90 Prakt. Met. Sonderband 46 (2014) 
Grain growth kinetic significantly affects the evolution of the final texture and consequently tester. The pri 
the final magnetic properties. To obtain the appropriate magnetic properties, NO steels are is show in Fig. 
subjected to various thermo-mechanical treatments. The reason for this is to develop a The heat trea 
microstructure with a favorable grain size and texture states. The grain size of processed control systen 
NO steels is very dependent on stored energy in the grains, released at elevated in cross secti 
deformation. The main difficulty is the control of final grain size and texture state as a microstructura 
result of production process. the other har 
The influence of mechanical deformation on the grain growth was investigated in this work. misorientation 
The stored energy of the grains depends on introduced deformation. It is well know, that means of EBS 
stored deformation energy accumulated in the material has the following form [4]: employed to | 
ro, were detected 
P = displayed by ( 
where p is dislocation density (~10'*/m?), uy chemical potential and b the dislocation 
Burgers vector. Deformation in combination with the temperature annealing plays an 
important role in study of grain boundary motion mechanism. The gradient deformation 3. RESULT: 
was applied to investigate the grain growth kinetic within the limits of one sample. 
The outgoing 
recrystallizatio 
2. EXPERIMENTAL PROCEDURE one can see, 
Non-oriented vacuum-degassed electrical steel with 1% of silicon content was used as 
experimental material. This steel was taken from industrial line after final cold rolling with 
reduction of 74% and then was subjected to primary recrystallization at 800°C for 10 
minutes in dry hydrogen atmosphere. The thickness and chemical composition of the 
investigated steel is presented in Table 1. In order to achieve gradient deformation through Fig. 2 Mat 
the cross section of experimental steel the three kinds of gradient deformation were used. primary rec 
Table. 1 The chemical composition of the investigated steel, in wt. J 800°C/10 mi 
Ele Ole ETE 8 TE 
des. mm % oh GB % % % represents the 
FIA 0.237 1 0.008 | 0.006 | 0.025 | 006 is taken at the 
In the first case, a uniform gradient deformation was performed along the whole length of see, the fractic 
the sample. The conducted gradient of deformation was varied from 0% to 6%, hence the grains. The gl 
deformation grad in 6% was generated within one investigated sample. This deformation about 30% of 
was made with specially prepared form, see Fig. 1a. In the second case, the stepwise 
deformation was carried out on the investigated samples. The deformation was performed 
by the specially prepared form which is shown in Fig. 1b. The first step deformation 
changes represent local deformation gradient in 6% and the second one in 4%, see Fig. 
1b. The third kind of gradient deformation was invented by different loads made by 8 
oo Fig. 3 Samg 
th "7 annealing at 
| wl, A Zr a £~0%, b) wit 
0.015 fm LL . 
b) WE A ns . surface of the 
g . . suggestion of 
Fig. 1 Prepared forms for deformation gradient. steel sheet. 1 
hardness tester ball which leads to concentration of stress in small volume of samples. maximum deft 
There were used three values of loads that lead to three different generated deformations grain size of & 
intensities on the investigated steel. The generated deformation intensities were controlled of the investic 
by diameter of indented ball and value of loading force applied to the ball of the hardness particular def: