US2770030A - Welded joint between dissimilar metals - Google Patents
Welded joint between dissimilar metals Download PDFInfo
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- US2770030A US2770030A US168385A US16838550A US2770030A US 2770030 A US2770030 A US 2770030A US 168385 A US168385 A US 168385A US 16838550 A US16838550 A US 16838550A US 2770030 A US2770030 A US 2770030A
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- United States
- Prior art keywords
- ferritic
- alloy
- austenitic
- carbon
- welded joint
- 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 - Lifetime
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- 229910052751 metal Inorganic materials 0.000 title description 8
- 239000002184 metal Substances 0.000 title description 8
- 150000002739 metals Chemical class 0.000 title description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 29
- 229910052799 carbon Inorganic materials 0.000 claims description 29
- 229910052804 chromium Inorganic materials 0.000 claims description 13
- 239000011651 chromium Substances 0.000 claims description 13
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims description 11
- 229910000851 Alloy steel Inorganic materials 0.000 claims description 10
- 239000000203 mixture Substances 0.000 claims description 9
- 239000000463 material Substances 0.000 description 19
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 18
- 230000035882 stress Effects 0.000 description 18
- 229910045601 alloy Inorganic materials 0.000 description 16
- 239000000956 alloy Substances 0.000 description 16
- 238000003466 welding Methods 0.000 description 15
- 229910052750 molybdenum Inorganic materials 0.000 description 7
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 6
- 239000011733 molybdenum Substances 0.000 description 6
- 239000000654 additive Substances 0.000 description 5
- 230000004927 fusion Effects 0.000 description 5
- 229910052759 nickel Inorganic materials 0.000 description 5
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 4
- 125000004122 cyclic group Chemical group 0.000 description 4
- 238000000034 method Methods 0.000 description 4
- 230000003647 oxidation Effects 0.000 description 4
- 238000007254 oxidation reaction Methods 0.000 description 4
- 229910052710 silicon Inorganic materials 0.000 description 4
- 239000010703 silicon Substances 0.000 description 4
- 238000009434 installation Methods 0.000 description 3
- 238000005728 strengthening Methods 0.000 description 3
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 2
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 2
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 description 2
- 230000000996 additive effect Effects 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 230000008602 contraction Effects 0.000 description 2
- 238000010790 dilution Methods 0.000 description 2
- 239000012895 dilution Substances 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- 229910052748 manganese Inorganic materials 0.000 description 2
- 239000011572 manganese Substances 0.000 description 2
- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000009740 moulding (composite fabrication) Methods 0.000 description 2
- 239000010955 niobium Substances 0.000 description 2
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 description 2
- 230000035515 penetration Effects 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 230000035939 shock Effects 0.000 description 2
- 239000010936 titanium Substances 0.000 description 2
- 229910052719 titanium Inorganic materials 0.000 description 2
- 230000007704 transition Effects 0.000 description 2
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 2
- 229910052721 tungsten Inorganic materials 0.000 description 2
- 239000010937 tungsten Substances 0.000 description 2
- 229910052720 vanadium Inorganic materials 0.000 description 2
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 description 2
- 229910052726 zirconium Inorganic materials 0.000 description 2
- YZCKVEUIGOORGS-UHFFFAOYSA-N Hydrogen atom Chemical compound [H] YZCKVEUIGOORGS-UHFFFAOYSA-N 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 229910002065 alloy metal Inorganic materials 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- 239000010953 base metal Substances 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- -1 chromium carbides Chemical class 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 230000001351 cycling effect Effects 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 230000009429 distress Effects 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 238000005304 joining Methods 0.000 description 1
- 229910001092 metal group alloy Inorganic materials 0.000 description 1
- 230000005012 migration Effects 0.000 description 1
- 238000013508 migration Methods 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000007778 shielded metal arc welding Methods 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
- B23K35/22—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by the composition or nature of the material
- B23K35/24—Selection of soldering or welding materials proper
- B23K35/30—Selection of soldering or welding materials proper with the principal constituent melting at less than 1550 degrees C
- B23K35/3053—Fe as the principal constituent
- B23K35/308—Fe as the principal constituent with Cr as next major constituent
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S428/00—Stock material or miscellaneous articles
- Y10S428/922—Static electricity metal bleed-off metallic stock
- Y10S428/9335—Product by special process
- Y10S428/939—Molten or fused coating
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/12—All metal or with adjacent metals
- Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
- Y10T428/12639—Adjacent, identical composition, components
- Y10T428/12646—Group VIII or IB metal-base
- Y10T428/12653—Fe, containing 0.01-1.7% carbon [i.e., steel]
Definitions
- This invention relates to the production of a Welded joint between austenitic and ferritic materials suitable for high temperature, high pressure service under conditions involving thermal shock and cyclic temperature and load applications.
