EP3034200A1

EP3034200A1 - Nozzle for cooling vacuum furnace

Info

Publication number: EP3034200A1
Application number: EP15836621.1A
Authority: EP
Inventors: Zhizhong Liang
Original assignee: ASSAB Tooling Technology Shanghai Co Ltd
Current assignee: ASSAB Tooling Technology Shanghai Co Ltd
Priority date: 2014-08-29
Filing date: 2015-05-07
Publication date: 2016-06-22
Also published as: EP3034200A4; WO2016029713A1; CN105364045A; US20160201156A1

Abstract

A nozzle for cooling a vacuum furnace, comprising: a vacuum heating furnace, nozzles, extended nozzles, thermocouples and a deep cavity die casting mold; the vacuum heating furnace is provided with a plurality of rows of nozzles therein, each row of nozzles are equally distributed in the vacuum heating furnace, which is characterized in that the nozzle is installed with the extended nozzle thereon, a length of the extended nozzle is set as 50-250mm in accordance with a depth of the shape of the deep cavity die casting mold so that a distance between an end surface of the extended nozzle and a cavity surface of the mold is 450-600mm; the vacuum heating furnace is provided with a tray therein, the deep cavity die casting mold is placed on the tray and located at a central position of the vacuum heating furnace, a plurality of thermocouples are placed on the surface of the deep cavity die casting mold. The advantage of the present invention is to obviously improve the cooling speed of the deep cavity die casting mold, of which the surface cooling speed is accelerated, so that the problem of cooling speed of the deep cavity die casting mold recess is solved, which improves the heat processing performance and solves the problem of uneven cooling speed of the deep cavity die casting mold surface.

Description

Technical Field

The present invention relates to a mold vacuum heat processing device, especially relates to a nozzle for cooling a vacuum furnace.

Background Technology

Die casting mold has a more and more wide application in various field in recent years and is developing into ultra-large die casting mold, of which the shapes are more and more complicated and the cavities are deeper and deeper, so it has higher requirements to mold materials and heat processing performance. At present, die casting mold generally uses vacuum air quenching furnace for heat processing, due to the mold is at a distance from the cold air source when cooling, the air cannot to be blown to the key position of the mold directly, all the general vacuum heat processing devices cannot make the cavity bottom or root of the mold achieve a fast cooling speed, so that some sections of the mold cannot reach a better performance during heat processing, due to the undesirable performance, it causes an initial failure in the sections of the mold during heat processing, while the bottom and root of the cavity are just key positions of die casting products, which influences the appearance quality of die casting products and finally causes early disuse of the mold because the product appearance cannot reach the requirements. Therefore, it will be a priority subject in the field that how to improve the heat processing performance of the cavity bottom and root of the mold. Much faster the cooling speed is during quenching, much better the heat processing performance of the mold will be. Then it will be the research orientation of improving the heat processing performance that how to improve the quenching cooling speed of the cavity bottom and root of the deep cavity die casting mold. Once the problem is solved, it will greatly improve the heat processing performance of the large and deep cavity mold so as to efficiently improving the life of the deep cavity die casting mold. Due to the cooling speed of the cavity bottom or root is slow when the vacuum heat processing device performing heat-processing on the deep cavity die casting mold, while the air ejected from the nozzle is at a distance from the mold when cooling, which will reduce cooling speed and influence the heat processing performance of the mold. And the molds are various in shapes, comprising recess molds, convex molds, steps and so on, the distances from the nozzle to different positions of the recess mold cavity or convex mold root are different, which causes the cooling speed to be uneven so as to causes disunity of the heat processing performance at each position of the deep cavity die casting mold, which will even cause the danger of large deformation and crack of the mold. For the undesirable heat processing effect caused by the uneven cooling speed, the main reason is that the cold air source is at a distance from the deep cavity die casting mold, then as long as the problem of a far distance between the cold air source and the deep cavity die casting mold is solved. Thereby, the research subject of the present invention is how to decrease the distance between the cavity and the cold air source so as to improve the cooling speed of the mold cavity.

