JP4015380B2 - Gas pressure welding method and gas pressure welding device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gas pressure welding method and a gas pressure welding device for carrying out the method, and more particularly to a method suitable for reducing the amount of carbon dioxide gas generated.
[0002]
[Prior art]
Gas pressure welding is widely applied, for example, when joining reinforcing bars and rails. In the gas pressure welding process, after grinding both end surfaces to be joined together, both end surfaces are butted against each other and pressurized, and the butted portions are heated to a desired temperature with an oxygen / acetylene flame, so that It can be joined.
[0003]
However, the acetylene gas that forms an oxygen / acetylene flame is highly dangerous and requires careful handling. Therefore, it is conceivable to use propane gas having high safety, and has been studied. However, since an oxide is easily generated on the joint surface in the propane gas flame, a pressure welding system using the propane gas flame has not been put into practical use in terms of quality.
[0004]
[Problems to be solved by the invention]
By the way, when acetylene gas or propane gas as described above is used as the combustion gas at the time of gas pressure welding, a large amount of carbon dioxide gas is generated, which is not preferable in terms of environment. Particularly in recent years, the global warming phenomenon has become a problem, and there is a demand for reducing carbon dioxide emissions.
On the other hand, a combustion gas that is relatively easy to handle and generates a small amount of carbon dioxide in a combustion reaction is being searched for today, and oxygen-hydrogen mixed gas obtained by electrolyzing water has attracted attention. It has already been applied in the field.
[0005]
Further, for example, as disclosed in Japanese Patent Application Laid-Open No. 2001-47255, acetylene gas is used as a combustion gas at the beginning of gas pressure welding, and thereafter, propane gas, LNG, ethylene gas, butane gas, methane gas, hydrogen gas, etc. A technique for performing the latter heating by switching to one of the above or a mixed gas thereof is disclosed.
However, for example, a flame containing hydrogen alone has a problem that it reduces not only the heating efficiency but also the reduction performance, and is difficult to put into practical use.
[0006]
In view of the above-mentioned problems of the prior art, the present invention can reliably reduce the amount of carbon dioxide generated, can also improve the safety of work, and further stably form a flame, It is an object of the present invention to provide a gas pressure welding method capable of improving the quality of the bonding interface, and to provide a gas pressure welding apparatus capable of accurately carrying out the above method.
[0007]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, in the present invention, when the end faces of both workpieces are butted against each other and pressurized, in the gas pressure welding method in which both butted portions are heated and joined by a gas flame of combustion gas, , water generates is that oxygen hydrogen mixed gas obtained by electrolysis, to generate a gas of carbon compound, by adding the carbon compound in the oxyhydrogen gas mixture, wherein the supply to the gas burner . In the present invention, the carbon compound added to the oxygen-hydrogen mixed gas is 0.02 to 0.27 times the amount of hydrogen in the oxygen-hydrogen mixed gas. The present invention is characterized in that oxygen is additionally supplied to the oxygen-hydrogen mixed gas. In the present invention, the amount of oxygen to be additionally supplied to the oxygen-hydrogen mixed gas is (x−0.02) to (9.0x−0.18) times the hydrogen amount of the oxygen-hydrogen mixed gas. (Where x is a value obtained by dividing the amount of carbon compound to be added by the amount of reaction hydrogen).
In the gas pressure welding apparatus according to the present invention, when the end faces of both workpieces are pressed against each other and pressurized, the butted portion is heated by the gas flame of the combustion gas supplied from the combustion gas supply unit and joined. The gas supply unit includes an oxygen / hydrogen mixed gas generating device that generates an oxygen-hydrogen mixed gas obtained by electrolyzing water, a carbon compound generating device that generates a carbon compound gas, and a carbon compound in the oxygen-hydrogen mixed gas. Mixing means for mixing and supplying to the gas burner. In the present invention, the combustion gas supply unit includes additional supply means for additionally supplying oxygen to a mixed gas of an oxygen-hydrogen mixed gas and a carbon compound.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to FIGS. FIG. 1 is a schematic view of a fuel supply unit showing an embodiment of a gas pressure welding apparatus for carrying out the method of the present invention, FIG. 2 is an explanatory view showing an external flame by a gas burner of the fuel supply unit of FIG. 1, and FIG. It is explanatory drawing which shows the temperature measurement state of the core part of the flame by a gas burner.
