Abstract: A mill roll has a working layer comprising alternate portions of unequal wear resistance properties along both the circumference and the generating line of the roll barrel. Each portion of the working layer may have the form of a square, rhomb, circle and others, if viewed on a developed surface of the working layer, while, in a plane of the roll cross-section, it is arranged so that its axis of symmetry is inclined at an angle to the radius of the roll.

Abstract: A method comprises feeding two or more, if necessary, alloying materials and simultaneously changing the ratio thereof. The ratio of the alloying materials is changed at the moment of transition from one section to the other one having different composition, the ratio being changed to such extent that the length of the transition portion is as small as possible. The time of transition is determined depending on the weld pool volume, rate of surfacing, cross section of the layer being built up, amount of the alloying elements both the required and the real one. Determining the time of transition for carrying out the method of the invention is disclosed in term of a preferred embodiment. An apparatus for carrying out the method of the invention is characterized in that it includes an adder-differentiator link, a voltage limiter, a switching device and an aperiodical link. The aperiodical link is a simulator of the weld pool.

Abstract: A surfacing method comprises feeding alloying material to the weld pool in between two consumable electrodes, with the distance between those electrodes being determined depending on the diameter of the electrodes, feed mass velocity of the alloying material and the total feed mass velocity of the electrodes. An apparatus for controlling the surfacing process according to the proposed method includes an electrode feed rate transducer connected to series-coupled converters, one of which converters determines the ratio of the amount of the alloying material to the total amount of metal being fed to the weld pool, and the other one determines the alloying degree of the surface layer being formed. The converters are connected to an adder unit connected to a device for delivering additional alloying material whereas the converter for determining the alloying degree includes a programmer device and is connected with the device for feeding the alloying material.