JPS62202019A - Method and apparatus for hardening metallic material - Google Patents

Abstract

PURPOSE:To effectively remove steam films and to improve the effect of hardening by bringing the continuous ascending flow of a gas-liquid mixture formed in a cooling liquid into contact with a metallic material heated to a prescribed hardening temp. CONSTITUTION:A partition plate 7 spaced from the vertical inside wall of a hardening vessel 1 is disposed along the inside wall of said vessel and is fixed via mounting plates 8 to the inside wall. Looped gas blow pipes 31, 32 are provided in a horizontal state to the bottom of the vessel 1 and gas conduits 41, 42 are respectively connected thereto. Warm water 2 is filled in the vessel 1 and gas is supplied to the gas blow pipes 31, 32 via the gas conduits 41, 42. The ascending flow region is formed on the inside of the partition plate 7 and the descending flow region on the outside. The warm water 2 is largely stirred. The material 3 for the treatment which is supported to a support 4 and is heated to the prescribed hardening temp. is immersed in the warm water in this state.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial Application Field The present invention relates to heat treatment of relatively large products and members made of metal materials, particularly to rapid cooling treatment (hereinafter referred to as "quenching") after solution treatment. More specifically, the present invention relates to a method for enhancing the cooling effect of a workpiece by a cooling liquid during quenching, and an apparatus therefor.

(b) Conventional technology When a cooling liquid is used as a cooling medium, the processing liquid that comes into contact with the high-temperature workpiece during quenching evaporates rapidly, and this film forms a heat insulating layer that covers the surface of the workpiece. Inhibits cooling effect. Therefore, removal of this "2 film" is considered to be the most important step in effectively performing rapid cooling during quenching.

Regarding quenching of steel materials, the following two measures have been generally taken in order to eliminate this vapor film.

One method is to install a cooling liquid injection nozzle in the quenching tank.
This method uses this jetting force to stir the cooling liquid and remove the vapor film from the surface of the material to be treated. Of course, a method in which the cooling liquid is injected onto the material to be treated that is positioned in the air also exhibits similar effects. Another method is to install a gas injection nozzle in the quenching tank and intermittently spray gas onto the surface of the workpiece immersed in the cooling liquid, thereby removing the vapor film (in practical use). (See Publication No. 54-29813).

The method of stirring the cooling liquid using the cooling liquid injection nozzle described above requires a large number of or powerful devices for large workpieces, which increases equipment costs and makes it difficult to obtain stable cooling conditions. .

In the method of intermittently spraying gas onto the material to be treated using a gas injection nozzle in the quenching tank, there remains the problem of how to remove the vapor film while the spraying is interrupted. If continuous injection is performed so as to eliminate this interruption time, the gas itself blown onto the surface of the material to be treated will form a heat insulating layer similar to a vapor film, making it impossible to achieve the intended improvement in the cooling effect.

In addition, in this method, a uniform hardening effect cannot be obtained unless the gas is uniformly injected onto the surface of the material to be treated, and the material to be treated does not always have a constant shape and size, so the above-mentioned publication discloses that As described above, considerations such as relative movement of the gas injection nozzle and the material to be treated are required, and as a result, as with the previous method, equipment costs are high and it is difficult to obtain stable cooling conditions. be.

(c) Problems to be Solved by the Invention The present invention has been made in view of the above-mentioned problems, and it solves the conventional drawbacks and can quickly and effectively remove the vapor film, thereby improving the quenching effect. The purpose of the present invention is to provide a quenching method that can improve the hardening process, and a device that achieves this with a simple structure and easy maintenance.

(d) Means for solving the problem In order to achieve this object, the method of the present invention brings a continuous upward flow of a gas-liquid mixture formed in a cooling liquid into contact with a metal material heated to a predetermined quenching temperature. It is characterized by

In addition, the device of the present invention used to carry out the method includes a gas blowing pipe provided with a gas blowing hole disposed at the bottom of the quenching tank, and a gas blowing pipe provided with a gas blowing hole installed at the bottom of the quenching tank. A partition plate is provided at a distance from the vertical inner wall.

(e) Function In quenching using a cooling liquid as a refrigerant, gas is continuously blown out from the bottom of the quenching tank, causing bubbles to rise, rather than blowing gas directly onto the surface of the workpiece to remove the vapor film. The present invention was completed based on the discovery that if the upward flow of the gas-liquid mixture generated by the process is allowed to rise along the surface of the material to be treated, the vapor film can be removed extremely effectively and the hardening can be improved. It was.

