The Texture Research On Low Grade Non-oriented Silicon Steel

As a magnetic alloy with excellent performance , non-oriented electrical steel is widely used in electricity power, electronic industry ,military and magnetic materials. It is a kind of indispensable metal functional material. The iron cores in all kinds of generators and motors are made in non-oriented electrical steel. There will be considerable economic benefits through improving the work efficiency of these long time running and big power equipments. The history of electrical steel is actually that of reducing the loss and improving the magnetic properties. Electrical steel manufacturing is so complicated in process, equipment and composition control, steel companies tends to protect it by patent. There is no systematic published papers about the study of non-oriented electrical steel. It is important to study the properties of non-oriented electrical steel in the manufacturing process. And there is very important theoretical and practical significance to study the texture control by the rolling and heat treatment process.The materials studied in this paper are hot rolling and cold rolling non-oriented electrical steel from industrial production. The main object of the study is focused on texture evolution in cold rolling and annealing process. The research was divided into four parts. Firstly, to study the texture evolution of 50WR1300 hot rolling plate after atmosphere annealing. Secondly, to study the texture evolution law of two process non-oriented electrical steel (traditional process and CSP process) after moisture atmosphere annealing. The third part is about the texture evolution of non-oriented electrical steel by cold rolling in different direction (parallel and perpendicular to hot rolling direction) and the texture characteristics of re-crystallization. The last part, to study the texture evolution law of CSP non-oriented electrical steel cold rolling plate when reply from low temperature annealing to high temperature annealing.The grain size and original texture of hot rolling plate will cause obvious influences to final product. For 50WR1300 atmosphere annealing, it was found that the average grain size grow up when increasing the content of hydrogen gas, while ,theαfiber texture was enhanced andγfiber texture became weakened.The experiments of moisture atmosphere annealing show that: moisture atmosphere annealing resulted in non-oriented electrical steel grain growth. After moisture atmosphere annealing, the surface texture of all kinds of non-oriented electrical steel isγfiber texture. The surface texture density of T600 decreased firstly and then increased when increasing the temperature of dew point, the density ofγfiber is the lowest when dew point temperature equals to 30℃. The main texture of T800 decreased and then was enhanced, the lowest level of texture appeared at the dew point temperature of 45℃. The texture evolution of C600 was enhanced and then decreased ,the greatest level of texture appears at the dew point of 45℃. The texture evolution of C800 is similar to T600, but the texture component of {111}<112>increased greatly at the dew point temperature of 60℃.The research of cold rolling experiments show that: the final micro-structure of two kind non-oriented electrical steel is flattened fibrous ferritic deformation organization when rolled in different directions. The main texture of T800 and C800 is {112}<110> when cold rolled by the direction parallel to hot rolling. And the path of texture evolution is: {111}<112>â†'{111}<110>â†'{223}<110>â†'{112}<110>. As the cold rolling direction perpendicular to hot rolling, the texture evolution path of C800 is: {110}<001>â†'{554}<225>â†'{111}<112>â†'{111}<110>â†'{112}<110>. The stable texture of non-oriented electrical steel is {112}<110> when cold rolled in different directions.The experiments of annealing show that: the texture of C600 and C800 is typical cold rolling texture after being annealed lower than 500℃, and part re-crystallization occured at 600℃. The grain growth rate of C600 is faster than that of C800, and the growth rate become faster with increasing temperature . The texture evolution path of C600 and C800 after annealing is:{001}<110>â†'{225}<110>â†'{112}<110>â†'{111}<110>â†'{111}<112>. Both texture of C600 and C800 areγfiber texture. Theγfiber enhanced by increasing temperature to the point lower than 850℃. Theγfiber became weakened by increasing temperature higher than 850℃.