EP0037446A1 - Austenitic iron base alloy - Google Patents
Austenitic iron base alloy Download PDFInfo
- Publication number
- EP0037446A1 EP0037446A1 EP80303047A EP80303047A EP0037446A1 EP 0037446 A1 EP0037446 A1 EP 0037446A1 EP 80303047 A EP80303047 A EP 80303047A EP 80303047 A EP80303047 A EP 80303047A EP 0037446 A1 EP0037446 A1 EP 0037446A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- alloy
- stainless steel
- molybdenum
- chromium
- nickel
- 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.)
- Granted
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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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
-
- 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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/50—Ferrous alloys, e.g. steel alloys containing chromium with nickel with titanium or zirconium
-
- 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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/54—Ferrous alloys, e.g. steel alloys containing chromium with nickel with boron
Definitions
- This invention relates to austenitic iron base alloys which find particular use in nuclear reactors and are characterized by improved swelling resistance and phase stability in both the annealed as well as the cold work condition in comparison with an AISI type 316 stainless steel.
- the AISI type 316 stainless steel because of its austenitic character and which is strengthened through a solid solution strengthening addition would prove to be ideally suited for use in a nuclear reactor.
- This conclusion was supported by the fact that the AISI type 316 stainless steel appeared to possess the desired strength characteristics at elevated temperatures. It was soon found however that even after low fluid reactor irradiation copious amounts radiation induced percipitation were evident in the microstructure and the material was subjected to relatively high swelling. It therefore became apparent that it was necessary to alter the chemical composition AISI type 316 stainless steel in an attempt to eliminate the phase instabilities and to provide improved swelling resistance without seriously adversely affecting the strength characteristics of the fundamental alloy. To this end, the alloys of the present invention appear to fulfill these primary requisites.
- the present invention resides in an austenitic iron base alloy having improved structural stability and swelling resistance compared to AISI type 316 stainless steel and which alloy is suitable for use in an atmosphere subject to neutron irradiation, characterized in that said alloy consisting essentially of from 14% to 16% nickel, from 12% to 14% chromium, from 1.2% to 1.7% molybdenum, from 0.5% to 1.1% silicon, from 1.5% to 2.5% manganese, up to 0.1% zirconium, from 0.2% to 0.5%.titanium, from 0.02% to 0.1% carbon, up to 0.01% boron and the balance iron with incidental impurities.
- the desired properties can be achieved by lowering the relative amounts of nickel, chromium, and molybdenum while still maintaining the austenitic characteristic of the alloy when the same is subjected to elevated temperature irradiation of the type normally found, for example, in the case of fuel pins in a nuclear reactor. More specifically, the alloy will exhibit improved swelling resistance at elevated temperatures in both the annealed as well as the cold work condition.
- Table 1 set forth hereinafter lists the chemical composition of the AISI type 316 stainless steel as well as the broad range, the preferred range, and the specific composition of a heat falling within the preferred as well as the broad ranges as set forth herein.
- the alloy of the present invention has less chromium, less nickel, and less molybdenum than that of a corresponding AISI type 316 stainless steel. Moreover, as can be seen from Table 1 the larger reduction of the chromium together with a smaller reduction of the molybdenum and the smaller reduction or even increase in the nickel is effective for maintaining the austenitic character of this alloy which austenitic character is strengthened by means of the molybdenum addition thereto. Note in particular that since the titanium and zirconium contents are quite limited, the microstructure of the alloy remains substantially precipitation free after extended exposures to the influence of neutron irradiation at elevated temperatures.
- Figure 1 which directly compares a solution annealed AISI type 316 stainless steel and the alloy of this invention having the composition of heat number 5976 as identified in Table 1 and the effect of the temperature at various fluence values in relation to the percent swelling.
- Curve 10 of Figure 1 is a plot of the AISI type 316 stainless steel material whereas curve 12 is a plot of the identical values exhibited by-the alloy of the present invention in the solution annealed condition which alloy has been arbitrarily designated D9B1.
- the alloy of the present invention has far superior swelling resistance to that exhibited by the AISI type 316 stainless steel.
- the curve 20 illustrates the data for AISI type 316 stainless steel in the 20% cold work condition and curve 22 shows the swelling resistance of alloy D9Bl in the 25% cold work condition. It is also believed significant to point out that in the cold work condition, the alloy of the present invention is still densifying while the AISI type 316 stainless steel is into the void swelling regiment regardless of the temperatures employed. Thus, these data make it clear that the alloys of the present invention are particularly suitable for use for example in a fast breeder reactor.
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Heat Treatment Of Steel (AREA)
Abstract
Description
- This invention relates to austenitic iron base alloys which find particular use in nuclear reactors and are characterized by improved swelling resistance and phase stability in both the annealed as well as the cold work condition in comparison with an AISI type 316 stainless steel.
