Prospects for the development of nickel-based alloys in China
High-temperature alloys generally refer to alloy materials that work under certain stress conditions above 600°C. It not only has good high-temperature oxidation resistance and corrosion resistance, but also has high high-temperature strength, creep strength and durability as well as good fatigue resistance. It is a key hot end component material for modern aviation engines, spacecraft and rocket engines, as well as ships and industrial gas turbines (such as turbine blades, guide vanes, turbine discs, combustion chambers and casings, etc.), and is also an important high-temperature structural material required for nuclear reactors, chemical equipment, coal conversion technology, etc.
1. Introduction to nickel-based alloys
Nickel-based alloys are further divided into nickel-based corrosion-resistant alloys, nickel-based wear-resistant alloys, nickel-based precision alloys, nickel-based shape memory alloys and nickel-based heat-resistant alloys according to their main properties.
1. Nickel-based corrosion-resistant alloys
The main alloying elements are copper, chromium and molybdenum. It has good comprehensive properties and can resist various acid corrosion and stress corrosion. The earliest application (produced in the United States in 1905) is nickel-copper (Ni-Cu) alloy, also known as monel alloy. In addition, there are nickel-chromium (Ni-Cr) alloy (that is, nickel-based heat-resistant alloy, heat-resistant corrosion alloy in corrosion-resistant alloy), nickel-molybdenum (Ni-Mo) alloy. Pure nickel is also a typical representative of nickel-based corrosion-resistant alloys. These nickel-based corrosion-resistant alloys are mainly used to manufacture various corrosion-resistant environment parts such as petroleum, chemical industry, and electricity. Nickel-based corrosion-resistant alloys mostly have austenitic structure. In the state of solid solution and aging treatment, there are intermetallic phases and metal carbonitrides on the austenite matrix and grain boundaries of the alloy. Various corrosion-resistant alloys are classified by composition and their characteristics are as follows: Ni-Cu alloy has better corrosion resistance than nickel in reducing medium. Ni-Cr alloy, that is, nickel-based heat-resistant alloy, is mainly used under oxidizing medium conditions. Ni-Mo alloy is mainly used under reducing medium corrosion conditions. Ni-Cr-Mo (W) alloy has the properties of the above-mentioned Ni-Cr alloy and Ni-Mo alloy. Ni-Cr-Mo-Cu alloy has the ability to resist both nitric acid and sulfuric acid corrosion, and also has good corrosion resistance in some oxidizing-reducing mixed acids.
2. Nickel-based wear-resistant alloy
The main alloying elements are chromium, molybdenum, tungsten, and also contain a small amount of niobium, tantalum and indium. In addition to wear resistance, it also has good oxidation resistance, corrosion resistance and welding properties. It can be used to manufacture wear-resistant parts, and can also be used as a coating material, which can be coated on the surface of other base materials through surfacing and spraying processes.
Nickel-based alloy powders include self-fluxing alloy powders and non-self-fluxing alloy powders. Non-self-fluxing nickel-based powder refers to nickel-based alloy powders that do not contain B, Si or have a low content of B and Si. Adding an appropriate amount of B and Si to the nickel alloy powder forms a nickel-based self-fluxing alloy powder.
3. Nickel-based precision alloys
Including nickel-based soft magnetic alloys, nickel-based precision resistance alloys and nickel-based electric heating alloys. The most commonly used soft magnetic alloy is Permalloy containing about 80% nickel. It has high maximum permeability and initial permeability, low coercivity, and is an important iron core material in the electronics industry.
The main alloying elements of nickel-based precision resistance alloys are chromium, aluminum, and copper. This alloy has high resistivity, low resistivity temperature coefficient, and good corrosion resistance, and is used to make resistors.
Nickel-based electrothermal alloy is a nickel alloy containing 20% chromium. It has good oxidation resistance and corrosion resistance and can be used for a long time at 1000-1100°C.
4. Nickel-based memory alloy
Nickel alloy containing 50 (at)% titanium. Its recovery temperature is 70°C and has a good shape memory effect. A small change in the ratio of nickel and titanium can change the recovery temperature within the range of 30-100°C. It is mostly used to manufacture automatically opening structural parts used on spacecraft, self-excitation fasteners used in the aerospace industry, and artificial heart motors used in biomedicine.
5. Nickel-based heat-resistant alloys
1) Representative materials of foreign nickel-based alloys are:
(1) Incoloy alloy, such as Incoloy800, the main components are; 32Ni-21Cr-Ti,Al; belongs to heat-resistant alloys;
(2) Inconel alloy, such as Inconel600, the main components are; 73Ni-15Cr-Ti,Al; belongs to heat-resistant alloys;
(3) Hastelloy alloy, such as Hastelloy C-276, the main components are; 56Ni-16Cr-16Mo-4W; belongs to corrosion-resistant alloys;
(4) Monel alloy, such as Monel 400, the main components are; 65Ni-34Cu; belongs to corrosion-resistant alloys;
2) Domestic deformable high-temperature alloys with nickel as the main matrix component
Indicated by the Chinese pinyin letter "GH" plus a serial number, such as GH36, GH49, GH141, etc. It can be processed into materials by conventional cold and hot deformation methods such as forging, rolling and extrusion.
According to the strengthening method, it can be divided into three categories: solid solution strengthened nickel-based deformed high-temperature alloy, weak aging strengthened nickel-based deformed high-temperature alloy and strong aging strengthened nickel-based deformed high-temperature alloy.
