JPH0369861B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a method for joining a boron nitride-based sintered material member to a tungsten carbide-based cemented carbide member (hereinafter simply referred to as a cemented carbide member) with high bonding strength. [Prior Art] Generally, boron nitride-based sintered materials contain at least one of Co powder and Ni powder, or both, as a binder phase forming component, and if necessary, a second binder phase forming component. A mixed powder containing one or more of carbides, nitrides, carbonitrides, and borides of group 4a and 5a metals of the periodic table, and aluminum oxide, with the remaining main portion being boron nitride powder. It is manufactured by heating and sintering at a high temperature of approximately 1,300°C under ultra-high pressure of over 40,000 atmospheres, and because it has high hardness and excellent chemical stability, it is mainly used for cast iron. It is used as a cutting tool to cut materials such as steel, heat-resistant alloys, and hardened steel. In this case, the above-mentioned boron nitride-based sintered material member usually also contains at least one binder phase forming component.
Contains either or both of Co and Ni,
The remaining main part is joined to a cemented carbide member with a composition consisting of tungsten carbide (hereinafter referred to as WC), and is used in practical applications such as throw-away tips, end mills, and bits. Since it is extremely difficult to join by ordinary means such as bonding, when the boron nitride-based sintered material is sintered, the cemented carbide member is inserted together with the boron nitride-based sintered material. Currently, bonding is performed at the same time. [Problems to be Solved by the Invention] As described above, since the joining of the boron nitride-based sintered material member and the cemented carbide member is performed simultaneously with the sintering of the boron nitride-based sintered material, The proportion of boron nitride-based sintered material produced is reduced by the amount occupied by the cemented carbide member, and this is a cause of high costs. Therefore, it is possible to produce boron nitride-based sintered materials without using ultra-high pressures, such as those used in the production of boron nitride-based sintered materials, and separately from the sintering of the boron nitride-based sintered materials. If a component can be joined to a cemented carbide component, the production rate of boron nitride-based sintered material will increase by the amount of the cemented carbide component that was previously inserted together, which will reduce costs accordingly. Be able to measure. [Means for solving the problem] Therefore, from the above-mentioned viewpoint, the present inventors have devised a method for joining the boron nitride-based sintered material member to the cemented carbide member without using ultra-high pressure. As a result of research, it was found that at least P
(Phosphorus): 5 to 40 atomic%, further containing C (carbon): 1 to 10 atomic% as necessary, and the remaining main part is Co and/or Ni. Alternatively, with a brazing filler metal having the same composition interposed, both components are heated to a temperature of 800 to 1000℃ while applying a pressure of 20Kg/ ^cm2 or ^more , practically 20 to 300Kg/cm2. Then, the P component or the P component and the C component in the brazing filler metal diffuse into the bonding phase of both the members, so that the bonding phase of both the members and the brazing filler metal become integrated. As a result, it was found that the two members could be joined with extremely high bonding strength, that is, with a high shear strength of 20 kg/mm ² or more. This invention was made based on the above findings, and includes at least
A boron nitride-based sintered material member containing either or both of Co and Ni, also containing at least either Co or Ni as a binder phase forming component,
or when bonding to a cemented carbide member containing both, the bonding surface of these two members contains at least 5 to 40 at% of P, and further contains 1 to 10 at% of C as necessary, The remaining main parts are Co
Both components are subjected to a pressure of 20 kg/cm ² or more, practically 20 to 300 kg/cm ² , with a brazing filler metal having a composition or component composition consisting of either or both of Ni and Ni. while adding 800
By heating to a predetermined temperature within the range of ~1000°C and diffusing the P component of the brazing filler metal and, if necessary, the C component, into the two members, a strong bonding surface between the two members is achieved. It is characterized by the following points. Next, the reason why the conditions in the joining method of the present invention are limited as described above will be explained. (a) P content in the brazing filler metal The P component lowers the melting point of the brazing filler metal, forms a liquid phase at a temperature of 800 to 1000℃, which is the bonding heating temperature, and is itself in a pressurized state. It also diffuses into Co and/or Ni, which are the main constituents of the binder phase of the joining parts, and has the effect of integrating these parts and ensuring a strong joint, but if the content is less than 5 at%, The desired effect is not obtained from the action,
On the other hand, if the content exceeds 40 atom%, a considerable amount of P component will remain on the joint surfaces of both parts, and this P component will form a brittle compound with the binder phase forming component and brazing material component of the joint part. If a large amount of this compound is formed, the bonding strength of the bonded surface will be significantly reduced, so its content was determined to be 5 to 40 atomic percent. (b) C content in the brazing filler metal The C content is relatively low as it coexists with the P component and has the effect of further lowering the melting point of the brazing filler metal and causing the brazing filler metal to become liquid at low temperatures. It is blended or contained depending on the bonding heating temperature required, but if the content is less than 1 atomic %, the desired effect cannot be obtained, whereas if it is contained in excess of 10 atomic %, the bonding Since free carbon remains on the surface and reduces the bonding strength, its content is set at 1 to 10 atomic percent. (c) Bonding heating temperature At a bonding heating temperature of less than 800°C, the diffusion rate of the P component into the bonding members is low, and as a result, a large amount of P component remains on the bonding surface, making it difficult to obtain high bonding strength. On the other hand, if the welding heating temperature exceeds 1000℃, deterioration occurs especially in the boron nitride-based sintered material components, and although high bonding strength can be obtained, cutting performance deteriorates. ,
The temperature was set at 800-1000℃. (d) Additional pressure When joining, pressure is applied to the joining surfaces of the joining members to prevent the formation of voids that will cause a reduction in joint strength, but the added pressure is 20Kg/cm ²
Since it is not possible to completely prevent the generation of voids if the pressure is less than 20 kg/cm ² , it is necessary to apply a pressure of 20 kg/cm 2 or more to obtain a uniform bonded surface without voids. Note that the higher the applied pressure, the higher the bonding strength;
Practically, sufficient bonding strength can be obtained with an additional pressure of 20 to 300 kg/cm ² . In carrying out the joining method of the present invention, it is preferable that the brazing filler metal is applied to the joint surfaces that have been ground smooth by a plating method or a powder coating method. The joining is
It is preferable to use a hot press machine capable of controlling the atmosphere in a non-oxidizing gas atmosphere or in a vacuum, and the atmosphere may be air if it can be carried out in a closed container. [Example] Next, the joining method of the present invention will be specifically explained with reference to Examples. Example 1 As a joining member, diameter: 7 mmφ x thickness: 1.5 mm
A boron nitride-based sintered material member having the dimensions and the composition shown in Table 1, and a diameter: 7 mm.
A cemented carbide member having dimensions of φ x 6 mm in thickness and having the same composition as shown in Table 1 was prepared. On the other hand, as a brazing filler metal forming powder, the average particle size:
Prepare a Co powder with a diameter of 1.2 μm, a Co-P alloy (containing 50 at% P) powder with a diameter of 1.5 μm, and a carbon powder with a diameter of 0.5 μm, and mix these powders into the composition shown in Table 1. Then, add an organic adhesive to this and mix to form a paste. Apply this paste to each bonding surface of the above bonding member in a 5 μm thick layer.
After applying the coating to an average thickness of
Joining was also carried out under the conditions shown in Table 1.

