Chemical Composition of high-temperature alloys
High temperature alloys are based on iron, nickel, cobalt, and other main elements such as chromium, aluminum, titanium, tungsten, molybdenum, etc. As primary metal materials, they can work for a long time at temperatures above 600 ℃ and certain stress conditions. They have multiple advantages in high temperature strength, oxidation resistance, hot corrosion resistance, fatigue performance, fracture toughness, and other aspects.
Application of high-temperature alloys
High temperature alloys are widely used in aerospace, nuclear power, automotive industry, gas turbine, petrochemical and other fields.
From the perspective of the global high-temperature alloy market application scenarios, the aerospace industry has long ranked first, with market demand accounting for over 56%, mainly used in the manufacturing of aviation engines and aviation fasteners.
Classification of high-temperature alloys
Iron Based High-temperature Alloy
Nickel Based High-temperature Alloy
Iron Based High-temperature Alloy
Used at lower temperatures, 600-850 ℃, generally used in parts of engines with lower operating temperatures such as turbine discs, casings, and shafts.There are many grades of iron-based high-temperature alloys, including:
Time hardening iron-based alloys. Such as GH2036, GH2132, GH2135, GH2018, GH2038, GH2130, GH2136, GH2302, GH2696, etc.
Solid solution reinforced iron-based alloy. Including GH1015, GH1035, GH1040, GH1131, GH1140, etc.
Other special types of iron-based high-temperature alloys. For example, GH747, GH214, GH455, etc., which have ultra-high temperature oxidation resistance or excellent performance in specific environments.
Nickel Based High-temperature Alloy
With the highest usage temperature of about 1000 ℃, Nickel based high-temperature alloy materials are widely used in the manufacturing of the hottest end parts of turbojet aircraft engines and various industrial gas turbines, such as working blades, guide blades, and turbines.Common grades of nickel based alloys: monel400, monelk500, Inconel600, Inconel601, Inconel625, Inconel690, Incoel718, InconelX750, Incoiloy800, Incoloy825, HastelloyC276, Hastelloyc22, Hastelloyb2, etc
Cobalt Based High-temperature Alloy
Cobalt based high-temperature alloy materails are used at a temperature of about 950 ℃, it has good castability and weldability, and is mainly used as a guide blade material. Due to the limited cobalt resources, this type of alloy is expensive.Cobalt based alloy is a widely used material for manufacturing heat-resistant components, with excellent high-temperature resistance and good mechanical strength.
Here are some typical cobalt based alloy grades and their applications:
Haynes series: including Haynes25 (L-605), Alloy S-816, UMCo-50, MP-159, FSX-414, X-40, Stellite6B, etc. These alloys are commonly used in the manufacturing of aircraft engines, turbines, and other high-temperature equipment.
Chinese brands such as GH5188 (GH188), GH159, GH605, K640, and DZ40M. These grades of alloys are also widely used in China.
WC Co series: Cobalt based hard alloys with tungsten carbide (WC) as the main hard phase and cobalt (Co) as the bonding phase. The grades include YG6, YG8, YG6X, YG8C, YG10, etc. This type of material is commonly used in manufacturing tools and molds.
TiC Ni series: Cobalt based hard alloys with titanium carbide (TiC) as the main hard phase and nickel (Ni) as the bonding phase. The grades include YT5, YT15, YT14, etc. These materials are suitable for manufacturing wear-resistant parts and cutting tools.
TiC NiMo series: Cobalt based hard alloys that combine hard phases of titanium carbide (TiC) and molybdenum carbide (Mo2C), as well as nickel (Ni) as the bonding phase. The grades include YXM1, YXM4, etc. These materials are suitable for manufacturing components that are resistant to corrosion and high temperature environments.
GH605: This is a typical grade of cobalt based deformation high-temperature alloys, similar or corresponding to grades such as L605, HS25, WF-11, AIS1670, UNSR30605, KC20WN, etc.
High temperature alloys are divided into:
Deformable high-temperature alloy: Used at a temperature of 600-1000 ℃, it is generally used in compressor discs and turbine discs in engines, with relatively low strength, good plasticity, hot working, and weldability.
Casting high-temperature alloys: can be divided into three categories: equiaxed high-temperature alloys, directionally solidified columnar high-temperature alloys, and single crystal high-temperature alloys.
1) Equiaxed crystal high-temperature alloy: used at a temperature of 1000 ℃ and using traditional investment casting methods, its temperature bearing capacity is relatively low. It is mainly used in the last few stages of low-pressure turbine blades, with a wide range of applications, accounting for 60-70% of all casting components, but the added profit of the product is low.
2) Directional solidification columnar high-temperature alloy: used at a temperature of 1000-1100 ℃, manufactured using directional solidification technology, with relatively high temperature bearing capacity. It is mainly used for the working blades of the first few stages of low-pressure turbines, as well as the first and second stages of working blades of some engine high-pressure turbines. The application scope is limited to working blades, and the product has high additional profits.
3) Single crystal high-temperature alloy: used at a temperature of 1200 ℃, manufactured using directional solidification and crystal selection technology. It has the highest temperature bearing capacity and is mainly used for advanced engine high-pressure impeller blades and low-pressure turbine front two stage blades. Its application scope is limited to working blades, and the product has the highest additional profit.
New high-temperature alloys
New high-temperature alloys refer to high-temperature alloy materials produced through new manufacturing processes, mainly including powder high-temperature alloys and dispersion strengthened high-temperature alloys (ODS).
1) Powder high-temperature alloy: used at a temperature of 1100 ℃, it is a production process that atomizes high-temperature alloys into powder and then forms them into high-temperature alloy products through hot isostatic pressing or hot isostatic pressing plus forging. It has the characteristics of high metal utilization rate, low cost, and relatively high temperature bearing capacity. Currently, it is mainly used in turbine discs and turbine blades, and is an excellent material for high-temperature components such as high thrust to weight ratio engine turbine discs, compressor discs, and turbine baffles
2) Dispersion strengthened high-temperature alloy (ODS): used at a temperature of 1200 ℃, made using a similar powder metallurgy process, with high temperature bearing capacity, mainly used in flame tubes, guide blades, and turbine blades.