Application: Nickel-based deformed high-temperature alloy is widely used to manufacture hot end parts of aviation jet engines and various industrial gas turbines, such as working blades, guide blades, turbine discs and combustion chambers.
3) Domestic cast high-temperature alloys with nickel as the main component
Indicated by "K" plus serial number, such as K1, K2, etc. With the increase of operating temperature and strength, the alloying degree of high-temperature alloys is getting higher and higher, and hot processing and forming are becoming more and more difficult, and casting technology must be used for production. In addition, the internal complex cavity of the hollow blade using cooling technology can only be produced by precision casting technology. In this way, the nickel-based deformed high-temperature alloy is converted into a nickel-based cast high-temperature alloy.
Nickel-based cast high-temperature alloys use γ phase as the matrix, and add aluminum, titanium, niobium, tantalum, etc. to form γ´ phase for strengthening. The amount of γ´ phase is large, and some alloys are as high as 60%; adding cobalt can increase the dissolution temperature of γ´ phase and increase the use temperature of the alloy; molybdenum, tungsten, and chromium have the effect of strengthening solid solution, and chromium, molybdenum, and tantalum can also form a series of carbides that strengthen the grain boundary; aluminum and chromium contribute to oxidation resistance, but chromium reduces the solubility and high-temperature strength of γ´ phase, so the chromium content should be lower; hafnium: improves the medium-temperature plasticity and strength of the alloy; in order to strengthen the grain boundary, add appropriate amounts of boron, zirconium and other elements.
Nickel-based cast high-temperature alloys are used for the most critical high-temperature components of gas turbines for aircraft, ships, industry and vehicles, such as turbine blades, guide blades and integral turbines.
II. Application fields of nickel-based alloys
1. Food field
Salt making, soy sauce brewing, etc. In the above many fields, ordinary stainless steel 304 is not competent. In these special fields, special stainless steel is indispensable and cannot be replaced. In recent years, with the rapid development of the economy and the continuous improvement of the level of the industrial field, more and more projects require higher-grade stainless steel. With the growth of demand for nickel-based alloys in various industries. In 2011, the market size of nickel-based alloys in my country reached 23.07 billion yuan, a year-on-year growth rate of 19.47%. Therefore, the development level of the industry is in a steady upward trend.
2. Environmental protection field
Flue gas desulfurization equipment for power generation, wastewater treatment, etc.
3. Energy field
Atomic power generation, comprehensive utilization of coal, tidal power generation, etc.
4. Petrochemical field
Oil refining, chemical and chemical equipment, etc.
5. Marine sea areas
Marine structures in the environment, seawater desalination, seawater aquaculture, seawater heat exchange, etc.
III. Outlook for the development of nickel-based alloys in China
(I) Market demand continues to expand 1. Growth in core application areas Aerospace : The application of nickel-based alloys in key parts such as high-temperature components and turbine blades of aircraft engines accounts for 25%, and the demand for major projects such as domestic large aircraft and fourth-generation nuclear power is accelerating.
New energy and high-end equipment: New energy vehicle battery materials, offshore wind power storage equipment, ultra-supercritical power generation technology and other fields have become new growth points, and the market size has exceeded 50 billion yuan in 2023.
Chemical and marine engineering: Corrosion resistance promotes its application in petrochemical equipment, deep-sea exploration equipment (such as 10,000-meter deep-sea submersibles) and other scenarios.
2. Market size forecast The domestic market size is expected to exceed 60 billion yuan in 2025, and is expected to reach 50 billion yuan in 2027, and the global market will increase to 3.535 billion yuan by 2029.
(II) Technological breakthroughs and accelerated localization 1. High-end material research and development
The 10,000-ton nickel-based alloy project in Lanzhou New District will focus on high-temperature corrosion-resistant alloys, pure nickel and other products to promote domestic substitution.
Single-crystal nickel-based superalloy technology is developing rapidly, and global sales are expected to reach US$183 million in 2030, with a compound annual growth rate of 4.0%.
2. Declining import dependence
In 2020, the domestic supply-demand gap depends on imports, and by 2023, the output will increase to 42,000 tons, but high-end products will still rely on imports; in the future, through technological iteration, the localization rate is expected to increase significantly.
(III) Deepening of regional industrial clusters
East China: With Shanghai and Jiangsu as the core, more than 60% of high-end enterprises are gathered, and the market size will reach 21 billion yuan in 2023, relying on the advantages of the equipment manufacturing cluster in the Yangtze River Delta.
South China: The new energy industry in the Guangdong-Hong Kong-Macao Greater Bay Area drives the application of nickel-based alloys in energy storage batteries and offshore wind power, and the market size will increase by 15% year-on-year in 2023.
IV. Challenges and future trends of nickel-based alloys
1. Raw material supply risks
China has limited nickel resource reserves and needs to rely on imports; Indonesia's nickel ore policy adjustments (such as slowing production licenses) may affect the global supply pattern.
2. Green manufacturing and industrial upgrading
Environmental protection policies promote clean energy-related demand (such as hydrogen energy equipment and battery materials), while digital manufacturing technology helps improve production efficiency.
3. Price and competition pattern
Nickel prices are expected to rebound in 2025, and oversupply on the supply side will be alleviated; enterprises will respond to international competition through technological innovation and quality improvement.
V. Summary
China's nickel-based alloy industry will continue to grow driven by breakthroughs in localization, expansion of demand in emerging fields, and regional coordinated development, but it needs to overcome raw material dependence and technological barriers to achieve transformation and upgrading from "scale expansion" to "high-end and green".
