JPS61193776A - Build-up welding method - Google Patents

Abstract

PURPOSE:To form the build-up clad having high cleanness and less residual stress and to prevent the generation of cracks by the composite build-up cladding consisting of a metal and ceramics by building up a single layer or multiple layers with giving the vibration in accordance with the number of its proper vibrations to the deposited metal. CONSTITUTION:A vibration baseplate 11 is borne rockably to a column 12 and vibrations are given by a spring 13, eccentric motor 14, etc, and the number of vibrations are detected by a frequency detecting sensor 15. The deposited metal is solidified with the state of the vibration coincided with the number of its proper vibrations being given when the deposited metal is applied on the surface of the base material by melting a filler rod 30 with the arc heat generated between electrode 21 and base material W with moving a welding torch 20 along the surface of the base material W at an adequate speed. The bead of the deposited metal is thus built-up and by laminating it by the necessary number of layers by the reciprocating movement of the welding torch 20 the build-up cladding C of the prescribed build up is formed.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a weld build-up method.

[Prior art]

By welding, we melt the electrode or filler rod and deposit weld metal on the surface of the base material in a single layer or multiple layers to create overlay cladding (
The so-called weld overlay method, which forms overlay cladding, improves the corrosion resistance and wear resistance of the surfaces of industrial furnace members (e.g., furnace rolls, skid rails), tanks, machine parts, steel frames, and other various steel structural members. , is widely used as a method for improving heat resistance, etc. There are a wide variety of welding methods, including gas welding, submerged arc welding, shielded arc welding, and tungsten inert gas arc welding (T[G welding).
, consumable electrode inert gas arc welding (MIG welding), etc. are applied, and the consumable electrodes and filler rods that form the weld metal are made of stainless steel or Cr-, depending on the material properties required for the overlay cladding. Materials such as Mo steel are used.

[Problem to be solved]

In order to fully utilize the material properties of the overlay cladding formed by welding, it is necessary that the weld metal has a fine structure, has few non-metallic inclusions and is highly clean, and has low residual stress. be.

However, although it depends on the welding conditions, the overlay crat formed by the conventional weld overlay method generally has a coarse structure in which the weld metal has developed columnar crystals, and also contains oxides etc. generated during welding. Because they are not sufficiently floated and separated, they are often contaminated with nonmetallic inclusions such as oxides. Furthermore, since the deposited metal cools at a relatively high cooling rate, it is generally accompanied by large residual stresses, which often causes cracks in the overlay cladding.

On the other hand, by performing weld overlay using a filler rod made of metal and ceramic particles, the metal is used as a matrix,
If it is possible to form a built-up cladding with a composite structure in which ceramic particles are uniformly dispersed, the combined effect of ceramic and metal will provide superior heat resistance, wear resistance, and Corrosion resistance etc. can be expected.

However, if this is done according to the conventional general welding overlay method, there is no particular problem with single-layer overlay, but when attempting to laminate multiple layers, especially three or more layers, cracks will occur in the bead, and in fact there will be more than three layers. It is not possible to form overlay cladding laminated to

The occurrence of this cracking is thought to be due to the coarse structure of the weld metal, contamination by nonmetallic inclusions, generation of residual stress, and the like. The occurrence of this cracking can be prevented to some extent by heating the weld overlay in a heating furnace at approximately 1000°C, but this requires the consumption of a large amount of thermal energy and harsh welding work. It is difficult to call this a practical method in that it causes problems such as

In view of the above, the present invention forms an overlay cladding with a fine metal structure, high cleanliness, and low residual stress, and when a composite overlay cladding consisting of metal and ceramic is desired, it is possible to avoid cracking. The purpose of the present invention is to provide a weld build-up method that allows formation by multi-layer build-up without the need for overlays.

[Technical means and effects]

The weld overlay method of the present invention is characterized in that a weld metal is applied with vibrations that match the natural frequency of the weld metal, and a weld metal is overlaid in a single layer or in multiple layers to form an overlay cladding with a required layer thickness. be.

