US imports of nickel-based superalloy GH738 stick Waspaloy corrosion fatigue resistance of nickel-chromium cobalt ..

GH738 Profile??? GH738 is γ 'phase precipitation strengthened nickel-base superalloy, has good resistance to gas corrosion, high yield strength and fatigue properties, good plasticity processes, organizational stability. Widely used in aviation engine rotating components, temperature no higher than 815 ℃. Material Grade?? ?? GH738 similar grade?? ?? Waspaloy (USA), technical standards NC20K14 (France) material?? ?? Z9-0106 1986 "turboshaft eight with GH738 alloy bar Interim technical conditions"??? ? Q / 6S1035-1992 "high temperature fasteners GH738 alloy bar"?? ?? high five on co-09-1986 "GH738 alloy disc Trial smoke machine technology" (the steel Wuchang) Chemical composition C Cr Ni Co Mo Al Ti 0.03 ~ 0.10 18.0 ~ 21.0 Balance 12.0 ~ 15.0 3.5 ~ 5.0 1.2 ~ 1.6 2.75 ~ 3.25 B Zr Fe Mn Si PS Cu 0.003 ~ 0.01 0.02 ~ 0.08 ≤2.0 ≤0.10 ≤0.15 ≤0.015 ≤0.015 ≤0.1? ? ?? Note: trace impurities ω (Pb) ≤0.001%, ω (As) ≤0.0025%, ω (Sn) ≤0.0012%, ω (Sb) ≤0.0025%, ω (Bi) ≤0.0001%. Physical and chemical properties thermal properties?? ?? Melting temperature range of? 1330 ~ 1360 ℃ thermal conductivity θ / ℃ 360 460 545 640 770 855 985 λ / (W / (m · C)) 16.8 18.3 20.2 22.4 24.1 25.3 28.0 Specific Heat Capacity θ / ℃ 360 460 545 640 770 855 985 c / (J / (kg · C)) 515 540 573 603 640 665 707 linear expansion coefficient θ / ℃ 20 ~ 100 20 ~ 200 20 ~ 300 20 ~ 400 20 ~ 500 20 ~ 600 20 ~ 700 20 ~ 800 20 ~ 900 α / 10-6C-1 12.47 12.73 13.04 13.53 13.97 14.47 15.05 15.68 15.95 density ρ = 8.22g / cm3 magnetic type?? ?? alloy non-magnetic. Chemical properties of oxidation resistance?? ?? Alloy oxidation rate test after test time 100h / h in the air in the oxidation rate of 9.001 million /(g/(m2.h)) 0.083 0.226 corrosion?? ?? Alloy salt fog corrosion resistance is good. Microstructure structure?? ?? Tissue alloy standard heat treatment by γ matrix, Ti (C, N), Nb (C, N), M23C6 carbide and γ '[Ni3 (Al, Ti, Nb)] phase , γ 'content of about 14.5%, which is an alloy of major strengthening phase. Process performance and requirements?? ?? 1. temperature alloys forged between 1220 ~ 950 ℃ are easy to shape. The alloy forming process after violent solution treatment. ?? ?? 2. The average size of the grain size and the degree of deformation of the alloy forging, the final forging temperature are closely related. ?? ?? 3 alloy has good weldability, can be a variety of welding. Aging treatment intensity obtained nearly complete heat treatment after welding. ?? ?? 4 parts heat treatment in a sulfur-free neutral or reducing atmosphere, in order to avoid the occurrence of vulcanization. Heat Treatment System?? ?? 1080 ℃ ± 10 ℃, 4h, air-cooled + 840 ℃, 24h, air-cooled + 760 ℃, 16h, air cooling. Variety specifications and state?? ?? Produce bars, sections, forging stock, annular member, plate, sheet, strip, tube, wire, sand casting, precision castings and fasteners, usually without heat treatment delivery goods, plate after solution treatment delivery. Melting and casting process?? ?? Alloy by vacuum induction plus vacuum arc remelting process. General and special application requirements?? ?? The alloy is widely used in the country's aviation gas turbine engines, mainly for turbine blades and turbine disk and other rotating parts, a mature experience. As the alloy containing higher cobalt in the country less used. Nickel-based superalloy Profile??? Ni-base superalloy is nickel substrate (content is generally greater than 50%) with high strength and good resistance to oxidation in the range of 650 ~ 1000 ℃, anti-gas corrosion of superalloys. The development process??? Ni-base superalloy (hereinafter referred to as nickel-based alloy) in the late 1930s started to develop. Britain in 1941 to produce the first nickel-based alloy Nimonic 75 (Ni-20Cr-0.4Ti); In order to improve the creep strength and the addition of aluminum, developed Nimonic 80 (Ni-20Cr-2.5Ti-1.3Al). The United States in the mid-1940s, the Soviet Union in the late 1940s, China in the mid-1950s also developed a nickel-based alloy. Development of nickel-based alloys include two