[0009]
In an embodiment of the gas pressure welding apparatus shown in FIG. 1, a combustion gas supply unit 1 and a gas burner 2 are connected, and the combustion gas supply unit 1 includes an oxygen / hydrogen mixed gas generator 3, a carbon compound vaporizer 4, and the like. The gas mixing chamber 5 is provided.
The oxygen / hydrogen mixed gas generating device 3 of the combustion gas supply unit 1 generates a mixed gas of oxygen and hydrogen (ratio of 1: 2) by electrolyzing water, so that the oxygen-hydrogen mixed gas is obtained. It has become.
[0010]
The carbon compound vaporizer 4 is used to stabilize the flame because it is difficult to stabilize only with the flame of the oxygen-hydrogen mixed gas obtained by the oxygen / hydrogen mixed gas generating device 3. A compound is produced. In this example, hexane, which is liquid at room temperature, is used as the carbon compound, and the hexane solution is vaporized by the vaporization means provided in the carbon compound vaporizer 4, thereby generating vaporized hexane. Yes.
The reason for using hexane is that if another carbon compound having a carbon value larger than that of hexane is used, the outer flame formation region from the gas burner 2 can be easily expanded, but there is a large-scale apparatus for vaporizing the carbon compound. This is because hexane can be vaporized relatively easily.
[0011]
The gas mixing chamber 5 is connected to the oxygen / hydrogen mixed gas generator 3 through a gas supply pipe 7 having a flow rate adjusting valve 6, and the carbon compound vaporizer 4 through a supply pipe 9 having a flow rate adjusting valve 8. Connected with. The gas mixing chamber 5 mixes the oxygen-hydrogen mixed gas fed from the oxygen / hydrogen mixed gas generator 3 and the hexane charged from the carbon compound vaporizer 4 so as to have a predetermined ratio, and the gas burner 2 To send.
[0012]
Accordingly, the combustion gas supply unit 1 adds the hexane vaporized from the carbon compound vaporizer 4 to the oxygen-hydrogen mixed gas from the oxygen / hydrogen mixed gas generator 3, and these mixed gases are mixed into the gas mixing chamber 5. As shown in FIG. 2, the flame from the gas burner 2 can form a desired external flame L having an external flame length L1 and an external flame width L2. The gas burner 2 is a single hole burner.
[0013]
Further, an oxygen gas cylinder 10 for additional supply is connected to the gas mixing chamber 5 via an oxygen supply pipe 11, and a predetermined amount of oxygen is also oxygen hydrogen by a flow rate adjusting valve 12 provided in the oxygen supply pipe 11. It is additionally supplied to a mixed gas of mixed gas and hexane. This is because when an oxygen amount from the oxygen gas cylinder 10 is additionally supplied, a core portion (high temperature portion) C is formed in the flame from the gas burner 2 as shown in FIG. The heating rate of the part is increased.
In FIG. 3, in order to measure the temperature of the flame core C by the gas burner 2, for example, a thermocouple 14 is embedded at a depth h of 1.5 mm from the surface of a copper plate (150 mmφ × 10 mmt) 13. The temperature is measured via the thermocouple 14 by heating the copper plate 13 in that state at the core portion C.
[0014]
Since the present embodiment is configured as described above, when gas pressure welding is performed by pressing the end surfaces of a workpiece (not shown) for gas pressure welding against each other, from the periphery of the butted portion, Gas pressure welding is performed in which both works are brought into contact with each other by heating with a mixed gas flame of oxygen-hydrogen mixed gas and vaporized hexane by a ring burner (see FIG. 8) in which the craters of the gas burner 2 are arranged on the circumference. .
[0015]
In this case, when vaporized hexane is added to the oxygen-hydrogen mixed gas, the outer flame L from the gas burner 2 can be formed into a desired shape as shown in FIG. 2, and the flame can be stably formed. it can.
In addition, since the formation region of the outer flame L can be expanded by adding hexane, and a reduction action region can be formed, the amount of oxygen entrapped in the butt portion of the workpiece during gas pressure welding is greatly reduced. In this way, it is possible to prevent an adverse effect such that an oxide film or the like remains at the abutting portion despite the gas pressure welding operation.
As a result, it is possible to satisfactorily perform gas pressure welding for butt-joining workpieces.
