JPH0363456B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method of casting a long steel material such as a rail with cast iron or the like.

(Prior art) As a method of manufacturing a composite member made of two metals with different hardness, toughness, etc., one metal is set in the cavity of a mold, and in this state, the molten metal of the other metal is injected into the cavity. The full mold method, in which the material is cast in a molded form, has been known for a long time.

When manufacturing a composite member using such a method, in order to ensure that the two metals are welded together, conventionally, as disclosed in Japanese Patent Publication No. 53-45167, a surface layer is applied to the metal member to be set in the cavity. The metal member is brought into contact with the molten metal by treatment or by raising the temperature of the metal member using a heat generating material as disclosed in Japanese Patent Publication No. 49-7299.

However, in the former case, welding is unstable, and in the latter case, there are disadvantages in terms of workability and cost, so as shown in Japanese Patent Publication No. 52-46884,
A method has been proposed in which a molten metal part is provided below the cavity and the molten metal is discharged from around the metal member set in the cavity through a discharge hole into the molten part while being cast.

(Problems to be Solved by the Invention) As described above, if a part of the molten metal is discharged into the molten metal part, welding can be performed while the temperature of the metal members provided in the mold is raised. The part from which the molten metal is discharged is limited to the lower periphery of the set metal member, and in other parts, the molten metal that first comes into contact becomes a solidified film and remains on the surface of the metal member, which tends to result in insufficient welding. In addition, in the method disclosed in Japanese Patent Publication No. 52-46884, a waste section is provided below the cavity, and the molten metal is directly discharged downward, so that the metal member can be made into a long piece like a rail. It cannot be applied directly to objects.

(Means for Solving the Problems) In order to solve the above problems, the present invention injects molten metal from the width direction of a long metal member provided in a mold, and also injects molten metal along the length direction of the long metal member provided in a mold. By discharging the molten metal, a swirling flow was created.

(Function) The surface of the long metal member provided in the mold is washed by the swirling flow (including turbulent flow) of the molten metal when pouring the metal, so the solidification of the molten metal formed on the surface of the long metal member occurs. The film is washed away, and the elongated metal member and the molten metal are reliably welded together.

(Example) Examples of the present invention will be described below based on the accompanying drawings.

FIG. 1 is a perspective view of a casting apparatus for carrying out the method of the present invention, FIG. 2 is a cross-sectional view of the main parts of the casting apparatus, and FIG. 3 is a cross-sectional view taken from the direction AA in FIG. 2.

The casting device integrates and sets a vanishing film mold 2 made of foamed polystyrene or the like and a long metal member 3 such as a rail in a metal frame 1, and a binder is placed around the vanishing model 2 and the long metal member 3. It is filled with a fireproof material 4 such as mixed sand and hardened.

Here, the disappearing model 2 includes a part 2a that will become a runner, a part 2b that will become a cavity, and a part 2 that will become a small weir connecting the part 2a that will become a runner and the part that will become a cavity.
c. It consists of a part 2d that will become the molten metal part, and a part 2e that will become the runner that connects the cavity and the molten metal part. When molten metal is poured from the part 2a that will become the runner, the model 2 will disappear due to the heat of the molten metal. It vaporizes, and a second mark appears on the vaporized trace.
As shown in the figure and FIG. 3, a runner 5, a cavity 6, a small weir 7, a runner 8 and a runner 9 are formed.

In the above, in order to cast the long metal member 3, molten cast iron is injected into the cavity 6 through the vertical runner 5 formed by the disappearance of the disappearance model 2, and the molten metal is poured into the cavity 6. swirling flow (turbulent flow)
The elongated metal member 3 and the molten metal are welded together without forming a solidified film of the molten metal on the surface of the elongated metal member 3.

By washing the surface of the elongated metal member 3 with the swirling flow of the molten metal in this way, the temperature at the boundary between the elongated metal member 3 and the molten metal is increased, preventing the formation of an unwelded solidified layer, and thereby keeping both of them together. Although strong welding can be achieved, it is preferable to perform welding under the following conditions in such a state. First, the small weir 7 should be positioned above the top surface of the long metal member 3. Therefore, it is necessary that the cavity 6 is opened from the width direction of the elongated metal member 3. By doing so, a swirling flow is generated along the inner circumferential surface of the elongated metal member 3 as shown by the arrows in FIGS. 2 and 3.