Here, bringing the continuous upward flow of gas-liquid mixture into contact with the metal material means positioning (immersing) the metal material to be treated in the cooling liquid while the gas-liquid mixture flow rises along the surface of the metal material. It means to cause. Therefore, it is possible to immerse the metal material in the coolant in which an upward flow of gas-liquid mixture is formed in advance, or to form an upward flow of gas-liquid mixture immediately after immersion of the metal material, but in practice, The former is preferable.

That is, the present invention removes the vapor film by the upward flow of this gas-liquid mixture, and naturally this upward flow causes a downward flow in other areas, and the strong stirring action of this circulation lowers the average temperature of the coolant. It is characterized by obtaining a uniform hardening effect on the material to be treated.

More specifically, it was found that the "flow" and "mixed bubbles" of the gas-liquid mixed flow that rises in contact with the surface of the material to be treated are extremely effective in removing the vapor film from the surface of the material to be treated. . In addition, this upward flow of gas-liquid mixture is not only effective for removing the vapor film, but also serves to form an overall strong circulation flow by forming rising and falling regions of the cooling liquid in the quenching tank. It has been found that by this method, it is possible to easily and easily obtain a strong stirring effect of the cooling liquid and to equalize the temperature of the cooling liquid.

In addition, by configuring the quenching device as described above, it is possible to form an upward flow of gas-liquid mixture in the cooling liquid by the gas that is continuously blown out from the gas blowing pipe installed at the bottom of the quenching tank. Become.

(f) Example An example of an apparatus for carrying out the hardening method of the present invention is shown in FIG. 1, and will be described below along with a hardening test carried out using this apparatus.

In the quenching apparatus shown in FIG. 1, reference numeral 1 indicates a quenching tank in which hot water 2 is stored as a cooling liquid.

Although not shown here, the quenching tank 1 is equipped with heating means such as steam or an electric heater as usual, so that the cooling liquid can be preheated to a predetermined temperature. Reference numeral 3 designates the first treated material 2 used in the quenching test. Reference numeral 4 indicates a jig for supporting the material to be treated 3, and is made of a highly heat-resistant material such as steel. This jig 4 is handled while supporting the material 3 to be processed throughout the steps of solution treatment and hardening of the material 3 to be processed. That is, it is used to take the material 3 into and out of the solution treatment furnace, transport it to the quenching tank 1, immerse it in hot water 2, pull it up, etc., and is subjected to the same thermal effects as the material 3.

For this purpose, the jig 4 for the material to be processed 3 is configured to have a support arm 4a extending radially at the lower end, as shown in detail in FIG. 6, so as not to impede the processing of the material to be processed 3. has been done. Reference numeral 4b indicates a reinforcing arm spanning the interval between the supporting arms 4a. Reference numeral 6 indicates a pedestal fixed to the upper surface of the bottom wall of the quenching tank 1, and the jig 4 is placed on this pedestal 6 during the quenching process.

Further, in FIG. 1, reference numeral 7 indicates a partition plate disposed inside the vertical wall of the quenching tank 1 at a distance from the inner surface thereof. This partition plate 7 is connected to the hot water 2 as will become clear later.
The main objective is to separate the upstream and downstream basins that serve the region. This partition plate 7 is fixed to the inner surface of the vertical wall of the quenching tank 1 via a plate 8. Of course, the mounting is such that the plates 8 are oriented and arranged so that the hot water 2 can flow within said spacing.

As a feature of the present invention, in this quenching apparatus, loop-shaped gas blowing pipes 31, 32 are disposed horizontally in the lower part of the quenching tank 1, and gas is not supplied to these gas blowing pipes 31, 32. Conduits 41, 42 are connected respectively. The gas blowing pipe 31 is mounted on the pedestal 6 here.
Fixed to . Further, the gas blowing pipe 32 is fixed near the lower end of the partition plate 7 here at a height corresponding to the support arm 4a of the jig 4. Also gas conduit 41.4
2 extends from the upper part of the quenching tank 1 to the outside as shown by the arrow 5, and is connected to a suitable gas supply source (not shown here) to supply gas to gas blowing pipes 31, 32. It is designed to guide you against Here, the gas must have no adverse effect on the material to be treated, the quenching equipment, etc., and compressed air or the like is considered the most practical since it can be obtained at low cost and is easy to handle.