[0016]
Further, since oxygen is additionally supplied from the oxygen gas cylinder 10 to the gas burner 2 through the gas mixing chamber 5, the core C can be formed in the flame of the gas burner 2 as shown in FIG. Heating efficiency can be reliably increased. Therefore, gas pressure welding can be performed more satisfactorily.
[0017]
Incidentally, the amount of hexane to be added is changed under the condition that the combustion gas supply unit of the illustrated embodiment is used and the supply amount of the oxygen-hydrogen mixed gas is 12 l / min (oxygen: hydrogen = 4 l / min: 8 l / min). Thus, when the formation state of the external flame (reduction action area) L was examined, the result shown in FIG. 4 was obtained. FIG. 4 shows the relationship between the outer flame formation region and the amount of hexane.
[0018]
According to FIG. 4, it can be understood that the outer flame can be stably formed when the addition amount (volume amount) of hexane is 0.02 or more with respect to the hydrogen amount in the oxygen-hydrogen mixed gas.
However, in this case, when the addition amount of hexane is less than 0.16 l / min, that is, less than 0.02 times the amount of hydrogen, the flame from the gas burner 2 is not stably formed, and an effective reduction action area is not formed. When the amount of addition exceeds 2.16 l / min, that is, when the amount of hydrogen supplied is much larger than 0.27 times the amount of hydrogen, hexane will be present in excess, resulting in degeneration of the external flame zone. By adjusting the amount, the flame from the gas burner 2 can be stably formed, and the outer flame forming area can be expanded.
Therefore, the amount of hexane added is preferably 0.02 to 0.27 times the amount of hydrogen.
In the above experiment, a single hole burner having a crater diameter of 1.3 mm was used as the gas burner 2 as shown in FIG. In addition to hexane as a carbon compound, it was confirmed that the same flame formation phenomenon as in FIG. 4 occurred when acetone or gasoline was applied.
[0019]
Further, when the generation amount of oxygen-hydrogen mixed gas is 6 l / min (oxygen: hydrogen = 2 l / min: 4 l / min), the addition amount of hexane is 0.7 l / min, that is, 0.175 times the supply hydrogen amount. Under the above conditions, the influence of the additional supply amount of oxygen on the temperature raising ability of the fire was examined by the heating test of the copper plate 13 shown in FIG. 3, and the result of FIG. 5 was obtained. FIG. 5 shows the relationship between the additional supply oxygen amount and the temperature raising capability of the flame.
[0020]
According to FIG. 5, when the amount of oxygen to be additionally supplied is 0.4 l / min, that is, 0.1 times the amount of hydrogen to be supplied, since the core portion is not formed in the flame, the heating efficiency is extremely low. It was confirmed that under the condition that the additional supply amount is 0.16 times or more of the supplied hydrogen amount, the core portion is formed and the heating efficiency can be improved as the additional supply amount of oxygen increases.
However, when the additional supply amount of oxygen was 6.4 l / min, that is, 1.6 times the supply hydrogen amount, a flashback phenomenon occurred in the gas burner 2, leading to digestion.
[0021]
Furthermore, in the experiment, the addition amount of hexane was 0.52 l / min (0.13 times the supply hydrogen amount), the additional supply oxygen amount was 1.0 l / min (0.25 times the supply hydrogen amount), and The same temperature measurement test was performed under two conditions of an additional amount of 1.0 l / min (0.25 times the amount of supplied hydrogen) and an additional amount of supplied oxygen of 2.8 l / min (0.7 times the amount of supplied hydrogen). When implemented, the results shown in FIG. 6 were obtained. FIG. 6 shows the relationship among the added amount of hexane, the amount of additional supplied oxygen, and the heating capability of the flame. It was confirmed that both of these conditions can form a stable flame having the core portion C.
[0022]
Therefore, the result shown in FIG. 7 is obtained from the contents of FIGS. That is, as shown in FIG. 7, the amount of hexane added is in the range of 0.02 to 0.27 times the amount of hydrogen in the oxygen-hydrogen mixed gas, and the amount of additional oxygen is (x−0.02). ) And (9.0x−0.18) times in the range (shaded portion) z is an appropriate range preferable for gas pressure welding. In this case, x is a ratio of the hexane addition amount to the hydrogen amount, and y is a ratio of the additional supply oxygen amount to the hydrogen amount.
These results confirm that almost the same phenomenon occurs when acetone or gasoline is used in addition to hexane.
