JP2013052398A - Gas pressure welding method for steel stock - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas pressure welding method for a steel stock, which applies a hydrogen-ethylene mixture gas to the gas pressure welding of a steel stock to improve workability.SOLUTION: The gas pressure welding method for a steel stock includes: butting steel stocks 1, 2 on each other; spraying the hydrogen-ethylene mixture gas together with an oxygen gas to a butting portion 3 of the steel stocks 1, 2; and heating the butting portion 3 of the steel stocks 1, 2 with flames of the hydrogen-ethylene mixture gas while applying a pressure to the steel stocks 1, 2, to joint the steel stocks 1, 2 to each other.

Description

  The present invention relates to a gas pressure welding method used for gas pressure welding of steel materials such as railroad rails and reinforcing bars.

  Conventionally, the gas pressure welding method is a joining method in which steel materials are butt-joined, the butt portion is heated with an oxygen / acetylene flame, and pressure welding is completed through an upset process, which is widely applied to rail rail joining. . However, the demand for acetylene gas, which is used as fuel gas in the current gas pressure welding method, is declining, so production will be discontinued depending on future rising gas prices or the profitability of the manufacturer. The possibility is feared. Moreover, since carbon dioxide gas is generated with the combustion reaction with oxygen, there is a concern about the influence on the environment. Therefore, in order to continue using the conventional gas pressure welding method in the future, it is necessary to establish a rail gas pressure welding method using an alternative gas instead of acetylene gas.

  In view of such a situation, there is a history of studying a rail gas pressure welding method using a hydrogen hexane mixed gas in which hexane, which is a hydrocarbon, is mixed with hydrogen gas (see Patent Document 1 below).

JP 2010-31465 A

However, in the rail gas pressure welding method using the hydrogen hexane mixed gas described above, it is necessary to mix hydrogen gas and hexane at the construction site, and the work is laborious. Therefore, the workability is higher than the method using the conventional acetylene gas. There was a problem of being inferior.
In addition, hydrogen gas has a very high combustion speed, and it is difficult to stably form a combustion flame. That is, it is difficult to use hydrogen gas alone for gas pressure welding, and assuming application in gas pressure welding, it is necessary to mix an appropriate amount of hydrocarbons and stabilize the combustion flame.

Therefore, the present invention focuses on ethylene gas that can be stored and transported in a gas cylinder even when mixed with hydrogen gas. If this hydrogen ethylene mixed gas can be applied to the rail gas pressure welding operation, the gas pressure welding operation can be performed by replacing the hydrogen ethylene mixed gas cylinder with a conventional acetylene gas cylinder, so that the workability is not lowered.
In view of the above situation, the present invention provides a gas pressure welding method for a steel material that improves workability and reduces the generation amount of carbon dioxide gas by applying a hydrogen ethylene mixed gas to the gas pressure welding of the steel material. Objective.

In order to achieve the above object, the present invention provides
[1] In the gas pressure welding method for steel materials, the steel materials are butted together, a hydrogen ethylene mixed gas is blown into the butt portion of the steel material together with oxygen gas, the butt portion of the steel material is heated with a hydrogen ethylene mixed gas flame, and the steel material is It is characterized by pressurizing and joining the steel materials.
[2] In the gas pressure welding method for a steel material according to [1], the hydrogen ethylene mixed gas is produced by previously mixing ethylene gas and hydrogen gas, and sealed in a hydrogen ethylene mixed gas cylinder to perform gas pressure welding. It is transported to a place where it is used.

[3] In the gas welding method for a steel material according to [2] above, the ethylene gas content of the hydrogen ethylene mixed gas is 38% by volume or more and 45% by volume or less.
[4] The gas pressure welding method for a steel material according to [3] above, wherein a pressure in the hydrogen-ethylene mixed gas cylinder is set to 1 MPa or more and 14.7 MPa or less at 35 ° C.

[5] The steel material gas pressure welding method according to [3], wherein a pressure in the hydrogen ethylene mixed gas cylinder is set to 5 MPa or more and 10 MPa or less at 35 ° C.
[6] The gas pressure welding method for a steel material according to any one of [1] to [5], wherein the steel material is a rail.