- With the advent of the nuclear age and the materials problems associated therewith, it was believed that the AISI type 316 stainless steel because of its austenitic character and which is strengthened through a solid solution strengthening addition would prove to be ideally suited for use in a nuclear reactor. This conclusion was supported by the fact that the AISI type 316 stainless steel appeared to possess the desired strength characteristics at elevated temperatures. It was soon found however that even after low fluid reactor irradiation copious amounts radiation induced percipitation were evident in the microstructure and the material was subjected to relatively high swelling. It therefore became apparent that it was necessary to alter the chemical composition AISI type 316 stainless steel in an attempt to eliminate the phase instabilities and to provide improved swelling resistance without seriously adversely affecting the strength characteristics of the fundamental alloy. To this end, the alloys of the present invention appear to fulfill these primary requisites.
- Accordingly, the present invention resides in an austenitic iron base alloy having improved structural stability and swelling resistance compared to AISI type 316 stainless steel and which alloy is suitable for use in an atmosphere subject to neutron irradiation, characterized in that said alloy consisting essentially of from 14% to 16% nickel, from 12% to 14% chromium, from 1.2% to 1.7% molybdenum, from 0.5% to 1.1% silicon, from 1.5% to 2.5% manganese, up to 0.1% zirconium, from 0.2% to 0.5%.titanium, from 0.02% to 0.1% carbon, up to 0.01% boron and the balance iron with incidental impurities.
- It has been found that the desired properties can be achieved by lowering the relative amounts of nickel, chromium, and molybdenum while still maintaining the austenitic characteristic of the alloy when the same is subjected to elevated temperature irradiation of the type normally found, for example, in the case of fuel pins in a nuclear reactor. More specifically, the alloy will exhibit improved swelling resistance at elevated temperatures in both the annealed as well as the cold work condition.
- In order that the invention can be more clearly understood, a preferred embodiment thereof will now be described, by way of example, with reference to the accompanying drawings in which:
- Figure 1 is a plot of- percent swelling verses the temperature of an alloy of the present invention in comparison with standard AISI type 316 stainless steel, the actual numbers of the data points being the actual fluence values; and
- Figure 2 is a similar plot to Figure 1 but with the alloys in the cold work condition.
-
- By inspection of Table 1 it becomes clear that the alloy of the present invention has less chromium, less nickel, and less molybdenum than that of a corresponding AISI type 316 stainless steel. Moreover, as can be seen from Table 1 the larger reduction of the chromium together with a smaller reduction of the molybdenum and the smaller reduction or even increase in the nickel is effective for maintaining the austenitic character of this alloy which austenitic character is strengthened by means of the molybdenum addition thereto. Note in particular that since the titanium and zirconium contents are quite limited, the microstructure of the alloy remains substantially precipitation free after extended exposures to the influence of neutron irradiation at elevated temperatures. In order to more clearly and graphically depict the improvement in swelling resistance exhibited by the allow of the present invention, attention is directed to Figure 1 which directly compares a solution annealed AISI type 316 stainless steel and the alloy of this invention having the composition of heat number 5976 as identified in Table 1 and the effect of the temperature at various fluence values in relation to the percent swelling.
Curve 10 of Figure 1 is a plot of the AISI type 316 stainless steel material whereascurve 12 is a plot of the identical values exhibited by-the alloy of the present invention in the solution annealed condition which alloy has been arbitrarily designated D9B1. As can be seen from the data set forth in Figure 1, the alloy of the present invention has far superior swelling resistance to that exhibited by the AISI type 316 stainless steel. This is especially so when the percent swelling is considered at about the temperature of 600°C and a fluence value of 5.7 x 10 22 neutrons per square centimeter. These same results are more outstanding when the data is compared for the material in the cold work condition. Thus in Figure 2, thecurve 20 illustrates the data for AISI type 316 stainless steel in the 20% cold work condition andcurve 22 shows the swelling resistance of alloy D9Bl in the 25% cold work condition. It is also believed significant to point out that in the cold work condition, the alloy of the present invention is still densifying while the AISI type 316 stainless steel is into the void swelling regiment regardless of the temperatures employed. Thus, these data make it clear that the alloys of the present invention are particularly suitable for use for example in a fast breeder reactor. It has been found however that the long term stress rupture properties at temperatures greater than 650°C appear to be weaker than AISI type 316 stainless steel based on the latest unradiated specimen testing. However, it is believed that comparable results can be obtained where the material is in the cold worked condition and the degree of cold working is limited to about 20% for optimum stress rupture and swelling resistance characteristics. While it will be appreciated that the swelling resistance characteristics will still be outstanding where the alloy is worked to a degree greater than 20%. The optimum results appear to be obtained when the cold working is limited to 20%. For swelling resistance alone, it has been found that cold working the material within the range between 15% and 40% does not appear to adversely affect the swelling resistance demonstrated by the alloy of the present invention.