[0023]
As a result, according to the method of the present invention, since the oxygen-hydrogen mixed gas obtained by electrolyzing water is used as a main component for gas pressure welding, compared with oxygen / acetylene flame or oxygen / propane flame, carbon dioxide gas The amount of generation can be greatly reduced. In addition, compared with an oxygen / acetylene flame that needs to be handled with care, it is advantageous in handling and can improve work safety.
[0024]
Further, by adding hexane gas to the oxygen-hydrogen mixed gas, not only can the outer flame L be stably formed, but also the formation area of the outer flame L can be expanded, so that the outer flame L is caught in the butt portion of the workpiece. The amount of oxygen is greatly reduced, good gas pressure welding can be realized, and the quality of the bonding interface can be improved.
Furthermore, since the core portion C of the flame can be formed by additionally supplying oxygen, the heating efficiency at the time of gas pressure welding can be increased.
[0025]
Then, according to the gas pressure welding apparatus of the present embodiment, as the gas supply unit, the oxygen / hydrogen mixed gas generator 3 that generates oxygen-hydrogen mixed gas by electrolyzing water, and vaporized like hexane Since the carbon compound vaporizing apparatus 4 for generating the carbon compound and the gas mixing chamber 5 for supplying the gas mixture of the oxygen-hydrogen mixed gas and the carbon compound to the gas burner 2 are configured, the above method is accurately performed. Can do.
Further, since the oxygen gas cylinder 10 for additionally supplying oxygen is connected to the gas mixing chamber 5, the heating efficiency can be improved by appropriately selecting the amount of additional supply oxygen and forming the core portion C. The pressure welding can be performed more satisfactorily.
[0026]
FIG. 8 shows another embodiment of the gas pressure welding apparatus for carrying out the method of the present invention.
In this embodiment, as the gas burner 2, a ring burner having eight craters provided at appropriate intervals around the periphery is adopted. The crater diameter is 1.5 mm. Then, the workpieces (not shown) to be pressed against each other are pressed against each other at the center of the gas burner 2, and both the workpieces can be pressed against each other by heating both butted portions from the surroundings. It is like that.
In FIG. 8, the same reference numerals as those in FIG.
[0027]
In this embodiment, a deformed steel bar (SD345, nominal name D25) is used as a workpiece for pressure welding, and the pressure welding conditions are an oxygen-hydrogen mixed gas of 30 l / min (oxygen: hydrogen = 10 l / min: 20 l / min), and the amount of added hexane. 3.5 l / min, additional supply oxygen amount 10 l / min, pressure applied to the workpiece was fixed at an upper limit of 35 MPa, a lower limit of 17 MPa, and a heating time of 80 seconds. Then, 10 joints of the workpiece were welded under the above conditions, and then the bulge portion of each joint of the workpiece obtained by the pressure welding was machined into a 28 mm diameter and subjected to a bending test. The following results were obtained: was gotten.
[0028]
That is, no abnormalities such as cracks and breaks were observed in all the workpieces at a bending angle of 90 °. The joint performance of this work is the joint obtained when heating is performed for 60 seconds with an applied pressure of 35 MPa and a lower limit of 17 MPa in a conventional oxygen / acetylene flame (oxygen: acetylene = 20 l / min: 20 l / min). The result was equivalent.
As a result, the joint strength of each joint was the same as in the case of gas pressure welding using an oxyacetylene flame. In addition, the amount of carbon dioxide gas generated under these pressure welding conditions was calculated in consideration of the heating time. As a result, it was about 1/3 that of the conventional pressure welding method using an oxygen acetylene flame. The result which can be reduced to the above was obtained.
Further, it has been confirmed that the same effect as that of the present invention can be obtained by using, for example, an oxygen gas cylinder and a hydrogen gas cylinder instead of the oxygen / hydrogen mixed gas generator 3. Since it is known as a dangerous gas, it is considered to use the oxygen / hydrogen mixed gas generator 3 that electrolyzes water and generates an oxygen-hydrogen mixed gas in consideration of ease of handling and safety. Yes.
Therefore, there is no fear of requiring the caution as in the case of acetylene gas, which is extremely advantageous in handling and can improve work safety.
[0029]
Therefore, according to the method of the present invention, since the gas pressure welding is performed by the mixed gas flame obtained by adding hexane to the oxygen-hydrogen mixed gas, it is possible to basically obtain the same functions and effects as those of the above-described embodiment. In addition, according to the present gas pressure welding apparatus, the above method can be accurately performed.
