Patent Publication Number: US-3878882-A

Title: Method for producing shaped ingots by electroslag remelting

Description:
Uaiite es tot n 1 Paton et all.  
 [4 1 Apr. 22, 1975 1 METHOD FOR PRODUCING SHAPED lNGOTS BY ELECTROSLAG REMELTHNG Filed: Mar. 12, 1974 Appl. No.2 450,389  
 Related US. Application Data Continuation of Scr. No. 319,648, Dec. 29, 1972, abandoned.  
 Foreign Application Priority Data Jan. 13, 1972 U.S.S.R 1732351 [52] U.S. Cl. 164/52 I 1 I 1 II ill [51] int. Cl B22d 27/02 [58] Field of Search 164/52, 136, 252; 219/73, 219/126 [56] References Cited UNITED STATES PATENTS 2,375,107 5/1945 Hopkins 164/82 X 2,445,670 7/1948 Hopkins 164/252 3,396,778 8/1968 Jensen et a]. 164/260 X FOREIGN PATENTS OR APPLICATIONS 1,269,295 5/1968 Germany 164/136 Primary Examiner-Francis S. Husar Assistant Examiner-John E. Roethel Attorney, Agent, or F irml-lolman &amp; Stern [57] ABSTRACT A method for producing shaped ingots by way of electroslag remelting of consumable electrodes in a smelting vessel having a slag batlh common with a split mould into which liquid metal is supplied through a slot made in a side wall thereof, and the vessel is displaced relative to the mould as the ingot grows, whereupon the shaped ingot is extracted.  
 3 Elaims, 4 Drawing Figures METHOD FOR PRODUCING SHAPED INGOTS BY ELECTROSLAG REMELTING &#39;j This is a continuation of application Ser. No. 3 19.648  
 ,filed Dec. 29, 1972, now abandoned.  
 BACKGROUND OF THE INVENTION The present invention relates to methods of producing shaped ingots having a variable cross section which are to be used as castings for manufacturing articles, for example, cranks of large crankshafts and gears.  
  Methods for manufacturing shaped ingots, including the feeding of liquid metal into a split jacketed mould with a subsequent extraction of a shaped ingot are known, with the liquid metal produced in different furnaces being poured into the mould in order to fill the latter and which is kept therein until the ingot is completely solidified.  
  An ingot thus produced must then be subjected to additional treatments. It is cleaned of moulding sand, ex cessive portions and gates. Various rolls and metal flows are removed, and pits are cleaned and eliminated by means of, for example, electric welding. However, in the case of manufacturing ingots of intricate shape such as cranks of crankshafts of ship diesel, foundary faults are not allowed and their elimination is a must.  
  Elimination of the outer defects of ingots involves the employment of manual labour and auxiliary equipment, and also requires considerable consumption of means and time.  
  Besides outer defects, ingots often have inner defects that cannot be eliminated at all.  
  Rather high and stable quality castings are ensured by methods of electroslag remelting metal and shaping the ingots in jacketed moulds. Such methods are usually used for producing ingots that are simple in shape and which are round, square or rectangular in their cross sections and which are, at the same time, constant.  
  Attempts have been made to provide an apparatus for producing ingots of variable longitudinal and cross sections, for instance, ingots having the shape of a truncated cone, by way of electroslag remelting of consumable electrodes in a split jacketed mould (cf. U.S.S.R. Inventor&#39;s Certificate No. 265,148).  
  These apparatus, however, do not make it possible to produce ingot shapes of the type necessary for crank webs of crankshafts for ship diesel engines and castings from which large gears may made. Such ingots can be produced by employing conventional methods of electroslag remelting, provided that use is made of complex units for fastening the consumable electrodes and the electrodes are fed from great power sources.  
  Absence of a method that would ensure accelerated economical smelting of high-quality shaped ingots with minimal machining allowances gives rise to serious difficulties, especially in heavy machine building of prior art methods.  
 SUMMARY OF THE INVENTION It is therefore an object of the present invention to eliminate the above mentioned difficulties.  
  The main object of the present invention is to develop a method for producing shaped ingots that will ensure a higher quality of the ingots produced.  
  Another important object of the present invention is to reduce the cost of producing the ingots.  
  Still another object of the invention is to considerably reduce the consumption of labour necessary for the production of the shaped ingots.  
  These objects are accomplished by providing a method for producing shaped ingots, whereby liquid metal is produced by way of electroslag remelting of at least one consumable electrode, with an ingot being shaped in a split jacketed mould and, after being shaped, is extracted. In accordance with which method, according to the present invention, the liquid metal is produced in a smelting vessel having a slag bath commonly associated with the split jacketed mould into which the metal is supplied through a longitudinal slot made in a side wall thereof, and a constant difference between the levels of the liquid metal baths in the smelting vessel and the split jacketed mould is maintained by way of a vertical displacement of one of them relative to the other as the ingot grows.  
  This method will provide for economical production of high-quality shaped ingots having an intricate shape, such as cranks of crankshafts for ship diesel engines.  
  It is expedient to remelt an additional consumable electrode in the slag bath of the split jacketed mould.  
