Precipitates in Compact Strip Production (CSP) Process Non-Oriented Electrical Steel

Abstract

Nitrogen and Sulfur in non-oriented electrical steel would form precipitates, which would severely affect its magnetic properties. Precipitates in compact strip production (CSP) process non-oriented electrical steel were investigated using a transmission electron microscope (TEM) and scanning electron microscopy (SEM). The precipitation mechanism and influence on grain growth were analyzed experimentally and theoretically. The results showed that the main particles in steel were AlN, TiN, MnS, Cu2S, and fine oxide inclusions. The spherical or quasi-spherical of MnS and Cu2S were more liable to precipitate along grain boundaries. During the soaking process, the amount of MnS precipitated on the grain boundary was much larger than that of Cu2S. AlN and TiN in cubic shape precipitated inside grains or grain boundaries. Precipitates preferentially nucleated at grain boundaries, and TiN, MnS mainly precipitated during soaking. In the subsequent processes after soaking, AlN and Cu2S would precipitate unceasingly with the decrease in the average size. The distribution density, the volume fraction, and the average size of the precipitates in the annealed sheets were 9.08 × 1013/cm3, 0.06%, and 54.3 nm, respectively. Precipitates with the grain size of 30–500 nm hindered the grain growth, the grains with 100–300 nm played a major role in inhibiting the grain growth, and the grains with the grain size of 70–100 nm took the second place.

Optimum Magnetic Properties of Non-Oriented Electrical Steel Produced by Compact Strip Production Process

“…The chemical composition of Fe-0.65%Si non-oriented electrical steel produced by CSP process with 70 mm in thickness used in the present study is given in Table 1 [18]. Hot rolled bands were plastically deformed from 2.5 mm to 0.5 mm with cold rolling.…”

“…Simultaneously, non-oriented electrical steel in the CSP process has the advantages of high efficiency and low energy consumption [16][17][18][19], and the fine and developed columnar crystals themselves belong to the <001> direction and the hot-rolling roughrolling process is omitted, which makes it beneficial to higher content of favorable texture components [20][21][22] and which is especially suitable for improving the magnetic properties. However, due to the large difference between CSP process and the conventional slab process, there are few systematic and in-depth studies on the influence of the microstructure and texture of non-oriented electrical steel in CSP process on the magnetic properties.…”

Combined Effects of EMBr and SEMS on Melt Flow and Solidification in a Thin Slab Continuous Caster

“…In recent years, the production of high-level steel grades has been a typical aim of thin slab continuous casting. For instance, electric-sheet steel, which should have high magnetic induction and low core loss [5], is mainly produced by Wuhan Iron & Steel. In response to these problems and potential challenges, the application of electromagnetic fields [6] is an attractive method, as the parameters of the fields can be adjusted during production.…”