en) | Iron-based sintered sliding product | |
| JP2012513541A (en) | Method for producing diffusion-alloyed iron or iron-based powder, diffusion-alloyed powder, composition comprising the diffusion-alloyed powder, and molded and sintered parts produced from the composition | |
| US20080075968A1 (en) | Metallurgical powder composition and method of production | |
| US4799955A (en) | Soft composite metal powder and method to produce same | |
| US4098608A (en) | Metal powder compositions | |
| US5217683A (en) | Steel powder composition | |
| US5969276A (en) | Manganese containing materials having high tensile strength | |
| CA1047804A (en) | Metal powder compositions | |
| US4343650A (en) | Metal binder in compaction of metal powders | |
| JP4201830B2 (en) | Iron-based powder containing chromium, molybdenum and manganese and method for producing sintered body | |
| US5556446A (en) | Machinable brass compositions | |
| US4702772A (en) | Sintered alloy | |
| US4915735A (en) | Wear-resistant sintered alloy and method for its production | |
| US4130422A (en) | Copper-base alloy for liquid phase sintering of ferrous powders | |
| US4015947A (en) | Production of sintered aluminum alloy articles from particulate premixes | |
| JP2022109749A (en) | Multi-component alloyed powder | |
| JP2001131660A (en) | Alloy powder for copper series high strength sintered parts | |
| JP3347773B2 (en) | Pure iron powder mixture for powder metallurgy | |
| JPH05302101A (en) | Mixed powder for powder metallurgy/and its sintered compact | |
| JPS61117202A (en) | Low alloy iron powder for sintering | |
| JPH0629441B2 (en) | Fe-Ni-B alloy powder for sintering addition and sintering method | |
| AT234741B (en) | Powder mixture for the production of objects from sintered nickel-manganese steel using powder metallurgy |