JP3282743B2 - Welding method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a welding method for a member having good heat conductivity such as a casting mold.

[0002]

2. Description of the Related Art In a case where a casting mold is subjected to repair welding, a so-called so-called heat exchanger having excellent characteristics capable of separately controlling the heat required for melting a base material and the supply of a filler material is provided. A welding method called “TIG welding” (TIG welding) is employed.

[0003] This welding method uses argon or helium,
Alternatively, an arc is generated between the tungsten electrode and the base material in an atmosphere of an inert gas in which these are mixed, and the base material and the filler material are melted and welded using this arc heat. When welding a member with high thermal conductivity made of a copper alloy made of copper and chrome, such as a casting mold, heat during welding escapes to the mold side, and there is no preheating. Can not form a normal molten pool, it is difficult to perform appropriate welding processing even if adopting the welding method, welding defects such as a gap at the boundary between the base metal and filler metal Occurs.

In order to solve such a problem, it is only necessary to preheat the member to be welded during welding. However, even if such a measure is taken, a block-like member such as a casting mold can be used. In such a case, since the heat diffusion effect at the time of welding is large, the welding heat transmitted to a necessary portion is reduced correspondingly, and there is a problem that welding is much more difficult than steel.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of such a problem.
It is an object of the present invention to provide a new welding method capable of forming a good weld bead on a copper alloy having good thermal conductivity.

[0006]

Means for Solving the Problems That is, the present invention relates to
As a welding method for achieving the above object, a base material made of a copper alloy having good thermal conductivity is heated, and a mold temperature is set to about 2
When the temperature falls below 00 ° C , the welding speed is reduced to 3 to 5 cm / min.
A first weld bead layer is formed on a required portion of the base material while lowering the current and setting a higher current . Then, the base material is reheated, and when the mold temperature becomes approximately 200 ° C. or less, welding is performed. speed
To 5 to 10 cm / min, and set the current higher.
While the constant, second on the first weld bead layer, is obtained as Yuku raised successively prime the third weld bead layer.

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. The figure shows an example of a welding apparatus applied to the welding method of the present invention. In the figure, reference numeral 1 denotes a welding torch, and a mixer 3 is connected to the welding torch 1 via a pipe 2. The respective cylinders 5 and 7 containing helium and argon are connected to the mixer 3 via flow control valves 4 and 6, and are configured to supply a mixed gas according to welding conditions to the welding torch 1. I have.

On the other hand, the welding power source 1 is connected to the welding torch 1 and the worktable 8 through an output control device 10 using a thyristor or the like.
1, a thermometer 12 for detecting and displaying the temperature at each time is provided on a casting mold W as a base material.
Is connected. Reference numeral 13 in the drawing indicates a filler wire.

Next, an embodiment of a welding method using such an apparatus will be described. First, the mold W is heated in a furnace to a temperature of 350 to 400 ° C. Next, for the heated mold W, that is, for a block-shaped base material having good heat conductivity, for example, helium is set to 75% and argon is set to 25% so that arc concentration is increased so that arc concentration is increased. The welding rate and current are set according to the initial mold temperature, and welding is performed. If the mold temperature falls below approximately 200 ° C, the welding speed is adjusted according to the temperature. And set the current slightly higher,
A first weld bead layer b1 is formed at a required portion of the mold W.

After the first welding process, the mold W is heated again to a temperature of 350 to 400 ° C.
In the same manner as in the first welding step, welding is performed on the weld bead layer b1 by setting the welding speed and current according to the mold temperature, and then, when the mold temperature becomes approximately 200 ° C. or less. For example, while the welding speed is lowered in accordance with the temperature and the state of the weld bead layer b1 and the current is set slightly higher, the second and third weld bead layers b2 are sequentially raised at required portions of the base metal W. Perform the required repair welding process.

Therefore, the newly welded bead layer b2 formed by the second and subsequent welding steps is based on the first weld bead layer b1 having the same material and the same coefficient of thermal expansion. Since the welding conditions are formed in accordance with the mold temperature, good weld bead layers b1 and b2 are formed in a state in which cracking due to a difference in residual stress or thermal expansion is minimized.

After the second welding step, the matrix W is cooled as it is, but since this kind of copper alloy itself has little quenching effect, its structure is dense and uniform.

(Example) When a TIG welding was repeatedly performed on a casting mold made of a copper-chromium alloy under the following welding conditions, extremely good welding results were obtained.

[0014]

[Table 1]

[0015]

As described above, according to the present invention, a base material made of a copper alloy having a good thermal conductivity is firstly treated with gold.
When the mold temperature falls below approximately 200 ° C , the welding speed is increased to 3-4.
was reduced to cm / min, and so on are formed a first weld bead layer in a required portion of the preform while set a higher current,
Then, after reheating the base material, the mold temperature was set to about 200
When the temperature drops below ℃, the welding speed is reduced to 5 to 10 cm / min.
Yu was, and the second on the first weld bead layer while set a higher current, increased sequentially prime the third weld bead layer is
Since the memorial, without causing such cracking in the weld bead layer formed directly on the base material, and a ruby over de layer material is having a same as and the same thermal expansion coefficient, based to the Teso can Yuku raised bloom in turn improve the new weld bead layer thereon.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an example of a welding device applied to a method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Welding torch 3 Mixer 4, 6 Flow control valve 5, 7 Inert gas cylinder 13 Filling wire W Casting mold

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-1-284494 (JP, A) JP-A-4-13477 (JP, A) JP-A-59-120368 (JP, A) JP-A-4- 59174 (JP, A) JP-A-58-99683 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B23K 9/04 B23K 9/167 B23K 9/23 B23K 9/235

Claims (1)

(57) [Claims] 1. A method of heating a base material made of a copper alloy having good thermal conductivity, and welding when a mold temperature becomes approximately 200 ° C. or less.
Reduce speed to 3-5cm / min and increase current
A step of forming a first weld bead layer on a required portion of the base material while setting, reheating the base material, and setting a mold temperature.
When the temperature drops below approximately 200 ° C , the welding speed is increased to 5 to 10 cm.
/ Min and while setting the current higher,
Second, welding method and a third weld bead layers slide into successively raised form steps on the first weld bead layer.