JPS61183418A - Production of raw material for casting - Google Patents

Abstract

PURPOSE:To produce easily briquettes having high strength by mixing preliminarily and uniformly raw materials by an agitating mixer in the stage of using cutting swarf of cast iron, etc., and powder ferro alloy as the raw material and producting the briquettes for a casting raw material. CONSTITUTION:The swarf 1 of cast iron is passed by a screw conveyor 7 through a primary combustion furnace 6 where the swarf is heated in the defi cient state of air by burners 8, 9. The swarf is then supplied to a rotary furnace 10 where air 11 is supplied to burn away the cutting oil, etc. sticking to the swarf. The swarf is then passed through a secondary calcination furnace 12 where the remaining oil, etc. are thoroughly removed. On the other hand, Fe-Si and other ferroalloy auxiliary materials 15, 16 are put together with the swarf, etc. emitted from the secondary calcination furnace into the agitating mixer 30 by a screw conveyor 21. Both materials are thoroughly agitated and mixed by the mixer. The mixture is pressurized by rolls 24, 25 provided with pockets 23 for forming the briquettes in succession thereto, by which the briquettes for casting consisting of the swarf and ferro alloy having the high strength are produced.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention forms a ricket-shaped compound using a casting material made of cutting waste of cast iron or steel and a casting side material made of an alloy material. The present invention relates to a method for producing a casting raw material as described above.

(Prior Art) Cutting waste of cast iron, steel, etc. produced by machining iron products is sometimes used as a raw material for casting. Since such cutting chips have cutting oil, water, etc. attached to them, if the cutting chips are directly fed into the melting furnace, the incomplete combustion of the deposits will cause soot and smoke, and the oxidation of the cutting chips will cause the casting material to deteriorate. May cause deterioration.

For this reason, the cutting waste containing oil and water is steam-burned in advance, and while the oil and water contained in the cutting waste are vaporized and separated, oxidation of the cutting waste is suppressed, and the vaporized oil and moisture are removed by combustion. There is.

In addition, for cast products, cast iron may be required to have certain mechanical properties, and ferroalloys such as ferrocarbon, ferrosilicon, ferrochrome, and ferromanganese are used as raw materials for casting to meet those properties. It is blended. In this case, in order to accurately maintain the blending amount of the ferroalloy, it is sufficient to use a powdered ferroalloy, but the ferroalloy powder will be scattered due to the air blowing in the melting furnace.

Therefore, conventionally, as shown in JP-A No. 55-85635 and JP-A No. 55-85636, cutting waste of cast iron or steel is used as the main raw material, and alloyed iron (ferroalloy) mixed therewith is used. With a predetermined blending amount of auxiliary raw materials,
The main raw material and auxiliary raw materials are formed into a priquet shape. After the cutting waste is heated to remove oil and moisture contained in the cutting waste, the cutting waste is fed into a melting furnace before being cooled, thereby reducing power consumption. FIG. 3 shows a conventional method for manufacturing raw materials for casting.

Cast iron cuttings, which are the main raw material for casting, are supplied from a passage 1 to a hopper 2 as a measuring device, and below this measuring device 2 is a discharge feeder that is integrally attached to the hopper 2. A belt conveyor 4 for conveying the cutting waste from 3 is installed as a conveying device. A primary combustion furnace 6 is installed adjacent to this conveyance device [4], and the cutting waste from the conveyance device 4 is transported to the primary combustion furnace 6 along with fuel such as heavy oil.
The fuel is supplied from the supply port 5 and is transported through the primary combustion furnace 6 by a transport device 7 consisting of a screw conveyor. This-
Heavy oil and air are supplied into the fire explosion furnace 6 by the burner 8.9, so the temperature inside the furnace is approximately 900 to 950°C, and when the cutting chips pass through the conveyor device 7, they are transferred to the conveyor device M7. It is heated from the outside and steamed under air-deficient conditions.

- The fire blasting furnace 6 is provided with a rotary furnace 1o, and the cutting waste that has been vaporized while being conveyed by the conveying device 7 is supplied to the rotary furnace 10. Since air is supplied to this rotary furnace 10 from the air supply port 11, the oil vaporized in the -fire explosion furnace 10 is rapidly ignited, and the temperature inside the furnace is about 850 to 900°C. The cutting chips supplied to the furnace 10 are heated to a predetermined temperature, for example, 650 to 750, while being stirred.
It is heated uniformly to about ℃.

