CRACKABILITY AT WELDING AND SURFACING DUE TO HIGH-TEMPERATURE ALLOY CASTINGSI NFLUENCE OF THE STRUCTURE

2019 ◽  
pp. 69-76
Author(s):  
Mykhailo Samokhin

The influence of the structure of casting high-temperature nickel alloys on their crack resistance at welding has been studied. It has been shown that crack formation in the weld-adjacent zone is promoted by the presence of lamellar precipitates of the σ-phase, large colonies and eutectic films of the γ΄-phase, carbides, and topologically close-packed phases on the grain boundaries, as well as the heterogeneity of distribution of the liquating elements. Homogenization heat treatment of the base metal before welding provides the maximum level of crack resistance and heat resistance of the joints. It is established that the ratio of Тc.d.γ΄, Teut. and Ts has a great influence on the formation of a ductile metal layer in the weld-adjacent zone of the cast workpiece, which improves its crack resistance at surfacing and welding. To prevent crack formation during welding of alloys with Teut. (Ts) < Тc.d.γ΄, it is necessary to apply new filler alloys with a zirconium-containing eutectic phase.

1995 ◽  
Vol 37 (1) ◽  
pp. 28-32
Author(s):  
Yu. V. Slov'ev ◽  
V. V. Isakov ◽  
S. G. Prokopinskaya ◽  
E. A. Maslenkova

Author(s):  
M.S. Grewal ◽  
S.A. Sastri ◽  
N.J. Grant

Currently there is a great interest in developing nickel base alloys with fine and uniform dispersion of stable oxide particles, for high temperature applications. It is well known that the high temperature strength and stability of an oxide dispersed alloy can be greatly improved by appropriate thermomechanical processing, but the mechanism of this strengthening effect is not well understood. This investigation was undertaken to study the dislocation substructures formed in beryllia dispersed nickel alloys as a function of cold work both with and without intermediate anneals. Two alloys, one Ni-lv/oBeo and other Ni-4.5Mo-30Co-2v/oBeo were investigated. The influence of the substructures produced by Thermo-Mechanical Processing (TMP) on the high temperature creep properties of these alloys was also evaluated.


Alloy Digest ◽  
1992 ◽  
Vol 41 (5) ◽  

Abstract INCO ALLOY 330 is a nickel/iron/chromium austenitic alloy, not hardenable by heat treatment. It is a solid solution strengthened high-temperature alloy. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as creep. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Ni-403. Producer or source: Inco Alloys International Inc..


Alloy Digest ◽  
1973 ◽  
Vol 22 (1) ◽  

Abstract HASTELLOY alloy S is a nickel-base high-temperature alloy having excellent thermal stability, good high-temperature mechanical properties and excellent resistance to oxidation up to 2000 F. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as creep. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Ni-184. Producer or source: Stellite Division, Cabot Corporation.


Alloy Digest ◽  
1981 ◽  
Vol 30 (7) ◽  

Abstract AISI No. 664 is a nickel-base high-temperature alloy that can be precipitation hardened because of its contents of aluminum and titanium. Vacuum melting is used in its production to provide excellent quality and reproducability. It is used for applications requiring a good combination of creep and stress-rupture properties up to about 1500 F. Typical applications are gas-turbine components, airframes and fasteners. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as creep. It also includes information on high temperature performance as well as forming, heat treating, machining, and joining. Filing Code: Ni-269. Producer or source: Nickel alloy producers.


Alloy Digest ◽  
1966 ◽  
Vol 15 (11) ◽  

Abstract Ti-679 is a titanium high temperature alloy having an excellent combination of short-time strength, creep strength and stability to 900 F. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as creep. It also includes information on high temperature performance as well as forming, heat treating, machining, and joining. Filing Code: Ti-48. Producer or source: Titanium Metals Corporation of America.


Alloy Digest ◽  
2001 ◽  
Vol 50 (8) ◽  

Abstract TIMETAL 829 is a Ti-5.5Al-3.5Sn-3Zr-1Nb-0.25Mo-0.3Si near-alpha titanium alloy that is weldable and has high strength and is a creep resistant high temperature alloy. The major application is as gas turbine engine components. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as fracture toughness, creep, and fatigue. It also includes information on forming and heat treating. Filing Code: TI-118. Producer or source: Timet.


Alloy Digest ◽  
2015 ◽  
Vol 64 (7) ◽  

Abstract NSSMC is a high temperature alloy with noted resistance to metal dusting. This datasheet provides information on composition. It also includes information on corrosion resistance as well as forming and joining. Filing Code: SS-1216. Producer or source: Nippon Steel and Sumitomo Metal Corporation.


2019 ◽  
pp. 43-48
Author(s):  
Ben Nengjun ◽  
Zhou Pengfei ◽  
Oleksandr Labartkava ◽  
Mykhailo Samokhin

This work involves an analysis of high-chromium high-temperature deformable wieldable nickel alloys for use in GTE repair assemblies. It is shown that the alloys EP868 (VZh98) and Haynes 230 can be used in welded assemblies with an operating temperature of 800-1100 °C. The alloys Nimonic 81, Nimonic 91, IN 935, IN 939, and Nicrotan 2100 GT also have a high potential for use in welded assemblies. They are characterized by a combination of good weldability, high-temperature strength, and resistance to scaling. There have been conducted studies on high-temperature salt corrosion of model nickel alloys. They allowed establishing the patterns of the impact of base metal alloying with chromium, aluminum, titanium, cobalt, tungsten, molybdenum, niobium, tantalum and rare earth metals on the critical temperature of the start of salt corrosion Tcor and the alloy mass loss. It has been established that alloys with a moderate concentration (13-16%) of chromium can possess satisfactory hightemperature corrosion resistance (HTC resistance) under the operating conditions of ship GTE. The HTC resistance of CrAl-Ti alloys improves upon reaching the ratio Ti/Al ˃ 1. Meanwhile, the ratio Ti/Al ˂ 1 promotes the formation of corrosion products with low protective properties. The positive effect of tantalum on the HTC resistance of alloys is manifested at higher test temperatures than that of titanium, and the total content of molybdenum and tungsten in alloys is limited by the condition 8Mo2 – 2W2 = 89. The presence of refractory elements stabilizes the strengthening phase and prevents formation of the ɳ-phase. However, their excess promotes formation of the embrittling topologically close packed (TCP) phases and boundary carbides of an unfavorable morphology. Based on the studies of the HTC resistance, there has been identified a class of model high-temperature corrosionresistant nickel alloys with a moderate or high chromium content (30%), Ti/Al ˃ 1, and a balanced content of refractory and rare-earth elements.


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