aspects: improvement of alloy composition and production process innovations. In the early 1950s, the development of vacuum melting technology for refining nickel-based alloys with high aluminum and titanium to create the conditions. Nickel-based alloys are mostly early wrought alloy. In the late 1950s, due to increased operating temperature of the turbine blades, requires high-temperature alloys have higher strength, but high-strength alloys, and it is difficult to deform, not even deformation, so the use of investment casting technology, the development of a series of good high-temperature strength of the cast alloy. The mid-1960s to develop a better performance of directional solidification and single crystal superalloys and powder metallurgy high-temperature alloys. In order to meet the needs of ships and industrial gas turbines, since the 1960s has also developed a number of hot corrosion resistance can be better organized and stable high-chromium nickel-based alloys. In about 40 years from the late 1940s early 1970s, nickel-based alloy operating temperature increased from 700 ℃ to 1100 ℃, the annual average increase of about 10 ℃. Category wrought superalloy?? ?? Wrought superalloy is one that can be hot, cold deformation processing, operating temperature range -253 ~ 1320 ℃, has good mechanical properties and integrated strong, toughness index, has a high antioxidant, A corrosion resistance alloys possible. Its heat treatment process can be divided into solid solution strengthening type alloy and aging strengthening alloy. ??? Solid solution hardening type alloy? Temperature range of 900 ~ 1300 ℃, the highest antioxidant temperature of 1320 ℃. E.g., GH128 alloy, tensile strength at room temperature is 850MPa, yield strength 350MPa; 1000 ℃ tensile strength of 140MPa, an elongation of 85%, 1000 ℃, 30MPa stress rupture life of 200 hours, the elongation of 40%. Solution alloy generally used for the production of aerospace engine combustion chamber, casing and other components. ??? Aging strengthening alloy? Use temperature of -253 ~ 950 ℃, generally used for structural parts, aerospace engine turbine disk and blade production. Making the turbine disk alloy operating temperature of -253 ~ 700 ℃, it requires a good high temperature strength and fatigue resistance. For example: GH4169 alloy, the highest yield strength of 650 ℃ up to 1000MPa; making blade alloy temperatures up to 950 ℃, such as: GH220 alloy, tensile strength of 950 ℃ 490MPa, 940 ℃, 200MPa lasting life of more than 40 hours. ? Wrought superalloy primarily to provide structural forgings, sheet cake, rings, rods, plates, tubes, strip and wire for the aerospace, aviation, nuclear energy, oil and civilian industry. Cast superalloy??? Superalloy is one that can only be used or cast molding method for a class of high-temperature alloy parts. The main features?? ?? 1. Since the composition has a wider range need not take into account their deformation processing performance, design alloy can concentrate on the optimization of its performance. As for nickel-based superalloy, can make by adjusting the composition of γ 'content of 60% or more, resulting in up to 85 percent under the alloy melting point temperature, the alloy can still maintain excellent performance. ??? ?? 2 have broader applications because of the special advantages of the casting method can be based on the use of required parts, design, produce near-net-shape or no margin of high temperature alloy castings have any complex structure and shape. ?? ?? Cast alloy according to temperature, can be divided into the following three categories:?? ?? First class: the -253 ~ 650 ℃ use equiaxed superalloy such alloys within a large temperature range has a good overall performance, especially at low temperatures to maintain strength and ductility are not dropped. Such as the amount in the aerospace engine larger K4169 alloy 650 ℃ tensile strength of 1000MPa, yield strength 850MPa, tensile ductility of 15%; 650 ℃, 620MPa stress rupture life of 200 hours. It has been used in the production of aerospace engine casing diffuser pumps and aerospace engines with complex structural parts. ?? ?? The second category: in 650 ~ 950 ℃ use equiaxed superalloy these alloys at high temperatures with high mechanical properties and thermal resistance. For example K419 alloy, 950 ℃, the tensile strength greater than 700MPa, tensile ductility more than 6%; 950 ℃, 200 hours lasting strength limit greater than 230MPa. Such alloys suitable for use as aviation engine turbine blades, vanes, and the whole cast turbine. ?? ?? The third category: the directional use of 950 ~ 1100 ℃ solidified columnar grain and single crystal superalloys such alloys have excellent performance and resistance to oxidation in this temperature range, hot corrosion resistance. For example DD402 single crystal alloy, 1100 ℃, 130MPa stress rupture life of greater than 100 hours. This is the highest temperature turbine blade material for the production of a new high-performance engine turbine blades. ?? ?? With the increasing precision casting technology, the new special technology is also emerging. Fine grain casting technology, directional solidification technology, complex thin-walled structure of CA technology and so the cast superalloy has greatly improved, the application continues to increase. PM superalloys?? ?? Atomization superalloy powder, the hot isostatic pressing or hot isostatic pressing and then forged molding production technology to manufacture high-temperature alloy powder products. By powder metallurgy process, the powder particles are small, fast cooling, thereby uniformly ingredients, no macro segregation, and fine grain size, thermal processing performance, the metal utilization, lower costs, especially the yield strength and fatigue properties of the alloy have greatly improved. ?? ?? FGH95 powder metallurgy superalloy, 650 ℃ tensile strength 1500MPa; lasting life of more than 50 hours, is currently at 650 ℃ operating conditions the highest intensity level of a powder metallurgy superalloy disc under 1034MPa stress. PM superalloys to meet the higher stress levels the requirements of the engine, a high thrust to weight ratio engine turbine disks, compressor and turbine baffle plate and other high temperature components material selection. Oxide dispersion strengthened (ODS) alloys?? ?? Is a unique mechanical alloying (MA) process, ultrafine (less than 50nm) with ultra-stable at high temperatures of oxide dispersion strengthened alloy phase is uniformly dispersed in the matrix. , and the formation of a special high-temperature alloys. An alloy strength at near the melting point of the alloy itself can still be maintained condition, with excellent high-temperature creep resistance, excellent high-temperature oxidation resistance, anti-carbon, sulfur corrosion. ??? ?? That have achieved commercial production there are three main ODS alloys:?? ?? MA956 alloys in an oxidizing atmosphere at a temperature up to 1350 ℃, ranking high temperature alloy oxidation resistance, carbon, sulfur corrosion first. It can be used for aero-engine combustor liner. ?? ?? MA754 alloys in an oxidizing atmosphere at a temperature up to 1250 ℃ and maintain a fairly high temperature strength, corrosion resistance, alkali glass. It has been used to make aero engine guide labyrinth ring and guide vanes. ?? ?? MA6000 alloy at 1100 ℃ tensile strength of 222MPa, yield strength 192MPa; 1100 ℃, 1000 hour endurance strength of 127MPa, ranking first in the high-temperature alloys, can be used for aero-engine blades. Intermetallic compound high-temperature materials?? ?? High temperature intermetallic compound material is a kind of recent research and development has important application prospects, hypobaric high-temperature materials. Over the past decade, research on intermetallic alloys design, development, and application of the basic compound process has matured, especially in the Ti-Al, Ni-Al and Fe-Al preparation processing technologies based material, toughening and strengthening mechanical properties and applied research has made remarkable achievements. ?? ?? Ti3Al based alloys (TAC-1), TiAl-based alloys (TAC-2) and Ti2AlNb based alloy has a low density (3.8 ~ 5.8g / cm3), high temperature and high strength, high stiffness and excellent resistance to