- Such conditions are encountered in high temperature process plants such as, for example, oil refineries, in vapor or steam generators, and in heat exchangers of various types.
- the particular problems in any one type of installation may differ in one or more aspects from those in another type.
- refineries involve high temperatures but only moderate pressures, in conjunction with alternating oxidation and reducing conditions, corrosive environments and the like.
- steam generators a more complex stress condition exists due to the combined actions of high operating pressures and high operating temperatures, which are further aggravated by cyclic variations in these factors.
- the invention is of general application under high temperature, high stress conditions in any type of installation, particular reference will be made, by way of example only, to the high temperature and high stress conditions encountered in steam generators.
- both aastenitic and ferritic materials for the outlet components of the steam generators.
- both types of material may be used in the superheater and its supports, and in the main steam line from the generator to the turbine.
- Use of both types of materials in the same component requiresthat particular attention be given to the junctions between these materials, which junctions must operate under the particular temperature and stress conditions encountered in producing steam at relatively high temperatures.
- the external surface and the superheater support lugs are at a higher temperature than the internal surface of the superheater tubes, due to the higher temperatures of the heating gases as compared to the temperature of the steam flowing through the superheater. The reverse is true with respect to the steam line leading to the turbine.
- the present invention is particularly directed to the production of a welded joint, between austenitic and ferritic materials, which has the requisite strength, ductility, and oxidation resistance to assure satisfactory performance under conditions of high stresses occasioned by thermal shock, cyclic temperature and load application, and diflferential thermal expansion. It has been found that these objectives can be obtained by forming the welded joint by fusion deposition of a ferritic alloy metal having substantially the composition of the ferritic alloy workpiece excepting for carbon. The carbon content of the fusion deposited ferritic weld is maintained at a value much lower than that of the ferritic alloy workpiece, and does not exceed 0.05%.
- a satisfactory joint can be produced by utilizing a Welding rod having the same composition as the fcrritic workpiece, but with a carbon content of 0.05% or less.
- strengthening additives may be used. Typical strengthening additives are molybdenum, manganese, chromium, and/or nickel. Tungsten, vanadium, zirconium, columbium, or titanium may also be used advantageously. Silicon may be incorporated to enhance oxidation resistance.
- Typical examples of the application of the invention are the welding of cast austenitic support lugs to ferritic superheater tubes and the butt welding of a ferritic high temperature-high pressure service tube to an austenitic high temperature-high pressure service tube.
- a typical example of a superheater support lug is shown in Gilg Patent No. 2,134,713.
- the stress conditions are due not only to the difference in expansion characteristics but also to temperature differences between the superheater tube and its support lug, one carrying relatively lower temperature steam and the other being enveloped by relatively higher temperature heating gases, and to the cantilever loading of the tube and lug.
- stresses result from internal pressures, high temperatures, and ditferential thermal expansion.
- ferritic electrodes of substantially the composition of the ferritic workpiece, but having a carbon content in excess of 0.05%, are used for welding austenitic alloy members to ferritic members
- the dilution of the deposited weld metal with chromium and nickel may result in extremely hard and brittle microstructures, such as chromium carbides, for example, in the Weld deposit.
- Such extremely hard and brittle microstructures are conducive to micro-fissuring when the welded component is used at high temperatures and under conditions of high stress.
- microstructures would comprise brittle regions which may serve as potential starting points for failure under the stresses due to substantial differential thermal expansion of the ferritic and austenitic workpiece.
