Manufacture Process Of Non-Oriented Silicon Steel With High Magnetic Induction

Abstract

A manufacture process of non-oriented silicon steel with high magnetic induction includes smelting and casting steel having a chemical composition by weight percent: Si 0.1˜1%, Al 0.005˜1.0%, C≦0.004%, Mn=0.10˜1.50%, P≦0.2%, S≦0.005%, N≦0.002, Nb+V+Ti≦0.006%, and the rest is Fe. The steel is cast into a billet, which is heated and hot-rolled to 1150˜1200° C. into a plate at a finish-rolling temperature 830˜900° C. The plate is cooled to a temperature ≧570° C. and cold-roll flattened at compression ratio 2˜5%. The flattened plate is normalized at temperature not below 950° C. for 30˜180s, and then pickled and cold-rolled into a sheet with thickness of the finished product. The sheet is finish-annealed quickly heating the sheet to 800˜1000° C. at temperature rise rate ≧100° C./s, soaking the heated sheet for 5˜60s at the temperature, and then slowly cooling the sheet to 600˜750° C.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]The present application is a continuation of PCT Patent Application No. PCT / CN2011 / 072775 filed on Apr. 14, 2011, which claims priority to Chinese Patent Application No. 201010517872.7 filed on Oct. 25, 2010, both of which are fully incorporated herein by reference.STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT[0002]Not applicable.FIELD OF THE INVENTION[0003]This invention relates generally to a manufacture process of non-oriented silicon Steel, and particularly, to a manufacture process of non-oriented silicon Steel with high magnetic induction.BACKGROUND OF THE INVENTION[0004]Non-oriented silicon Steel is an important magnetic material and widely used in manufacture of various electric machines, compressors and so on. In general, it contains silicon of less than 6.5%, aluminum of less than 3%, carbon of less than 0.1%, and other trace elements. Manufacture process of silicon Steel includes the procedures of hot-rolling,...

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Benefits of technology

[0027]The intension to have the hot-rolled plate normalized and pre-annealed is to improve grain structure and texture. A research on non-oriented silicon Steel indicates that to make grain structure become coarse prior to cold-rolling can weaken texture component {111} of the cold-rolled sheet and can intensify texture component {ok1} of the cold-rolled sheet after it is finish-annealed, texture component {ok1} is advantageous to magnetic property. Moreover, the incidental phenomenon of separated substance becoming coarser can make grains grow up even easier so as to improve magnetic induction and reduce iron loss. In the invention, normalization temperature of high-magnetic-induction non-oriented silicon steel plate is not below 950° C., soakage period is 30˜180s.

[0028]The grains of {110} Gauss texture which are advantageous to magnetic property are usually to nucleate and grow up in the shear-deformed zone of the cold-rolled material. If temperature rise rate is too low, in the phase of temperature being lower, a recovery process in material will occur, which will reduce lattice distortion, thus, the probability of Gauss texture to nucleate will greatly fall down. To use a high temperature rise rate in annealing procedure can rapidly go through the temperature range adverse to evolution of Gauss texture and can make the surface texture {ok1} advantageous to magnetic property evolute even better, and thereby, can optimize magnetic induction and iron loss. To cool the annealed sheet slowly can improve its magnetic property. In the invention, the cold-rolled sheet is finish-annealed by quickly heating to a temperature between 800˜1000° C. at a temperature rise rate of ≧100° C. / s and a soakage period of 5˜60s, thereafter, is slowly cooled to 600˜750° C. at cooling rate of 3˜15° C. / s.

[0029]In comparison to conventional manufacture processes, the manufacture process of the invention can raise magnetic induction of non-oriented silicon Steel by at least 200 Gauss under the precondition to maintain the same iron loss.

Problems solved by technology

The magnetic properties of non-oriented silicon Steel are very prone to be affected by various factors such as material compositions, thickness, heat treatment procedure, and so on.

If soakage temperature is too high and soakage period is too long, the crystal grains of annealed silicon Steel will be rather coarse, the surface texture {111} will be intensified, and magnetic induction of the sheet will be weakened; contrarily, if diameters of the grains are on the small side, the hysteresis loss of material will be on the large side, which will increase electric loss in end use.

In anneal procedure, as compared to heating at a lower temperature rise rate, heating at a higher temperature rise rate will bring about quite intensive Gauss texture.

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