oxidation, creep, etc., can make structural members 35 to 50% by weight. Ni3Al based alloy, MX-246 has good resistance to corrosion, abrasion and cavitation performance, demonstrating the excellent prospects. Fe3Al based alloys have good resistance to oxidation abrasion performance, temperature (less than 600 ℃) have high strength, low cost, can be partially replaced by stainless steel it is a new material. Environmental superalloys??? In many areas of civilian industries, service members are in the material in high temperature corrosive environments. To meet market needs, according to the material environment, classified a series of high-temperature alloys. ?? ?? 1. superalloy master alloy series??? ?? 2 high temperature corrosion-resistant alloy plate, bar, wire, strip, tube and forgings??? ?? 3 high strength, corrosion-resistant high-temperature alloy bar, spring wire, welding wire, sheet, strip, forgings??? ?? 4. The corrosion-resistant glass products??? ?? 5 Environmental corrosion resistance, high temperature resistant surface hard alloy series??? ?? 6 special precision Cast parts (blades, turbo, turbine rotor, guide, instrument fittings)??? ?? 7 with a centrifuge glass wool production, high temperature shaft and accessories 8, billet heating furnace with a cobalt-based alloy, heat resistant pad and rails??? ?? 8 valve seat ring??? ?? 9 casting "U" shaped resistance band??? ?? 10 centrifugal casting series??? ?? 11 nano material products? ?? ?? 12. hypobaric high temperature structural materials??? ?? 13. Functional Materials (expansion alloys, high temperature and high elastic alloy, constant elastic alloy series)??? ?? 14. biomedical materials products???? ? 15. Electronic Engineering with a target range of products??? ?? 16. powerplant nozzle series??? ?? 17. Stellite resistant film??? ?? 18 ultra high temperature oxidation corrosion of furnace rollers radiant tube. Composition and performance?? ?? Nickel-based alloy is the most widely used high-temperature alloys, high temperature strength up to a class of alloys. The main reason, one nickel-based alloys can be dissolved more alloying elements, and can maintain good organizational stability; the second is to form a compound γ between coherent ordered A3B metal '[Ni3 (Al, Ti) ] phase as a strengthening phase, effectively strengthening the alloy to obtain than iron-based superalloy and cobalt-based superalloys higher temperature strength; Third, nickel-based alloy containing chromium than iron-based superalloys better resistance to oxidation and Anti-gas corrosion. Nickel-based alloys contain a dozen elements, mainly from Cr antioxidant and anti-corrosion effect, other elements mainly from the strengthening effect. According to their strengthening effect can be divided into: solid solution strengthening elements, such as tungsten, molybdenum, cobalt, chromium and vanadium; precipitation strengthening elements, such as aluminum, titanium, niobium and tantalum; grain boundary strengthening elements, such as boron, zirconium, magnesium and rare earth elements. ??? Nickel-base superalloy Way to strengthen the solid solution strengthening and precipitation strengthening type alloy alloy. ?? ?? Solid solution hardening type alloy?? ?? Has a high temperature strength, good resistance to oxidation and hot corrosion resistance, cold resistance, thermal fatigue properties and good ductility and weldability, etc., it can be used in the manufacture of temperature higher withstand the stress was small (a few kilograms of force per square millimeter, see Table 1) components, such as a gas turbine combustor. ?? ?? Precipitation hardening type alloy?? ?? Usually using a combination of solid solution strengthening, precipitation strengthening and grain boundary strengthening three kinds of enhancement, which has a good high-temperature creep strength, fatigue resistance, resistance to oxidation and hot corrosion resistance It can be used to withstand the stresses produced under high temperature (more than ten kilograms of force per square millimeter or more, and Table 2) components, such as turbine blades of the gas turbine, the turbine disk and so on. Organization?? ?? Microstructure