The gas blowing pipe 31 blows out gas toward the inner circumferential surface of the cylindrical material 3 to be treated, and the gas blowing tube 32 blows out gas toward the outer circumferential surface. This is to form an upward flow of liquid mixture. Here, the upward flow of the gas-liquid mixture caused by the gas blown out from the gas blowing pipe 31 rises through between the support arms 4a of the jig 4, and the support arms 4a do not pose a particular obstacle. For such gas blowing, gas blowing holes 9 are formed in the gas blowing pipes 31 and 32, respectively, as shown in FIGS. 2 and 3. In this embodiment, the hole 9 of the gas blowing pipe 31 is connected to the material 3 to be treated.
In order to form an upward flow of gas-liquid mixture in a wide area on both sides of the gas blowing pipe 31, the inclination is, for example, about 45°. As shown in FIG. 4, they are arranged in a staggered manner at appropriate intervals a and b. On the other hand, the holes 9 of the gas blowing pipe 32 are designed to form an overall downward flow on the outside of the partition plate 7, and the holes 9, for example,
It is oriented at an angle of about 100°. It is desirable that these holes 9 are each opened downward. The reason for this is
This is because hot water initially enters the gas blowing pipes 31 and 32, and unless this hot water is completely discharged by supplying gas, it will not be possible to blow out from all the holes 9. That is, if it is facing downward, the gas will first be guided to the upper part of the entire circumference inside the gas blowing pipe, and after the internal water level has gradually decreased, blowing will start, so blowing from all the holes 9 will start. This is because, on the other hand, if the pipes are provided facing upward, the air can only be blown out from the holes 9 near the conduits 41 and 42.

In the quenching apparatus having such a configuration, preheating of the hot water 2 for quenching (for example, to about 80° C.), immersion and unloading of the material 3 to be treated are performed in the same manner as in the past. However, as a feature of the present invention, before the material to be treated is immersed, gas is supplied to the gas blowing pipe 31.32 through the conduit 41.42, and this gas is blown out from each hole 9 to raise the gas-liquid mixture to the desired position. A flow is formed. This gas supply is continued until the quenching is completed. As a result, the hot water 2 in the quenching tank 1 is largely agitated (circulated) by this upward flow and the corresponding downward flow.

Here, an ascending region is formed on the inside of the partition plate 7, and a descending region is formed on the outside.

With respect to the hot water 2 being circulated in this way, the material to be treated 3 is placed so that its inner and outer circumferential surfaces are located within the upward flow of the gas-liquid mixture (the upward flow of the gas-liquid mixture flows into the material to be treated). immersed (so that it rises along the surface). Due to immersion in this state, the vapor film (not shown) generated on the surface of the material to be treated 3 immediately becomes strong due to the "upward flow" and "action of bubbles (bubble colliding with the surface)" as described above. It will be destroyed and removed. Also, the gas-liquid mixed flow flows along the surface (
The broken vapor film rises with the bubbles, and the area immediately contacts the hot water and is cooled, resulting in a much higher cooling efficiency. Moreover, these bubbles stagnate like a vapor film. It does not impede cooling.

Next, (a> The following test was conducted to examine the strength of the upward flow of gas-liquid mixing due to gas blowing, which is a feature of the present invention.

A hole 9 with a diameter of 1.5 mm oriented downward at an angle of 45'' as shown in FIG.
Outer diameter A = arranged in a staggered manner with mm, b = 25 mm
A 25 mm gas blowing pipe was held at a depth of 1 m, and the amount of air supplied and the flow rate of the upward flow were measured.

As a result, the length of the gas blowing pipe is 601! When an air volume of /min is supplied, the flow velocity of the upward flow is approximately 22m/min.
It was a minute.

When the amount of air supplied was 801/min, the flow rate of the upward flow was approximately 28 m/min.

In addition, the width of the rise on the water surface due to the upflow (strong upwelling area) is approximately 15mm around the gas outlet pipe.
It was about 0 to 200 mm.

It is clear that during actual quenching, it is extremely easy to increase the flow rate of the upward flow in order to obtain the flow rate (circulation, stirring) of the gas-liquid mixed flow necessary for removing the vapor film.