- the welded joint of the present invention being formed from a low carbon ferritic weld deposit, will not result in excessively hard and brittle microstructures in view of the low carbon level of the weld metal which would tend to prevent dilution with the austenitic base metal.
- the low carbon ferritic weld deposit has the advantage that it is able to satisfactorily withstand the high stresses associated with high temperature operations, particularly under cyclically varying temperature and pressure conditions, to a far greater degree than an austenitic weld deposit.
- a preferred composition of a weld rod for use in form ing the welded joint with the invention method includes carbon from 0.00 to 0.05% and one or more of the following:
- the composition may further include up to 4% of tungsten, vanadium, zirconium, columbium or titanium.
- the weld rod may be formed in any desired manner, either by providing an alloy of the foregoing materials, or by coating an iron rod with the additive alloying elements included in the coating. The proportions of the additive elements are selected in such manner that a predominantly ferritic structure is provided.
- the actual welding may be performed by any of the processes known to those skilled in the art, such as shielded metal arc welding, atomic hydrogen welding, inert gas arc welding, submerged flux arc welding, or the like, depending upon the particular application involved.
- the use of the low carbon weld deposit between a ferritic alloy, having 2%% chromium and up to 0.15 carbon, and an austenitic material reduces carbon migration and thus reduces somewhat the tendency to failure under repeated cyclic stresses, due to such carbon depletion. Additionally, in such applications as the welding of austenitic support members to ferritic superheater tubes, the low carbon ferritic weld deposit removes the point of high stress due to expansion, from the colder face of the tube to a higher temperature zone having a lesser range of temperature cycling and consequently lower operating stresses. It improves the metallurgical transition between the austenitic alloy and the ferritic alloy, advantageously relieving the expansion stress problems by eliminating the sharp transition from a hard to a soft zone at the fusion line.
- Typical examples of austenitic materials which have been successfully welded to ferritic materials by the present invention are alloys such as 18 Cr8 Ni, 25 Cr12 Ni, 19 Cr9 Ni, and 25 Cr20 Ni, the ferritic material being, by way of example, an alloy containing from 2 4% to 5% Cr and 1% Mo.
- the particular ferritic weld metal used to form the joint is selected to have an as-welded composition substantially the same as that of the ferritic workpiece except for the carbon content.
- the low carbon ferritic weld metal of the invention must have sufficient strength to resist creep at elevated temperatures andthis can be attained by using sufl'icient strengthening elements such as manganese, molybdenum, etc., to replace the carbon not present and provide an alloy which is non-air-hardening.
- sufl'icient strengthening elements such as manganese, molybdenum, etc.
- the weld metal alloy should have sufiicient oxidation resistance at elevated temperatures to make it practicable for use in high temperature installations without the danger of formation of notches due to oxide penetration. This may be effected by adding silicon up to 4%, for example.
- a welded joint for use under cyclically variable elevated temperatures and pressures comprising a Cr-Ni austenitic alloy steel member, a low alloy ferritic steel member of the chromium containing type and having a carbon content in the range of 0.10% to 0.15%, and a weld deposit uniting said members and consisting of a ferritic alloy steel having substantially the same composition as said ferritic steel alloy member but containing carbon in an amount not exceeding 0.05
- balance iron with the usual incidental impurities the relative proportions of the additives being selected to produce a predominantly ferritic weld structure.
- a welded joint for use under cyclically variable elevated temperatures and pressures comprising a Cr-Ni austenitic alloy steel member, a ferritic alloy steel member containing approximately 2.25% chromium and having a carbon content of the order of 0.15%, and a weld deposit uniting said members and consisting of a ferritic alloy steel having substantially the same composition as said ferritic steel alloy member but containing carbon in an amount not exceeding 0.05
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Arc Welding In General (AREA)
Description
ariaasa Patented Nov. 13, 1956 ice WELDED JOINT BETWEEN DISSEMILAR METALS Otis R. Carpenter, Barberton, and Nicholas C. Jessen, Akron, Ohio, assignors to The Babcock 8.; Wilcox Company, Rockleigh, N. 3., a corporation of New Jersey No Drawing. Application June 15, 1950, Serial No. 168,385
3 Claims. (Cl. 29196.1)
This invention relates to the production of a Welded joint between austenitic and ferritic materials suitable for high temperature, high pressure service under conditions involving thermal shock and cyclic temperature and load applications.
