摘要:

Laser scribing can be used to reduce the ferromagnetic domain size, and thus core loss, in grain‐oriented electrical steels. The localized stress required for domain‐size control can be produced either by shock deformation, optimally associated with beam dwell times (pulse lengths) less than 2×10−8sec, or by thermal stressing occurring with dwell times optimally longer than 1×10−4sec. In this paper we show that comparable core loss improvements can be obtained at greatly different dwell times, but that the associated changes in the surface condition of coated silicon steel laser scribed for maximum core loss reduction vary dramatically as dwell time varies. At the very short times characterizing shock deformation, achieved using aQ‐switched solid‐state laser, the coating is almost completely removed, but there is little effect on the steel itself, and recoating has been used to restore coating integrity. Under optimum dwell times for thermal expansion effects, achieved using continuous‐wave radiation, there is no significant effect on the coating, and no postscribing treatment is required. At intermediate dwell times, however, significant core loss reduction is associated with extensive disruption of the coating and with melting of the steel. At dwell times of approximately 1×10−6sec using CO2laser radiation, there is an unstable transition between the shock (vaporization) and heating modes, with intermittent melting.

ISSN:0021-8979    

DOI:10.1063/1.334615

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

The power loss of grain oriented electrical steel can be usefully reduced by refinement of the ferromagnetic domain structure in cases where overlarge grains support widely spaced domains. Artificial grain boundaries can be produced by laying down lines of ablated spots on the steel surface to generate a stress and atomic disruption pattern which pins domain walls and leads to a smaller wall spacing. A high voltage electrical discharge from capacitors or otherwise can be used to give high enough energy rates and spatial densities to achieve suitably ablated spots on the metal surface. The method is readily adaptable to a production situation.

ISSN:0021-8979    

DOI:10.1063/1.334616

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

Two types of mill glass, one of which is conventional and the other is characterized by its irregular surface morphology and stronger tension, were prepared on the surface of high permeability 3%Si‐Fe sheets in order to clarify the effects of the mill glass on core loss and domain structure. The results are twofold. Firstly, the mill glass of the latter type was, by itself, found to reduce the total loss in the induction range of 1.7 T. Secondly, considerable change in magnetization, characterized by its heavily constricted curve occurred, and corresponding change in the domain structure was observed.

ISSN:0021-8979    

DOI:10.1063/1.334617

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

Primary surface textures and magnetic properties were determined on specimens of a high‐permeability grain‐oriented silicon steel processed with and without interpass aging treatments of 5 min at 175 °C during cold rolling. The steel contained AlN and MnS as primary grain growth inhibitors. The main primary texture changes associated with the use of interpass aging were significant decreases in the amounts of material with orientations near {111}⟨112¯⟩ and {554}⟨225¯⟩ and smaller increases in the amounts of material with orientations near {110}⟨001⟩ and {100}⟨UVW⟩. Interpass aging improved the core loss and permeability, in agreement with prior work.

ISSN:0021-8979    

DOI:10.1063/1.334618

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

Transitions of the magnetization from the [100] to [010] and [001] directions were observed by inductive methods. Enhancement of the signals was obtained by a crossed excitation‐signal windings arrangement. The results are interpreted in terms of the internal [010], [001] domains.

ISSN:0021-8979    

DOI:10.1063/1.334619

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

Various organic and inorganic coatings are used for electrical steels to improve their punchability and interlaminar resistance. However, very little information is available in the literature on the effect of these coatings on structure and magnetic properties of electrical steels. In this study, the influence of a commercial mono‐aluminum‐phosphate coating was investigated for a 1.0 wt. % silicon steel. It was noted that this type of coating is responsible for the following: (1) rate of decarburization is essentially unaffected, (2) the growth of subsurface oxide is substantially reduced, (3) 1.5 T permeability is improved via reduction in the subsurface oxide layer, and (4) core loss is decreased by reducing anomalous loss. A possible mechanism to suppress the subsurface oxidation by phosphorus segregation is suggested on the basis of results obtained by AES analysis.

ISSN:0021-8979    

DOI:10.1063/1.334620

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

A recent study on low‐alloy, nonoriented, semiprocessed electrical steels indicated that at 60 Hz and 15 and 17 kG the anomalous loss per cycleWaincreased linearly witht2/&rgr;, i.e.,Wa=Wao+kt2/&rgr;, wheretis sheet thickness, &rgr; is resistivity, andWaoandkare empirical constants. The present study explores the above relationship over inductionsBof 5 to 17 kG and frequenciesfof 20 to 200 Hz. A separation of hysteresis lossWhinto synchronous and asynchronous components is also considered. Six laboratory heats with Si+Al<1.1 wt. % were hot and cold rolled to 0.035, 0.07, and 0.11 cm. The sheets were annealed, critically strained, and decarburized. Longitudinal strips were tested with dc as well as ac current in a 25‐cm Epstein frame. The above linear equation was generally valid. At each combination ofBandf, the interceptsWaowere always positive, but the slopeskwere negative at 5 and 10 kG and positive at 15 and 17 kG. Furthermore, a fifth of theWavalues were negative. The negativeWaandkwere associated with lack of flux penetration.Wh, but notWa, increased with increasing oxygen and decreasing grain size, and these effects resided in theB1.6component ofWh.  

ISSN:0021-8979    

DOI:10.1063/1.334621

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

As part of an investigation into the effects of stress on magnetic properties, the stress dependence of the anhysteretic magnetization of three samples of ferromagnetic constructional steel was measured. Measurements were taken using a specially designed apparatus which enabled small samples to be subjected to uniaxial stresses of up to 3.2×108Pa while held between the pole pieces of a conventional 2Tlaboratory electromagnet with a pole gap of 70 mm. In each case, the anhysteretic magnetization decreased under compressive stress but increased slightly under tensile stress at low fields. Compared with hysteresis curves, the anhysteretic has a particularly simple form which can be modeled using an equation given previously. The results allowed the stress dependence of three of the four parameters governing hysteresis to be determined.

ISSN:0021-8979    

DOI:10.1063/1.334622

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

The mean field model has been used to analyze the hysteresis loops in textured and strained steel. We observe an increase of the pinning constant with plastic deformation and a strong variation of the pinning parameter in various directions in Fe‐Si steel. The interpretation of changes of the pinning parameter is related to the dislocation density for deformed specimens. It has also been demonstrated that in textured Fe‐Si steel the changes in the mean value of magnetocrystalline energy follow closely the observed changes of the pinning parameter.

ISSN:0021-8979    

DOI:10.1063/1.334623

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

Increasing aluminum content from 0.02 to 0.10%, lower reheat temperature, higher coiling temperature, and hot band annealing all promote a reduced proportion of the (111) texture component and higher permeability in box annealed, semiprocessed lamination steel. These results are consistent with observations of  a greater degree of precipitation of AlN in the hot band.

ISSN:0021-8979    

DOI:10.1063/1.334624

出版商:AIP    

年代:1985

数据来源: AIP