Characteristics and development of nickel-based alloys, alloy addition to austenitic matrix in vitro, as well as in the matrix Mi scattered distribution of γ 'phase, secondary carbides at the grain boundaries and precipitated during solidification primary carbides and borides. With the improvement in the level of alloying, change its microstructure has the following trends: γ 'phase gradually increased the number, size increases by the cube become spherical, size and shape are not the same the same alloys appear γ' phase . Also in the cast alloy solidification process occurs in the formation of γ + γ 'eutectic, grain boundary precipitation of discrete carbide particles and γ' phase surrounded by a thin film, these organizational changes to improve the performance of the alloy. ?? ?? Modern nickel-base alloy chemical composition is very complex, high degree of saturation of the alloy, thus requiring the content of each alloying elements (especially the main strengthening elements) strictly controlled, otherwise they will be in use is likely to precipitate harmful phases such as σ, & micro; phase, compromising the strength and toughness of the alloy. Developed a directionally solidified and single crystal turbine blade turbine blades in nickel-base superalloy. ?? ?? Directionally solidified blades eliminates voids and cracks sensitive lateral boundaries, so that all of the grain boundary parallel to the stress axis, thereby improving the performance of the alloy. Single crystal blades eliminate all grain boundaries, without the addition of grain boundary strengthening elements, so that the incipient melting temperature of the alloy is relatively increased, thereby increasing the high-temperature strength of the alloy, and further improve the overall performance of the alloy. Production process?? ?? Nickel-based alloys, especially precipitation hardening type alloy containing high aluminum, titanium and other alloying elements. Usually vacuum induction furnace and vacuum furnace or consumable electroslag remelting furnaces. Thermal processing forging, rolling technology, for high alloyed alloy, since the thermoplastic difference, is used after extrusion slabbing or mild steel (or stainless steel) wrap direct extrusion process. Casting alloys typically vacuum induction furnace mother alloy, and vacuum remelting - Precision Casting Process into parts. ?? ?? Wrought alloys and cast alloys require heat treatment section, including solution treatment, intermediate treatment and aging treatment to Udmet 500 alloy for example, the heat treatment system is divided into four sections: solution treatment, 1175 ℃, 2 小时, air-cooled; intermediate processing, 1080 ℃, 4 hours, and air cooling; an aging treatment, 843 ℃, 24 hours, and air cooling; secondary aging treatment, 760 ℃, 16 hours, and air cooling. In order to obtain the desired tissue status and good overall performance. Nickel-based alloy Description??? Nickel-based alloy refers to a class of alloys at 650 ~ 1000 ℃ high temperature high strength and corrosion certain antioxidant capacity overall performance. According to the main performance subdivided into nickel-based heat-resistant alloys, nickel-based corrosion resistant alloys, nickel-based wear-resistant alloys, nickel-based alloys and nickel-based precision shape memory alloys. Superalloy according to the different substrate divided into: iron-based superalloys, nickel-based superalloy and cobalt-based superalloys. Wherein the nickel-base superalloy called nickel-based alloys. CRAs?? ?? Major alloying elements are copper, chromium, molybdenum. Has a good overall performance, it can be resistant to various acid corrosion and stress corrosion. The first application (1905 US production) is a nickel-copper (Ni-Cu) alloy, known as Monel (Monel alloy Ni 70 Cu30); in addition to nickel-chromium (Ni-Cr) alloys (nickel-based heat-resistant alloy is , corrosion resistant alloy corrosion resistant alloys), nickel-molybdenum (Ni-Mo) alloy (mainly Hastelloy B series, domestic enterprises specializing in the production of corrosion resistant alloys Beijing Iron and Steel Research Institute, Baoji Titanium Group Metal