Claims (2)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US11052580A | 1980-01-09 | 1980-01-09 | |
US110525 | 1998-07-06 |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0037446A1 true EP0037446A1 (en) | 1981-10-14 |
EP0037446B1 EP0037446B1 (en) | 1985-06-05 |
Family
ID=22333507
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP19800303047 Expired EP0037446B1 (en) | 1980-01-09 | 1980-09-02 | Austenitic iron base alloy |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP0037446B1 (en) |
JP (1) | JPS5698460A (en) |
DE (1) | DE3070736D1 (en) |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0078440A2 (en) * | 1981-11-02 | 1983-05-11 | INTERATOM Gesellschaft mit beschränkter Haftung | Austenitic steel with resistance to neutron induced swelling |
EP0089436A2 (en) * | 1982-03-18 | 1983-09-28 | Westinghouse Electric Corporation | Method of thermomechanically treating alloys |
EP0106426A1 (en) * | 1982-09-02 | 1984-04-25 | Westinghouse Electric Corporation | Austenitic alloys and reactor components made thereof |
EP0121630A2 (en) * | 1983-04-12 | 1984-10-17 | Westinghouse Electric Corporation | Improved austenitic stainless steel alloys for high temperature applications |
FR2642437A1 (en) * | 1989-01-30 | 1990-08-03 | Kernforschungsz Karlsruhe | AUSTENITIC STEEL HAVING IMPROVED RESISTANCE TO NEUTRON-INDUCED SWELLING AND HELIUM FRAGILIZATION |
FR2790089A1 (en) * | 1999-02-23 | 2000-08-25 | Commissariat Energie Atomique | Monitoring and prediction of physical, mechanical or chemical properties of a metal alloy, namely austenitic stainless steel used as nuclear reactor core material, involves determining the total mass fraction precipitated in the alloy |
US7311875B2 (en) * | 2001-06-13 | 2007-12-25 | Höganäs Ab | High density stainless steel products and method for the preparation thereof |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS6187853A (en) * | 1984-09-28 | 1986-05-06 | Kobe Steel Ltd | Austenitic stainless steel used as structural material for core or fast breeder reactor |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB993613A (en) * | 1963-11-22 | 1965-06-02 | Sandvikens Jernverks Ab | Alloy steels and articles made therefrom |
US4158606A (en) * | 1977-01-27 | 1979-06-19 | The United States Department Of Energy | Austenitic stainless steel alloys having improved resistance to fast neutron-induced swelling |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4011133A (en) * | 1975-07-16 | 1977-03-08 | The United States Of America As Represented By The United States Energy Research And Development Administration | Austenitic stainless steel alloys having improved resistance to fast neutron-induced swelling |
-
1980
- 1980-09-02 DE DE8080303047T patent/DE3070736D1/en not_active Expired
- 1980-09-02 EP EP19800303047 patent/EP0037446B1/en not_active Expired
- 1980-09-09 JP JP12414780A patent/JPS5698460A/en active Pending
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB993613A (en) * | 1963-11-22 | 1965-06-02 | Sandvikens Jernverks Ab | Alloy steels and articles made therefrom |
US4158606A (en) * | 1977-01-27 | 1979-06-19 | The United States Department Of Energy | Austenitic stainless steel alloys having improved resistance to fast neutron-induced swelling |
Cited By (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0078440A2 (en) * | 1981-11-02 | 1983-05-11 | INTERATOM Gesellschaft mit beschränkter Haftung | Austenitic steel with resistance to neutron induced swelling |
EP0078440A3 (en) * | 1981-11-02 | 1984-02-08 | Interatom Internationale Atomreaktorbau Gmbh | Austenitic steel with resistance to neutron induced swelling |
EP0089436A2 (en) * | 1982-03-18 | 1983-09-28 | Westinghouse Electric Corporation | Method of thermomechanically treating alloys |
EP0089436A3 (en) * | 1982-03-18 | 1984-10-17 | Westinghouse Electric Corporation | Method of thermomechanically treating alloys |
EP0106426A1 (en) * | 1982-09-02 | 1984-04-25 | Westinghouse Electric Corporation | Austenitic alloys and reactor components made thereof |
EP0121630A2 (en) * | 1983-04-12 | 1984-10-17 | Westinghouse Electric Corporation | Improved austenitic stainless steel alloys for high temperature applications |
EP0121630A3 (en) * | 1983-04-12 | 1985-01-09 | Westinghouse Electric Corporation | Improved austenitic stainless steel alloys for high temperature applications |
FR2642437A1 (en) * | 1989-01-30 | 1990-08-03 | Kernforschungsz Karlsruhe | AUSTENITIC STEEL HAVING IMPROVED RESISTANCE TO NEUTRON-INDUCED SWELLING AND HELIUM FRAGILIZATION |
FR2790089A1 (en) * | 1999-02-23 | 2000-08-25 | Commissariat Energie Atomique | Monitoring and prediction of physical, mechanical or chemical properties of a metal alloy, namely austenitic stainless steel used as nuclear reactor core material, involves determining the total mass fraction precipitated in the alloy |
US7311875B2 (en) * | 2001-06-13 | 2007-12-25 | Höganäs Ab | High density stainless steel products and method for the preparation thereof |
Also Published As
Publication number | Publication date |
---|---|
EP0037446B1 (en) | 1985-06-05 |
DE3070736D1 (en) | 1985-07-11 |
JPS5698460A (en) | 1981-08-07 |
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