CA1038205A - Low expansion iron-nickel based alloys - Google Patents
Low expansion iron-nickel based alloysInfo
- Publication number
- CA1038205A CA1038205A CA191,069A CA191069A CA1038205A CA 1038205 A CA1038205 A CA 1038205A CA 191069 A CA191069 A CA 191069A CA 1038205 A CA1038205 A CA 1038205A
- Authority
- CA
- Canada
- Prior art keywords
- cast
- nickel
- titanium
- cobalt
- alloy
- 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
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/10—Ferrous alloys, e.g. steel alloys containing cobalt
- C22C38/105—Ferrous alloys, e.g. steel alloys containing cobalt containing Co and Ni
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Turbine Rotor Nozzle Sealing (AREA)
- Heat Treatment Of Articles (AREA)
- Moulds For Moulding Plastics Or The Like (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
Low expansion alloys consisting essentially of Ni-Fe-Ti and optionally containing Co and/or Nb are provided which in the as-cast, age hardened condition have a thermal expansion coefficient between 20 and 300°C of less than 6 x 10-6/°C
and a 0.2% proof stress at 20°C higher than 350 N/mm2.
Low expansion alloys consisting essentially of Ni-Fe-Ti and optionally containing Co and/or Nb are provided which in the as-cast, age hardened condition have a thermal expansion coefficient between 20 and 300°C of less than 6 x 10-6/°C
and a 0.2% proof stress at 20°C higher than 350 N/mm2.
Description
103~Z05 BACKGROUND~OF THE INVENTION
This invention relates to low-expansion nickel-iron alloys and is concerned with the provision of such an alloy which in the cast form has high strength and low thermal expansion char-acteristics at service temperatures.
It is known that certain nickel-iron alloys have a remarkably low coefficient of thermal expansion such as, for example, an alloy of 36% nickel and 64% iron known under the trade name "Invar"
which has a coefficient of thermal expansion approaching zero over the temperature range O to around 200 C. A major problem with low-expansion nickel-iron alloys is their low strength. One method by which the strength of such alloys can be increased is by the addition of elements such as aluminum, titanium or niobium, and a subsequent ageing treatment.
Titanium has generally been added in amount of between 0.75% and 2.5% by weight to increase the strength of wrought alloys, and we have found that to achieve an increase in strength to comparable levels in cast alloys requires the addition of rather more titanium, that is, between 1.5 and 5% titanium by weight. However, as is well known, the increase in strength resulting from titanium additions is achieved at the expense of the low coefficient of thermal expansion which is increased in proportion to the increasing titanium content I of the alloy.
! Surprisingly we have now found that an optimum balance between high strength and a low coefficient of thermal expansion at temperatures in the range of 20 to 300 C can be achieved in a cast and aged nickel-iron alloy strengthened with titanium, by correlating the nickel and titanium contents and optional cobalt and niobium contents according to a specific relationship.
,,~
,~ . , .
103~05 It ls an ob~ect of the present invention to provide im-proved age-hardened iron-nickel-titanium alloys with predetermined low expansion characteristics whicll have high mechanical strength.
It is another object of this invention to provide low expansion iron-nickel-titanium alloys which may contain cobalt, and/or niobium and in which concentrations of nickel, cobalt, titanium and niobium are controlled and correlated.
It is a further obJect to provide low expansion iron-nickel-titanium alloys having in the as-cast and aged condition a thermal expansion coefficient between 20 and 300C of less than about 6 x 10 6/oC and preferably less than about 5 x 10 6/oC, and a 0.2%
proof stress at 20C higher than about 350N/n~ .
A still further object is to provide an alloy having low expansivity and high strength at working temperatures - which can be cast directly into intricately-shaped castings with good surface properties.
The invention also contemplates providing stnlctural com-ponents of machinery, for example turbine shafts and blades, in which close dimensional tolerances must be maintained at temperatures up to about 500C, made of cast, age-hardenable alloys.
Other objects and advantages will become apparent from the following description and examples.
THE INVENIION
According to one aspect of the invention there is provided an alloy which, when in the as-cast and aged condition, has a thermal expansion coefficient between 20 and 300C of less than 6 x 10 6/oC and a 0.2% proof stress at 20C higher than 350 N/mm (Newtons per square millimeter), comprising by weight up to about 47%, e.g. from about 27 to about 47% nickel, from above 5% to about 16% cobalt, from about 1 to about 4% titanium, up to about 1.5~ niobium, the contents of nickel, cobalt, titanium and niobium being such that:
~03~Z05 %Ni + 0.7(%Co) - 1.25 [%Ti + 0.35(%Nb)] - 2 (%Ti) / (%Ti + ~Nb) = 37 to ~0, and the balance, apart from impurities and residual elements, being essentially iron.
According to another aspect of the invention there is provided an alloy which, when in the as-cast and aged condition, has a thermal expansion coefficient between 20 and 30QC of less than 5 x 10 /C and a 0.2% proof stress at 20C higher than 350N/mm , comprising by weight up to about 47%, e.g. from about 27 to about 47%
nickel, from above 5% to about 16% cobalt, from about 1 to about 4 titanium, up to about 1.5% niobium, the contents of nickel, cobalt, titanium and niobium being such that:
%Ni + 0.7 (%Co) - 1.25 [%Ti + 0.35(%Nb)~ - 2 (%Ti)/~%Tî + ~Nb?
= 37 to 39, and the balance, apart from impurities and residual elements, being essentially iron.
Alloys according to the invention may also contain by weight, up to about 1%, e.g. up to about 0.3% silicon, up to about a. 4% manganese and up to about 0.2% aluminum and not more than about 0.1% carbon. The presence of silicon, manganese and/or aluminum is particularly beneficial when the alloys are to be produced by melting in air.
The attainment of high strength in alloys according to the invention depends upon precipitation hardening by the formation of a precipitate, Ni3(Ti), when ageing the alloy at elevated temperature.
The ageing treatment preferably carried out in the temperature range 550 to 700C, with the optimum temperature being dependent upon the titanium content of the alloy. For lower levels of titanium content, optimum properties may be achieved after heat treating at the lower end of the temperature range, e.g. 575 to 625C for about 24 hours, whereas for higher levels of titanium content, a heat treatment of about 24 hours at the higher end of the temperature range e.g. 625 to 675C, may give optimum properties.
. ., ,~
~- - 3 -1~3~ZOS
The tensile strength of alloys according to the invention is thought to be a function of the titanium content. It will be noted that Canadian Patent No. 991,889 discloses nickel-cobalt-iron-titanium alloys having low expansion characteristics and high strength in the wrought condition. Approximately twice the level of titanium is required in the cast and aged alloy to give comparable strengths to similar alloys in the wrought and aged state. For example, an iron-base alloy containing nominally 34% nickel and 13% cobalt would require approximately 3% titanium to achieve in the cast condition the strength achieved in the wrought condition by the same iron-base alloy containing approximately 1.5% titanium. The alloys of the invention con~ain titanium in an amount of between 1 and 4% by weight, preferably between 1.5 and 3.5% and most preferably between 1.7 and
This invention relates to low-expansion nickel-iron alloys and is concerned with the provision of such an alloy which in the cast form has high strength and low thermal expansion char-acteristics at service temperatures.