Materials companies, etc.), nickel-chromium-molybdenum (Ni-Cr-Mo) alloy (mainly Hastelloy C series, domestic enterprises specializing in the production of corrosion resistant alloys Beijing Iron and Steel Research Institute, Beijing Financial Products Ltd., Baoji Titanium Group rare metal materials, etc.). At the same time, pure nickel is typical of nickel-based corrosion resistant alloys. These nickel-based corrosion resistant alloy is mainly used in the manufacture of petroleum, chemical, power and other corrosion-resistant components of the environment. ?? ?? More than nickel-based corrosion resistant alloy having austenite. Under state solution and aging treatment, the alloy austenite matrix and grain boundaries as well as intermetallic phases and metal carbonitrides exists, according to a variety of corrosion resistant alloy composition classification and characteristics are as follows:?? ?? Ni -Cu alloy in a reducing medium corrosion resistance than a nickel, and in an oxidizing medium corrosion resistance is better than copper, which in the absence of oxygen and oxidant conditions, high temperature resistant fluorine gas, hydrogen fluoride and hydrofluoric acid The best materials (see metal corrosion). ?? ?? Ni-Cr alloy is nickel-based heat-resistant alloys; mainly used in oxidizing media conditions. High temperature oxidation and sulfur, vanadium and other corrosive gases, corrosion resistance increases with the chromium content is enhanced. These alloys also has good resistance to hydroxides (eg NaOH, KOH) ability to corrosion and stress corrosion. ?? ?? Ni-Mo alloys are mainly used in reducing medium corrosion conditions. It is the best kind of hydrochloric acid corrosion-resistant alloys, but in the presence of oxygen and an oxidizing agent, the corrosion resistance will be significantly reduced. ?? ?? Ni-Cr-Mo (W) alloy both performance above Ni-Cr alloys, Ni-Mo alloy. Mainly in the oxidation - under reducing conditions mixed media. Such alloys in high temperature hydrogen fluoride gas, hydrochloric acid, hydrofluoric acid solution containing oxygen and oxidants as well as good corrosion resistance in wet chlorine gas at room temperature. Ni-Cr-Mo-Cu alloy has the ability to both anti-corrosion resistance to sulfuric acid and nitric acid, and in some oxidation - reduction of the mixed acid also has good corrosion resistance. Wear-resistant alloy?? ?? Main alloying elements chromium, molybdenum, tungsten, also contain small amounts of niobium, tantalum and indium. In addition to having a wear resistance, but its resistance to oxidation, corrosion resistance, weldability or. Wear parts can be manufactured, but also as a cladding material, by welding to coating and spraying process in the other surface of the substrate. ?? ?? Nickel-based alloy powder has a self-fluxing alloy powder and the non-self-fluxing alloy powder. ?? ?? Non-self-fluxing nickel-based powder refers not contain B, Si or B, and the lower Si-containing nickel-based alloy powder. Such plasma arc powder, widely used in coatings, such as spraying, flame spray coating and plasma surface strengthening. Including: Ni-Cr alloy powder, Ni-Cr-Mo alloy powder, Ni-Cr-Fe alloy powder, Ni-Cu alloy powder, Ni-P and Ni-Cr-P alloy powder, Ni-Cr-Mo-Fe alloy powder, Ni-Cr-Mo-Si high wear-resistant alloy powder, Ni-Cr-Fe-Al alloy powder, Ni-Cr-Fe-Al-B-Si alloy powder, Ni-Cr-Si alloy powder, Ni- Cr-W-based alloy powder wear and corrosion. ?? ?? Adding an appropriate amount of nickel alloy powder B, Si formed a self-fluxing nickel-based alloy powder. The so-called self-fluxing alloy powder also known as the eutectic alloy, hardfacing alloys, alloying elements can be added to form a low melting point eutectic of nickel, cobalt, iron-based alloys (mainly boron and silicon) and the formation of a series of powder material. Common self-fluxing nickel-based alloy powder has Ni-B-Si alloy powder, Ni-Cr-B-Si alloy powder, Ni-Cr-B-Si-Mo, Ni-Cr-B-Si-Mo-Cu, high molybdenum nickel base self-fluxing alloy powder, high nickel-chromium-molybdenum-based self-fluxing alloy powder, Ni-Cr-WC-based self-fluxing alloy powder, high copper self-fluxing alloy powder, tungsten