  [7] The gas pressure welding method for a steel material according to any one of [1] to [5], wherein the steel material is a reinforcing bar.

  According to the present invention, when a hydrogen ethylene mixed gas is applied to a steel gas pressure welding method, a joint having the same performance as that of a conventional method using acetylene gas can be produced with a significantly reduced carbon dioxide generation amount. That is, since the hydrogen ethylene mixed gas can be applied as an alternative gas in place of the acetylene gas, the gas pressure welding operation can be performed without impairing workability.

It is a schematic diagram of the gas pressure welding process of the steel materials which show the Example of this invention. 1 is an overall schematic view of a rail gas pressure welding apparatus showing an embodiment of the present invention.

  The gas pressure welding method of the steel material of the present invention is to butt the steel material, blow a hydrogen ethylene mixed gas together with oxygen gas to the butt portion of the steel material, heat the butt portion of the steel material with a hydrogen ethylene mixed gas flame and Pressurize and join this steel.

Hereinafter, embodiments of the present invention will be described in detail.
FIG. 1 is a schematic diagram of a gas pressure welding method for steel according to an embodiment of the present invention, and FIG. 2 is an overall schematic diagram of the gas pressure welding apparatus.
The construction procedure of the gas pressure welding method for steel of the present invention is shown in FIG.
(1) First, as shown to Fig.1 (a), the steel materials 1 and 2 are faced | matched.

(2) Next, as shown in FIG. 1 (b), heated at steel 1 and 2 of the butt portion 3 oxygen gas O ₂ with hydrogen ethylene mixed gas H ₂ + C ₂ H ₄ and comprises a combustion flame.
(3) Next, as shown in FIG.1 (c), an upset process is performed.
(4) Next, as shown in FIG.1 (d), joining of steel materials is completed.
In FIG. 2, 11 is a welding gas generator, 12 is an oxygen cylinder, 13 is an oxygen gas supply pipe, 14 is an oxygen gas flow rate adjusting valve, 15 is a hydrogen ethylene mixed gas cylinder, 16 is a hydrogen ethylene mixed gas flow rate adjusting valve, 17 is a hydrogen ethylene mixed gas supply pipe, 18 is a gas mixing chamber, 21 is a mixed gas supply pipe, 22 is a flame burner, 23 is a crater arranged in the flame burner 22, and 24 is a rail.

  In the process of examining the construction conditions for gas pressure welding according to the present invention, the selection of gas combustion conditions is important. At this time, the combustion flame shield is important in reducing the heating ability of the combustion flame and the oxidation of the joining end face. We must pay attention to sex. In the present invention, gas combustion conditions suitable for rail pressure welding were investigated for these. In addition, the hydrogen ethylene mixed gas with a gas composition of hydrogen: 60% and ethylene: 40% was applied. Table 1 shows an example of combustion conditions in the present invention.

  The gas flow rate (volume ratio) of oxygen is 130 (L / min), and the gas flow rate of the hydrogen ethylene mixed gas is 145 (L / min).

According to the gas flow rate shown in Table 1, it is possible to obtain a combustion flame having an excellent balance between heating characteristics and shielding properties.
Two test joints of JIS-60kg ordinary rail were produced using the gas pressure welding method of the present invention, and the joint quality was investigated. Table 2 shows the joint manufacturing conditions.

The joint quality was evaluated by a magnetic particle inspection test and a static bending test. The static bending test was carried out with a distance between supporting points of 1 m and a central concentrated load, and the breaking posture was one each for HU and HD. Table 3 shows the results of the magnetic particle inspection test and the static bending test.

As shown in Table 3, in any of the test joints a and b, no defective magnetic powder pattern was observed in the magnetic particle testing. Moreover, in the static bending test, the breaking load and the deflection amount of both joints exceed the bending fracture reference value of the gas joint of the JIS-60kg ordinary rail.

  Table 4 shows the results of comparing the amount of carbon dioxide generated when joining JIS-60kg ordinary rails with the joint production conditions shown in Table 2 with the amount of gas generated using conventional acetylene gas.