It is known that certain nickel-iron alloys have a remarkably low coefficient of thermal expansion such as, for example, an alloy of 36% nickel and 64% iron known under the trade name "Invar"
which has a coefficient of thermal expansion approaching zero over the temperature range O to around 200 C. A major problem with low-expansion nickel-iron alloys is their low strength. One method by which the strength of such alloys can be increased is by the addition of elements such as aluminum, titanium or niobium, and a subsequent ageing treatment.
Titanium has generally been added in amount of between 0.75% and 2.5% by weight to increase the strength of wrought alloys, and we have found that to achieve an increase in strength to comparable levels in cast alloys requires the addition of rather more titanium, that is, between 1.5 and 5% titanium by weight. However, as is well known, the increase in strength resulting from titanium additions is achieved at the expense of the low coefficient of thermal expansion which is increased in proportion to the increasing titanium content I of the alloy.
! Surprisingly we have now found that an optimum balance between high strength and a low coefficient of thermal expansion at temperatures in the range of 20 to 300 C can be achieved in a cast and aged nickel-iron alloy strengthened with titanium, by correlating the nickel and titanium contents and optional cobalt and niobium contents according to a specific relationship.
,,~
,~ . , .
103~05 It ls an ob~ect of the present invention to provide im-proved age-hardened iron-nickel-titanium alloys with predetermined low expansion characteristics whicll have high mechanical strength.
It is another object of this invention to provide low expansion iron-nickel-titanium alloys which may contain cobalt, and/or niobium and in which concentrations of nickel, cobalt, titanium and niobium are controlled and correlated.
It is a further obJect to provide low expansion iron-nickel-titanium alloys having in the as-cast and aged condition a thermal expansion coefficient between 20 and 300C of less than about 6 x 10 6/oC and preferably less than about 5 x 10 6/oC, and a 0.2%
proof stress at 20C higher than about 350N/n~ .
A still further object is to provide an alloy having low expansivity and high strength at working temperatures - which can be cast directly into intricately-shaped castings with good surface properties.
The invention also contemplates providing stnlctural com-ponents of machinery, for example turbine shafts and blades, in which close dimensional tolerances must be maintained at temperatures up to about 500C, made of cast, age-hardenable alloys.
Other objects and advantages will become apparent from the following description and examples.
THE INVENIION
According to one aspect of the invention there is provided an alloy which, when in the as-cast and aged condition, has a thermal expansion coefficient between 20 and 300C of less than 6 x 10 6/oC and a 0.2% proof stress at 20C higher than 350 N/mm (Newtons per square millimeter), comprising by weight up to about 47%, e.g. from about 27 to about 47% nickel, from above 5% to about 16% cobalt, from about 1 to about 4% titanium, up to about 1.5~ niobium, the contents of nickel, cobalt, titanium and niobium being such that:
~03~Z05 %Ni + 0.7(%Co) - 1.25 [%Ti + 0.35(%Nb)] - 2 (%Ti) / (%Ti + ~Nb) = 37 to ~0, and the balance, apart from impurities and residual elements, being essentially iron.
According to another aspect of the invention there is provided an alloy which, when in the as-cast and aged condition, has a thermal expansion coefficient between 20 and 30QC of less than 5 x 10 /C and a 0.2% proof stress at 20C higher than 350N/mm , comprising by weight up to about 47%, e.g. from about 27 to about 47%
nickel, from above 5% to about 16% cobalt, from about 1 to about 4 titanium, up to about 1.5% niobium, the contents of nickel, cobalt, titanium and niobium being such that:
%Ni + 0.7 (%Co) - 1.25 [%Ti + 0.35(%Nb)~ - 2 (%Ti)/~%Tî + ~Nb?
= 37 to 39, and the balance, apart from impurities and residual elements, being essentially iron.
Alloys according to the invention may also contain by weight, up to about 1%, e.g. up to about 0.3% silicon, up to about a. 4% manganese and up to about 0.2% aluminum and not more than about 0.1% carbon. The presence of silicon, manganese and/or aluminum is particularly beneficial when the alloys are to be produced by melting in air.
The attainment of high strength in alloys according to the invention depends upon precipitation hardening by the formation of a precipitate, Ni3(Ti), when ageing the alloy at elevated temperature.
The ageing treatment preferably carried out in the temperature range 550 to 700C, with the optimum temperature being dependent upon the titanium content of the alloy. For lower levels of titanium content, optimum properties may be achieved after heat treating at the lower end of the temperature range, e.g. 575 to 625C for about 24 hours, whereas for higher levels of titanium content, a heat treatment of about 24 hours at the higher end of the temperature range e.g. 625 to 675C, may give optimum properties.
. ., ,~
~- - 3 -1~3~ZOS
The tensile strength of alloys according to the invention is thought to be a function of the titanium content. It will be noted that Canadian Patent No. 991,889 discloses nickel-cobalt-iron-titanium alloys having low expansion characteristics and high strength in the wrought condition. Approximately twice the level of titanium is required in the cast and aged alloy to give comparable strengths to similar alloys in the wrought and aged state. For example, an iron-base alloy containing nominally 34% nickel and 13% cobalt would require approximately 3% titanium to achieve in the cast condition the strength achieved in the wrought condition by the same iron-base alloy containing approximately 1.5% titanium. The alloys of the invention con~ain titanium in an amount of between 1 and 4% by weight, preferably between 1.5 and 3.5% and most preferably between 1.7 and
2.7%. Although niobium i6 not essential for obtaining the required properties, it can be added in an amount of up to 1.5% to help in the achievement of good mechanical properties.
The nickel content of alloys according to the invention is from about 27 to about 47%. The correlation between the nickel and titanium contents in alloys of the invention is critical if the desired balance of strength and low expansion properties are to be achieued between 20 and 300C. To this end the nickel, cobalt, titanium and niobium contents of the alloy should satisfy the following relation-ships:
%NI + 0.7 ~%Co) - 1.25 [%Ti + 0.35(%Nb)] - 2 t%Ti~/(%Ti + %Nb) = 37 to 40 - - - _ _ (1) or %Ni + 0.7 (%Co) - 1.25 [%Ti +`0.35~%Nb)] - 2 (%Ti)/(%Ti + %Nb) = 37 to 39 - - - - - (2) ,, . ' ~03~2~5 Cast and aged alloys which do not satisfy the foregoing relationships, whilst possibly having a 0.2~ proof stress at 20 C higher than 350N/mm2 depending upon their titanium content will not also have the desired thermal expansion coefficient between 20 and 300 C of less than 6 x 10 / C for relationship (1) and less than 5 x 10 / C for relationship (2).
