JPS6334780Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to the shape of a heating pad used in casting.

In the manufacturing of castings, steel castings having thin wall sections, wall thickness crossing sections, or wall thickness variation sections will have casting defects such as centerline shrinkage cavities due to insufficient supply of hot water to the center of wall thickness during solidification, resulting in poor quality. In order to prevent casting defects such as center shrinkage cavities, a heating pad P is provided as shown in the example of a thin L-shaped casting C in Fig. 1.
The heat generated when the heating pad comes into contact with molten steel is used to prevent premature solidification and prevent the formation of large shrinkage cavities. Heat generating pads range from metal pads, which require complicated removal, to aluminum,
Heat-resistant heating pads containing alumina as a main component have come into use.

This invention aims to improve the quality of castings by a casting method using heat-generating pads.
Alternatively, the present invention relates to a heating pad that is used in combination with a heating pad that is formed into a hollow semi-tubular or columnar U-shaped cross section.

As shown in Figs. 3 and 4, the heat generating pad of the present invention has one open end having a U-shaped, half-tubular, etc., recess filled with molten metal, and the other end having a closed prismatic or semi-cylindrical recess. It has a tubular shape. The material of the heating pad is conventionally known Al5-40 parts, oxidizing agent 0-15 parts.
It is a heat-generating material made of parts, other refractories, etc. Further, according to the present invention, as shown in FIGS. 5 and 6, a gas vent hole is provided at the top of the heating pad to remove the generated gas and prevent casting defects.

FIG. 7 shows a specific example of applying the heating pad of the present invention to a flat casting. As shown in FIGS. 7, 2 and 2', the pads of the present invention are installed at both ends and the conventional pad 5 with both ends open is installed in the middle, and the molten metal is fed into a mold whose surroundings are filled with molding sand. As shown in 4, hot water or excess meat is generated which is partially surrounded by the heating pads 2 and 2'. The riser or excess wall portion surrounded by the heat generating pad is delayed in solidification and cooling due to the action of the heat generating pad and remains in a molten state even after the body 1 has solidified, so hot water is supplied to the shrinkage cavity that occurs on the body side. Demonstrates defect prevention effect. The effect of molten metal supply on shrinkage cavities that occur in the main body is as shown in Fig. 2. In the conventional method, hot water is supplied from the feeder 3 to the bottom end, whereas in the present invention, the molten metal is supplied from the feeder 3 and 4, and from the excess material to the bottom end of the main body 1. Since the hot water supply distance is short, it is advantageous in preventing shrinkage cavities caused by insufficient hot water supply. After cooling, the riser and the excess wall portion shown in FIGS. 7 and 4 are removed by gas cutting to complete a flat plate casting.

At this time, since the products 2 and 2' of the present invention are used in combination with the conventional product 5 so that both ends are closed as shown in FIG. 7, all surfaces other than the molten metal supply surface are covered with heat generating pads. This method has the advantage of increasing the effectiveness and making it difficult for sand on the top and bottom of the mold to get mixed into the space inside the heating pad, making molding easier and reducing the number of man-hours.

Example As shown in Figure 8, the thickness is 50mm, the width is 1000mm,
For the production of flat plate castings with a length of 1200 mm,
An example using the pad of the present invention is shown below. Two each of the heat generating pads (thickness 20 mm, claw length 30 mm, bottom length 70 mm, length 200 mm) shown in Figure 3 (without gas vent hole) and Figure 5 (with gas vent hole) of this invention. One conventional product with both ends open, and three connected products were installed in two locations as shown in the figure. JLS standard SC49 molten metal was poured into this casting at 1560°C, and after cooling and removing sand, the excess metal was removed to form a flat plate. This flat plate was subjected to gamma ray inspection, and it was confirmed that the meat part quality was JIS gamma ray class 1 or higher. In this case, the amount of heat generating pad used was approximately 20% of the conventional method, and the yield of molten steel was significantly improved to 1.3 times that of the conventional method.

[Brief explanation of drawings]

Fig. 1 is a diagram for generally explaining a heating pad, Fig. 2 is a diagram showing the shape of a conventional heating pad and its installation method, and Fig. 3, 4,
Figures 5 and 6 are perspective views showing the shape of the heat generating pad of the present invention, and Figures 7 and 8 are views showing specific examples of the use of the heat generating pad of the present invention in manufacturing castings. In FIG. 7, 2 and 2' are heat generating pads of the present invention, 1 is a casting body, 3 is a feeder portion, 4 is an excess portion, and 5 is a conventional product.

Claims (1)

[Scope of utility model registration request] Among heating pads used during casting, one open end is U-shaped or semicircular, and the other end is closed in the shape of a prism or semi-tube.