Summary

The object of present invention is to the existed defects in the prior art and provides a nozzle for cooling the vacuum furnace. The technical solution of the present invention comprises: a vacuum heating furnace, nozzles, extended nozzles, thermocouples and a deep cavity die casting mold; the vacuum heating furnace is provided with a plurality of rows of nozzles therein, each row of nozzles are equally distributed in the vacuum heating furnace, in which each row is generally distributed at 30 degree; the whole vacuum heating furnace is divided into twelve rows of nozzles, each row is provided with six nozzles, wherein the nozzle is installed with an extended nozzle thereon, the length of the extended nozzle is set as 50-250mm in accordance with a depth of the shape of the deep cavity die casting mold so that the distance between the end surface of the extended nozzle and the cavity surface of the mold is 450-600mm; the vacuum heating furnace is provided with a tray therein, the deep cavity die casting mold is placed on the tray and located at a central position of the vacuum heating furnace, a plurality of thermocouples are placed on the surface of the deep cavity die casting mold.
The extended nozzle formed from graphite-like materials has a cylindrical shape, which has a circular hole in the interior, a front half section of the interior has a circular step shape, the extended nozzle is installed on the nozzle opening, a wall of a rear section of the extended nozzle is provided with a plurality of screwed holes for fixing the extended nozzle, a bolts fixes the extended nozzle to the nozzle through the screwed holes.
The advantage of the present invention is to efficiently solve the problem of uneven cooling speed of the surface of the deep cavity die casting mold. The extended nozzle ejects cold air during cooling, which is directly sprayed to the mold surface, the heated air passes through the heat exchanger and is again ejected from the extended nozzle, so as to form a cycle and achieve the object of cooling the deep cavity die casting mold quickly and evenly. The cooling speed of the deep cavity die casting mold is obviously improved, the cooling speed of the surface is accelerated, so as to solve the problem of the cooling speed of the recesses of the deep cavity die casting mold and the heat processing performance is improved.

Drawings Description

Fig 1 A schematic diagram showing the layout of the vacuum heating furnace nozzles;
Fig 2 A schematic diagram showing the structure of the extended nozzle and the nozzle outfit;
Fig 3 A schematic diagram showing left view of the structure of the extended nozzle and the nozzle outfit;
Fig 4 A schematic diagram showing A-A side section view of the structure of assembly of the extended nozzle and the nozzle;
Fig 5 A schematic diagram showing the structure in case that the deep cavity die casting mold is placed on the tray in the embodiments;
Fig 6 A schematic diagram showing A-A side section view of the structure in Fig. 5;
Fig 7 A schematic diagram showing B-B side section view of the structure in Fig. 6;

In above figures : 1 nozzle, 2 extended nozzle, 3 vacuum heating furnace, 4 deep cavity die casting mold, 5 screwed hole, 6 bolt, 7 thermocouple

Embodiments

Hereby combining the figures to further explain the embodiments of the present invention :

The vacuum heating furnace 3 in the present embodiment is provided with twelve rows of nozzles therein, each row of nozzles are equally distributed in the vacuum heating furnace 3 at 30 degrees. As shown in Fig. 1, the positions of twelve rows of nozzles are 0 to 330 degrees in the figure, the position of each row of nozzles is provided with six nozzles 1, the vacuum heating furnace 3 has 72 nozzles 1 in all therein, each nozzle is installed with an extended nozzle 2 thereon. The extended nozzle 2 is formed from graphite-like materials and has a cylindrical shape, which has a circular hole in the interior, a front half section of the interior has a circular step shape, the extended nozzle 2 is installed on the nozzle opening 1, a wall of a rear section of the extended nozzle 2 is provided with a plurality of screwed holes 5 for fixing the extended nozzle, bolts 6 fix the extended nozzle 2 to the nozzle 1 through the screwed holes 5. The length of the extended nozzle is set as 50-250mm in accordance with a depth of the shape of the deep cavity die casting mold. The deep cavity die casting mold 4 of the present embodiment has the recess and convex mold, the mold installing positions are widely different, for the deep cavity die casting mold 4, the cooling speed can be accelerated or cooling can be evenly by extending the nozzle 1 by selectively adding 72 extended nozzles 2 at different positions and have different amount or different length, so as to achieve the desirable heat processing performance of the mold. Selecting the length, the installing position and number proper for the extended nozzle 2 in accordance with the specific shape and installing position of the deep cavity die casting mold 4, so that the distance between the end surface of the nozzle and the cavity surface of the mold is 450-600mm after the extended nozzle 2 is installed. Therefore, the problem of bad and uneven cooling caused by the different distance between the nozzle end surface and the surface of the deep cavity die casting mold is solved. The vacuum heating furnace 3 is provided with a tray therein, the deep cavity die casting mold 4 is placed on the tray and located at a central position of the vacuum heating furnace, nine thermocouples 7 are placed on the surface of the deep cavity die casting mold 4.

