JPS6377749A - Surface-coated cermet dot wire - Google Patents

Abstract

PURPOSE:To improve the wear resistance and corrosion resistance of a WC-base carbide alloy dot wire by providing a specific dispersed phase and a coupling phase and coating the surface by metal coating of 0.5-50mum with Al, Cu, Ti, etc. CONSTITUTION:50-90wt.% of composite carbon nitride in which one or more group 4a, 5a and 6a metals except Ti are substituted in a range of 10-70wt.% for part of Ti in a titanium carbon nitride having 1 or more C/N, and the residue of 50-10wt.% of one or more iron group metal, and unavoidable impurities are contained in a coupling phase as dispersed phase components, the surface is further coated one or more metals, such as Al, Cu, Ti in a range of 0.5-50mum to form a surface-coated cermet dot wire.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to improvements in the wear resistance, iJ corrosion resistance, and chipping resistance of 1-to-1 wires used in dot printers.

[Conventional technology]

Conventionally, high speed steel and tungsten carbide (WC) cemented carbide are mainly used as dot wires. Since high speed steel has inferior corrosion resistance and abrasion resistance compared to WC-based super-alloy steel,
There is a shift towards WCC cemented carbide. On the other hand, although WC-based cemented carbide has corrosion resistance and abrasion resistance compared to high speed steel, depending on the type of ink, corrosion resistance may become a problem.

In addition, it has a high specific gravity of 13 to 14 g/cnj, and has a large inertial force, making it unable to keep up with higher printing speeds.

[Problem that the invention seeks to solve]

The object of the present invention is to further improve the abrasion resistance and corrosion resistance of the WCC cemented carbide dot wire, and to reduce the weight in order to keep pace with higher speeds.

[Means for solving problems]

In order to improve wear resistance and corrosion resistance, we investigated a titanium carbonitride Tj (CN)-based cermet instead of the conventional WC-based super-superalloy. The specific gravity of Ti(CN)-based cermet is also 6~
It is small at 9g/a&, and can keep up with higher speeds.
WCC cemented carbide also has superior wear resistance and corrosion resistance. However, T"1 (CN)-based cermets have the disadvantage of lacking toughness compared to WC-based superalloys due to the nature of the carbide that is their main component, so they have not been used for small diameter drive wires, etc. It was impossible.

The present inventor pursued and studied the cause of the above-mentioned Tj(CN)-based cermet lacking in toughness, and as a result, the following facts were obtained.

'I'1(CN)-based cermets are generally added with Mo, W, Ta, etc. in order to improve the wettability of the bonding phase and the carbonitrided homogeneous phase. However, when the behavior of these additives is investigated, as shown in FIG. 1(A), a so-called peripheral structure containing a large amount of Mo + W + Ta etc. is formed around the Ti(CN) particles. This surrounding tissue is related to its components F
, has better wettability to the binder phase than Ti(CN), and T
This improves the toughness of the i(ON)-based Thermeso 1, but on the other hand, it tends to bring the carbonitride particles into contact with each other, as shown in FIG. 1 (r3). This contact between carbonitride particles (hereinafter referred to as skeleton) lowers crack propagation resistance and is the biggest factor in preventing further improvement of toughness. For example, when we quantitatively measured the degree of Ti(CN)-based cermet and WCC cemented carbide skeleton from actual microstructure photographs in the binder phase with the same volume fraction (15Vo1%), we found that Ti(CN)-based cermet Then, the area of the contact part is 30 to 40% of the total surface area of carbonitride particles,
This is a much higher value than the 10-15% for WCC cemented carbide. As a result of various studies in order to suppress the skeleton of carbonitrides from the viewpoint of I-, the present inventors have found that, for example, by using a raw material in which peripheral structure-forming elements are dissolved in Ti (CN) in advance, the amount of peripheral structure formation can be reduced. We have discovered that it is possible to Alternatively, it is also possible to suppress the amount of skeleton formation by adjusting the carbonitride particle size, amount of binder phase, sintering conditions, etc. without placing any restrictions on the raw materials. It is clear that the Ti, (CN) based cermet, which has been manufactured with various manufacturing conditions in mind, has a ratio of 10 to 5% for the scale mentioned above, and has a toughness comparable to that of WCC cemented carbide. It became. The cermet driver 1~ wire with improved toughness has a higher T i (
It has the advantage of being superior in wear resistance and corrosion resistance to CN), has a long life, and is lightweight, so it can support future speed increases.