Thus experiments have shown that for iron-base alloys containing nominally 2.5% titanium and 13.5% cobslt it is necessary to have a nickel content of between approximately 32.5% and approximately 34.5% in order to maintain in the cast and aged ~ondition a mean coefficient of thermal expansion between 20 and 300 C of le~s than 5 x 10 / C. If the nickel content falls below approximately 32.5% in the nomlnally 2.5% titanium, 13.5% cobalt alloy there is a possibility of martensite formation, which has a high coefficient of thermal expansion, by refrigerating or cold working. Nickel contents higher than approximately 34.5%
in the nominally 2.5% titanium, 13.5% cobalt alloy result in thermal expansion coefficients greater than the tesired 5 x 10 / C.
. _ .
The inclusion of c ~ ~ ~ nZ ~ ~oys of the lnvention is not essential to achieve the desired 1QW expansion coefficient between 20 and 300 C or the desired strength, but it is desirable for alloy parts which ~ust withstand temperatures greater than 300 C. This is because the effect of cobalt is to reduce thermal expansivity at temperatures above 300 C. Preferably the cobalt content i9 between above 5 and about 16 wt.%, and most preferflbly between abou~ 10 and above 15 wt.%. The effect of the inclusion of cobalt can be seen from Example I of the following examples.
EXAMPLE I
Samples of an alloy containing, by weight 13~5~/o cobalt, 33. 0% nickel, 2. 5% titanium, balance iron and samples of a cobalt-free alloy containing 43% nickel, 2~5Z titanium, balance iron, were tested and the thermal expansion coefficient measured for various temperature3 for the cobalt-free alloy and the cobal~ containing alloy with the results shown in Table 1.
.
Mean Coefficient of Thermfll Expansion Wt% Cobalt ~ X 10 /C
:
0 5 7~1 8~8 10~0 13~5 5 5~7 7~6 9~2 The reduction in thermal expanslon coefficient at temperature~ in excess of 300 C due to the addition of cobalt i~ clearly apparent from Table 1.
.
EXAMPLE II
An alloy of composition 33.0% nickel, 13.4~ cobalt, 2.5%
titanium, less than 0.002~ carbon balance apart from impurities being iron, was inventment cast in vacuum, was given an ageing heat treatment at 650C for 24 hours and when tested had the properties shown in Tables 2 and 3:
Test Tensile Properties, N/mm Temperature (1) (2) U.T.S. 0.2~ P.S.
20C 8~0 750 (1) ~ltimate Tensile Strength ; (2) Proof Stress Test Temperature Coefficient of Thermal Expansion /C
RangeC c~ X 10 20 - 100 4.2 20 - 200 3.8 2020 - 300 3.9 20 - 400 5.5 20 - 600 9.1 EXAMPLE III
An alloy of nominal composition 37% nickel, 8% cobalt, 2.1%
titanium, 0.002% carbon balance, apart from impurities, being iron, was invest~ent cast in vacuum, WhS given an ageing heat treatment at 650C
for 24 hours and when tested had the properties shown in Tables 4 and 5:
'' ~03B~S
~ .
Test TemperatureTensile Properties, N/mm U. . 0.2% P.S.
Room temp. (20 C) 820 680 Test TemperatureCoefficient of Thermal Expansion / C
Range C ~c X 10 20 - 100 4.6 20 - 200 4.3 10 20 - 300 4.3 20 - 350 4.6 20 - 400 5.6 20 - 500 7.7 20 - 600 9.4 Alloys of the invention can, if required, be cast directly into intricately-shaped inve~tment castings with good surface properties requiring little or no surface machining prior to use. Nickel-iron(-cobalt) castings wbich are not strengthened are prone to surface cracking due in part to "hot shortness" and in part to poor oxidation resistance.
The presence of æuch cracks cansevere~y limit or reduce mechanicfll properties, such as fatigue life, and their presence, particularly in investment castings, i8 undesirable. The presence of titanium in nickel-iron(-cobalt) alloys of the invention remarkably limits the incidence of cracking due to hot shortness and poor oxidation resistance, and such castings have good surface finishes over castlng~ lacking in titanium.
Tkese good surface propertles are p~rticularly noticeable in cHstlngs made from alloys of the invention containing hlgh titanium levels (e.g.
2% and above). Alloys according to the invention can be produced by air melting and casting, but it is preferred to melt in vacuo or under an inert atmosphere.
' ~ '' : .' .~ , -lO;~ S
Alloys according to the invention are particularly useful for structural components which reach high temperatures in use and must have such a combination of low expansivity and high strength at working temperatures. Such structural components include parts of rotating and reciprocating machinery, for example turbine shafts and blades, in which close dimensional tolerances have to be maintained under varying temperatures from ambient temperature up to 300 C or even higherS for example up to 500 C.
These requirements arise in a p rticularly acute form in high-efficiency propulsion machinery for land, ~ea and air uses.
Although the present invention has been described in conjunction with preferred embodiments, it is to be understood that modificaeions and variations may be resorted to without departin~ from the spirit and scope of the invention as those skilled in the art will readily understand. Such modifications and variations are considered to be within the purview and scope of the invention and appended claims.
_g_ 103~0S
SUPPLEMENTAX~ DISCLOSURE
_ . .
As noted previously, the present invention is concerned with cast alloys. Heretofore, many low expansion alloys were wrought alloys for which the desired properties have been developed after processing which consisted of casting, hot or cold working, solution treatment and final ageing. After such treatment the alloys consist of an essentially homogeneous matrix containing Ni3Ti precipitate. According to the present invention the alloy is a cast material which has t~e desired properties after simply ageing the casting, or even (as explained previously) in the as-cast condition. In the alloys of this invention the - ~-microstructure in the as-cast condition is inhomogeneous, there being a significant segregation o the major alloying elements, viz. Ni, Co, Fe and Ti. Because of the sensitivitv of expansivity to compositional effects it is surprising that such inhomogeneous products have low expansivities.
It is a significant feature of the present invention that the cast alloys can be age-hardened directly to achieve dimensionally stable castings having the indicated properties, viz. a linear thermal expansivity over a temperature range of 20 to 300C of less than 6 x 10 6/oC, and preEerably less than 5 x 10 6/oC .and a 0.2 proof stress at 20C greater than 350 N/mm~.
Casting temperatures of about 1500C have been found particularly suitable. However, casting temperatures for the alloys of this invention may range from about 1475C to about 1600C.
