JPH04351297A - Manufacture of welding auxiliary material - Google Patents

Abstract

PURPOSE:To inexpensively manufacture a welding auxiliary material capable of performing welding many times repeatedly and excellent in heat resistance and impact resistance, and also having a low adhesive property for molten metal. CONSTITUTION:The welding auxiliary material 30 is formed of composite ceramics consisting of >=20weight% boron nitride and >=1 kind selected from among alumina, zirconia, mullite, zirconium boride, titanium boride, silicon nitride, aluminum nitride and SIALON by the atmospheric pressure sintering method. In addition, the welding auxiliary material 30 is formed of the composite ceramics consisting of >=20weight% boron nitride and >=1 kind selected from among silicon nitride, aluminum nitride and SIALON by the reaction sintering method.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a method for producing a welding aid material, which is mainly used to cover a welded part during welding, to dam the outflow of molten metal, and to mold the molten metal into a certain shape. The present invention relates to a method for manufacturing a welding auxiliary material used for use or for isolating a welded part from the outside air.

0002

2. Description of the Related Art Conventionally, in arc stud welding, a cylindrical welding aid 2 called an arc shield (ferrule) has been used, as shown in FIG. When welding the stud 4 to the workpiece 6, the arc shield 2 is fitted onto the stud 4 as shown in the figure to cover the welded part of the stud 4 (the lower end of the stud 4), and is used to insert molten metal into the mold. Isolate the welding area from the outside air.

[0003] Conventional arc shields are cylindrical, one is attached to each stud, and after welding, they are generally crushed with a hammer or the like and removed from the welded area, so they cannot be recycled again. It was an unusable consumable item. Furthermore, for example, ceramic arc shields have been used as conventional arc shields, but these conventional ceramic arc shields are damaged by thermal shock (over 1300°C) during welding.
From this point of view, it was a consumable item that could not be reused.

[0004] On the other hand, for example,
As disclosed in Publication No. 69 and Japanese Unexamined Patent Publication No. 141379/1980, a cylindrical arc shield is divided into two parts and held in a welding machine so that they can be approached and separated, and both arc shield divided bodies are A cylindrical arc shield is formed by abutting and abutting each other, and the cylindrical arc shield is used as shown in FIG. 6 above.
As shown in Fig. 2, a method has been proposed in which arc stud welding is performed covering the welded portion of the stud, and after welding is completed, the two arc shield segments are separated from each other and removed from the welded stud. According to this method, arc stud welding can be repeated many times using the same arc shield.

[0005] When the arc shield is repeatedly used as described above, the arc shield becomes extremely hot during welding and is likely to break, so it must be made of a material with excellent thermal shock resistance. However, the above-mentioned Utility Model Application No. 60-18126
In Publication No. 9, ceramics is simply described as a material with excellent thermal shock resistance, and it has higher thermal shock resistance than conventional ceramic arc shields, and can withstand many times of welding (thermal shock). No specific materials are disclosed that can withstand this. In addition, the above-mentioned Japanese Patent Application Laid-Open No. 59-141
No. 379 mentions silicon nitride ceramics as a material with excellent thermal shock resistance, but according to experiments conducted by the present inventors, this silicon nitride ceramic is damaged by one or two thermal shocks during stud welding. However, it does not have sufficient thermal shock resistance to enable repeated use many times.

As a result of various studies, the applicant found that ceramics containing 20% by weight or more of boron nitride have superior thermal shock resistance compared to other ceramics.
Moreover, due to the action of boron nitride, the adhesion with molten metal is extremely low, and welding aids made of such ceramics can be used many times, and we have previously applied for a patent as Japanese Patent Application No. 1-294338. .

[0007]

[Problems to be Solved by the Invention] By the way, boron nitride is extremely difficult to sinter, and when products are formed from boron nitride and ceramics containing boron nitride, hot pressing is generally used. Special application Hei 1
-294338 also mentions the hot press method as an example of the manufacturing method.

However, in the case of the above-mentioned hot press method, if the shape of the product is complex, it is difficult to directly finish it into the final product shape.Usually, raw materials are heated under pressure and sintered to form a hot pressed body in the form of a disc, for example. The final product shape is completed by machining, and this method of machining after sintering wastes expensive raw materials and increases processing costs, resulting in higher product costs. There's a problem.

SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a method for manufacturing a welding auxiliary material that can be used repeatedly and that has excellent thermal shock resistance and low adhesion to molten metal at a low cost. It is about providing.

