JPH0433861B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to improving the abrasion resistance, corrosion resistance, and chipping resistance of a dot printer wire used in a dot printer. [Prior Art] Conventionally, high speed steel and cemented carbide have been mainly used as dot wires. Since high speed steel has inferior corrosion resistance and wear resistance compared to WC-based cemented carbide,
There is a transition to WC-based cemented carbide. On the other hand, although WC-based cemented carbide has better corrosion and abrasion resistance than high-speed steel, corrosion resistance may become a problem depending on the type of ink. Further, it has a high specific gravity of 13 to 14 g/cm ³ and has a large inertial force, which makes it unable to keep up with higher printing speeds. [Problems to be solved by the present invention] The present invention aims to further improve the abrasion resistance and corrosion resistance of the above-mentioned WC-based cemented carbide dot wire, and to reduce the density in order to keep up with higher speeds. purpose. [Means for Solving the Problems] The present invention uses one or more C/C as a dispersed phase forming component.
A part of the titanium carbonitride in the titanium carbonitride having an N ratio is in the range of 10 to 70% by weight, and one or two of the metals of Groups 4a, 5a and 6a of the periodic table excluding Ti are added.
50 to 90% by weight of double carbonitride substituted with one or more carbides, the remainder containing one or more iron group metals and unavoidable impurities as binder phase forming components.
This is a cermet dot wire consisting of 50 to 10% by weight and characterized by a contact ratio of 15% or less between the particles forming the dispersed phase. In place of the base cemented carbide, we investigated titanium carbonitride Ti (CN)-based cermet. Ti(CN) based cermet is
Since it has a light density of 6 to 9 g/cm ³ and is lower than copper, it is also possible to follow higher speeds. Also corrosion resistance,
It also has better wear resistance than WC-based cemented carbide. However, compared to WC-based cemented carbide, Ti(CN)-based cermets lack toughness due to the nature of their main component, Ti carbonitride, so they have not been used for small-diameter dot wires, etc. That was impossible. The present inventor investigated and investigated the cause of the lack of toughness of the above-mentioned Ti(CN)-based cermet, and as a result, the following facts were obtained. Ti(CN) based cermet is used as a dispersed phase.
It consists of a solid solution double carbonitride phase such as TiCN, Mo ₂ C, TaC, and WC and a binder phase, and it is recommended to add Mo, W, Ta, etc. to improve the wettability of the binder phase and the carbonitride phase. It is becoming common. However, when we investigate the behavior of these additives, we find that Ti
A core (CORE) containing a large amount of Ti and nitrogen is formed at the center of the (CN) particle, and a so-called peripheral structure containing a large amount of MO, W, Ta, etc. is formed at the periphery. Due to its composition, this surrounding structure has better wettability to the binder phase than Ti(CN) and improves the toughness of the Ti(CN) group, but on the other hand, as shown in Figure 1B, It tends to bring carbonitride particles into contact with each other. This contact between carbonitride particles (hereinafter referred to as skeleton) reduces crack propagation resistance and is the biggest factor in not improving toughness. for example,
In the bonded phase with the same volume fraction (15% by volume), Ti
When we quantitatively measured the degree of skeleton of (CN)-based cermet and WC-based cemented carbide from actual microstructure photographs, we found that in Ti(CN)-based cermet, the contact area The area is 30-40%, which is much higher than the 10-15% for WC-based cemented carbide. As a result of various studies in order to suppress the skeleton of carbonitrides from the above viewpoint, the inventors of the present invention found that, for example, by using a raw material in which surrounding structure-forming elements were previously solid-dissolved with Ti (CN), the amount of surrounding structure formation We have found that it is possible to reduce the In particular, the effect is large when solid solution treatment is performed on W, which forms an interstitial solid solution with Ti carbonitride, and when forming a substitutional solid solution of Ta, Mo, etc., it is possible to suppress the amount of skeleton formation. be. In this way, Ti(CN) was produced with various manufacturing conditions in mind.