A secondary combustion furnace 12 is attached to the rotary furnace 10, and cutting waste is supplied from the rotary furnace 10 to this secondary combustion furnace 12. In this secondary combustion furnace 12, oil and other components are completely burned, and the combustion gas is discharged from the system through a conduit 13 through a dust collector 14 such as a bag filter, Cottrell, or cyclone.

On the other hand, powdered ferroalloys such as ferrocarbon, ferrosilicon, ferrochrome, and ferromanganese are supplied from each passage 15.16 to a metering device 17.18 as a raw material for casting. Weighing device 17.18
Below, a screw conveyor 21 is installed as a conveying device, which conveys the auxiliary materials from the discharge feeders 19.20 attached to the respective metering devices 17.18. The auxiliary raw materials conveyed while being uniformly mixed by the conveying device 21 are supplied to the briquetting machine 22 together with the main raw material from the rotary furnace 10.

This briquetting machine 22 consists of rolls 24 and 25 each having a pocket 23 on its surface which serves as a matrix for briquettes.
A hopper 27 with a built-in screw 26 is provided at the top of the machine. The mixture of the heated main raw material for casting and the side raw material for casting is supplied from the supply port 28 into the hopper 27, and is pumped between the rolls 24 and 25 by the rotation of the screw 26.

By passing between these rolls, the compound is formed into prickets the size of the pockets 23 and exits at the outlet 29.
It is discharged from the passage 29a. This compound is 500~
It has a temperature of about 600°C, and is put directly into a melting furnace such as a low-frequency induction electric furnace without being particularly cooled.

(Problems to be Solved by the Invention) However, in such a conventional method for manufacturing raw materials for casting, the main raw material consisting of cutting waste and the auxiliary raw material consisting of alloy iron are supplied to the briquetting machine 22. Since the main raw material and the auxiliary raw material are not mixed sufficiently, the priquet may be in a state where the auxiliary raw material is segregated into the main raw material. Therefore, in this case, the cutting chips that have reached the plasticizing temperature are separated from the ferroalloy, so the rickets may not be formed well, or even if they can be formed, their strength is very low and they are used as the raw material for casting. There was a problem that it was difficult to use it for practical purposes. Furthermore, if cast iron is manufactured in a melting furnace using priquets that have segregation, it will not be possible to obtain highly accurate cast iron in which alloy iron is blended in a predetermined ratio.

The present invention has been made in view of the above-mentioned problems of the prior art, and is intended to produce a high quality casting raw material in which the main raw material consisting of cutting waste and the auxiliary raw material consisting of ferroalloy are sufficiently and uniformly dispersed. The purpose is to obtain.

(Means for Solving the Problems) The present invention to achieve the above object is to heat the main raw material for casting containing cutting waste such as cast iron to a temperature above the plasticity temperature in a non-oxidizing atmosphere d1. When mixing the main raw material with a casting material made of an alloy material and forming the mixture consisting of the main casting material and the casting material into a priquet shape, the main material is mixed with the main material before or after the heating of the main material is completed. This is a method of melting Kawahara I, characterized by stirring and mixing the raw material and the casting side raw material.

(Function) The main raw material and the auxiliary raw material are sufficiently mixed in the stirring and mixing process before or after the heating of the main raw material is completed, so that the main raw material consisting of cutting waste and the auxiliary raw material consisting of ferroalloy are sufficiently uniform. A blended priquette-like compound is obtained,
A ricket-like compound with a certain strength is reliably obtained. Using such a prickle formulation, the cast iron produced in the melting furnace is of high quality.

(Example) Hereinafter, one embodiment of the present invention will be explained based on the present invention.

FIG. 1 is a flow diagram showing a manufacturing apparatus embodying the method for manufacturing casting raw materials according to the present invention. Furthermore, the first
In the figure, parts that are common to parts in the conventional manufacturing apparatus shown in FIG. 3 are given the same reference numerals.