[0030]
In addition, according to the illustrated embodiment so far, since the carbon compound vaporizer 4 can vaporize the carbon compound relatively easily, an example using hexane has been shown. Of course, it may be.
[0031]
【The invention's effect】
As described above, according to the present invention, since the oxygen-hydrogen mixed gas obtained by electrolyzing water is used for gas pressure welding, compared with oxygen / acetylene flame or oxygen / propane flame, carbon dioxide gas is generated. The amount of oxygen can be greatly reduced, and it is advantageous in terms of handling and can improve the safety of work. Further, the amount of oxygen trapped in the butt part of the workpiece is greatly reduced, and the quality of the joining interface can be improved. There is an effect that can be done.
[Brief description of the drawings]
FIG. 1 is a schematic view of a combustion gas supply unit showing an embodiment of a gas pressure welding apparatus for carrying out the method of the present invention.
2 is an explanatory view showing an external flame by a gas burner of the combustion gas supply unit of FIG. 1 during gas pressure welding.
FIG. 3 is an explanatory diagram for measuring the temperature state of the core part of the flame by the gas burner.
FIG. 4 is an explanatory diagram showing a relationship between an outer flame formation region and an amount of hexane.
FIG. 5 is an explanatory diagram showing the relationship between the amount of additional supplied oxygen and the temperature raising ability of the flame.
FIG. 6 is an explanatory diagram showing the relationship among the added amount of hexane, the amount of additional supplied oxygen, and the temperature raising ability of the flame.
FIG. 7 is an explanatory diagram showing the relationship between the amount of hexane added and the amount of additional supply oxygen with respect to the amount of hydrogen in the oxygen-hydrogen mixed gas.
FIG. 8 is a view corresponding to FIG. 1 showing another embodiment of the gas pressure welding apparatus for carrying out the method of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Combustion gas supply part 2 Gas burner 3 Oxygen / hydrogen mixed gas generator 4 Carbon compound vaporizer 5 Gas mixing chamber 6 Flow rate adjustment valve 7 Gas supply pipe 8 Flow rate adjustment valve 9 Supply pipe 10 Oxygen gas cylinder 11 Oxygen supply pipe 12 Flow rate adjustment Valve 13 Copper plate 14 Thermocouple L Outer flame L1 Outer flame length L2 Outer flame width C Core part (high temperature part)

Claims (6)

In the gas pressure welding method in which when the end faces of both workpieces are pressed against each other and pressurized, the butted portions of both workpieces are heated and bonded by a gas flame of combustion gas,
As the combustion gases, it produces a is that oxygen hydrogen mixed gas obtained electrolyzing water,
Produces a carbon compound gas,
A gas pressure welding method , wherein the carbon compound is added to the oxygen-hydrogen mixed gas and supplied to a gas burner. The carbon compound to be added to the oxyhydrogen gas mixture, relative to the amount of hydrogen oxygen hydrogen mixed gas, a gas welding method according to claim 1, characterized in that a 0.02 to 0.27 times. The gas pressure welding method according to claim 1 or 2 , wherein oxygen is additionally supplied to the oxygen-hydrogen mixed gas. The amount of oxygen additionally supplied to the oxygen-hydrogen mixed gas is (x−0.02) to (9.0x−0.18) times the amount of hydrogen in the oxygen-hydrogen mixed gas. The gas pressure welding method according to claim 3 . (Where x is the value obtained by dividing the amount of carbon compound to be added by the amount of reaction hydrogen) In the gas pressure welding apparatus that heats and joins the butted portions of both workpieces with the gas flame of the combustion gas supplied from the combustion gas supply unit when the end surfaces of both workpieces are pressed against each other and pressurized,
The combustion gas supply unit
An oxygen-hydrogen mixed gas generator that generates an oxygen-hydrogen mixed gas obtained by electrolyzing water;
A carbon compound generator for generating a carbon compound gas;
A gas pressure welding apparatus comprising: mixing means for mixing a carbon compound with an oxygen-hydrogen mixed gas and supplying the mixture to a gas burner. The combustion gas supply unit
6. The gas pressure welding apparatus according to claim 5 , further comprising additional supply means for additionally supplying oxygen to a mixed gas of oxygen-hydrogen mixed gas and carbon compound.

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