A precision alloy with abnormal thermal expansion characteristics, also known as thermal expansion alloy, is widely used in the electronics industry, precision measuring tools, precision instruments, and cryogenic engineering.
In addition to having a specific thermal expansion coefficient, expansion alloys are also required to have good sealing, weld-ability, corrosion resistance, process-ability, and easy cutting according to different uses, and are not allowed to have expansion-causing properties within the use temperature range. Significant changes in phase transition.
Specific Classification
1. FeNi29Co17, brand name: 4J29, also called Kovar alloy
2. Vacodil42, 4J42, 4J33, 4J34
3. FeNi32CO4Cu, also called Invar alloy
Production Process
Since Invar alloy contains high nickel, the harden-ability of steel is improved. Through the analysis of the chemical composition, metallographic structure, and mechanical and physical properties of Invar alloy, it can be seen that Invar alloy mainly has the characteristics of large cutting force, high cutting temperature, and rapid tool wear during processing. Therefore, when processing Invar alloy, High-performance carbide-coated tools and new processing methods must be used to ensure smooth cutting.
Main Application:
Low-expansion alloys are mostly used in components that require approximately constant dimensions at a certain ambient temperature. There are:
(1)Precision instruments and components in optical instruments, such as arms of precision balances, swing rods of standard parts, balance wheels, etc.;
(2)Length scale;
(3)Various resonant cavities, microwave communication wave-guides, standard frequency generators, etc.;
(4)Blades and support rods of standard capacitors;
(5)Storage tanks and transportation pipelines for liquid natural gas, liquid hydrogen, liquid oxygen, etc.;
(6)Passive layer of thermal bimetallic sheet;
(7)Shadow mask in high-resolution cathode ray tube (picture tube);
(8)Molds for composite parts in the aerospace industry;
(9)Used in artificial satellites, lasers, ring laser gyroscopes, and other advanced high-tech products.