JPS58184081A - Composite tempering welding method using laser - Google Patents

Abstract

PURPOSE:To improve toughness of heat affected zone, by heat treating the heat affected zone caused by welding with succeeding laser beam. CONSTITUTION:The heat affected zone is heated to high temperature by preceding welding of MIG electrode and becomes a coarse grained domain. Welding is performed while tempering and heat treating by heating to tempering temperature or normalizing temperature by succeeding laser beam 5. This can be applied to the case where preceding welding is submerged arc welding instead of MIG welding. Objective materials are carbon steel, stainless steel etc.

Description

[Detailed description of the invention] The present invention relates to a nine complex thermal welding method using a laser.

Conventional welded joints of O carbon steel have a base metal 1 as shown in Fig. 1.
and weld metal 2. The center of the plate thickness of this welded joint (
The toughness and maximum heating temperature distribution of (indicated by arrow a) are K as shown in Figure 2, and the heat affected zone from the base metal to the base metal is
This may result in an area where the toughness is exposed. For this reason,
As shown in Figure 2, Mu C1 or Ac1 change point (Mu C1,
MuC1 differs depending on the material, but in the case of 2a Cr-I Mo steel, it is hardened when heated above 4IKjIliILK (approximately SOO℃, MuC1 is about 900℃), and becomes coarse and dusty when heated. In some cases, the quality deteriorated. 1 The present invention has been made in view of the above points, and by combining the laser method with the conventional S welding method, a composite thermal welding method using a radar that can improve the toughness of the heat affected zone is achieved. The purpose is to provide.

An embodiment of the present invention will be described below with reference to the drawings. stripes 3
In the figure, 1 is the base material, 2 is the weld metal, and 3 is the conventional 11
! I method For example, MIG # contact method MIG electrode, 4 is radar
A device 5 is a laser beam from this radar device 4. In other words, in this example, multi-layer deposition is performed using the MIGJ method.
When performing one contact, the MIG electrode 3 is used to make the first contact, and the radar device 4 is used to perform subsequent heat treatment.

Due to the preliminary welding, the heat affected zone has a height of l1 as shown in Figure 4.
L (approximately 1,000 to 1,500 degrees Celsius) to form a coarse grain region, but it can be tempered by the subsequent radar beam 5, or at a simple temperature of about 650 to 8
Toughness is improved by heating to 00°C.

FIG. 5 shows a conceptual diagram of a specific heat treatment according to the present invention. In order to heat-treat the coarse grain region 6 caused by the preceding peed, the heat-affected zone 2 is heated by the heating zone 7 of the laser beam 5, as shown in FIG. In order to distribute the light to both the right and left sides, the radar beam 5 may be weaved left and right. Further, the heating temperature is adjusted by inputting the radar beam 5.

The characteristics of the Lehde method are as shown in Fig. 6(b).
Compared to the conventional method shown in Figure (&), heating is performed locally and by heat conduction to the concavity, so penetration is greater than that of the conventional method, and the heat-affected zone is vertical as shown in Figure 5. Even if there is, you can improve the quality of that part.

In addition, in the above example, a case was explained in which MIG welding was used as the preliminary welding, but other methods such as sag merge welding or conventional welding can be used, and materials such as carbon steel and stainless steel can be used. As described above, according to the present invention, the welding is performed while the heat affected zone of the preceding weld bead is subjected to tempering heat treatment by the subsequent radar beam, thereby improving the toughness of the heat affected zone. Nine composite temper welding methods can be provided using the available radar.

[Brief explanation of the drawing]

Figure 41 is a diagram showing a conventional welded joint of carbon steel.
The figure shows the toughness and IIL16 heating temperature distribution at the center of the plate thickness of the joint, Figure 3 shows the welding method according to an embodiment of the present invention, and Figure 4 shows the temperature of the heat-affected zone in the same embodiment. FIG. 5 is a diagram showing the specific heat treatment conceptual diagram of the present invention, and FIG. 6 (1) (b) is a diagram showing the welding state of conventional and laser methods. 1...Base metal, 2...Weld metal, 3...MIG electrode,
4...v f ti equipment 1. , '...Lede-
Beam, 6...1,' Coarse grain area, 7... Radey beam heating area. Applicant's sub-agent Patent attorney Takehiko Suzue Figure 1, Figure 2, Figure 3, Figure 4 are above 1. Figure 5 Figure 6 (a) (b)

Claims (1)

[Claims] 9. A composite temper welding method using a laser, characterized in that the heat-affected zone of the preceding weld bead is welded while being subjected to temper heat treatment by a subsequent radar beam.