Such conditions are encountered in high temperature process plants such as, for example, oil refineries, in vapor or steam generators, and in heat exchangers of various types. The particular problems in any one type of installation may differ in one or more aspects from those in another type. Thus, refineries involve high temperatures but only moderate pressures, in conjunction with alternating oxidation and reducing conditions, corrosive environments and the like. In steam generators a more complex stress condition exists due to the combined actions of high operating pressures and high operating temperatures, which are further aggravated by cyclic variations in these factors. While the invention is of general application under high temperature, high stress conditions in any type of installation, particular reference will be made, by way of example only, to the high temperature and high stress conditions encountered in steam generators.
In order to obtain higher efiiciencies, the outlet steam temperatures and the operating pressures of central station steam generators have been constantly increasing, and presently some central station steam generating units have outlet temperatures of 1050 F. and operating pressures of over 2000 p. s. i. The increasing use of such high temperatures and pressures has brought with it problems of providing materials and joints between such materials Which will successfully withstand the stresses encountered thereat.
The long time load carrying characteristics of metals at high temperatures, together with the economics involved, have led steam generator designers to use both aastenitic and ferritic materials for the outlet components of the steam generators. For example, both types of material may be used in the superheater and its supports, and in the main steam line from the generator to the turbine. Use of both types of materials in the same component requiresthat particular attention be given to the junctions between these materials, which junctions must operate under the particular temperature and stress conditions encountered in producing steam at relatively high temperatures. In a superheater, for example, the external surface and the superheater support lugs are at a higher temperature than the internal surface of the superheater tubes, due to the higher temperatures of the heating gases as compared to the temperature of the steam flowing through the superheater. The reverse is true with respect to the steam line leading to the turbine.
Operation under stress at such high temperatures introduces many problems due to the difierential expansion and contraction of the dissimilar materials on either side of the joint, their relative surface and structural stability, etc. Aside from mechanical stresses, such as, for example,
those due to differential thermal expansion and contraction, the factors influencing the service life of Welded joints between ferritic and austenitic materials have been basically of a metallurgical nature, such as carbon depletion in the heat affected zone of the ferritic material, notching due to oxide penetration occurring therein, micro-fissuring in the weld junction, and accelerated creep due to these conditions. Examples of joints between ferritic and austenitic materials, with which these problems are encountered, are the joining of a ferritic alloy having substantially 2 4% chromium to an austenitic alloy of the l88 or 25-20 type.
The present invention is particularly directed to the production of a welded joint, between austenitic and ferritic materials, which has the requisite strength, ductility, and oxidation resistance to assure satisfactory performance under conditions of high stresses occasioned by thermal shock, cyclic temperature and load application, and diflferential thermal expansion. It has been found that these objectives can be obtained by forming the welded joint by fusion deposition of a ferritic alloy metal having substantially the composition of the ferritic alloy workpiece excepting for carbon. The carbon content of the fusion deposited ferritic weld is maintained at a value much lower than that of the ferritic alloy workpiece, and does not exceed 0.05%.
For example, in weld uniting a ferritic alloy workpiece having a chromium content of substantially 2%% and 1% molybdenum to an austenitic alloy workpiece having, for example, 18 to 25% chromium, and 8 to 20% nickel, a satisfactory joint can be produced by utilizing a Welding rod having the same composition as the fcrritic workpiece, but with a carbon content of 0.05% or less. To compensate for the possible reduction in strength of the fusion deposited weld metal due to the low carbon content thereof, strengthening additives may be used. Typical strengthening additives are molybdenum, manganese, chromium, and/or nickel. Tungsten, vanadium, zirconium, columbium, or titanium may also be used advantageously. Silicon may be incorporated to enhance oxidation resistance.