According to the method of the present invention, the weld metal applied to the surface of the base material by melting the consumable electrode and/or the filler rod is moved into the weld metal by the vibrations applied during the period from the molten state to the time when the weld metal is cooled and solidified. The flotation and separation of non-metallic inclusions such as oxides (impurities contained in the consumed electrode, filler rod, oxides generated during welding, etc.) mixed in the welding process is promoted. Further, the growth of columnar crystals generated during the solidification process is inhibited by vibration, and fine grained crystals are generated, thereby forming a fine structure. Furthermore, by continuing to apply vibration to the weld metal for a while after solidification (preferably until the temperature drops to below the freezing point of 900°C), dislocation movement is promoted and residual stress is reduced. I see a decline.

FIG. 1 shows an example of the implementation procedure of the weld overlay method of the present invention. (
10) is a vibration device, and (W) is a base material. Vibration device (1
0) includes a vibrating table (11), a column (12) that swingably supports the vibrating table, and a spring (1) attached to the column (12).
3), eccentric motor (14) attached to the vibration table (11)
), a frequency detection sensor (15) attached to the base material (W) for detecting vibration frequency, and a controller (16) for adjusting the rotation speed of the eccentric motor (14). (
20) is a welding torch equipped with a non-consumable electrode (21);
(30) is a filler rod, and while moving the welding torch (20) along the surface of the base material at an appropriate transfer speed, the electrode (2
1) The filler rod (30) is melted by the heat of the arc generated between the base material (W) and the base material (W), and weld metal is applied to the surface of the base material. The weld metal is vibrated by a vibration device (1
It solidifies in the state where it is added by 0). In this way, the bead of weld metal is built up, and this is connected to the welding torch (20).
By repeating this process, a required number of layers are laminated to form a built-up cladding (C) of a predetermined thickness.

In the present invention, the vibration applied to the weld metal is made to match the natural frequency of the weld metal due to vibration effects on the weld metal (cleaning by flotation of nonmetallic inclusions, inhibition of columnar crystal growth, and refinement of the structure). This is to maximize the effect of promoting dislocation movement and reducing residual stress. The natural frequency of weld metal depends on the elastic modulus of the steel type. Furthermore, in the process of cooling and solidifying from the initial high-temperature molten state, the natural frequency increases as the temperature decreases. An example is shown in FIG. Therefore, when applying vibration to the weld metal, it is necessary to control the vibration in accordance with changes in the vibration frequency. In the case of the weld overlay device shown in Fig. 1, this added vibration is controlled by detecting momentary changes in the natural frequency of the weld metal with a frequency detection sensor (15), and sending the signal to the controller (16).
This can be done by adjusting the rotational speed of the eccentric motor (14) by inputting a

The weld overlay of the present invention is performed by various welding methods such as gas welding, submerged arc welding, covered arc welding, MIG welding, TIG welding, plasma welding, and laser beam welding. Further, the vibration applying device to the weld metal is configured to
The present invention is not limited to the example shown in the figure, and in addition to this, for example, a vibrating terminal may be brought into contact with the vicinity of the welded metal of the base material (W) to apply vibration to the welded metal.

According to the present invention, a built-up cladding having a composite structure in which ceramic particles are dispersed in a metal matrix can be formed by multi-layer building up. In this case, it is preferable to use a composite filler rod made of ceramic powder and a metal serving as a matrix, and perform TIG welding. A composite filler rod is a metal tube filled with a homogeneous powder mixture of ceramic powder and metal powder in the desired ratio, or a homogeneous mixture of ceramic powder and metal powder formed into a rod shape. It is best to use one that has been sintered. Examples of ceramics that make up the composite filler rod include carbide-based (chromium carbide, silicon carbide, tungsten carbide, titanium carbide, etc.), oxide-based (alumina, zirconia, etc.), and nitride-based (silicon nitride, boron nitride, etc.) Examples of metals include various stainless steels, heat-resistant alloys, and the like.

These may be selected as appropriate depending on the required material characteristics of the target overlay cladding. In addition, the proportion of ceramic in the filler rod is preferably 30 to 99% (by weight) from the viewpoint of heat resistance, wear resistance, etc. of the overlay cladding, and the appropriate particle size is 30 to 100 μm. It is.

〔Example〕

Example I By TIG welding, while applying vibration to the weld metal as shown in Fig. 1, an overlay cladding having a composite structure consisting of metal 7 trisox and ceramic particles dispersed therein was formed on the surface of the base material. Formed.