[Table] Inventive joining methods 1 to 11 and comparative joining methods 1 to 4 were carried out, respectively. Note that Comparative Bonding Methods 1 to 4 were all carried out under conditions in which the composition of the brazing filler metal and the bonding conditions (marked with *) were outside the scope of the present invention. be. Next, the shear strength of the bonded surfaces of the resulting bonded members was measured, and the condition of the bonded surfaces was observed. The results of these measurements and observations are shown in Table 1. Example 2 As a joining member, a boron nitride-based sintered material member having dimensions of diameter: 6 mmφ x thickness: 3 mm and having the component composition shown in Table 2, and a boron nitride-based sintered material member having a diameter: 6 mmφ
x Thickness: A cemented carbide member having dimensions of 4 mm and having the same composition as shown in Table 2 was prepared. On the other hand, as a brazing filler metal forming powder, the average particle size:
Ni-P alloy with 1.5μm (P: 50 atomic% content)
Prepare powder, Co-P alloy (containing 33 at% P) powder of 1.5 μm, Co powder of 1.2 μm, Ni powder of 1.5 μm, and carbon powder of 0.5 μm, and these powders are shown in Table 2. The organic adhesive is added and mixed to form a paste, and this paste is applied to the bonding surface of the cemented carbide member.
The cemented carbide member prepared in this way is then superimposed on the boron nitride-based sintered material member with the bonding surfaces in contact with each other.
This was inserted into a cavity having an inner diameter of 6.1 mmφ in a hot press pressurized by upper and lower graphite punches, and bonding was carried out under the conditions shown in Table 2. Comparative joining methods 5 to 8 were each carried out. In addition, comparative joining methods 5 to 8 are all based on Example 1.
As in , some of the conditions were outside the scope of the present invention. For these as well, the shear strength of the bonded surfaces was measured in the same manner as in Example 1, and the conditions of the bonded surfaces were observed. The results are shown in Table 2. In addition, for the joining methods 12, 13, and 14 of the present invention, P and