Typical examples of the application of the invention are the welding of cast austenitic support lugs to ferritic superheater tubes and the butt welding of a ferritic high temperature-high pressure service tube to an austenitic high temperature-high pressure service tube. A typical example of a superheater support lug is shown in Gilg Patent No. 2,134,713. In the first example, the stress conditions are due not only to the difference in expansion characteristics but also to temperature differences between the superheater tube and its support lug, one carrying relatively lower temperature steam and the other being enveloped by relatively higher temperature heating gases, and to the cantilever loading of the tube and lug. In the butt welded tube assembly, stresses result from internal pressures, high temperatures, and ditferential thermal expansion.
When standard, commonly available ferritic electrodes of substantially the composition of the ferritic workpiece, but having a carbon content in excess of 0.05%, are used for welding austenitic alloy members to ferritic members, the dilution of the deposited weld metal with chromium and nickel may result in extremely hard and brittle microstructures, such as chromium carbides, for example, in the Weld deposit. Such extremely hard and brittle microstructures are conducive to micro-fissuring when the welded component is used at high temperatures and under conditions of high stress. Furthermore, such microstructures would comprise brittle regions which may serve as potential starting points for failure under the stresses due to substantial differential thermal expansion of the ferritic and austenitic workpiece. Failures have been known to occur in the ferritic workpiece at the carbon depleted region thereof, where the carbon has migrated toward the line of fusion of the weld joint, producing thereat a very hard structure. The carbon depleted area is correspondingly weakened.
The welded joint of the present invention being formed from a low carbon ferritic weld deposit, will not result in excessively hard and brittle microstructures in view of the low carbon level of the weld metal which would tend to prevent dilution with the austenitic base metal. As compared with a weld deposit of an austenitic material, such as 25-20 or 18-8 alloys, the low carbon ferritic weld deposit has the advantage that it is able to satisfactorily withstand the high stresses associated with high temperature operations, particularly under cyclically varying temperature and pressure conditions, to a far greater degree than an austenitic weld deposit.
A preferred composition of a weld rod for use in form ing the welded joint with the invention method includes carbon from 0.00 to 0.05% and one or more of the following:
Percent Manganese from 0.00 to 3.00 Silicon from 0.00 to 3.00 Chromium from 0.00 to 30.00 Molybdenum from 0.00 to 4.00 Nickel from 0.00 to 10.00
The composition may further include up to 4% of tungsten, vanadium, zirconium, columbium or titanium. The weld rod may be formed in any desired manner, either by providing an alloy of the foregoing materials, or by coating an iron rod with the additive alloying elements included in the coating. The proportions of the additive elements are selected in such manner that a predominantly ferritic structure is provided.
The actual welding may be performed by any of the processes known to those skilled in the art, such as shielded metal arc welding, atomic hydrogen welding, inert gas arc welding, submerged flux arc welding, or the like, depending upon the particular application involved.
Welds between austenitic and ferritic members made in accordance with the present invention have given satisfactory performances, under conditions of high temperature and under the high stresses involved in steam generation, particularly as compared with welds formed from austenitic weld deposits. In a particular example, specimens were prepared involving the welding of a 25 Crl2 Ni cast superheater lug to a 2%, chromiuml% molybdenum tube utilizing, in one case, a 25 Cr20 Ni electrode and in the other case the low carbon 2%% chromiuml% molybdenum electrode according to the present invention. After about 15 quenches from 1150 F. to 80 F., the lugs welded with the austenitic material separated from the tube, whereas those welded with the invention low carbon electrode showed no visible cracking or other signs of distress even after 100 such quenches.
The use of the low carbon weld deposit between a ferritic alloy, having 2%% chromium and up to 0.15 carbon, and an austenitic material, reduces carbon migration and thus reduces somewhat the tendency to failure under repeated cyclic stresses, due to such carbon depletion. Additionally, in such applications as the welding of austenitic support members to ferritic superheater tubes, the low carbon ferritic weld deposit removes the point of high stress due to expansion, from the colder face of the tube to a higher temperature zone having a lesser range of temperature cycling and consequently lower operating stresses. It improves the metallurgical transition between the austenitic alloy and the ferritic alloy, advantageously relieving the expansion stress problems by eliminating the sharp transition from a hard to a soft zone at the fusion line.