0010

[Means for Solving the Problems] In order to achieve the above object, a method for manufacturing a welding auxiliary material according to the first invention of the present application is a method for manufacturing a welding auxiliary material made of ceramics, in which the ceramics weighs 20% by weight. % or more of boron nitride and one or more selected from alumina, zirconia, mullite, zirconium boride, titanium boride, silicon nitride, aluminum nitride, and sialon. It is characterized in that it is manufactured by molding it into a shape close to that of , and sintering the molded product under no pressure using an atmospheric pressure sintering method. The molding method may be any one of pressure molding, injection molding, and cast molding.

[0011] In order to achieve the above object, a method for producing a welding aid according to a second invention of the present application is a method for producing a welding aid made of ceramic, wherein the ceramic contains boron nitride in an amount of 20% by weight or more. It is a composite ceramic made of one or more selected from silicon nitride, aluminum nitride, and sialon.The raw material is molded into the final shape or a shape close to the final shape, and the molded product is sintered under non-pressure using a reaction sintering method. It is characterized by being manufactured by sintering. The molding method may be any one of pressure molding, injection molding, and cast molding.

0012

[Operation] According to the manufacturing method according to the first and second inventions, the welding auxiliary material is formed of ceramics containing 20% by weight or more of boron nitride,
As will be described in detail later, ceramics containing 0% by weight or more have superior thermal shock resistance and low adhesion to molten metal compared to other ceramics, so that a welding auxiliary material that can be used repeatedly can be obtained.

[0013] Furthermore, the manufacturing method according to the first invention includes:
The raw material is molded into the final shape or a shape close to the final shape, and the molded product is sintered under no pressure using the pressureless sintering method, so there is no need for machining as in the hot press method. The number of machined parts can be reduced, so expensive raw materials are not wasted, processing costs are low, and manufacturing can be done at low cost. Furthermore, in the manufacturing method according to the first invention, the partner material of 20% by weight or more of boron nitride is selected from alumina, zirconia, mullite, zirconium boride, titanium boride, silicon nitride, aluminum nitride, and sialon. Even if boron nitride, which is difficult to sinter, is contained, atmospheric pressure sintering is possible.

[0014] Furthermore, the manufacturing method according to the second invention includes:
The raw material is molded into the final shape or a shape close to the final shape, and the molded product is manufactured by sintering it under no pressure using the reaction sintering method, so there is no need for machining or mechanical processing as in the hot press method. The number of processed parts can be reduced, so expensive raw materials are not wasted, processing costs are low, and manufacturing can be done at low cost. Furthermore, in the manufacturing method according to the second invention, the partner material of 20% by weight or more of boron nitride is one or more selected from silicon nitride, aluminum nitride, and sialon, and contains boron nitride that is difficult to sinter. It is possible to carry out reaction sintering even if the

[0015]

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view showing an embodiment of the welding auxiliary material according to the present invention. The welding auxiliary material shown in this example is a substantially semi-cylindrical arc shield divided body 30 made by dividing a cylindrical arc shield into two parts, and contains 20% by weight or more of boron nitride, as will be explained in detail later. It is made of ceramics.

A plurality of communication grooves 32 having a predetermined opening area are formed on the lower surface of the arc shield division body 30 to communicate the inside and outside of the arc shield for degassing during welding, and the inner surface 34 is described below. As shown in FIG. 5, a stud insertion hole is formed that is slightly larger than the outer diameter of the stud 80, and a recess 38 is formed on the outer surface 36 for holding the arc shield divided body 30 in the arc shield holding section described below. has been done.

FIG. 2 is a front view showing an arc stud welding machine that performs arc stud welding using the arc shield division body 30, and FIG. 3 is a right side view of the welding machine shown in FIG.
Figure 4 is an enlarged view taken along the line IV-IV in Figure 2, and Figure 5 is Figure 4.
It is a sectional view taken along the line V-V of

