JPS61126979A - Rotary type nozzle for welding - Google Patents

Abstract

PURPOSE:To improve the durability of a rotary type nozzle for welding by forming the nozzle of a silicon nitride sintered body. CONSTITUTION:A sintered assistant and binder such as paraffin are added to Si3N4 powder having 0.5-1mum average grain size and a bar-shaped body is molded by a high-pressure rubber press method, etc. Such bar-shaped body is provided internally with apertures 1c, 1d by machining and is bored with an insertion hole 1a for a W electrode and a hole 1b for introducing a shielding gas so that the bisected nozzles 1 are formed. The nozzles 1 are fixed to the inside peripheral surface of an outer ring 2 and a motor 4 is driven to rotate the ring 2a, by which the welding of a joint 5 and a piping 6 is executed. Since the nozzle 1 is constituted of the sintered Si3N4 body, the nozzle is extremely highly resistant to heat, thermal impact and wear. The durability of the nozzle 1 is thus improved.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a rotary welding nozzle that performs welding while sliding around a workpiece, and more specifically, it relates to a rotary welding nozzle that has excellent heat resistance and thermal shock resistance, and has excellent heat resistance and thermal shock resistance. , relates to a welding nozzle whose sliding parts do not wear out.

[Technical background of the invention and its problems]

Tung (TIG) is a type of welding method.
stenInert Gas) welding method is Ar or He
This is a method of fusion welding by generating an arc between a tungsten (W) electrode and the workpiece in an inert gas atmosphere such as tungsten (W) electrodes, and is especially used for welding materials that are sensitive to oxidation and nitridation, such as non-ferrous metals and high-alloy steel. suitable for

By the way, when carrying out this TIG welding, it is common to use a welding torch. For /8 welding, attempts have been made to use a rotary welding nozzle as shown in FIG.

In FIG. 1, a rotary welding nozzle 1 has a cylindrical shape with a welding space formed inside, and is divided into two at the center along the axial direction. A tungsten electrode insertion hole 1a and a plurality of shield gas introduction holes 1b are formed in the peripheral wall in the radial direction. Further, openings lc and 1d (only the IC is shown) are provided in the opposite side walls of the nozzle 1.
is formed.

FIG. 2 shows an example of the configuration of a welding apparatus in which such a nozzle 1 is actually used to weld, for example, a pipe and a joint. In the figure, a nozzle 1 is fixed to the inner peripheral surface of an outer ring 2 with screws.

The outer ring 2 is divided into two parts like the nozzle 1,
Both are configured to be detachable from the object to be welded. A portion of the outer circumferential surface of the outer ring 2 is provided with teeth 2a over the entire circumference.
is engraved, and these teeth 2a mesh with the spur gear 3. A drive shaft 3a of the spur gear 3 is connected to a motor 4.

During welding, for example, the nozzle l and the outer ring 2 are positioned so that the annular welding part 7 (the area indicated by the broken line in the figure) formed by the joint 5 and the pipe 6 is located within the welding space le. do. At this time, a joint 5 and a pipe 6 are fitted into the openings 1c and 1d of the nozzle 1, respectively, as shown in the figure. Then, the W electrode 8 is fitted into the insertion holes 1a and 2b of the nozzle 1 and the outer ring 2, and is fixed to the welding part 7 while maintaining a predetermined distance (arc length). When the spur gear 3 is driven by the motor 4, the outer ring 2 and the nozzle l are driven accordingly.
and rotate as one. At the same time, a shielding gas such as Ar or He is introduced into the welding space 1e from the outside, and the W electrode 8 is energized from an external power supply device (both not shown) via the energizing brush attached to the outer ring 2. do.

Therefore, the W electrode 8 rotates around the welding part 7 while generating an arc between it and the welding part 7, and welds the joint 5 and the pipe 6 together.

In such a rotary welding nozzle, when the nozzle 1 rotates, the inner peripheral surface of the opening IC11d formed in the side wall rotates while slidingly contacting the outer peripheral surfaces of the joint 5 and the pipe 6, respectively. That is, both openings not only support the workpiece to be welded, but also have the function of setting the arc length, that is, positioning the workpiece. Therefore, the diameter of the opening of the nozzle is set according to the outer diameter of the workpiece, which inevitably leads to production of a wide variety of products in small quantities. Therefore, materials such as general ceramics, which require molding, are not suitable for the nozzle because they increase manufacturing costs.

Conventionally, therefore, crystallized glass with good machinability has been used, but nozzles made of such materials have insufficient heat resistance and thermal shock resistance, resulting in inconveniences such as cracking during cooling. Therefore, it has been proposed to use boron nitride (BN), which has excellent heat resistance and thermal shock resistance. However, this is expensive and does not have good wear resistance, and when the nozzle rotates, the sliding part with the workpiece wears out, creating a gap between the nozzle and the workpiece, and the nozzle itself It becomes impossible to perform such positioning functions.