Typical examples of austenitic materials which have been successfully welded to ferritic materials by the present invention are alloys such as 18 Cr8 Ni, 25 Cr12 Ni, 19 Cr9 Ni, and 25 Cr20 Ni, the ferritic material being, by way of example, an alloy containing from 2 4% to 5% Cr and 1% Mo. In each case, the particular ferritic weld metal used to form the joint is selected to have an as-welded composition substantially the same as that of the ferritic workpiece except for the carbon content.
For high temperature and high pressure steam generating service, the low carbon ferritic weld metal of the invention must have sufficient strength to resist creep at elevated temperatures andthis can be attained by using sufl'icient strengthening elements such as manganese, molybdenum, etc., to replace the carbon not present and provide an alloy which is non-air-hardening. Also, the weld metal alloy should have sufiicient oxidation resistance at elevated temperatures to make it practicable for use in high temperature installations without the danger of formation of notches due to oxide penetration. This may be effected by adding silicon up to 4%, for example.
While specific examples of the invention have been described above, it should be understood that the invention principles may be otherwise embodied within the the scope of the invention.
We claim:
1. A welded joint for use under cyclically variable elevated temperatures and pressures, comprising a Cr-Ni austenitic alloy steel member, a low alloy ferritic steel member of the chromium containing type and having a carbon content in the range of 0.10% to 0.15%, and a weld deposit uniting said members and consisting of a ferritic alloy steel having substantially the same composition as said ferritic steel alloy member but containing carbon in an amount not exceeding 0.05
2. A welded joint as claimed in claim 1 in which said ferritic alloy steel weld deposit includes at least one of the following elements:
Percent Manganese not exceeding 3.00 Silicon not exceeding 3.00 Chromium not exceeding 30.00 Molybdenumnot exceeding 4.00 Nickel not exceeding 10.00
balance iron with the usual incidental impurities; the relative proportions of the additives being selected to produce a predominantly ferritic weld structure.
3. A welded joint for use under cyclically variable elevated temperatures and pressures, comprising a Cr-Ni austenitic alloy steel member, a ferritic alloy steel member containing approximately 2.25% chromium and having a carbon content of the order of 0.15%, and a weld deposit uniting said members and consisting of a ferritic alloy steel having substantially the same composition as said ferritic steel alloy member but containing carbon in an amount not exceeding 0.05
References Cited in the file of this patent UNITED STATES PATENTS (Other references on following page) 6 UNITED STATES PATENTS Welding Handbook, third ed., pp. 609, 640, 641, 650, 2,544,336 Linnert Man 6 1951' 651 and 670. Published by American Welding Society, 2,564,474 Field Aug. 14, 1951 New Ymk,
Welding Handbook, 1942 ed., pp. 773, 794 and 795.
OTHER REFERENCES 5 Published by the American Welding Society, 33 West 39th Procedure Handbook of Arc Welding Design and Prac- St, New York,
tice. Eighth ed., p. 398. Published by The Lincoln Elec- American Machinist, March 1, 1945, ,pp-
tric Co., Cleveland, Ohio.