The illustrated welding machine 42 has a base 44 and a base 4.
A fulcrum pin 48 is attached to each of the two legs 46 fixed to the
A pair of levers 50 are rotatably supported through the levers 50, one end is rotatably connected to the upper end of each lever 50 through a joint pin 52, and the other end is rotatably connected through a joint pin 54. A pair of links 56 that are possibly connected, a handle 58 that is fixed to the one end of one link 56 and extends in the left and right lateral directions (in the direction of arrow B in FIG. 2), and both links 5
A long hole member 62 is fixed to the base 44 and has a long hole 60 extending in the vertical direction (direction of arrow C in FIG. 2) through which a joint pin 54 connecting the other ends of the base 4 is inserted.
4, a welding gun 66 attached to a pair of rods 64 erected, a chuck 68 for holding the head of a stud 80 provided at the lower end of the welding gun 66; and a handle 70 having a welding switch 69 provided at the welding switch 69. Furthermore, an arc shield holding part 72 is detachably attached to the lower end of each of the levers 50, and each arc shield holding part 72 holds the arc shield divided body 30, respectively.

The arc shield holding section 72 is shown in FIG.
As shown in 5, it comprises a holding part main body 74 and a clamping body 76. The holding portion main body 74 is formed by a stepped portion 50a of the lever 50 and a nut 50b screwed onto the lower end of the lever 50.
It is attached to the lever 50. Further, a protrusion 74c formed on the inner surface 74a of the arc shield holding body is fitted into the recess 38 of the arc shield divided body, and a screw 76a is screwed onto the upper end surface 30a of the arc shield holding body. A clamping body 76 fixed to 74
is arranged, and the arc shield division body 30 is
The upper surface 38 of the concave portion is formed by the convex portion 74c and the clamping body 76.
a and the upper end surface 30a are vertically sandwiched and held by the arc shield holding portion 72.

Arc stud welding by the welding machine 42 is performed as follows. First, the handle 58 is rotated upward from the position shown by the solid line in FIG. 2 to the position shown by the broken line. Then, the link 56 tilts, the joint pin 54 moves downward in the elongated hole 60, the joint pin 52 rotates around the fulcrum pin 48, and the two levers 50 open, as shown by broken lines. It becomes open. After that, the chuck 68 is made to grip the head of the stud 80,
The handle 58 is rotated downward to close both levers 50 to the closed state shown by the solid line. In this closed state,
Arc shield holding part 7 provided on each lever 50
2 are brought into contact with each other, and the arc shield divided bodies 30 are also brought into contact with each other facing each other to form a cylindrical arc shield, and the stud 80 is fitted into this arc shield. Next, from this state, the welding machine 42 is lowered to bring the lower end of the stud 80 and the lower end surface of the arc shield divided body 30 into contact with a predetermined position of the workpiece 82, and the switch 69 is pressed to perform welding. . After welding is completed, the handle 58 is rotated upward to open the lever 50, and arc stud welding is repeated in the same manner.

<Material of Welding Auxiliary Material> Next, the material of the arc shield will be explained. As mentioned above, the arc shield is made of ceramics containing 20% by weight or more of boron nitride, and by being made of such a material, the arc shield is made of such a material that the thermal shock (1, It can withstand temperatures above 300°C and has low adhesion to molten metal, so it can be used many times.

Table 1 below shows that arc shield divided bodies as shown in Fig. 1 above were made from various ceramics, and arc stud welding experiments were repeated using the welding machine shown in Figs. 2 and 3 using the arc shield divided bodies. The table shows the number of times each arc shield can be repeatedly welded and the pass/fail judgment results of the weldability evaluation JIS test (JIS B1198 "headed stud").

[0023]

[Table 1]

Note that the above welding is carried out using a welding current of 1200 to 1
The test was carried out at 300A and an arc time of 0.8 seconds. Also,
All materials used had a purity of 99% or less. Furthermore, in the JIS test, repeated use is 100
For welding more than 100 times, the necessary number of welded pieces from the 100th time were used for the test. Others are normal JIS
The test was conducted according to B1198.

As is clear from Table 1 above, all welding using arc shields made of ceramics containing boron nitride pass the JIS test, and the number of welding cycles that can be repeated is 100 or more, which is superior to other conventional welding methods. It is recognized that the thermal shock resistance is significantly superior to that of the Example ceramics and the Comparative Example ceramics, and that the number of repeatable welding cycles is greatly improved.

Next, experiments similar to those described above were conducted using various boron nitride ceramics having different boron nitride contents to examine the influence of the boron nitride content. The results are shown in Table 2 below.