  This will make it possible to accelerate the process of ingot growth and will provide additional heat for the slag bath in the split jacketed mould.  
  The additional consumable electrode may be periodically remelted in the slag bath of the split jacketed mould when its wider portions are being filled with the liquid metal.  
  This will ensure an additional supply of the liquid metal that will allow maintenance of the linear rate of the ingot growth at a preset temperature for the slag bath.  
 BRIEF DESCRIPTION OF THE DRAWINGS The following description of the exemplary embodiments of the present invention is given with reference to the accompanying drawings, in which:  
  FIG. 1 shows the apparatus for the realization of the present method, comprising a split jacketed mould and a smelting vessel; an uplifted longitudinal sectional view;  
  FIG. 2 is the same as in FIG. I, with an additional electrode disposed in the wider portion of the mould;  
  FIG. 3 is a view taken along arrow A at the mould (FIG. 2) from the side at which the longitudinal slot is disposed; a part of the zone of the consumable electrodes being extracted; and  
  FIG. 4 is the same view as FIG. 3 showing a split jacketed mould without the electrodes and smelting vessel of FIG. 3.  
  DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS In accordance with the present method a shaped ingot is produced by way of electroslag remelting of at least one consumable electrode 1 (FIG. I) in a smelting vessel 2 having a slag bath 3 common with a split jacketed mould 4. The mould 4 with a working space 5 imparting a preset shape to an ingot 6 is mounted on a stationary support (not shown in the drawing). A longitudinal slot 7 made in a side wall of the mould 4 accommodates a slide 8 designed to hold the metal 9 and slag 3 baths. The slide 8 partially overlaps the slot 7 along the height thereof and is mounted therein so that it is capable of travelling in the vertical direction. The slide 8 is mounted in the lower portion of the slot 7 and has a drive (not shown in the drawing) used todisplace it in the upward direction as the ingot 6 grows in the mould 4.  
  The operating voltage is applied to the slag bath 3 through the consumable electrode 1 and a nonconsumable electrode positioned in the smelting vessel 2 and isolated from its casing with the aid of, for example, a slag insulation 11.  
  The method according to the present invention is realized in the following way.  
  Molten slag (flux) is poured into the smelting vessel 2 communicated with the space 5 of the mould through the slide 8, whereupon the consumable electrode 1 is introduced into the slag bath 3 of the smelting vessel 2 and the supply of electric current is started thereupon. The consumable electrode l-melts down and the liquid metal 9 flows from the smelting vessel 2 into the mould 4. In order to maintain a constant difference between the levels of the liquid metal baths 9 in said smelting vessel 2 and the mould 4, one of them is vertically displaced relative to the other, preferably the smelting vessel 2 being vertically displaced relative to the mould 4.  
  In another variant of the realization of the method when an opening 13 is provided in the upper portion of the split jacketed mould 12 (FIGS. 2 and 3) and is sufficient for the introduction of an additional electrode 14, the latter may be remelted simultaneously with the consumable electrode 1 that is being remelted in the smelting vessel 2.  
  The remelting of the additional consumable electrode 14 in the slag bath 3 of the split jacketed mould 12 will allow the growth of the ingot 6 to accelerate and will provide for additional heat for the slag bath 3. The additional consumable electrode 14 is preliminarily introduced into the wider portion 15 of the mould 12 space to be melted down while being sunk into the slag bath 3.  
  Sometimes, the additional consumable electrode 14 is remelted by introducing it periodically when filling the wider portion 15 of the split jacketed mould 12 with liquid metal, this resulting in the supply of additional liquid metal necessary for maintaining the linear rate of the ingot growth and the required temperature of the slag bath 3.  
  While realizing the variants of the method, it is possible to displace the mould relative to the smelting vessel or the smelting vessel relative to the mould, as well as to displace both simultaneously relative to each other.  
  Tests have shown that the above-disclosed method ensures production of high-quality castings and makes it possible to obtain ingots of rather intricate shapes. By using this method it is possible to obtain ingots having intricate shapes and weighing many to&#39;ns by utilizing simple equipment, at relatively small power usage.  
 What is claimed is:  
  l. A method for producing shaped ingots comprising the following steps: producing a slag bath in a smelting vessel communicating with the internal&#39;space of a split jacketed mould so that the level of the slag bath in said mould is an extension of the level of the slag bath in the smelting vessel; producing liquid metal by electro slag remelting a consumable electrode in the smelting vessel; feeding the liquid metal from said vessel into said mould having a variable cross section; maintaining a constant difference between the levels of the liquid metal baths in said smelting vessel and said split jacketed mould by vertically displacing one of them relative to the other as the ingot grows; shaping said ingot in said split jacketed mould; and subsequently extracting the shaped ingot from the mould.  
  2. The method asclaimed in claim 1, further comprising remelting an additional consumable electrode in the slag bath of said split jacketed mould.  
  3. The method as claimed in claim 2, whereby the additional consumable electrode is remelted periodically in the slag bath of said split jacketed mould as wider portions of the mould are being filled with the liquid metal.