(b) In order to investigate whether the removal of the vapor film was improved by the effect of the upward flow of the gas-liquid mixture, that is, whether quenching could be performed well, a quenching test was actually conducted using a specimen.

The test contents are as follows.

As the first test specimens, three specimens made of forged A6061 aluminum alloy and shaped as shown in detail in FIG. 5 were used. These specimens are TAI and TA, respectively.
2. It will be referred to as TA3. The dimensions of each part shown in Figure 5 are A+ = 1180 in mm, A
2=1440° A3=1630, B, -1470, BZ
=1750, C=130, D,=100. DZ=18
It was about 0 and weighed about 3.3 tons.

The quenching conditions for specimens TAR1TA2 were 80° C. hot water with gas blown out, and the quenching conditions for specimen TA3 were 80° C. hot water without gas blown out.

As the second test specimens, two specimens made of forged A6061 aluminum alloy and shaped as shown in FIGS. 7 and 8 were used. These specimens are TBI and TB, respectively.
I will call it 2. The dimensions of each part shown in Figures 7 and 8 are in mm: w, -319, W2 =
230SH=205, H+=97, and S-210.

80° C. hot water with gas blowing was used as the quenching condition for specimen TBI, and 10° C. cold water without gas blowing was used as the quenching condition for specimen TB2.

Incidentally, all of the specimens mentioned above had been previously subjected to solution treatment at 555°C.

After the above-mentioned quenching treatment, each specimen was left at room temperature for 1 to 2 days, and then artificially aged at 175° C. for 24 hours.

These specimens TAI, TA2, TA3, TBL, TB
In order to understand the quenching effect of No. 2, the strength characteristics and quenching strain after artificial aging treatment were measured. The measurement results are shown in Table 1.

As shown in Table 1, the measurement results of the strength characteristics of the specimen TAI
, TA2, and TA3, the quenching method of the present invention obtains superior results in tensile strength and yield strength compared to the conventional method even when using the same refrigerant, hot water. This indicates that the Moreover, in such a large specimen, the temperature was increased to 80°C in order to reduce the strain.
When using hot water refrigerant, JIS H4140A6061 can be achieved by utilizing the gas-liquid mixed flow of the present invention.
It was confirmed that although the required values of mechanical properties specified by FH-T6 could be fully satisfied, the standards could not be satisfied unless a gas-liquid mixed flow was used.

Comparison of specimens TBI and TB2 shows that cooling with 80° C. hot water according to the method of the present invention can provide almost the same hardening effect as quenching with 10° C. cold water according to the conventional method.

(G) Effects of the Invention As described above, the present invention can reliably improve the hardening effect using simple means. Further, according to the method of the present invention, 80°C
Not only can cooling with hot water provide the same strength as cold water, but
The quenching distortion is small, and it is possible to quench particularly large workpieces that could not be done conventionally, resulting in great industrial effects.

[Brief explanation of drawings]

FIG. 1 is an overall schematic longitudinal sectional view of a quenching apparatus according to an embodiment of the present invention. 2 and 3 are partial sectional views showing a gas blowing pipe having a gas blowing hole, which is a feature of the present invention, in the apparatus shown in FIG. 1. FIG. FIG. 4 is a bottom view showing an example of the arrangement of gas blowing holes in the gas blowing pipe. FIG. 5 is a longitudinal cross-sectional view of the first specimen used for testing the hardening method of the present invention. FIG. 6 is a plan view of the support jig for the first specimen shown in FIG. 5. FIG. 7 and FIG. 8 are a side view and a front view, respectively, of a second specimen used for testing the hardening method of the present invention. 1... Quenching tank 2... Warm water as cooling liquid 3... Material to be treated 4... Support jig 7... Partition plate 9... Gas blowing hole 31.32... Gas blowing pipe 41.42... Gas conduit

Claims (2)

[Claims] (1) A method for quenching a metal material, which comprises bringing a continuous upward flow of a gas-liquid mixture formed in a cooling liquid into contact with a metal material heated to a predetermined quenching temperature. (2) It is characterized by having a gas blowing pipe provided with a gas blowing hole arranged at the bottom of the quenching tank, and a partition plate arranged along the vertical inner wall of the quenching tank at a distance from the vertical inner wall. Hardening equipment for metal materials.