The extended nozzle 2 ejects cold air during cooling, which is directly sprayed to the surface of the deep cavity die casting mold 4, the heated air passes the heat exchanger and is again ejected from the extended nozzle 2 to form a cycle, so as to achieve the target of cooling the deep cavity die casting mold 4.

In the present embodiment, by using identical heat processing technology, comparing the data obtained after quenching cooling with the data that the extended nozzle 2 is not installed, as shown in table 1.

Table 1: Testing data comparison table with and without an extended nozzle

	the mold is placed at the center position of the tray, and the nozzle is not extended	the mold is placed at the center position of the tray, and the nozzle is extended with 200 mm
	(1020-540 degree) cooling speed °C/min	(1020-540 degree) cooling speed °C/min
Controlled surface temperature at opening end surface B2	65.56	90.77
Upper position of bottom of recess B3	29.56	38.77
Middle position of bottom of recess B4	34.33	57.85
Lower position of bottom of recess B5	23.78	40.00
100 mm upward from the opening end surface in the recess B6	48.00	67.08
100 mm from the opening end surface in the recess B7	44.00	62.92
100 mm downward from the opening end surface in the recess B8	43.22	69.69
100 mm from the opening end surface in the recess B9	47.33	64.92

It can be seen from above table, after the nozzle 1 is installed with the extended nozzle 2, the cooling speed is obviously improved, the surface cooling speed is commonly improved by 50 percent, so that the problem of the cooling speed at the recess of the deep cavity die casting mold 4 is solved and the heat processing performance is improved. In the meantime, it can also solve the problem of uneven cooling speed of the mold surface by installing nozzles at different positions and have different amount. It can be seen from above experiment: the cooling speed will be obviously improved by way of installing the extended nozzle 2.
The application of the nozzle in the present embodiment has a high commonality. Besides the mold of recess mold type as above, regarding to other types of molds, for example, the mold thickness is not uniform, that is a mold having a great thickness difference, it can also extend the nozzle to reinforce cooling on the thicker end of the mold, so as to achieve conformity with the cooling speed of the thinner end, so that the risk of deformation and crack will be reduced and the heat processing performance of the material will be improved. Regarding to different types of molds, the distance between the end surface of the extended nozzle and the mold-typed cavity surface is adjusted to between 450-600mm by extending the nozzle, that is, the whole cooling even state and cooling speed of the mold can be controlled.
Based on above experiment and producing practice, it can be said to thoroughly solve the problem of partial slow cooling and cooling evenness of heat processing quenching of all molds, so that the heat processing performance is improved and quenching is not easy to crack. This application will be a qualitative advance in the mold heat processing field, which will have great influence to extend the life of the mold.

Claims

A nozzle for cooling a vacuum furnace, comprising: a vacuum heating furnace, nozzles, extended nozzles, thermocouples and a deep cavity die casting mold; the vacuum heating furnace is provided with a plurality of rows of nozzles therein, each row of nozzles are equally distributed in the vacuum heating furnace, which is characterized in that the nozzle is installed with the extended nozzle thereon, a length of the extended nozzle is disposed set as 50-250mm in accordance with a depth of the shape of the deep cavity die casting mold so that a distance between an end surface of the extended nozzle and a cavity surface of the mold is 450-600mm; the vacuum heating furnace is provided with a tray therein, the deep cavity die casting mold is placed on the tray and located at a central position of the vacuum heating furnace, a plurality of thermocouples are placed on a surface of the deep cavity die casting mold.
A nozzle for cooling the vacuum furnace according to claim 1, which is characterized in that the extended nozzle formed from graphite-like materials has a cylindrical shape, which has a circular hole in the interior, a front half section of the interior has a circular step shape, the extended nozzle is installed on the nozzle opening, a wall of a rear section of the extended nozzle is provided with a plurality of screwed holes for fixing the extended nozzle, bolts fix the extended nozzle to the nozzle through the screwed holes.