carbide dispersion type nickel-based self-fluxing alloy powder. ?? The various elements in the alloy effect: ?? action boron, silicon element: significant reduction in the melting point of the alloy, expand the solid-liquid phase temperature region, the formation of low melting eutectic; deoxygenation reduction and slagging function; for Tu hardened layer, strengthening the role; improve operational process performance copper ?? effect: the increase of the non-oxidizing acid corrosion resistance of chromium ?? effect: solid solution strengthening effect, passive role; improve the resistance???? After the atomic radius, solution: easy to form a surplus of chromium and chromium carbide carbon, boron, chromium boride hard phase thereby increasing the alloy hardness and wear resistance of Mo ?? action; corrosion resistance and high temperature oxidation resistance?? so large lattice distortion, significantly strengthen the alloy matrix, improving high-temperature strength of the matrix and red hard; you can cut, reducing coating meshwork; improve anti-cavitation, erosion capacity. Precision alloy?? - Including nickel-based soft magnetic alloys, nickel-based alloys and nickel-based precision resistance heating alloy and the like. The most commonly used permalloy soft magnetic alloy is about 80% nickel, the maximum permeability and initial permeability, low coercivity, the electronics industry is an important core material. Nickel-based alloy precision resistor main alloying elements chromium, aluminum, copper, this alloy has a high resistivity, low temperature coefficient of resistivity and good corrosion resistance, for the production of resistors. Nickel-based alloy electric nickel alloy containing chromium is 20%, with good resistance to oxidation, corrosion resistance, long-term use at a temperature of 1000 ~ 1100 ℃. Memory alloy?? ?? 50 (at)% nickel alloy containing titanium. Their recovery temperature is 70 ℃, good shape memory effect. A small change in nickel-titanium composition ratio, can be varied within the range of 30 ~ 100 ℃ recovery temperature. Automatically open structure used for the manufacture of the spacecraft used, the aerospace industry with a self-excited fasteners used on biomedical artificial heart motors. Representative materials resistant alloy of nickel-based alloys are: ?? 1.Incoloy alloys such as Incoloy800, the main component; 32Ni-21Cr-Ti, Al; belong resistant alloy; ?? 2.Inconel alloys, such as???? Inconel600, the main component; 73Ni-15Cr-Ti, Al; belong resistant alloy;?? ?? 3.Hastelloy alloys, namely Hastelloy, such as Hastelloy C-276, the main component; 56Ni-16Cr-16Mo- 4W; belong corrosion resistant alloy;?? ?? 4.Monel alloys, namely Monel, Monel 400, for example, the main component; 65Ni-34Cu; belong corrosion resistant alloy; alloying elements ?? Major alloying elements are?? chromium, tungsten, molybdenum, cobalt, aluminum, titanium, boron, zirconium and the like. Wherein Cr, Ai and other major plays antioxidant effects, other elements are solid solution strengthening, precipitation strengthening and grain boundary strengthening effect. At 650 ~ 1000 ℃ it has high strength and high temperature oxidation corrosion certain, since a sufficiently high temperature strength and corrosion antioxidant capacity, so commonly used in the manufacture of the aero-engine blades and rocket engines, nuclear reactors, energy conversion devices high temperature components. Development history?? ?? Nickel-base superalloy (hereinafter referred to as nickel-based alloy) in the late 1930s started to develop. Britain in 1941 to produce the first nickel-based alloy Nimonic 75 (Ni-20Cr-0.4Ti); In order to improve the creep strength and the addition of aluminum, developed Nimonic 80 (Ni-20Cr-2.5Ti-1.3Al). The United States in the mid-1940s, the Soviet Union in the late 1940s, China in the mid-1950s also developed a nickel-based alloy. Development of nickel-based alloys include two aspects: improvement of alloy composition and production process innovations. In the early 1950s, the development of vacuum melting technology for refining nickel-based alloys with high aluminum and titanium to create the