Second, it is preferable that the molten metal parts 8 be provided on the left and right sides of the cavity 6 to discharge the molten metal from both lengthwise ends of the elongated metal member 3. By doing this, the swirling flow of the molten metal becomes smooth and the resistance is reduced.

Thirdly, the amount of waste hot water is such that the surface temperature of the elongated metal member 3 is 1/2 to 1/3 of the freezing point of the molten metal. This is because when the surface temperature of the long metal member 3 becomes less than 1/3 of the freezing point of the molten metal, non-welding occurs.
This is because if it exceeds 1/2, melting loss is likely to occur. By the way, the amount of hot water to be disposed of is determined by the thickness and length of the long metal member 3, but the thickness (t) = 10 mm, 15
mm, 20mm, length (l) = 600mm, 1000mm, 1500mm,
2000mm S50C and alloy steel cast iron (casting temperature 1460
Figure 4 shows the amount of waste hot water when casting at a temperature of Based on the graph in Figure 4, amount of hot water and length (t)
The relationship between the length (l) and the length (l) was determined as follows.

Amount of discarded hot water (Kg) = (t-10) x 20 + l x 0.2 The actual amount of discarded hot water is 100Kg to 300Kg in addition to the amount in the above formula.
A somewhat larger amount is preferable, and if the amount is within this range, the surface temperature of the metal member will be 1/2 to 1/3 of the freezing point of the molten metal. The above formula also applies well to materials other than steel and cast iron, such as when a copper alloy plate (liquidus line 1010°C) is cast with aluminum alloy (liquidus line 630°C).

Furthermore, fourthly, the total flow area (S1) of the small weirs 7... has the following relationship with the total flow area (S2) of the runners 9... that connect the cavity 6 and the hot water section 8. is preferred.

0.6S2≦S1≦1.3S2 This means that if S1>1.3S2, the resistance will be large and it will be difficult for the molten metal to flow to the waste molten metal part 8, making it difficult for swirling flow to occur at the end surface and causing non-welding to occur.
In the case of <0.6S2, the contact of the swirling flow to the metal member becomes insufficient and poor welding tends to occur.

5A and 5B are sectional views showing other embodiments, in which the shape of the metal member 3 set in the cavity 6 is different, and small weirs 7 are formed on both sides of the cavity 6. The other configurations, such as the drain section, are the same as those of the previous embodiment, and the surface of the metal member 3 is washed by the swirling flow of the molten metal.

In addition, in the example, an example was shown in which a metal member is cast using a vanishing model, but the method of the present invention involves setting the metal member in the cavity in the mold in advance,
It can also be applied when pouring molten metal into this cavity.

(Effects of the Invention) As explained above, according to the present invention, the entire surface of the elongated metal member as a casting material that comes into contact with the molten metal during casting is washed by the swirling flow of the molten metal, so that the metal member The temperature of the entire welding surface of the metal member can be raised to the temperature required for welding, and no unwelded coagulated film remains on the surface of the metal member, making it possible to reliably weld dissimilar metals.

[Brief explanation of drawings]

Fig. 1 is a perspective view of a casting apparatus used to carry out the method of the present invention, Fig. 2 is a sectional view showing the cavity portion, Fig. 3 is a sectional view taken from the direction A-A in Fig. 2, and Fig. 4 A graph showing the relationship between the amount of discarded hot water and the thickness and length of the metal member, FIGS. 5A and 5B are cross-sectional views similar to FIG. 2 showing another embodiment. In addition, in the drawing, 2 is a lost model, 3 is a long metal member, 5 and 9 are runners, 6 is a cavity, 7 is a small weir,
8 is the abandoned Yube.

Claims (1)

[Scope of Claims] 1. Injecting molten metal from the width direction of a long metal member provided in a mold, and discharging the injected molten metal along the length direction of the long metal member to a discarding hot water section. to create a swirling flow of molten metal on the surface of a long metal member,
After this, when the temperature of the surface of the long metal member that comes into contact with the molten metal rises to a predetermined value, the discharge of the molten metal to the molten metal part is stopped, and the long metal member is cast with the molten metal. A casting method for long metal members, characterized by: 2. The long metal member according to claim 1, characterized in that the surface temperature of the long metal member that stops discharging the molten metal to the waste portion is 1/3 or more of the freezing point of the molten metal. Method for casting shaku metal parts. 3. The elongated metal according to claim 1, wherein while the molten metal is generating a swirling flow, the level of the molten metal is higher than the upper surface of the elongated metal member. Method of casting parts.