As a result of repeated studies to improve not only the toughness but also the fatigue strength of this cermet dot wire, the present inventor discovered that fatigue strength is influenced not only by the toughness of the alloy but also by the surface properties of the dot wire. As a result, by coating the surface with a soft metal, the occurrence of fatigue cracks on the surface was suppressed and the fatigue strength was improved. Furthermore, in order to further improve the corrosion resistance, we investigated several dozen additive elements and found that rhenium and chromium improved the corrosion resistance of cermet by -1. Furthermore, we examined the particle size of the double carbide in the dispersed phase and found that fine particles of 1 μm or less can further improve toughness. This is because the fine grains have a wide surface area, and when the same amount of surrounding tissue is formed, the thickness of the surrounding tissue decreases, and the proportion of the above-mentioned skeleton formation decreases.

Next, we will discuss the numerical values and the reasons for the limitations.

If the amount of double carbonitride is less than 50%, the desired wear resistance cannot be obtained, and if it exceeds 90%, the toughness of the alloy will be impaired, so the amount is set at 50 to 90%.

If the substitution amount of <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 is contained in more than 70%, the original Ti (CN) Since wear resistance and corrosion resistance deteriorate, it was set at 10 to 70%.

If the binder phase is less than 10%, the fracture resistance of the alloy is poor;
If the content exceeds 0%, wear resistance will be impaired, so 10 to 5
It was set to 0%.

If the thickness of the surface coating is less than 0.5μ, the effect of improving fatigue strength will be small, and if it exceeds 50μ, the wear resistance will deteriorate, so it was set to 0.5 to 50μ.

If rhenium is contained in an amount less than 0.5%, no improvement in corrosion resistance is observed, and if it is contained in an amount exceeding 5%, the sinterability of the alloy is deteriorated, so the content is set at 0.5 to 5%.

If chromium is less than 0.5%, no improvement in corrosion resistance is observed, and if it exceeds 15%, it deteriorates the toughness of the alloy.
The content was set at 0.5 to 15%. The grain size was set to 1 μm or less for the above-mentioned reason, since the toughness of the alloy is further improved if the grain size is set to 1 μm or less.

〔Example〕

Next, the dot 1-wire made of cermet 1 according to the present invention will be explained using examples while comparing it with the comparative dot 1-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 to a diameter of 0.5 mm. Next, it was degreased and sintered at 1350°C for 30 minutes to create a wire.

Next, this wire was centerless ground to φ0.31ff11, and then T'i and AQ were coated with 3μ coats by vacuum evaporation.
-C, Drawer 1-Wire was created. The physical properties of this alloy are also listed in Table 1. Transverse rupture strength is Span Kiyori 10III1
These are the results of the three-point bending test 1-.

Next, with a cantilever, amplitude 4wl, 50Hz, stress 130kg/
A fatigue test was conducted 10 times using lInI2, and the average number of fatigue failures was determined and is shown in Table 2. In addition, we conducted a mounting test and measured the amount of wear on the tip according to Figure 2, and the results are shown in Figure 3.
Shown in the table.

〔Effect of the invention〕

From the results of 4-4 below, it is clear that the dot-wire manufactured by the present invention can significantly improve wear resistance without deterioration of toughness. Incidentally, the density of the present invention is approximately 6.0 to 9.0 g/a#, which is about half that of WCC cemented carbide, and can sufficiently follow future high speeds.

[, Qj- Explanation of Drawings 40] Fig. 1 is a diagram schematically showing contact between surrounding tissues and carbonitrides by the surrounding tissues, and Fig. 2 shows the measurement position of the amount of wear.

a: Amount of wear

Claims (1)

[Scope of Claims] 1) Part of Ti in titanium carbonitride having a C/N ratio of 1 or more as a dispersed phase forming component is excluded from Ti in the range of 10 to 70% by weight from 4a and 5a of the periodic table. and double carbonitrides substituted with one or more of group 6a metals 50 to 90
% by weight, and the remaining 50 to 10% by weight is a binder phase consisting of one or more iron group metals and unavoidable impurities,
A surface-coated cermet dot wire characterized in that the surface is coated with one or more metals such as Al, Cu, and Ti to a thickness of 0.5 to 50μ. 2) In the alloy according to claim 1, 0.5-5% rhenium or 0.5-15% rhenium based on the entire binder phase.
A surface-coated cermet dot wire characterized by containing chromium. 3) A surface-coated cermet dot wire characterized in that the average particle size of the double carbonitride as a dispersed phase in the alloy according to claim 1 is 1 μm or less.