[Purpose of the invention]

An object of the present invention is to solve these conventional problems and provide a rotary welding nozzle that has excellent heat resistance and thermal shock resistance, good wear resistance, and is easy to manufacture.

[Summary of the invention]

The rotary welding nozzle of the present invention has a cylindrical shape with a welding space defined inside, and a tungsten electrode insertion hole and a shield gas introduction hole are respectively bored in the radial direction on the peripheral wall thereof, Further, in a rotary welding nozzle in which an opening for fitting and supporting a workpiece to be welded is formed in each opposing side wall, the nozzle is made of silicon nitride (S).
It is characterized by being formed from an i 3 N4 )-based sintered body.

The Si3N+ type sintered body which is the material of such a rotary welding nozzle has not only excellent heat resistance and thermal shock resistance but also good wear resistance. Furthermore, in the manufacturing process, the Si3N4-based sintered body can be easily subjected to machining such as cutting after being formed by a rubber press method or the like. Therefore, there is no need to create a mold each time according to the outer diameter of the object to be welded, which is advantageous in terms of manufacturing costs.

An example of a method for manufacturing a nozzle made of this Si3N4-based sintered body will be described below. First, Si with an average particle size of 0.5 to 1 μm
Y2O3゜A120B, A as a sintering aid to 3N4 powder
IN, TiO2, etc.) and further add paraffin as a binder, for example, a pressure cuff 00
A rod-shaped body is manufactured by applying the Lahar press method at ~1000 Kg/cot. By performing machining on this rod-shaped body, a cylindrical nozzle having a welding space inside and openings with a predetermined diameter on both side walls is manufactured. Thereafter, the binder is removed by heating, and as a finishing process, a W electrode insertion hole, a shield gas introduction hole, etc. are bored in the nozzle peripheral wall, and the whole is further divided into two parts. And 1700-180
S i by sintering at 0 °C for 1 to 3 hours
3 Complete a rotary welding nozzle made of Nn-based sintered body.

[Embodiments of the invention]

To 100 parts by weight of 3i3N4 powder with an average particle size of 1 μm, sintering aids of 2035 parts by weight, 2033 parts by weight of Al, and 3 parts by weight of A]N were added and rubber press molded at a pressure of 1000 Kg/a (to a diameter of 70 mmφ and a length of 200 mm. A rod-shaped body was manufactured.This rod-shaped body was machined to produce a nozzle as shown in Fig. 1.The outer diameter of this nozzle was 60 mm, the length was 25 mm, and the opening diameter was 23 mm.
m and 27 mm, and the wall thickness was 5 mm. Next, a W electrode insertion hole and a shielding gas introduction hole were formed in the peripheral wall, and the whole was further divided into two along the axis. Thereafter, it was sintered at about 1750° C. for 3 hours to complete a welding nozzle.

A welding nozzle made of such a 513N4 sintered body is used as a second welding nozzle.
Straight f-strip 22mmφ suitable for welding equipment as shown in the figure.
SO3! ! ! The pipe 6 and the SUS joint 5 having an end diameter of 26 mmφ were welded. The W electrode diameter at this time is 3mmφ
, the arc length was about 30 mm.

With the nozzle of the present invention, there is almost no wear on the nozzle opening even after welding more than 400 locations (and there is no cracking due to heat shock even though the welding temperature is around 1500°C). On the other hand, when a nozzle of the same shape made of BN was used, if more than 100 welding points were to be welded, the nozzle opening would wear out and the arc length would fluctuate, making welding conditions unstable. Met.

〔Effect of the invention〕

As is clear from the above description, the rotary welding nozzle of the present invention is made of a 513N4 sintered body, so it goes without saying that it has excellent heat resistance and thermal shock resistance, as well as excellent wear resistance. The durability of the nozzle is much better than that of conventional nozzles. Moreover, in manufacturing it, there is no need to create a mold according to the dimensions of the workpiece, and the desired shape can be formed only by machining, making it possible to fully respond to high-mix, low-volume production. , its industrial value is great.

[Brief explanation of drawings]

FIG. 1 is a perspective view of the rotary welding nozzle of the present invention, and FIG.
This figure is a schematic cross-sectional view showing an example of the configuration of a TIG welding apparatus to which the nozzle of FIG. 1 is applied. 1...Rotary welding nozzle, la...W electrode insertion hole. 1b...shielding gas introduction hole, lc, ld...opening. 1e...Welding space, 7...Welding part, 8...W electrode. Figure 1 chewing

Claims (1)

[Claims] It has a cylindrical shape with a welding space defined inside, and has an electrode insertion hole and a shield gas introduction hole radially perforated on its peripheral wall, and a welding object on both opposite walls. 1. A rotary welding nozzle having an opening for fitting and supporting the rotary welding nozzle, the nozzle being formed of a silicon nitride-based sintered body.