(11 Base material: heat resistant fNA (27Cr -17N i -40
Co-Fe).

, (2) filler rod silicon carbide ceramic powder (particle size: 108 m) and Cr-C
o-Ni-Fe heat-resistant steel (Cr27%, Co40%, N
A homogeneous powder mixture of i17%, balance Fe, particle size: 50 μm) was heated at a pressure of 1500 kg/ctl and at a temperature of:
Sintered rod obtained by sintering at 1400℃ (diameter: 6mm,
Ceramic: Metal = 50750).

(3) Welding conditions Welding current/voltage: 250 A/200 V Welding speed near 0 m/min Number of deposited metal layers = 15 layers Welding layer area/thickness: 5. OcmX6. Ocm・1
0+n added vibration: See Figure 2.

(4) Overlay layer quality Micro ML of overlay cladding formed by the above weld overlay
The weave is shown in Figure 3.

As a comparative example, FIG. 4 shows the microstructure of a built-up cladding formed under the same conditions as above except that no vibration was applied.

The metal structure of the overlay cladding of the example of the present invention has a finer structure than that of the overlay cladding of the comparative example, and has a small amount of non-metallic inclusions and is excellent in cleanliness.

Moreover, no cracking occurs.

Example 2 By TIG welding, an overlay cladding having a composite structure consisting of a metal matrix and ceramic particles dispersed therein was formed on the surface of the base material while applying vibration to the weld metal as shown in Fig. 1. did.

+1+ Base material; heat-resistant steel (27Cr -17N i -40Co
-Fe).

(2) Filler rod silicon carbide ceramic powder (particle size: 10 μm) and Cr-C
0-Ni-Fe heat-resistant steel (Cr27%, Co40%, N
A sintered rod (diameter = 6
fin, ceramic bimetallic = 70:30).

(3) Welding conditions Welding current/voltage: 25OA/200cm Welding speed = 70 carbon dioxide/min Number of deposited metal layers: 30 layers Area/thickness of built-up layer: 5cm x 4cm-18 Tsuruzuki excitation vibration: See Figure 2 ( 4) Quality of build-up layer Micro and macro observations show that it has excellent cleanliness and a fine structure similar to Example 1.

Moreover, no cracking occurs.

Example 3 A built-up clad made of carbon steel was formed on the surface of a base material by TMG welding while applying vibration to the deposited metal as shown in FIG.

(1) Base material carbon wI (345C) (2) Filler rod material: 545C equivalent diameter: 4 iris 1 (3) Welding conditions Welding current/voltage: 140A/14V Welding speed = 150 fin/min Number of deposited metal layers: 10-layer overlay area/thickness: 5. Ocm x5. Ocm ・7 vibration vibration: See Figure 2 (4) Macro and microscopic observation of build-up layer quality reveals that there are almost no non-metallic inclusions (
, and is recognized to have a fine structure. Moreover, no cracking occurs.

〔Effect of the invention〕

According to the present invention, it is possible to form a built-up cladding that is highly clean, has a fine structure, and has little residual stress.

Further, by using a composite filler rod and performing multi-layer build-up, it is possible to form a built-up cladding having a composite structure made of metal-ceramic particles without causing cracks.

The method of the present invention is applied as a method for forming overlay cladding for various structural members, but in particular, composite overlay cladding made of metal and ceramics has excellent heat resistance, abrasion resistance, scale resistance, etc. Since this method is significantly superior to single-phase metal overlay cladding made of heat-resistant alloys, it is suitable as a method for forming overlay cladding for industrial furnace members, such as skid rails and furnace rolls.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an example of the implementation procedure of the method of the present invention, and FIG.
The figures are graphs showing the natural frequencies of welded metal, Figures 3 and 4.
The figure is a photomicrograph substituted for a drawing showing the microstructure of the overlay cladding. 10: Vibration device, ll: Vibration table, 14: Eccentric motor,
15: vibration frequency detection sensor, 16: controller, 20:
Welding torch, 30: filler rod, W: base material, C: overlay cladding.

Claims (1)

[Claims] (1) A welding overlay method characterized by forming an overlay cladding of a required thickness by applying a vibration to the weld metal that matches its natural frequency, in a single layer or in multiple layers.