[0027]

[Table 2]

As is clear from Table 2 above, the higher the boron nitride content, the greater the number of repeatable weldings, and it was also found that good results were obtained in the weldability evaluation JIS test. If the boron nitride content is 20% by weight or more, it passes the above JIS test and can be repeatedly welded 10 times or more. Therefore, ceramics containing 20% by weight or more of boron nitride can be repeatedly welded as a material with excellent thermal shock resistance. It is recognized that this is applicable to In addition, more practically, it is considered that ceramics that can be repeatedly welded 100 times or more, ie, ceramics containing 40% by weight or more of boron nitride, are desirable materials.

Next, in order to investigate appropriate welding conditions, tests were conducted with varying welding current and arc time using an arc shield made of ceramics with a boron nitride content of 40% or more by weight (arc shield B in Table 2). , E, F, G) using the same JIS test and JASS test (JAS
S6 Steel Construction Supplementary Regulations 5 "Quality Test of Stud Welding") was conducted. The results are shown in Table 3.

[0030]

[Table 3]

[0031] In addition, JIS and JASS in Table 3 above
In the test, the required number of welding test pieces from the 100th welding were used for the test.

[0032] From Table 3 above, when using an arc shield made of ceramics containing 40% by weight or more of boron nitride, there is a wide range of suitable welding conditions that is equal to or greater than when using conventional arc shields. It is recognized that

As is clear from the various experiments described above, an arc shield made of ceramic containing 20% by weight or more of boron nitride has sufficiently superior thermal shock resistance compared to conventional arc shields made of other ceramics. As a result, when used in combination with a welding machine such as the one described above, the drawbacks of conventional ceramic arc shields, that is, the arc shield can be used only once, can be avoided. Therefore, it is necessary to prepare as many arc shields as the number of studs to be welded, and to eliminate all the disadvantages of requiring the troublesome work of attaching an arc shield to each stud before welding and crushing and removing the arc shield after welding. Can be done.

<Method of Manufacturing Welding Auxiliary Material> Next, a method of manufacturing the arc shield segment 30 will be described in detail. The arc shield divided body 30 is produced by an atmospheric pressure sintering method, in which a predetermined raw material is cold-formed into a final product shape or a shape close to the final product shape, and then heated and sintered in a controlled atmosphere, or by a reaction sintering method. Formed by law.

[0035] When formed by the pressureless sintering method, the ceramic from which the arc shield segment is formed contains 20% by weight or more of boron nitride, alumina, zirconia, mullite, zirconium boride, titanium boride, and silicon nitride. It is a composite ceramic consisting of one or more partner materials selected from among , aluminum nitride, and sialon.

[0036] When formed by the reaction sintering method, the ceramic from which the arc shield segment is formed contains at least 20% by weight of boron nitride and one or more partners selected from silicon nitride, aluminum nitride, and sialon. It is a composite ceramic made of materials.

[0037] Hereinafter, examples will be explained separately for the case of the pressureless sintering method and the case of the reaction sintering method.

[0038] Atmospheric pressure sintering method (1) Boron nitride-alumina◆ In the case of boron nitride-alumina composite ceramics, nitrogen boron powder and alumina powder are mixed and formed into the shape of a welding aid, and then nitrogen or inert 1500-17 in atmosphere
Heat to 00°C to sinter.

<Example> ◆ 30 parts by weight of BN powder (specific surface area: 6 m2 /g) and 7
0 parts by weight of Al2O3 powder (15m2/g) was mixed in ethanol and then dried to form granules. This was press-molded into the shape of a welding auxiliary material using a mold at a pressure of 2 t/cm2, and sintered by heating to 1650° C. in nitrogen.

(2) Boron nitride-zirconia ◆ In the case of boron nitride-zirconia composite ceramics, boron nitride powder and zirconia powder are mixed, formed into the shape of a welding aid, and heated to 1,500 to 170
Heat to 0°C to sinter.

<Example> ◆ 4 parts by weight of CaCO3 powder (calculated as CaO) was added to 30 parts by weight of BN powder (6 m2 /g) and 66 parts by weight of ZrO2 powder (12 m2 /g), and the mixture was mixed in ethanol. It was dried and made into granules. This was press-molded into the shape of a welding aid using a mold at a pressure of 2t/cm2, and sintered by heating to 1600°C in nitrogen.

(3) Boron nitride-mullite ◆ In the case of boron nitride-mullite composite ceramics, boron nitride powder and mullite powder are mixed, formed into the shape of a welding aid, and then heated to 1500 to 1000 ml in a nitrogen or inert atmosphere. Heat to 1700°C to sinter.

