The invention provides an electroslag fusion process for manufacturing a blade slab having a large curved surface, and it is more particularly effectively in making a blade slab which has a big width-to-thickness ratio, a large difference between the thin and the thick edges and a large curved surface. Firstly, dividing the blade slab into two or three regions according to the external shape and the sectional size of the blade slab, wherein the region which has difficulty in unilateral or bilateral mold-filling is pre-fabricated by the electroslag casting technology to produce a pre-fabricated curved slab, and then it is placed in advance in a side of an internal cavity of a mold, and then fusing the molten metal melted from a consumable electrode and one or two electroslag pre-fabricated slabs which are placed in advance in the mold by utilizing the electroslag fusion process, so as to produce the blade slab having a large curved surface. The large curved blade slab prepared by the process of the present invention has good internal and surface qualities, which can improve material utilization rate, shorten the processing period and improve quality, and in particular, has high anti-fatigue performance, high crack resistance and extensibility performances. The process of the present invention is more suitable for producing large or very large curved blade slab castings having a width-to-thickness ratio >10 and a single weight over 10 tons.

A method for manufacturing a forged steel roll comprises: casting, by the ESR method, a steel ingot which contains, by mass %, C: 0.3% or more, Si: 0.2% or more, Cr: 2.0-13.0% and Mo: 0.2% or more, and further contains Bi at 10-100 ppm by mass; and forging the steel ingot to manufacture the roll. According to this method, since freckle defects can be sealed near the center of the steel ingot, the roll can be stably used over a long period of time.

A method for manufacturing a forged steel roll comprises: casting, by the ESR method, a steel ingot which contains, by mass %, C: 0.3% or more, Si: 0.2% or more, Cr: 2.0-13.0% and Mo: 0.2% or more, and further contains Bi at 10-100 ppm by mass; and forging the steel ingot to manufacture the roll. According to this method, since freckle defects can be sealed near the center of the steel ingot, the roll can be stably used over a long period of time.

An electro-slag remelting installation includes a mold and a consumable electrode that extends into the mold. The consumable electrode has an axis that is oriented obliquely to a vertical axis.

An electro-slag remelting installation includes a mold and a consumable electrode that extends into the mold. The consumable electrode has an axis that is oriented obliquely to a vertical axis.

Method for producing ingots made of metal having cross-sectional areas of at least 0.10 m.sup.2 of a round, square or rectangular shape through casting of metal or molten steel either directly from the casting ladle (1) or using a fireproof lined intermediate vessel (3) in a short, water-cooled ingot mold open downwards (4) and withdrawing of the solidified ingot (6) from the same downwardly movable withdrawing tool (8), wherein the casting process is continued with a casting rate determined in accordance with the casting cross-section for as long as the desired or maximum ingot length determined by the height of lift of the withdrawing tool (8) is reached, and additional liquid metal is fed at the end of the regular casting process to an extent that at least the contraction of the metal and steel melt occurring during solidification is balanced during, and whereby after completion of the regular casting process and completion of the ingot withdrawal, the casting process is continued with a casting rate reduced by at least the Factor 10 from the heatable casting ladle (1) or the heatable intermediate vessel (3) or a distribution container, and is reduced progressively or continuously at the end of the solidification to 10% the rate at the start of the additional casting.

Method for producing ingots made of metal having cross-sectional areas of at least 0.10 m.sup.2 of a round, square or rectangular shape through casting of metal or molten steel either directly from the casting ladle (1) or using a fireproof lined intermediate vessel (3) in a short, water-cooled ingot mold open downwards (4) and withdrawing of the solidified ingot (6) from the same downwardly movable withdrawing tool (8), wherein the casting process is continued with a casting rate determined in accordance with the casting cross-section for as long as the desired or maximum ingot length determined by the height of lift of the withdrawing tool (8) is reached, and additional liquid metal is fed at the end of the regular casting process to an extent that at least the contraction of the metal and steel melt occurring during solidification is balanced during, and whereby after completion of the regular casting process and completion of the ingot withdrawal, the casting process is continued with a casting rate reduced by at least the Factor 10 from the heatable casting ladle (1) or the heatable intermediate vessel (3) or a distribution container, and is reduced progressively or continuously at the end of the solidification to 10% the rate at the start of the additional casting.

A method of repairing defect in cast iron workpiece, including: machining the workpiece in the area of the defect to remove the defective material and form a chamber opening at a surface of the workpiece; anchoring a receptacle to the workpiece above the chamber (2), the receptacle is provided with an orifice in communication with the chamber; adding molten iron (4) into the receptacle so that it at least part of it flows into the chamber; adding slagging agent (5) into the receptacle; heating the slagging agent and the molten iron with an electrode (6); adding nodulizing agent into the molten iron so as to segregate graphite; and allowing the molten iron and the workpiece to cool down slowly. The above-described technique also has applicability for connecting two cast iron workpieces (11,12) together.

A method of repairing defect in cast iron workpiece, including: machining the workpiece in the area of the defect to remove the defective material and form a chamber opening at a surface of the workpiece; anchoring a receptacle to the workpiece above the chamber (2), the receptacle is provided with an orifice in communication with the chamber; adding molten iron (4) into the receptacle so that it at least part of it flows into the chamber; adding slagging agent (5) into the receptacle; heating the slagging agent and the molten iron with an electrode (6); adding nodulizing agent into the molten iron so as to segregate graphite; and allowing the molten iron and the workpiece to cool down slowly. The above-described technique also has applicability for connecting two cast iron workpieces (11,12) together.