JPS604260B2 - super hard alloy - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cemented carbide having strong balling properties, and more particularly to a cemented carbide suitable for cutting tools.

As a conventional cemented carbide, WC-based bran alloy (cemented carbide)
and TIC-based bonded gold (cermet) are well known.

However, although WC-based sintered alloys have excellent toughness, they have poor wear resistance, and when used as cutting tools, they tend to cause clay (rake face) wear, making them unsuitable for high-speed cutting. Since tungsten (tungsten) is extremely expensive, the resulting product has the drawback of being expensive.

On the other hand, although TIC-based sintered alloys have excellent wear resistance properties, they have poor hardness, making them unsuitable for interrupted cutting.Also, although they are suitable for high-speed cutting, if the workpiece has a high hardness, the cutting edge This has the disadvantage that it tends to sag, and, for example, during milling, it can lead to chipping. The present invention was devised in view of the above-mentioned drawbacks, and is a cemented carbide alloy that combines the respective advantages of conventional cemented carbide and cermet.
That is, the object of the present invention is to provide a new superhard alloy that can significantly improve transverse rupture strength and cutting life characteristics without reducing hardness, and can reduce manufacturing costs.

The superhard alloy of the present invention contains 10 to 50% by weight of niobium carbide, 10 to 4% by weight of titanium carbide, and 10 to 2% by weight of tungsten carbide.
5% by weight, molybdenum carbide 5-2% by weight, titanium nitride 5-1% by weight, and iron group metal 5-2% by weight.

Niobium carbide (N
Ratio) is a component for imparting impact resistance and abrasion resistance to the alloy. If the amount added is less than 1% by weight, the desired properties will not be imparted, and if it exceeds 50% by weight, the alloy will An abnormality occurs in the composition of the alloy, and the alloy becomes porous and cannot be used for practical use.

Further, titanium carbide (TIC) is a component for imparting wear resistance to the alloy, and if the amount added is less than 1% by weight, the desired properties will not be imparted, and when used as a cutting tool, Crater wear is large and it cannot be used. Furthermore, if the amount added is more than 4% by weight, the quality of the alloy will deteriorate, making it unsuitable for interrupted cutting. Furthermore, titanium nitride (TIN)
is a component for imparting toughness to the alloy, and if the amount added is less than 5% by weight, the desired properties will not be imparted.
If the content exceeds 1% by weight, the grain setting properties of the alloy will be poor and ultra-hard leech bodies will not be obtained.

Like titanium nitride, tungsten carbide (WC) is also a component for imparting toughness to the alloy, but if the amount added is less than 1% by weight, the desired properties will not be imparted;
If it exceeds 5% by weight, the wear resistance of the alloy decreases, and when used as a cutting tool, crater wear becomes so great that it becomes unusable.

Molybdenum carbide (Mo2C) is a component that improves the wettability of each component of the alloy and the iron group metal that binds these components and improves the silkiness, and its addition amount is 5% by weight.
If it is less than 2% by weight, the desired effects described above cannot be obtained, and if it is more than 2% by weight, the toughness will decrease.

Iron group metals (for example, nickel, cobalt, etc.) are components for bonding the carbides and nitrides that make up the alloy, and if the amount added is less than 5% by weight, a sufficient bonding effect cannot be obtained; If the amount is more than 2% by weight, the wear resistance will decrease. The superhard alloy of the present invention has the characteristics of transverse rupture cutting life without reducing hardness by setting niobium carbide, titanium carbide, tungsten carbide, molybdenum carbide, titanium nitride, and iron group metals within the above-mentioned predetermined ranges. has been significantly improved, and as a result, it can be suitably used as a cutting tool.Furthermore, the amount of tungsten carbide used has been dramatically reduced compared to conventional products, resulting in lower costs. Satisfactory results were also confirmed in terms of realization.

Next, the present invention will be explained in detail based on examples.

Nbc, TIC, WC, TIN, Mo2 as starting materials
C and Ni are weighed so as to have the composition shown in the table below, a suitable solvent such as acetone is added thereto, and wet mixing is carried out using a vibrating mill.

After mixing, they are dried, the solvent is removed by evaporation, paraffin wax is added, and the mixture is granulated through a 40-mesh pass. The powder thus obtained was molded at a pressure of 1000 k9/s, then calcined at a temperature of 300 qo to remove the wax, and further heated at a pressure of 1400 k9/s in a non-oxidizing atmosphere.
It is fired at a firing temperature of oo to obtain an aggregate sample. Note that sample 6 is a sample for comparing the effects of the present invention and is JISP-10, which is generally commercially available as a cemented carbide.

Similarly to sample 6, sample 7 is a sample for comparing the effects of the present invention, and is generally a cermet competitive alloy (TIC80
%, Nil 5%, Mo 5%).

Using these as samples, the hardness was measured according to the Rockwell hardness test method specified in JIS Z-2245, and the bending strength was measured according to JIS Z-2245.
Each measurement was performed using the three-point bending test method specified in B4104.

Furthermore, when these samples were used as cutting tools, the intermittent cutting life was measured by the test method described below.

The results are shown in Table 1.

[Intermittent cutting test]

Cutting conditions Workpiece material: S4 (carbon steel) 4 rods introduced Cutting speed: 100 min Depth of cut: 2 legs Feed: 0.41 side/rev Bit shape: Side length 12.7 legs, thickness 4.8 Ribs (TNGG
432) Each sample was formed into a triangular hide chip (TNGG432) with a side length of 12.7 ribs and a thickness of 4.8 legs, and each of these bit tips was cut intermittently under the above cutting conditions to form each bite tip. The number of impacts applied to the bite tip until the chip broke was counted, and the average number of impacts was determined.

Table 1 As can be seen from the above experimental results, the cemented carbide of the present invention has an extremely high hardness equivalent to that of conventional cermet competitive alloys, and its transverse rupture strength is 20k higher than that of conventional cemented carbide.
9/It is extremely large, increasing in size by more than the size of a rock.

Therefore, when the superhard alloy of the present invention is used as a cutting tool, the transverse rupture strength increases. -While the conventional product could only withstand about 800 impacts during interrupted cutting, it can withstand 2,000 impacts during interrupted cutting. This makes it possible to withstand more than twice as much impact as the conventional products, achieving a dramatically longer life as a cutting tool. Furthermore, according to the present invention, conventional cemented carbide contains 50 to 80 (wt%) of expensive tungsten.
In contrast to conventional products, only 10 to 25% (by weight) of tungsten is used, and the product cost, which depends on the amount of tungsten added, can be reduced to approximately 1'2, resulting in lower product costs. became possible.

Incidentally, the superhard alloy of the present invention is not limited to the above-mentioned embodiments, and one or more other substances may be added to further control other properties.

Claims (1)

[Claims] 1 Niobium carbide 10-50% by weight Titanium carbide 10-40% by weight Tungsten carbide 10-25% by weight Molybdenum carbide 5-20% by weight Titanium nitride 5-10% by weight and a superhard alloy consisting of 5 to 20% by weight of an iron group metal.