With respect to the alloy composition, it was noted that the present low expansion alloy contains about 27~ to about 47% nickel. The minimum and maximum nickel must be cor-related to the Co, Ti and Nb contents and the composition factor, according to the given equation. ~or example, if the cobalt range is 0 to 16% and the composition factor is 37 to 40, to satisfy the equation, the minimum nickel content in the alloy o can be calculated, and it is about 29%. Similarly, if the compo-sition factor is 37 to 39 and the cobalt 5 to 16%, the nickel content is about 29% to about 44%. Thus, preferred embodiments of this invention contain about 29% to about 44% nickel. ~ore preferred embodiments contain ahout 32% to 33% nickel. Where the cohalt content is a minimum oE 5%, the maximum nickel present is between about 42% and 43% for alloys having an expansivity at 20-300C of less than 5 x 10 6/oC. As indicated previously, the cobalt content is preferably between above 5% and about 16%.
More preferably, it is between about 7% and about 14%, e.g. about 7.5 to about 8.5%. The attainment of high strength in alloys according to the invention depends upon precipitation hardening by the formation of a precipitate, ~i3(Ti), when ageing the alloy at elevated temperature, and it is known that titanium combined with carbon will not enter this precipitate. For this reason it is the content of titanium that is not combined with carbon which is important. The total amount of titanium preferably exceeds the uncombined amount by four times the weight of the carbon content, which itself must not exceed 0.1%. Preferably, carbon should not exceed 0.04%, e.g. it is lower than 0.02% or even lower than 0.002%. When the carbon content is so low, the total titanium content is effectively the same as the uncombined titanium. As indicated above, the alloys of the present invention contain titanium (uncombined) in an amount of between 1 and 4% by weight, preferably between 1.5 and 3.5~ more preferably between 1.7 and 2.7%. Most preferably the uncombined titanium level is above 1.75%, e.g. between 1.9% and 2.2%. Although niobium is not es-sential for obtaining the re~uired properties, it can be added in an amount of up to about 1.5% to help in the achievement of good mechanical properties.
.,~ -s, .. .
103~9Z05 To obtain good castings according to the invention it is preferable to control the silicon, manganese and aluminum con-tent of the alloy from which the casting is made. Less than 0.3%
and preferably less than 0.1~ silicon in alloys used for castings according to the invention decreases the expansion coefficient.
More than 0.3% silicon can increase the proof stress but undesir-ably increases the expansion coefficient. ~langanese facilities deoxidation, castability and improved proof stress but at the expense of increased expansion and for this reason the manganese content must not exceed 0.4% and for optimum proof stress and expansion properties preferably should not exceed 0.3%. Aluminum assists the production of castings by the air melting and air casting route. For this purpose it is advarltageous for the alloy to contain at least 0.05% aluminum but it must not be present in quantities greater than 0.3% otherwise it increases the expansion coefficient. Preferably, for optimum proof stress and expansion properties the aluminum content should not exceed 0.2%. Magnesium may be present, e.g. preferahly in an amount not more than 0.1%.
Briefly, in preferred embodiments of this invention alloys used for castings, the nickel content preferably is from about 32% to about 38%, the cobalt content is from 7% to about 14%, the uncombined titanium content is from above 1.75% up to about 2.7%, the carbon content does not exceed 0.04%, with the nickel, cobalt, titanium and niobium correlated as indicated previously. Up to 1.5% niobium may be ~resent. The alloys may contain up to about 0.3% Si, up to 0.3% aluminum and up to 0.3~
manganese. More preferably, alloys used for castings according to the invention contain from about 36.5% to about 38% nickel, from about 7.5% to about 8.5% cobalt, from about 1.9% to about 2.2%
uncombined titanium and from about 0.3% to about 0.6% niobium.
103~ 5 A particularly pre~erred alloy composition range from which castings according to the invention can be made is, by weight, 36.5% to 38% nickel, 7.5~ to 8.5~ cobalt, 1.9~ to 2.2%
uncombined titanium, 0.3~ to 0.6~ niobium, not more than 0.002%
carbon, not more than 0.3% silicon, not more than 0.2% aluminum, not more than 0.3% manganese, balance, apart from impurities, being iron. Test results of a casting made from such an allov are described in the following Example IV.
EXAMPLE IV
An alloy of composition, by weight, 37.3~ nickel, 7.9%
cobalt, 2.02% uncombined titanium, 0.54~ niobium, 0.002% carbon, 0.05% aluminum, %Ni + 0.7(%Co~ - 1.25[%Ti + 0.35(%Nb)] -2 (%Ti)/(%Ti + %Nb) = 38.49, balance, apart from impurities, being iron was vacuum melted and investment cast in vacuum at a temperature in the range of 1500 to 1550C to a casting according to the invention. The casting was given an ageing heat treatment ~` -in air at 650C -for 24 hours and when tested had the properties shown in Tables 6 and 7.
Test Tensile Properties (N~mm ? Elongation Temperature ~C) U.T.S. 0.2% P.S. (%) Test Coefficient of Thermal Ex~ansion Range C ~-~ C) 20 - 100 4.3 x 10 6 20 - 200 4.5 x 10 6 20 - 300 4.6 x 10 6 20 - 350 4.9 x 10 6 20 - 400 6.0 x 10 6 t3 , .
The nickel content of alloys according to the invention is from about 27 to about 47%. The correlation between the nickel and titanium contents in alloys of the invention is critical if the desired balance of strength and low expansion properties are to be achieued between 20 and 300C. To this end the nickel, cobalt, titanium and niobium contents of the alloy should satisfy the following relation-ships:
%NI + 0.7 ~%Co) - 1.25 [%Ti + 0.35(%Nb)] - 2 t%Ti~/(%Ti + %Nb) = 37 to 40 - - - _ _ (1) or %Ni + 0.7 (%Co) - 1.25 [%Ti +`0.35~%Nb)] - 2 (%Ti)/(%Ti + %Nb) = 37 to 39 - - - - - (2) ,, . ' ~03~2~5 Cast and aged alloys which do not satisfy the foregoing relationships, whilst possibly having a 0.2~ proof stress at 20 C higher than 350N/mm2 depending upon their titanium content will not also have the desired thermal expansion coefficient between 20 and 300 C of less than 6 x 10 / C for relationship (1) and less than 5 x 10 / C for relationship (2).
Thus experiments have shown that for iron-base alloys containing nominally 2.5% titanium and 13.5% cobslt it is necessary to have a nickel content of between approximately 32.5% and approximately 34.5% in order to maintain in the cast and aged ~ondition a mean coefficient of thermal expansion between 20 and 300 C of le~s than 5 x 10 / C. If the nickel content falls below approximately 32.5% in the nomlnally 2.5% titanium, 13.5% cobalt alloy there is a possibility of martensite formation, which has a high coefficient of thermal expansion, by refrigerating or cold working. Nickel contents higher than approximately 34.5%
in the nominally 2.5% titanium, 13.5% cobalt alloy result in thermal expansion coefficients greater than the tesired 5 x 10 / C.
. _ .