Claims (1)
1. A WELDED JOINT FOR USE UNDER CYCLICALLY VARIABLE ELEVATED TEMPERATURES AND PRESSURES, COMPRISING A CR-NI AUSTENITIC ALLOY STEEL MEMBER, A LOW ALLOY FERRITIC STEEL MEMBER OF THE CHROMIUM CONTAINING TYPE AND HAVING A CARBON CONTENT IN THE RANGE OF 0.10% TO 0.15%, AND A WELD DEPOSIT UNITING SAID MEMBERS AND CONSISTING OF A FERRITIC ALLOY STEEL HAVING SUBSTANTIALLY THE SAME COMPOSITION AS SAID FERRITIC STEEL ALLOY MEMBER BUT CONTAINING CARBON IN AN AMOUNT NOT EXCEEDING 0.05%.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
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US168385A US2770030A (en) | 1950-06-15 | 1950-06-15 | Welded joint between dissimilar metals |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
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US168385A US2770030A (en) | 1950-06-15 | 1950-06-15 | Welded joint between dissimilar metals |
Publications (1)
Publication Number | Publication Date |
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US2770030A true US2770030A (en) | 1956-11-13 |
Family
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Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US168385A Expired - Lifetime US2770030A (en) | 1950-06-15 | 1950-06-15 | Welded joint between dissimilar metals |
Country Status (1)
Country | Link |
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US (1) | US2770030A (en) |
Cited By (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2955353A (en) * | 1956-01-18 | 1960-10-11 | Allis Chalmers Mfg Co | Fabrication of large structural members and method therefor |
US3123447A (en) * | 1964-03-03 | Zirconium to stainless steel connection | ||
US3177577A (en) * | 1960-02-27 | 1965-04-13 | Japan Atomic Energy Res Inst | Method of bonding graphite articles with iron-base brazing alloys |
US4178417A (en) * | 1977-03-23 | 1979-12-11 | The Japan Steel Works, Ltd. | Clad steel |
US4333671A (en) * | 1980-05-05 | 1982-06-08 | General Atomic Company | Friction welded transition joint |
US4333670A (en) * | 1980-05-05 | 1982-06-08 | General Atomic Company | Stepped transition joint |
US5346096A (en) * | 1991-10-24 | 1994-09-13 | GNS Gesellschaft fur Nuklear-Service mbH | Radiation-shielding transport and storage container |
EP0668120A1 (en) * | 1994-02-17 | 1995-08-23 | Mitsubishi Jukogyo Kabushiki Kaisha | Method of forming a weld joint of austenitic stainless steel |
US6107595A (en) * | 1995-07-19 | 2000-08-22 | Inland Steel Company | Method for resistance welding with dilution metal and product thereof |
US20060233681A1 (en) * | 2005-04-18 | 2006-10-19 | Sylvia Hartmann | Exhaust system and associated exhaust treatment device |
US20120272929A1 (en) * | 2009-09-04 | 2012-11-01 | Thoralf Berndt | Once-through steam generator for burning dry brown coal |
US20120291720A1 (en) * | 2009-09-04 | 2012-11-22 | Thoralf Berndt | Once-through steam generator for using at steam temperatures of above 650°c |
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US1959791A (en) * | 1931-02-06 | 1934-05-22 | Krupp Ag | Welding iron, steel, and their alloys |
US2011706A (en) * | 1934-02-20 | 1935-08-20 | Kellogg M W Co | Arc welding electrode |
US2054405A (en) * | 1933-10-18 | 1936-09-15 | Union Carbide & Carbon Corp | Welding chromium-nickel-titanium steels |
US2056765A (en) * | 1934-07-28 | 1936-10-06 | Union Carbide & Carbon Corp | Chromium alloy steel and welding rod |
US2113937A (en) * | 1935-06-06 | 1938-04-12 | Union Carbide & Carbon Corp | Welded joint and method of making the same |
US2187525A (en) * | 1929-09-19 | 1940-01-16 | Krupp Nirosta Company Inc | Article of welded construction |
US2200229A (en) * | 1929-01-04 | 1940-05-07 | Nirosta Corp | Welded construction |
US2240672A (en) * | 1938-08-15 | 1941-05-06 | Deutsche Edelstahlwerke Ag | Welding rod |
US2253812A (en) * | 1940-02-06 | 1941-08-26 | Air Reduction | Carbon molybdenum welding rod |