conditions. Nickel-based alloys are mostly early wrought alloy. In the late 1950s, due to increased operating temperature of the turbine blades, requires high-temperature alloys have higher strength, but high-strength alloys, and it is difficult to deform, not even deformation, so the use of investment casting technology, the development of a series of good high-temperature strength of the cast alloy. The mid-1960s to develop a better performance of directional solidification and single crystal superalloys and powder metallurgy high-temperature alloys. In order to meet the needs of ships and industrial gas turbines, since the 1960s has also developed a number of hot corrosion resistance can be better organized and stable high-chromium nickel-based alloys. In about 40 years from the late 1940s early 1970s, nickel-based alloy operating temperature increased from 700 ℃ to 1100 ℃, the annual average increase of about 10 ℃. Component performance?? ?? Nickel-base superalloys most widely used. The main reason is that, first, nickel-based alloys can be dissolved more alloying elements, and can maintain good organizational stability; the second is to be formed between the coherent ordered A3B metal compound γ [Ni3 (Al, Ti)] phase as a strengthening phase, effectively strengthening the alloy to obtain than iron-based superalloy and cobalt-based superalloys higher temperature strength; Third, nickel-based alloy containing chromium alloys with more than iron-based high temperature anti-oxidation and anti- gas corrosion. Nickel-based alloys contain a dozen elements, mainly from Cr antioxidant and anti-corrosion effect, other elements mainly from the strengthening effect. According to their strengthening effect can be divided into: solid solution strengthening elements, such as tungsten, molybdenum, cobalt, chromium and vanadium; precipitation strengthening elements, such as aluminum, titanium, niobium and tantalum; grain boundary strengthening elements, such as boron, zirconium, magnesium and rare earth elements. ?? ?? Nickel-base superalloy Way to strengthen the solid solution strengthening and precipitation strengthening type alloy alloy. ?? Smelting production process: In order to obtain a more pure of molten steel, to reduce the gas content and harmful elements; and because there are easily oxidized portion of the alloy elements such as Al, Ti and the like from the way non-vacuum smelting difficult to control; it is?? For better thermoplastic, nickel-based heat-resistant alloy, commonly used vacuum induction furnace, even plus vacuum consumable furnace slag remelting furnace or manner vacuum induction smelting production. ?? ?? Deformation areas: forging, rolling process, the difference of the thermoplastic alloy extrusion even after slabbing or pack of mild steel (or stainless steel) sets direct extrusion process. Deformation is intended to break the cast structure, microstructure optimization. ?? ?? Casting: the usual vacuum induction furnace mother alloy composition and control to ensure that the gas and impurities, and vacuum remelting - Precision Casting Process into parts. ?? ?? Heat treatment areas: wrought alloys and cast alloys require heat treatment section, including solution treatment, intermediate treatment and aging treatment to Udmet 500 alloy for example, the heat treatment system is divided into four sections: solution treatment, 1175 ℃ 2 hours, air cooling; intermediate processing, 1080 ℃, 4 hours, and air cooling; an aging treatment, 843 ℃, 24 hours, and air cooling; secondary aging treatment, 760 ℃, 16 hours, and air cooling. In order to obtain the desired tissue status and good overall performance. Applications nickel-based alloys in many fields, such as:?? ?? 1 ocean: the marine environment of the marine structures, desalination, aquaculture, seawater heat exchange. ?? ?? 2 field of environmental protection: flue gas desulfurization equipment of thermal power generation, wastewater treatment. ?? ?? 3 energy: nuclear power, comprehensive utilization of coal, tidal power generation. ?? ?? 4 petrochemical industry: oil refining, chemical engineering equipment. ?? ?? 5 food sector: salt, soy sauce and so on.