The base cermet has the aforementioned skeleton ratio of 10
~15%, making it possible to obtain toughness that is as good as, if not better than, that of WC-based cemented carbide. Furthermore, the cermet dot wire with improved toughness has a Ti
(CN) has the advantage of superior wear and corrosion resistance, has a long lifespan, and is lightweight, making it suitable for high-speed applications. Next, we will discuss the reason for limiting the numerical values. The amount of double carbonitride forming the dispersed phase was set at 50 to 90% because if it was less than 50%, the desired wear resistance could not be obtained, and if it was more than 90%, the toughness of the alloy would be impaired. If the substitution amount of carbides of the 4a, 5a, and 6a groups excluding Ti is less than 10%, it will have little effect on improving the wettability of Ti(CN) and the binder phase, and if it exceeds 70%, Ti(CN) ) Since the original wear resistance and corrosion resistance deteriorate, it was set at 10 to 70%. If the binder phase is less than 10%, the chipping resistance of the alloy will be poor, and if it exceeds 50%, the wear resistance will be impaired, so the content was set at 10 to 50%. Contact is measured by observing the microstructure on the lap surface, measuring the area of particles in contact with each other, and the area of particles approximated to a spherical shape, and expressing it as a percentage, with the total area of the hard phase being 1. If it exceeds 15%, contact between the skeletons increases and bending strength deteriorates, so it was set to 15% or less. [Example] Next, the cermet dot wire of the present invention will be explained based on an example while comparing it with a comparative dot wire. The raw material powder was mixed and ground in a ball mill for 96 hours to have the composition shown in Table 1 with C/N=3, and after adding a plasticizer, it was kneaded and extruded into a round bar with a diameter of 0.5 mm. Next, after degreasing and sintering at 1350°C for 30 minutes, this round bar sintered body was centerless ground to produce a wire material for dot printers with a diameter of 0.3 mm. The physical properties of this alloy are also listed in Table 1. The transverse rupture strength test was conducted in accordance with JIS B7704 "Metallic material transverse fracture test piece" with a diameter of 0.3 mm, a length of 20 mm, and a distance between fulcrums of 10 mm. Next, with a cantilever, the amplitude is 4
mm, 50Hz, stress 130Kg/ ^mm2 , fatigue test was performed 10 times, the average number of fatigue failures was calculated, and this was used for the second test.
Shown in the table. In addition, a mounting test was conducted and the amount of wear at the tip was measured at a shown in FIG. The result is the third
Shown in the table. [Effects of the Invention] The cermet dot wire of the present invention suppresses the amount of skeleton formation, improves the toughness of Ti(CN)-based cermet, and improves the wear resistance of Ti(CN).
In addition to its corrosion resistance, it has a density of 6.0 to 9.0 g/ ^cm3 , which is about half that of conventionally used WC-based cemented carbide.
The weight of the wire of the present invention is also about half that of conventional wires made of WC-based cemented carbide, and can fully support future speed increases.

【table】

【table】

【table】 [Brief explanation of drawings]

In Figure 1A, Mo, W,
An explanatory diagram of the so-called peripheral tissues containing large amounts of Ta, etc.
FIG. 1B shows an explanatory diagram when carbonitride particles contact each other and form a skeleton. Figure 2 shows the measurement positions for the amount of wear.

Claims (1)

[Claims] 1. As a dispersed phase forming component, a part of titanium carbonitride in titanium carbonitride having a C/N ratio of 1 or more is used as a dispersed phase forming component.
4 of the periodic table, excluding Ti, in the range of 10 to 70% by weight.
50 to 90% by weight of double carbonitride substituted with one or more carbides of group a, 5a and 6a metals, one or more iron group metals and unavoidable impurities as a binder phase forming component. Including, remaining 50~10
% by weight, and the contact ratio between particles forming a dispersed phase is 15% or less.