<Example> ◆ 40 parts by weight of BN powder (6 m2 /g) and 60 parts by weight of mullite (3Al2O3 .2SiO2) powder (1
6 m2/g) were mixed in ethanol and dried to form granules. 2 tons of this was molded into the shape of a welding auxiliary material using a mold.
/cm2 pressure and heated to 1600°C in nitrogen to sinter.

(4) Boron nitride-zirconium boride ◆For boron nitride-zirconium boride composite ceramics, mix boron nitrogen powder and zirconium boride powder,
After forming it into the shape of a welding aid, it is heated in an inert atmosphere.
Sinter by heating to 800-2000°C.

<Example> ◆ 40 parts by weight of BN powder (35 m 2 /g) and 53 parts by weight of ZrB 2 powder (average particle size 1.0 μm) were mixed in ethanol and then dried to form granules. This was press-molded into the shape of a welding auxiliary material using a mold at a pressure of 3 t/cm2, and sintered by heating to 1950° C. in argon.

(5) Boron nitride-titanium boride◆
In the case of boron nitride-titanium boride composite ceramics, nitrogen boron powder and titanium boride powder are mixed, formed into the shape of a welding aid, and then heated for 1800 min in an inert atmosphere.
Heat to ~2000°C to sinter.

<Example>◆ 40 parts by weight of BN powder (35 m2/g) and 60 parts by weight of TiB2 powder (average particle size 1.2 μm) were mixed in ethanol and then dried to form granules. This was press-molded into the shape of a welding auxiliary material using a mold at a pressure of 3 t/cm2, and sintered by heating to 2000°C in argon.

(6) Boron nitride-silicon nitride ◆ In the case of boron nitride-silicon nitride composite ceramics, boron nitride powder and silicon nitride powder are mixed with a sintering aid, and then formed into the shape of a welding aid material. , sintering by heating to 1600-1800° C. in nitrogen or a non-oxidizing atmosphere containing nitrogen. Sintering aids include oxides of group IIIa elements or Al2O.
3, ZrO2, and MgO can be used.

<Example> ◆ Al2O3 powder (12m2/g) was added as a sintering aid to 40 parts by weight of BN powder (10m2/g) and 60 parts by weight of Si3N4 powder (8m2/g). 3
3 parts by weight of Y2 O3 powder (17 m2/g) were added, mixed in ethanol, and dried to form granules. This is then molded into the shape of a welding auxiliary material with a size of 2t/cm2.
The material was press-molded at a pressure of 1,700° C. and sintered by heating to 1,750° C. in nitrogen.

(7) Boron nitride-aluminum nitride◆
In the case of boron nitride-aluminum nitride composite ceramics, boron nitride powder and aluminum nitride powder are mixed with a sintering aid, formed into the shape of a welding aid, and then heated for 1600 min in nitrogen or a non-oxidizing atmosphere containing nitrogen. Heat to ~1800°C to sinter. As the sintering aid, one or more selected from oxides of group IIIa elements, oxides of group IIa elements, and Al2 O3 can be used.

<Example> ◆ Y2O3 powder (17m2/g) was added as a sintering aid to 30 parts by weight of BN powder (10m2/g) and 70 parts by weight of AlN powder (7m2/g) in 4 parts. Parts by weight were added and mixed in ethanol, followed by drying to form granules. This was press-molded into the shape of a welding auxiliary material using a mold at a pressure of 2 t/cm2, and sintered by heating to 1700° C. in nitrogen.

(8) Boron nitride-silicon nitride-aluminum nitride◆ In the case of boron nitride-silicon nitride-aluminum nitride composite ceramics, boron nitride powder, silicon nitride powder, and aluminum nitride powder are mixed with a sintering aid. After forming the material into the shape of a welding aid, it is heated to 1600 to 1800°C in nitrogen or a non-oxidizing atmosphere containing nitrogen to sinter it. Sintering aids include oxides of group IIIa elements or A
One or more selected from l2O3, ZrO2, and MgO can be used.

<Example 1> ◆ Sintering aid added to 40 parts by weight of BN powder (10 m2 /g), 40 parts by weight of Si3 N4 powder (8 m2 /g) and 20 parts by weight of AlN powder (7 m2 /g) Then, 5 parts by weight of Y2O3 powder (17m2/g) was added to the mixture, mixed in ethanol, and dried to form granules. This was press-molded into the shape of a welding auxiliary material using a mold at a pressure of 2 t/cm2, and sintered by heating to 1750° C. in nitrogen.