US2306421A (en) * | 1935-07-26 | 1942-12-29 | Rustless Iron & Steel Corp | Rustless iron |
US2432773A (en) * | 1944-04-11 | 1947-12-16 | Mckay Co | Coated welding electrode |
US2464836A (en) * | 1944-08-24 | 1949-03-22 | Arcos Corp | Welding |
US2544336A (en) * | 1949-05-02 | 1951-03-06 | Armco Steel Corp | Weld composition |
US2564474A (en) * | 1948-01-21 | 1951-08-14 | Armco Steel Corp | Weld rod and coating therefor |
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1950
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US2200229A (en) * | 1929-01-04 | 1940-05-07 | Nirosta Corp | Welded construction |
US2187525A (en) * | 1929-09-19 | 1940-01-16 | Krupp Nirosta Company Inc | Article of welded construction |
US1959791A (en) * | 1931-02-06 | 1934-05-22 | Krupp Ag | Welding iron, steel, and their alloys |
US2054405A (en) * | 1933-10-18 | 1936-09-15 | Union Carbide & Carbon Corp | Welding chromium-nickel-titanium steels |
US2011706A (en) * | 1934-02-20 | 1935-08-20 | Kellogg M W Co | Arc welding electrode |
US2056765A (en) * | 1934-07-28 | 1936-10-06 | Union Carbide & Carbon Corp | Chromium alloy steel and welding rod |
US2113937A (en) * | 1935-06-06 | 1938-04-12 | Union Carbide & Carbon Corp | Welded joint and method of making the same |
US2306421A (en) * | 1935-07-26 | 1942-12-29 | Rustless Iron & Steel Corp | Rustless iron |
US2240672A (en) * | 1938-08-15 | 1941-05-06 | Deutsche Edelstahlwerke Ag | Welding rod |
US2253812A (en) * | 1940-02-06 | 1941-08-26 | Air Reduction | Carbon molybdenum welding rod |
US2432773A (en) * | 1944-04-11 | 1947-12-16 | Mckay Co | Coated welding electrode |
US2464836A (en) * | 1944-08-24 | 1949-03-22 | Arcos Corp | Welding |
US2564474A (en) * | 1948-01-21 | 1951-08-14 | Armco Steel Corp | Weld rod and coating therefor |
US2544336A (en) * | 1949-05-02 | 1951-03-06 | Armco Steel Corp | Weld composition |
Cited By (15)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3123447A (en) * | 1964-03-03 | Zirconium to stainless steel connection | ||
US2955353A (en) * | 1956-01-18 | 1960-10-11 | Allis Chalmers Mfg Co | Fabrication of large structural members and method therefor |
US3177577A (en) * | 1960-02-27 | 1965-04-13 | Japan Atomic Energy Res Inst | Method of bonding graphite articles with iron-base brazing alloys |
US4178417A (en) * | 1977-03-23 | 1979-12-11 | The Japan Steel Works, Ltd. | Clad steel |
US4333671A (en) * | 1980-05-05 | 1982-06-08 | General Atomic Company | Friction welded transition joint |
US4333670A (en) * | 1980-05-05 | 1982-06-08 | General Atomic Company | Stepped transition joint |
US5346096A (en) * | 1991-10-24 | 1994-09-13 | GNS Gesellschaft fur Nuklear-Service mbH | Radiation-shielding transport and storage container |
EP0668120A1 (en) * | 1994-02-17 | 1995-08-23 | Mitsubishi Jukogyo Kabushiki Kaisha | Method of forming a weld joint of austenitic stainless steel |
US5556561A (en) * | 1994-02-17 | 1996-09-17 | Mitsubishi Jukogyo Kabushiki Kaisha | Method of forming a weld joint of austenitic stainless steel/ferritic steel |
US6107595A (en) * | 1995-07-19 | 2000-08-22 | Inland Steel Company | Method for resistance welding with dilution metal and product thereof |
US20060233681A1 (en) * | 2005-04-18 | 2006-10-19 | Sylvia Hartmann | Exhaust system and associated exhaust treatment device |
US7788912B2 (en) * | 2005-04-18 | 2010-09-07 | J. Eberspaecher Gmbh & Co. Kg | Exhaust system and associated exhaust treatment device |
US20120272929A1 (en) * | 2009-09-04 | 2012-11-01 | Thoralf Berndt | Once-through steam generator for burning dry brown coal |
US20120291720A1 (en) * | 2009-09-04 | 2012-11-22 | Thoralf Berndt | Once-through steam generator for using at steam temperatures of above 650°c |
AU2010291653B2 (en) * | 2009-09-04 | 2016-03-17 | General Electric Technology Gmbh | Once-through steam generator for burning dry brown coal |
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