As illustrated, a secondary combustion furnace 12 and a conveyance device 21,
A secondary combustion furnace 1 is provided between the briquetting machine 22 and the briquetting machine 22.
A stirring/mixing device 30 is provided for stirring and mixing the main raw material heated by 2 and the auxiliary raw material supplied from the conveying device 21. 30a is a motor, and 30b is a cutting blade. Therefore, the cast iron cuttings, which are the main raw material for casting, supplied from the passage 1 to the metering device f2 are vaporized in the -fire blasting furnace 6 under an oxygen-deficient condition; Furnace 10. In a heating step consisting of a secondary combustion furnace 12 and a secondary combustion furnace 12, it is heated to a predetermined plasticity temperature or higher.

The main raw material heated in this way and the auxiliary raw material made of ferroalloy supplied from the conveying device 21 are mixed in the stirring mixer @ 30 which constitutes the stirring and mixing process, and then the briquetting machine 22 A mixture of shapes is molded. The compound, which has undergone the molding process in the briquetting machine 22 and has a predetermined shape and has a predetermined temperature, is put into a melting furnace (not shown) before being cooled. In this way, by directly charging the mixture that has reached a predetermined temperature in the heating process into the melting furnace, it is possible to reduce the heat required to melt the mixture in the melting furnace. Moreover, before forming the compound into priquettes,
The main raw material and the auxiliary raw material are mixed, and the main raw material and the auxiliary raw material are uniformly dispersed in the prickle-shaped compound.

FIG. 2 is a diagram showing an apparatus embodying a method for producing casting raw materials according to another embodiment of the present invention, in which a discharge feeder 3 for weighing and discharging main raw materials and a discharge feeder 3 for weighing and discharging auxiliary raw materials are shown. The discharge feeders 19 and 20 are provided below the feeders 19 and 20, and above the conveying device 4 for conveying these raw materials to the primary combustion 6. Therefore, the main raw material and the auxiliary raw material are mixed and stirred while moving through the conveying device 7, the rotary furnace 10, and the secondary combustion furnace 12, and the process of heating the main raw material and the main raw material mainly in the rotary furnace 10 are performed. A step of stirring and mixing the auxiliary raw materials is performed at the same time. Further, this stirring and mixing is performed before the heating of the main raw materials is completed.

The main raw material and the auxiliary raw material that have passed through the secondary combustion furnace 12 are supplied to a briquetting machine 22, and a briquette-like compound having a predetermined shape is formed as in the previous embodiment. Before this mixture is cooled, it is placed in a melting furnace (not shown). still,
In the embodiment shown in FIG. 2, the stirring and mixing device 30 shown in FIG. 1 is not required, so the initial investment for the entire casting raw material manufacturing device is small, and the equipment is easy to maintain. .

(Effects of the Invention) As described above, according to the present invention, there is a step of stirring and mixing the main raw material made of cast iron, steel, etc. and the auxiliary raw material made of ferroalloy before or after the heating of the main raw material is completed. Therefore, in the priquet-shaped mixture of the main raw material and the auxiliary raw material, the blending state of the raw materials is uniform, and not only can the priquet be reliably formed, but its strength has a value sufficient for practical use.

Then, the raw materials are automatically measured with high precision, and it becomes possible to use inexpensive granular or powdery alloy materials in place of generally expensive bulk alloy materials.

[Brief explanation of the drawing]

FIG. 1 is a flow diagram showing a method for producing a casting raw material according to one embodiment of the present invention, and FIG. 2 is a flow diagram showing a method for producing a casting raw material according to another embodiment of the present invention. , FIG. 3 is a flow diagram showing a conventional method for producing raw materials for casting. 1.15.16...Aisle, 2.17.18...Measuring device. 4.7.21...Transfer device, 6...-Fire blasting furnace, 12...Secondary combustion furnace, 10...Rotary furnace, 22...
... Briquerating machine, 30... Stirring and mixing device.

Claims (1)

[Claims] The main raw material for casting, including cutting waste of cast iron, etc., is heated above the plastic temperature in a non-oxidizing atmosphere, and the heated main raw material for casting is mixed with a casting side material made of an alloy material to form the main raw material for casting. A casting raw material characterized in that, when a mixture consisting of a raw material and a casting auxiliary raw material is formed into a priquet shape, the main raw material and the casting auxiliary raw material are stirred and mixed before or after the heating of the main raw material is completed. manufacturing method.