[Table] The maximum diffusion depth of Ni and Ni were measured using an XMA (X-ray microanalyzer).
The results are shown in Table 3.

[Table] [Effects of the Invention] As is clear from the results shown in Tables 1 to 3, according to the joining method of the present invention, the brazing filler metal components are sufficiently diffused into the joining members, and the joining surfaces are Good bonding condition with no voids, and 20
Boron nitride-based sintered material parts can be firmly joined to cemented carbide parts with a high shear strength of Kg/mm ² or more, but as seen in comparative joining methods 1 to 8, brazing filler metal If any of the component composition and bonding conditions deviate from the scope of this invention,
The joint condition is poor and the shear strength of the joint surface is 20kg/
It can be seen that the bonding strength is as low as mm ² or less, making it impossible to bond with high bonding strength. In addition, a drill with a diameter of 5 mmφ was machined from the joining parts joined by the joining method 13 of the present invention, and using this drill, the work material: hardened die steel (hardness: H _R C54), peripheral cutting speed: 40 m /min, Cutting oil: When drilling was performed under the conditions of use, the drilling was performed in good condition, and it was found that drilling of high-hardness steel, which was considered extremely difficult in the past, could be performed easily. It was something that made it possible. As mentioned above, according to the joining method of the present invention,
Boron nitride-based sintered material components can be firmly bonded to cemented carbide components without using ultra-high pressure, which reduces the manufacturing cost of boron nitride-based sintered materials and significantly expands the field of use. This brings about industrially useful effects, such as making it possible to expand.

Claims (1)

[Claims] 1 At least Co and
When joining a boron nitride-based sintered material member containing either or both of Ni to a tungsten carbide-based cemented carbide member that also contains at least one of Co and/or Ni as a binder phase forming component. A brazing filler metal containing at least 5 to 40 atomic % of P and having a composition or component composition in which the remaining main portion consists of Co and/or Ni was interposed on the joint surfaces of these two members. In this state, both members are heated to a predetermined temperature within a range of 800 to 1000°C while applying a pressure of 20 kg/cm ² or more, and the P component in the brazing filler metal is diffused into the members. A method for joining a boron nitride-based sintered material member to a tungsten carbide-based cemented carbide member, characterized in that: 2 At least Co and
When joining a boron nitride-based sintered material member containing either or both of Ni to a tungsten carbide-based cemented carbide member that also contains at least one of Co and/or Ni as a binder phase forming component. , the joint surfaces of these two members contain at least 5 to 40 atomic % of P and 1 to 10 atomic % of C, with the remaining main portion being either Co or Ni,
Or, while applying a pressure of 20 kg/cm ² or more with a brazing filler metal having a blending composition or component composition consisting of both,
A boron nitride-based sintered material member is heated to a predetermined temperature within a range of 1000°C to diffuse P and C components in the brazing filler metal into both members. How to join parts.