The inclusion of c ~ ~ ~ nZ ~ ~oys of the lnvention is not essential to achieve the desired 1QW expansion coefficient between 20 and 300 C or the desired strength, but it is desirable for alloy parts which ~ust withstand temperatures greater than 300 C. This is because the effect of cobalt is to reduce thermal expansivity at temperatures above 300 C. Preferably the cobalt content i9 between above 5 and about 16 wt.%, and most preferflbly between abou~ 10 and above 15 wt.%. The effect of the inclusion of cobalt can be seen from Example I of the following examples.
EXAMPLE I
Samples of an alloy containing, by weight 13~5~/o cobalt, 33. 0% nickel, 2. 5% titanium, balance iron and samples of a cobalt-free alloy containing 43% nickel, 2~5Z titanium, balance iron, were tested and the thermal expansion coefficient measured for various temperature3 for the cobalt-free alloy and the cobal~ containing alloy with the results shown in Table 1.
.
Mean Coefficient of Thermfll Expansion Wt% Cobalt ~ X 10 /C
:
0 5 7~1 8~8 10~0 13~5 5 5~7 7~6 9~2 The reduction in thermal expanslon coefficient at temperature~ in excess of 300 C due to the addition of cobalt i~ clearly apparent from Table 1.
.
EXAMPLE II
An alloy of composition 33.0% nickel, 13.4~ cobalt, 2.5%
titanium, less than 0.002~ carbon balance apart from impurities being iron, was inventment cast in vacuum, was given an ageing heat treatment at 650C for 24 hours and when tested had the properties shown in Tables 2 and 3:
Test Tensile Properties, N/mm Temperature (1) (2) U.T.S. 0.2~ P.S.
20C 8~0 750 (1) ~ltimate Tensile Strength ; (2) Proof Stress Test Temperature Coefficient of Thermal Expansion /C
RangeC c~ X 10 20 - 100 4.2 20 - 200 3.8 2020 - 300 3.9 20 - 400 5.5 20 - 600 9.1 EXAMPLE III
An alloy of nominal composition 37% nickel, 8% cobalt, 2.1%
titanium, 0.002% carbon balance, apart from impurities, being iron, was invest~ent cast in vacuum, WhS given an ageing heat treatment at 650C
for 24 hours and when tested had the properties shown in Tables 4 and 5:
'' ~03B~S
~ .
Test TemperatureTensile Properties, N/mm U. . 0.2% P.S.
Room temp. (20 C) 820 680 Test TemperatureCoefficient of Thermal Expansion / C
Range C ~c X 10 20 - 100 4.6 20 - 200 4.3 10 20 - 300 4.3 20 - 350 4.6 20 - 400 5.6 20 - 500 7.7 20 - 600 9.4 Alloys of the invention can, if required, be cast directly into intricately-shaped inve~tment castings with good surface properties requiring little or no surface machining prior to use. Nickel-iron(-cobalt) castings wbich are not strengthened are prone to surface cracking due in part to "hot shortness" and in part to poor oxidation resistance.
The presence of æuch cracks cansevere~y limit or reduce mechanicfll properties, such as fatigue life, and their presence, particularly in investment castings, i8 undesirable. The presence of titanium in nickel-iron(-cobalt) alloys of the invention remarkably limits the incidence of cracking due to hot shortness and poor oxidation resistance, and such castings have good surface finishes over castlng~ lacking in titanium.
Tkese good surface propertles are p~rticularly noticeable in cHstlngs made from alloys of the invention containing hlgh titanium levels (e.g.
2% and above). Alloys according to the invention can be produced by air melting and casting, but it is preferred to melt in vacuo or under an inert atmosphere.
' ~ '' : .' .~ , -lO;~ S
Alloys according to the invention are particularly useful for structural components which reach high temperatures in use and must have such a combination of low expansivity and high strength at working temperatures. Such structural components include parts of rotating and reciprocating machinery, for example turbine shafts and blades, in which close dimensional tolerances have to be maintained under varying temperatures from ambient temperature up to 300 C or even higherS for example up to 500 C.
These requirements arise in a p rticularly acute form in high-efficiency propulsion machinery for land, ~ea and air uses.
Although the present invention has been described in conjunction with preferred embodiments, it is to be understood that modificaeions and variations may be resorted to without departin~ from the spirit and scope of the invention as those skilled in the art will readily understand. Such modifications and variations are considered to be within the purview and scope of the invention and appended claims.
_g_ 103~0S
SUPPLEMENTAX~ DISCLOSURE
_ . .
As noted previously, the present invention is concerned with cast alloys. Heretofore, many low expansion alloys were wrought alloys for which the desired properties have been developed after processing which consisted of casting, hot or cold working, solution treatment and final ageing. After such treatment the alloys consist of an essentially homogeneous matrix containing Ni3Ti precipitate. According to the present invention the alloy is a cast material which has t~e desired properties after simply ageing the casting, or even (as explained previously) in the as-cast condition. In the alloys of this invention the - ~-microstructure in the as-cast condition is inhomogeneous, there being a significant segregation o the major alloying elements, viz. Ni, Co, Fe and Ti. Because of the sensitivitv of expansivity to compositional effects it is surprising that such inhomogeneous products have low expansivities.
It is a significant feature of the present invention that the cast alloys can be age-hardened directly to achieve dimensionally stable castings having the indicated properties, viz. a linear thermal expansivity over a temperature range of 20 to 300C of less than 6 x 10 6/oC, and preEerably less than 5 x 10 6/oC .and a 0.2 proof stress at 20C greater than 350 N/mm~.
Casting temperatures of about 1500C have been found particularly suitable. However, casting temperatures for the alloys of this invention may range from about 1475C to about 1600C.
With respect to the alloy composition, it was noted that the present low expansion alloy contains about 27~ to about 47% nickel. The minimum and maximum nickel must be cor-related to the Co, Ti and Nb contents and the composition factor, according to the given equation. ~or example, if the cobalt range is 0 to 16% and the composition factor is 37 to 40, to satisfy the equation, the minimum nickel content in the alloy o can be calculated, and it is about 29%. Similarly, if the compo-sition factor is 37 to 39 and the cobalt 5 to 16%, the nickel content is about 29% to about 44%. Thus, preferred embodiments of this invention contain about 29% to about 44% nickel. ~ore preferred embodiments contain ahout 32% to 33% nickel. Where the cohalt content is a minimum oE 5%, the maximum nickel present is between about 42% and 43% for alloys having an expansivity at 20-300C of less than 5 x 10 6/oC. As indicated previously, the cobalt content is preferably between above 5% and about 16%.