<Example 2> ◆ Sintering aid added to 50 parts by weight of BN powder (10 m2 /g), 35 parts by weight of Si3 N4 powder (8 m2 /g) and 15 parts by weight of AlN powder (7 m2 /g) Then, 4 parts by weight of Y2O3 powder (17m2/g) was added to the mixture, mixed in ethanol, and dried to form granules. This was press-molded into the shape of a welding auxiliary material using a mold at a pressure of 2 t/cm 2 and sintered by heating at 1750° C. in nitrogen.

(9) Boron nitride-sialon ◆ In the case of boron nitride-sialon composite ceramics, aluminum nitride and alumina are added to boron nitride powder and silicon nitride powder, mixed, formed into the shape of a welding aid, and then heated with nitrogen. Alternatively, it is sintered by heating to 1,600 to 1,800°C in a non-oxidizing atmosphere containing nitrogen.

<Example> ◆ 30 parts by weight of BN powder (10 m2 /g), 46 parts by weight of Si3N4 powder (8 m2 /g), 8 parts by weight of A
1N powder (7 m2/g) and 16 parts by weight of Al2
O3 powder (12 m2/g) was mixed in ethanol and dried to form granules. This was press-molded into the shape of a welding auxiliary material using a mold at a pressure of 2 t/cm2, and sintered by heating to 1750° C. in nitrogen.

Reaction sintering method (1) Boron nitride-silicon nitride◆ In the case of boron nitride-silicon nitride composite ceramics, boron nitride powder is mixed with metallic silicon powder, formed into the shape of a welding aid, and then heated with nitrogen or silicon nitride. It is heated to 1,400 to 1,500° C. in a non-oxidizing atmosphere containing nitrogen, and is sintered by utilizing the reaction between metal silicon and nitrogen.

<Example>◆ 50 parts by weight of BN powder (10 m 2 /g) and 40 parts by weight of Si powder (5 m 2 /g) were mixed in ethanol and then dried to form granules. This was press-formed into the shape of a welding auxiliary material using a mold at a pressure of 2t/cm2, and then
It was heated to 500°C to cause Si and N2 to react and sinter.

(2) Boron nitride-aluminum nitride◆
In the case of boron nitride-aluminum nitride composite ceramics, boron nitride powder is mixed with metal aluminum powder, formed into the shape of a welding aid, and then heated to 1400-1500°C in nitrogen or a non-oxidizing atmosphere containing nitrogen. Sintering is performed using the reaction between aluminum and nitrogen.

<Example>◆ 70 parts by weight of BN powder (10 m 2 /g) and 30 parts by weight of Al powder (2 m 2 /g) were mixed in ethanol and then dried to form granules. This was press-formed into the shape of a welding auxiliary material using a mold at a pressure of 2t/cm2, and then
It was heated to 450°C to cause Al and N2 to react and sinter.

(3) Boron nitride-silicon nitride-aluminum nitride◆ In the case of boron nitride-silicon nitride-aluminum nitride composite ceramics, boron nitride powder is mixed with aluminum nitride powder or metal aluminum powder and metal silicon powder, After forming it into the shape of a welding aid, it is heated to 1400 to 1500°C in nitrogen or a non-oxidizing atmosphere containing nitrogen.
Sintering is performed using the reaction of metal aluminum and metal silicon with nitrogen.

<Example 1> ◆ 70 parts by weight of BN powder (10 m2 /g), 10 parts by weight of AlN powder (7 m2 /g) and 20 parts by weight of Si
The powder (5 m2/g) was mixed in ethanol and then dried to form granules. 2 tons of this was molded into the shape of a welding auxiliary material.
After pressure molding at a pressure of /cm2, 1500
It was heated to ℃ to cause Si and N2 to react and sinter.

<Example 2> ◆ 50 parts by weight of BN powder (10 m2 /g), 15 parts by weight of AlN powder (7 m2 /g) and 35 parts by weight of Si
The powder (5 m2/g) was mixed in ethanol and then dried to form granules. 2 tons of this was molded into the shape of a welding auxiliary material.
/cm2 pressure and then 1500°C in nitrogen.
was heated to react with N2 and sintered.

