Abstract: Apparatus for applying a coating of an insulation lacquer to a moving surface of a strip comprises a rotatable roller whose surface defines a multiplicity of cells and a reservoir containing a bath of heated organic/inorganic insulating lacquer in which a part of the roller surface is immersed when rotating. Insulating lacquer enters the cells of the roller surface and excess lacquer is wiped from the roller surface. A rotatable applicator roll having a substantially plain surface free of grooves or other indentations is rotated with its surface in contact with the surface of the lacquer carrying roller whereby lacquer present in the cells of the roller is transferred to the surface of the applicator roll. The surface to be coated is moved continuously past and in contact with the roll surface to apply a uniform coating of lacquer to that surface. The strip is preferably a strip of non-oriented electrical steel.

Abstract: A method of estimating mechanical hardness of a steel by the measurement of a plurality of magnetic parameters of the steel, comprises the steps of estimating for each parameter one or more probable hardness ranges by reference to a stored set of hardness ranges and associated parameters and combining these estimates to provide an estimate of the hardness range. Preferably three parameters are measured and these may be coercivity, power loss and permeability. These parameters may be measured simultaneously.

Abstract: A continuous method of measuring magnetic properties of a strip or sheet of an electrical steel comprises the steps of inducing in the strip or sheet electro magnetic forces and measuring the value of such induced electro magnetic forces by passing the strip or sheet continuously through a flux density detecting search coil. The search coil comprises along a part of its length a jet of fluid electrolyte.

Abstract: A method of forming continuous or spot-sequenced lines across the surface of grain oriented steel strip by spark discharge from electrodes closely spaced from said strip, characterized in that the atmosphere through which the discharge is effected is inert. Preferably the inert atmosphere is nitrogen but other gases, e.g. argon may readily be employed.

Abstract: This invention relates to a method of enhancing linear impressions formed in the surface of grain oriented electrical steel strip, by electrolytically etching said impressions with e.g. citric acid. The impressions may be formed by mechanical wheel scribing or by surface ablation, e.g. by spark discharge or laser treatment, and may be continuous or discontinuous in the form of spots or lines. In accordance with this invention therefore, the initial generation of light impressions in steel strip formed by mechanical wheel scribing or spark ablation techniques can readily be enhanced by application of the electrolytic etching technique to produce a material exhibiting values of power loss (reduced from the original unscribed loss value) which are substantially anneal-proof. In comparison, conventionally scribed material shows no resistance to a high temperature anneal as far as loss reduction is concerned.

Abstract: The invention provides a method of treating grain oriented steel sheet or strip to refine domain spacing by subjecting the steel sheet or strip to electrical discharge to create a line of surface ablation and stress thereacross, together with apparatus for carrying out the method.

Abstract: Apparatus for magnetic testing of sheet or strip includes a magnetizing system comprising spaced arrays of substantially parallel rectilinear conductors supported adjacent the plane of sheet or strip to be tested, the conductors being connected to carry magnetizing current so that the fields generated by the arrays are opposed.

Abstract: A safety device for lifting magnet has sensor means responsive to flux produced by the device in the magnetic circuit including the body to be lifted, a transducer responsive to the lifting tension produced by the device together with a signal translation circuit effective to compare signals from the sensor and from the transducer and to provide an output indicative of a safety margin between lifting tension and the field available for lifting.