More preferably, it is between about 7% and about 14%, e.g. about 7.5 to about 8.5%. The attainment of high strength in alloys according to the invention depends upon precipitation hardening by the formation of a precipitate, ~i3(Ti), when ageing the alloy at elevated temperature, and it is known that titanium combined with carbon will not enter this precipitate. For this reason it is the content of titanium that is not combined with carbon which is important. The total amount of titanium preferably exceeds the uncombined amount by four times the weight of the carbon content, which itself must not exceed 0.1%. Preferably, carbon should not exceed 0.04%, e.g. it is lower than 0.02% or even lower than 0.002%. When the carbon content is so low, the total titanium content is effectively the same as the uncombined titanium. As indicated above, the alloys of the present invention contain titanium (uncombined) in an amount of between 1 and 4% by weight, preferably between 1.5 and 3.5~ more preferably between 1.7 and 2.7%. Most preferably the uncombined titanium level is above 1.75%, e.g. between 1.9% and 2.2%. Although niobium is not es-sential for obtaining the re~uired properties, it can be added in an amount of up to about 1.5% to help in the achievement of good mechanical properties.
.,~ -s, .. .
103~9Z05 To obtain good castings according to the invention it is preferable to control the silicon, manganese and aluminum con-tent of the alloy from which the casting is made. Less than 0.3%
and preferably less than 0.1~ silicon in alloys used for castings according to the invention decreases the expansion coefficient.
More than 0.3% silicon can increase the proof stress but undesir-ably increases the expansion coefficient. ~langanese facilities deoxidation, castability and improved proof stress but at the expense of increased expansion and for this reason the manganese content must not exceed 0.4% and for optimum proof stress and expansion properties preferably should not exceed 0.3%. Aluminum assists the production of castings by the air melting and air casting route. For this purpose it is advarltageous for the alloy to contain at least 0.05% aluminum but it must not be present in quantities greater than 0.3% otherwise it increases the expansion coefficient. Preferably, for optimum proof stress and expansion properties the aluminum content should not exceed 0.2%. Magnesium may be present, e.g. preferahly in an amount not more than 0.1%.
Briefly, in preferred embodiments of this invention alloys used for castings, the nickel content preferably is from about 32% to about 38%, the cobalt content is from 7% to about 14%, the uncombined titanium content is from above 1.75% up to about 2.7%, the carbon content does not exceed 0.04%, with the nickel, cobalt, titanium and niobium correlated as indicated previously. Up to 1.5% niobium may be ~resent. The alloys may contain up to about 0.3% Si, up to 0.3% aluminum and up to 0.3~
manganese. More preferably, alloys used for castings according to the invention contain from about 36.5% to about 38% nickel, from about 7.5% to about 8.5% cobalt, from about 1.9% to about 2.2%
uncombined titanium and from about 0.3% to about 0.6% niobium.
103~ 5 A particularly pre~erred alloy composition range from which castings according to the invention can be made is, by weight, 36.5% to 38% nickel, 7.5~ to 8.5~ cobalt, 1.9~ to 2.2%
uncombined titanium, 0.3~ to 0.6~ niobium, not more than 0.002%
carbon, not more than 0.3% silicon, not more than 0.2% aluminum, not more than 0.3% manganese, balance, apart from impurities, being iron. Test results of a casting made from such an allov are described in the following Example IV.
EXAMPLE IV
An alloy of composition, by weight, 37.3~ nickel, 7.9%
cobalt, 2.02% uncombined titanium, 0.54~ niobium, 0.002% carbon, 0.05% aluminum, %Ni + 0.7(%Co~ - 1.25[%Ti + 0.35(%Nb)] -2 (%Ti)/(%Ti + %Nb) = 38.49, balance, apart from impurities, being iron was vacuum melted and investment cast in vacuum at a temperature in the range of 1500 to 1550C to a casting according to the invention. The casting was given an ageing heat treatment ~` -in air at 650C -for 24 hours and when tested had the properties shown in Tables 6 and 7.
Test Tensile Properties (N~mm ? Elongation Temperature ~C) U.T.S. 0.2% P.S. (%) Test Coefficient of Thermal Ex~ansion Range C ~-~ C) 20 - 100 4.3 x 10 6 20 - 200 4.5 x 10 6 20 - 300 4.6 x 10 6 20 - 350 4.9 x 10 6 20 - 400 6.0 x 10 6 t3 , .
Claims (18)
1. A Low thermal expansion nickel-containing cast alloy having a cast structure said cast alloy having in the as-cast and aged condition a thermal expansion between 20° and 300°C of less than 6x10-6/°C and a 0.2% proof stress at 20°C higher than 350 N/mm2 consisting essentially of, by weight, up to about 47%
nickel, from about 1% to about 4% titanium, from about 5% to about 16% cobalt, up to about 1.5% niobium, up to about 0.3% silicon, up to about 0.4% manganese, and up to about 0.2% aluminum, and the balance, apart from impurities and residual elements, being essentially iron, and said contents of nickel, cobalt, titanium and niobium being such that:
%Ni + 0.7 (%Co) - 1.25 [%Ti + 0.35 (%Nb)] - 2 (%Ti)/(%Ti + %Nb) = 37 to 40.
nickel, from about 1% to about 4% titanium, from about 5% to about 16% cobalt, up to about 1.5% niobium, up to about 0.3% silicon, up to about 0.4% manganese, and up to about 0.2% aluminum, and the balance, apart from impurities and residual elements, being essentially iron, and said contents of nickel, cobalt, titanium and niobium being such that:
%Ni + 0.7 (%Co) - 1.25 [%Ti + 0.35 (%Nb)] - 2 (%Ti)/(%Ti + %Nb) = 37 to 40.
2. A cast alloy according to claim 1, wherein the titanium content is from about 1.5% to about 3.5%.
3. A cast alloy according to claim 2, wherein the titanium content is from about 1.7% to about 2.7%.
4. A cast alloy according to claim 1, wherein the cobalt content is from about 10% to about 15%.
5. A cast alloy according to claim 1 consisting essentially of about 37% nickel, about 8% cobalt, about 2.1% titanium, snd the balance essentially iron.
6. A cast alloy according to claim 4, wherein the titanium content is about 2.5%, the cobalt content is about 13.5%, and the nickel content is from about 32.5% to about 34.5%.
7. A cast alloy according to claim 6 wherein the nickel content is about 33%.
8. A cast article having dimensional stability at temperatures from about ambient to at least about 300°C, said article consisting essentially of, by weight, nickel up to about 47%, from about 1% to about 4% titanium, from above 5% to about 16% cobalt, up to about 1.5% niobium, up to about 0.3% silicon, up to about 0.4%
manganese, and up to about 0.2% aluminum, and the balance, apart from impurities and residual elements being essentially iron, and said contents of nickel, cobalt, titanium and niobium being such that:
%Ni + 0.7(%Co) - 1.25 [%Ti + 0.35 (%Nb)] - 2(%Ti)/(%Ti + %Nb) = 37 to 40, having in the as-cast age-hardened condition a thermal coefficient of expansion between about 20°C to about 300°C of less than about 6 x 10-6/°C and 0.2% proof stress at 20°C greater than about 350 N/mm2.
manganese, and up to about 0.2% aluminum, and the balance, apart from impurities and residual elements being essentially iron, and said contents of nickel, cobalt, titanium and niobium being such that:
%Ni + 0.7(%Co) - 1.25 [%Ti + 0.35 (%Nb)] - 2(%Ti)/(%Ti + %Nb) = 37 to 40, having in the as-cast age-hardened condition a thermal coefficient of expansion between about 20°C to about 300°C of less than about 6 x 10-6/°C and 0.2% proof stress at 20°C greater than about 350 N/mm2.
9. A cast article according to claim 8 comprising about 33% to about 37% nickel, about 5% to about 16% cobalt, about 1.7% to about 2.7% titanium, and less than about 0.002% carbon.
10. A shaped casting made of a nickel-containing alloy con-sisting essentially of, by weight, up to about 47% nickel, from about 1% to about 4% titanium, from about 5% to about 16% cobalt, up to about 1.5% niobium, up to about 0.3% silicon, up to about 0.4% manganese, and up to about 0.2% aluminum, and the balance, apart from impurities and residual elements, being essentially iron, and said contents of nickel, cobalt, titanium and niobium being such that:
%Ni + 0.7(%Co) - 1.25 [%Ti + 0.35 (%Nb)] - 2 (%Ti)/(%Ti + %Nb) = 37 to 40, said shaped casting being prepared by forming the alloy into a shaped casting and subjecting said casting directly to age-hardening condi-tions to obtain a shaped casting having in the as-cast age-hardened condition a thermal coefficient of expansion between about 20°C to about 300°C of less than about 6 x 10-6/°C and 0.2% proof stress at 20°C greater than about 350 N/mm2.
%Ni + 0.7(%Co) - 1.25 [%Ti + 0.35 (%Nb)] - 2 (%Ti)/(%Ti + %Nb) = 37 to 40, said shaped casting being prepared by forming the alloy into a shaped casting and subjecting said casting directly to age-hardening condi-tions to obtain a shaped casting having in the as-cast age-hardened condition a thermal coefficient of expansion between about 20°C to about 300°C of less than about 6 x 10-6/°C and 0.2% proof stress at 20°C greater than about 350 N/mm2.
11. A shaped casting according to claim 10 wherein the age-hardening treatment is carried out in the temperature range of about 550° to about 700°C.
12. A shaped casting according to claim 10 wherein the alloy is investment cast to form the shaped casting and the investment casting is subjected directly to the age-hardening heat treatment.
CLAIMS SUPPORTED BY SUPPLEMENTARY DISCLOSURE
CLAIMS SUPPORTED BY SUPPLEMENTARY DISCLOSURE
13. A metallic cast article adapted to be employed under stress at temperatures in excess of ambient temperature and having enhanced utility by virtue of dimensional stability over the tempera-ture range from ambient temperature to at least 300°C and high strength and consisting of an alloy having an as-cast and age-hardened micro-structure being characterized by a Ni3Ti precipitate and by substantial segregation of elemental constituents within the as-cast structure but on the average consisting essentially, in percent by weight, of about 32% to about 38% nickel, from above 1.75% to about 2.7% uncombined titanium, from about 7 to about 14% cobalt, up to about 1.5% niobium, up to about 0.3% silicon, up to about 0.3% manganese, up to about 0.3%
aluminum and up to about 0.1% magnesium, up to about 0.04% carbon, with the balance, except for impurities and residual elements, being essentially iron, said nickel, cobalt, titanium and niobium contents being correlated such that:
%Ni + 0.7(%Co) - 1.25 [%Ti + 0.35 (%Nb)] - 2 (%Ti)/(%Ti + %Nb) = 37 to 39, to provide in said as-cast age-hardened alloy a linear thermal expan-sion coefficient between 20° and 300°C of less than about 5 x 10-6/°C
and a 0.2% proof stress at 20°C greater than about 350 N/mm2.
aluminum and up to about 0.1% magnesium, up to about 0.04% carbon, with the balance, except for impurities and residual elements, being essentially iron, said nickel, cobalt, titanium and niobium contents being correlated such that:
%Ni + 0.7(%Co) - 1.25 [%Ti + 0.35 (%Nb)] - 2 (%Ti)/(%Ti + %Nb) = 37 to 39, to provide in said as-cast age-hardened alloy a linear thermal expan-sion coefficient between 20° and 300°C of less than about 5 x 10-6/°C
and a 0.2% proof stress at 20°C greater than about 350 N/mm2.
14. A metallic cast article according to claim 13, wherein the alloy contains from about 36.5% to about 38% nickel, about 7.5%
to about 8.5% cobalt, from about 1.9% to about 2.2% uncombined titanium, and about 0.3% to about 0.6% niobium.
to about 8.5% cobalt, from about 1.9% to about 2.2% uncombined titanium, and about 0.3% to about 0.6% niobium.
15. A metallic cast article according to claim 13, wherein the alloy contains about 37% nickel, about 8% cobalt, about 2% un-combined titanium and about 0.5% niobium.
16. A metallic cast article according to claim 15, wherein the alloy contains up to about 0.002% carbon.
17. A shaped casting according to claim 10 wherein the formed of said alloy into a shaped casting is carried out at a temperature in the range of about 1475° to 1600°C.
18. A low thermal expansion nickel-containing cast alloy having a cast structure said cast alloy having in the as-cast and aged condition a thermal expansion between 20° and 300°C of less than 6 x 10-6/°C and a 0.2% proof stress at 20°C higher than 350 N/mm2 consisting essentially of, by weight, up to about 47% nickel, from about 1% to about 4% titanium, from above 5% to about 16% cobalt, up to about 1.5% niobium, up to about 0.3% silicon, up to about 0.47 manganese, and up to about 0.3% aluminum, and the balance, apart from impurities and residual elements, being essentially iron, and said contents of nickel, cobalt, titanium and niobium being such that:
%Ni + 0.7 (%Co) - 1.25 [%Ti + 0.35 (%Nb)] - 2 (%Ti)/(%Ti + %Nb) = 37 to 40.