(4) Boron nitride-sialon ◆ In the case of boron nitride-sialon composite ceramics, boron nitride powder is blended with metallic silicon, alumina, and aluminum nitride or metallic aluminum, and the mixture is formed into the shape of a welding aid. This molded body is heated to 1400 to 1600° C. in nitrogen or a non-oxidizing atmosphere containing nitrogen to sinter it.

<Example> ◆ 60 parts by weight of BN powder (10 m2 /g), 22 parts by weight of Si powder (5 m2 /g), and 13 parts by weight of Al2O
3 powder (12 m2/g) and 5 parts by weight of AlN powder (7 m2/g) were mixed in ethanol and then dried to form granules. This is molded into the shape of a welding auxiliary material by 2 tons/
After pressure molding at a pressure of cm2, it was heated to 1550°C in nitrogen.
It was heated to sinter.

According to the above manufacturing method, the raw material is molded into the final shape, and the molded material is sintered under no pressure by the pressureless sintering method or the reaction sintering method to manufacture the welding auxiliary material. Unlike the hot press method, there is no need for mechanical processing, so expensive raw materials are not wasted, processing costs are low, and manufacturing can be done at low cost.

In the case of pressureless sintering, the partner material for boron nitride containing 20% by weight or more is selected from alumina, zirconia, mullite, zirconium boride, titanium boride, silicon nitride, aluminum nitride, and sialon. In the case of reaction sintering, the mating material is one or more selected from silicon nitride, aluminum nitride, and sialon. It is possible to sinter it.

The welding auxiliary material according to the present invention is not limited to the above-mentioned arc shield, but may also be used for various other welding auxiliary materials, such as welding auxiliary materials (tabs) for arc welding of joints between plates. It may also be used as a welding auxiliary material (covering material) in joint welding between steel bars.

[0069]

Effects of the Invention As described above, according to the manufacturing methods according to the first and second inventions of the present application, the welding auxiliary material is formed of a ceramic containing 20% by weight or more of boron nitride, so it is free from other ceramics. It is possible to obtain a welding auxiliary material that has excellent thermal shock resistance and low adhesion to molten metal, and can be used repeatedly many times.

[0070] Furthermore, in the manufacturing methods according to the first and second aspects of the present invention, a raw material is molded into a final shape or a shape close to the final shape, and the molded product is processed under normal pressure or by a reactive sintering method without pressure. Since it is manufactured by sintering, unlike the hot press method, there is no need for machining or the number of machined parts can be reduced, so expensive raw materials are not wasted, and processing costs are low, making it inexpensive to manufacture. be able to.

Furthermore, in the manufacturing method according to the first invention, 20% by weight or more of boron nitride as a partner material is mixed into alumina, zirconia, mullite, zirconium boride, titanium boride, silicon nitride, aluminum nitride, or sialon. In the manufacturing method according to the second invention, the mating material is one or more selected from silicon nitride, aluminum nitride, and sialon, and contains boron nitride, which is difficult to sinter. It is also possible to carry out atmospheric pressure and reaction sintering, respectively.

[Brief explanation of the drawing]

[Fig. 1] A perspective view showing an embodiment of the present invention.

[Fig. 2] Front view of an arc stud welding machine using the embodiment shown in Fig. 1.

[Figure 3] Right side view of the arc stud welding machine shown in Figure 2

[
Figure 4: IV-IV line arrow view in Figure 2

[Figure 5] Cross-sectional view taken along the line V-V in Figure 4

[Figure 6] Diagram explaining arc stud welding using an arc shield

[Explanation of symbols]

30 Welding auxiliary materials

Claims (2)

[Claims] 1. A method for manufacturing a welding aid made of ceramics, wherein the ceramics contain 20% by weight or more of boron nitride, alumina, zirconia, mullite, zirconium boride, titanium boride, silicon nitride, aluminum nitride, sialon. It is a composite ceramic made of one or more selected from the above, and is manufactured by molding the raw material into the final shape or a shape close to the final shape, and sintering the molded product without pressure using the pressureless sintering method. A method for manufacturing a welding auxiliary material, characterized by: 2. A method for manufacturing a welding aid made of ceramics, wherein the ceramic is a composite ceramic made of 20% by weight or more of boron nitride and one or more selected from silicon nitride, aluminum nitride, and sialon. A method for producing a welding auxiliary material, which comprises shaping a raw material into a final shape or a shape close to the final shape, and sintering the molded material without pressure using a reaction sintering method.