Characterization and analysis of non-metallic inclusions in
Ni42–Fe expansive alloy
Ni42–Fe expansive alloy
(1. Key Laboratory of Non-ferrous Metal Alloys, The Ministry of Education，Lanzhou University of Technology, Lanzhou 730050, China;
2. Jinchuan Nickel and Cobalt Research and Engineering Institute, Jinchuan Group Ltd., Jinchang 737100, China;
3. State Key Laboratory of Gansu Advanced Non-ferrous Metal Materials,
Lanzhou University of Technology, Lanzhou 730050, China)
2. Jinchuan Nickel and Cobalt Research and Engineering Institute, Jinchuan Group Ltd., Jinchang 737100, China;
3. State Key Laboratory of Gansu Advanced Non-ferrous Metal Materials,
Lanzhou University of Technology, Lanzhou 730050, China)
Abstract: Cracks and ruptures always occur during wire drawing process of 42% nickel-iron expansive alloy. In order to study the reasons of these phenomena, a method of metallographic observation in combination with sample electrolysis was used to characterize the non-metallic inclusions in the alloy wire. The results indicate that the inclusions in the alloy are oxidation products during the process of melting. There are single or complex phase inclusions composed of elements such as Al, Si, Ca, Ti, Fe, and O2. Among them, the macro-inclusions are TiO2 compound inclusions formed by the adhesion of Al and Si oxides on them. These inclusions are fragile ones with a low strain rate, as well as a rather high hardness, so that they are the main reason that leads to the surface cracks and ruptures in the alloy wires. The analysis has educed that the key point to enhance the product quality is to promote the cleanliness of the melt, control the types and quantity of non-metal inclusions in the alloy.
Key words: non-metallic inclusions; characterization; analysis