%Ni + 0.7 (%Co) - 1.25 [%Ti + 0.35 (%Nb)] - 2 (%Ti)/(%Ti + %Nb) = 37 to 40.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB2118773A GB1401259A (en) | 1973-05-04 | 1973-05-04 | Low expansion alloys |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1038205A true CA1038205A (en) | 1978-09-12 |
Family
ID=10158656
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA191,069A Expired CA1038205A (en) | 1973-05-04 | 1974-01-28 | Low expansion iron-nickel based alloys |
Country Status (11)
| Country | Link |
|---|---|
| JP (1) | JPS575867B2 (en) |
| BE (1) | BE814527A (en) |
| CA (1) | CA1038205A (en) |
| CH (1) | CH602949A5 (en) |
| DE (1) | DE2421680C3 (en) |
| ES (1) | ES425925A1 (en) |
| FR (1) | FR2228117B1 (en) |
| GB (1) | GB1401259A (en) |
| IT (1) | IT1011325B (en) |
| NL (1) | NL166281C (en) |
| SE (1) | SE409729B (en) |
Families Citing this family (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4200459A (en) * | 1977-12-14 | 1980-04-29 | Huntington Alloys, Inc. | Heat resistant low expansion alloy |
| JPS5597453A (en) * | 1979-01-18 | 1980-07-24 | Daido Steel Co Ltd | Alloy with high strength and low thermal expansion |
| JPS55122855A (en) * | 1979-03-12 | 1980-09-20 | Daido Steel Co Ltd | High strength low thermal expansion alloy |
| JPS55128565A (en) * | 1979-03-27 | 1980-10-04 | Daido Steel Co Ltd | High-strength, low-thermal expansion alloy |
| JPS55131155A (en) * | 1979-04-02 | 1980-10-11 | Daido Steel Co Ltd | High strength low thermal expansion alloy |
| CH643594A5 (en) * | 1979-09-12 | 1984-06-15 | Bbc Brown Boveri & Cie | Iron-nickel casting alloy |
| US4487743A (en) * | 1982-08-20 | 1984-12-11 | Huntington Alloys, Inc. | Controlled expansion alloy |
| US4685978A (en) * | 1982-08-20 | 1987-08-11 | Huntington Alloys Inc. | Heat treatments of controlled expansion alloy |
| JPS60234950A (en) * | 1984-05-09 | 1985-11-21 | Univ Kyoto | Fe-ni-ti-co alloy indicating shape memory effect and pseudoelasticity effect and its manufacture |
| JPS62110821A (en) * | 1985-11-11 | 1987-05-21 | Toshiba Corp | Metal die |
| JP3127471B2 (en) * | 1990-12-18 | 2001-01-22 | 日立金属株式会社 | Low thermal expansion super heat resistant alloy |
| JPH0725234Y2 (en) * | 1991-02-06 | 1995-06-07 | 財団法人鉄道総合技術研究所 | sprinkler |
| DE4120346A1 (en) * | 1991-06-19 | 1992-12-24 | Krupp Industrietech | IRON-NICKEL-COBALT-TITANIUM SHAPED ALLOY ALLOY AND METHOD FOR THEIR PRODUCTION |
| DE102006005250B4 (en) | 2006-02-02 | 2010-04-29 | Thyssenkrupp Vdm Gmbh | Iron-nickel alloy |
| CN106756582B (en) * | 2016-12-30 | 2018-08-10 | 钢铁研究总院 | A kind of enhanced low-expansion alloy of intermetallic compound and preparation method |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1416264A (en) * | 1973-01-29 | 1975-12-03 | Int Nickel Ltd | Lox expansion alloys |
| JPH0422646A (en) * | 1990-05-17 | 1992-01-27 | Brother Ind Ltd | Impact printer head |
-
1973
- 1973-05-04 GB GB2118773A patent/GB1401259A/en not_active Expired
-
1974
- 1974-01-28 CA CA191,069A patent/CA1038205A/en not_active Expired
- 1974-04-30 IT IT5071174A patent/IT1011325B/en active
- 1974-05-03 NL NL7405967A patent/NL166281C/en not_active IP Right Cessation
- 1974-05-03 FR FR7415407A patent/FR2228117B1/fr not_active Expired
- 1974-05-03 BE BE143899A patent/BE814527A/en not_active IP Right Cessation
- 1974-05-03 ES ES425925A patent/ES425925A1/en not_active Expired
- 1974-05-03 SE SE7405924A patent/SE409729B/en unknown
- 1974-05-03 CH CH606474A patent/CH602949A5/xx not_active IP Right Cessation
- 1974-05-04 JP JP5019074A patent/JPS575867B2/ja not_active Expired
- 1974-05-04 DE DE19742421680 patent/DE2421680C3/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| ES425925A1 (en) | 1976-12-16 |
| JPS5030729A (en) | 1975-03-27 |
| DE2421680A1 (en) | 1974-11-21 |
| NL166281B (en) | 1981-02-16 |
| BE814527A (en) | 1974-11-04 |
| AU6855374A (en) | 1975-11-06 |
| IT1011325B (en) | 1977-01-20 |
| DE2421680B2 (en) | 1980-05-08 |
| GB1401259A (en) | 1975-07-16 |
| CH602949A5 (en) | 1978-08-15 |
| SE409729B (en) | 1979-09-03 |
| FR2228117A1 (en) | 1974-11-29 |
| DE2421680C3 (en) | 1981-01-15 |
| FR2228117B1 (en) | 1978-08-04 |
| JPS575867B2 (en) | 1982-02-02 |
| NL166281C (en) | 1981-07-15 |
| NL7405967A (en) | 1974-11-06 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA1038205A (en) | Low expansion iron-nickel based alloys | |
| Remy et al. | Twinning and strain-induced fcc→ hcp transformation on the mechanical properties of Co Ni Cr Mo alloys | |
| KR870001284B1 (en) | Fe-cr-al alloy & article and method therefor | |
| US3767385A (en) | Cobalt-base alloys | |
| GB2178758A (en) | Titanium base alloy | |
| US3971677A (en) | Low expansion alloys | |
| IL134342A (en) | Precipitation hardenable martensitic stainless steel alloy | |
| EP0104738B1 (en) | Controlled expansion alloy | |
| US3982972A (en) | Semihard magnetic alloy and a process for the production thereof | |
| US4857120A (en) | Heat-resisting steel turbine part | |
| CA1313110C (en) | Heat treated alloy | |
| US4661169A (en) | Producing an iron-chromium-aluminum alloy with an adherent textured aluminum oxide surface | |
| US3759758A (en) | High strength aluminum casting alloy | |
| US4525325A (en) | Copper-nickel-tin-cobalt spinodal alloy | |
| US4732625A (en) | Copper-nickel-tin-cobalt spinodal alloy | |
| US3318690A (en) | Age hardening manganese-containing maraging steel | |
| EP0476043A4 (en) | Improved nickel aluminide alloy for high temperature structural use | |
| JP3597211B2 (en) | Spheroidal graphite cast iron with excellent high-temperature strength | |
| US3005705A (en) | High temperature alloys | |
| US3940295A (en) | Low expansion alloys | |
| US3772095A (en) | Copper base alloys | |
| CA1101699A (en) | High-strength, high-expansion manganese alloy | |
| US4406858A (en) | Copper-base alloys containing strengthening and ductilizing amounts of hafnium and zirconium and method | |
| US3772093A (en) | Copper base alloys | |
| US3954509A (en) | Method of producing low expansion alloys |