Thus, by applying the hydrogen-ethylene mixed gas of the present invention, the amount of carbon dioxide generated can be reduced by about 40% compared to the conventional method using acetylene gas.
Next, the ratio of ethylene, the remaining hydrogen and unavoidable impurity gas in the hydrogen ethylene mixed gas of the present invention will be described.

  In the present invention, by setting the ethylene content to 38% by volume or more and 45% by volume or less, the hydrogen ethylene mixed gas can be stored and transported in a compressed gas state. Mass transport using large containers is easy. If the ethylene content is too low, backfire may occur during combustion or fire extinguishing, but backfire is suppressed by setting the ethylene content to 38% by volume or more. Thus, according to the hydrogen-ethylene mixed gas of the present invention, storage, transportation, etc. are easy, and it is possible to contribute to quality improvement of the finished state after gas welding processing.

Inevitable impurity gas is 0.5 volume% or less. Thereby, the characteristics of the hydrogen ethylene mixed gas are stabilized, and the effects of the present invention can be obtained more reliably. In order to further stabilize the characteristics of the hydrogen-ethylene mixed gas, the inevitable impurities are desirably 0.1% by volume or less of the gas.
Further, the hydrogen-ethylene mixed gas of the present invention is produced by mixing ethylene gas and hydrogen gas in advance, and after being sealed in a container, it is transported to a place where gas pressure welding is carried out while being held in the container. It is desirable to be used. In this case, in order to carry efficiently, it is desirable to increase the pressure in the container. However, if the pressure is increased too much, ethylene is liquefied at a low temperature, and a desired mixing ratio of ethylene and hydrogen is used at the time of use. Therefore, by setting the pressure in the container to 1 MPa or more and 14.7 MPa or less at 35 ° C., it is possible to suppress the occurrence of such a problem and perform efficient transportation. it can. Moreover, in order to perform more efficient conveyance, it is more preferable that the pressure in a container shall be 5 MPa or more and 10 MPa or less in 35 degreeC.

  In addition, this invention is not limited to the said Example, Based on the meaning of this invention, a various deformation | transformation is possible and these are not excluded from the scope of the present invention.

  The steel gas pressure welding method of the present invention can be used as a steel gas pressure welding method in which a hydrogen ethylene mixed gas is applied to the steel gas pressure welding to improve workability and reduce the generation amount of carbon dioxide gas.

DESCRIPTION OF SYMBOLS 1, 2 Steel materials 3 Butt part of steel materials 11 Welding gas generation part 12 Oxygen cylinder 13 Oxygen gas supply pipe 14 Oxygen gas flow control valve 15 Hydrogen ethylene mixed gas cylinder 16 Hydrogen ethylene mixed gas flow control valve 17 Hydrogen hydrogen mixed gas Supply pipe 18 Gas mixing chamber 21 Mixed gas supply pipe 22 Flame burner 23 Crater arranged in the flame burner 24 Rail

Claims (7)

  A steel material is abutted, hydrogen gas mixed with oxygen gas is blown to the abutting portion of the steel material, the abutting portion of the steel material is heated with a hydrogen ethylene mixed gas flame, the steel material is pressurized, and the steel materials are joined. A gas pressure welding method for steel materials.   2. The method of gas pressure welding of a steel material according to claim 1, wherein the hydrogen ethylene mixed gas is produced by mixing ethylene gas and hydrogen gas in advance, enclosed in a hydrogen ethylene mixed gas cylinder and transported to a place where gas pressure welding is performed. A gas pressure welding method for steel materials characterized by being used.   3. The gas pressure welding method for a steel material according to claim 2, wherein the ethylene gas content of the hydrogen-ethylene mixed gas is 38 volume% or more and 45 volume% or less.   The method for gas pressure welding of steel material according to claim 3, wherein the pressure in the hydrogen-ethylene mixed gas cylinder is set to 1 MPa or more and 14.7 MPa or less at 35 ° C.   The method for gas pressure welding of steel materials according to claim 3, wherein the pressure in the hydrogen-ethylene mixed gas cylinder is set to 5 MPa or more and 10 MPa or less at 35 ° C.   6. The gas pressure welding method for steel according to any one of claims 1 to 5, wherein the steel is a rail.   6. The method of gas pressure welding of steel material according to claim 1, wherein the steel material is a reinforcing bar.