JPS5941436A - Sintered hard alloy - Google Patents

Abstract

PURPOSE:To provide a sintered hard alloy excellent in anti-wear property and high temp. strength, obtained by adding a specific amount of a Zr compound to a sintered hard alloy containing WC, TiC and a B-1 type solid solution as a hard phase in a state bonded by a ferrous metal. CONSTITUTION:WC, one kind or more among TiC, TaC, NbC and HfC and a B-1 type solid solution which is a solid solution carbide with WC are contained as a hard phase and bonded by a ferrous metal to obtain a sintered hard alloy. To this hard alloy, one kind or more among Zr metal, Zr carbide, Zr nitride and Zr oxide is further added in a sum amount within a range of 1.0wt% or more and less than 5wt%. By this method, a new hard alloy excellent in high temp. strength and anti-wear property is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cemented carbide having one less wear resistance and high temperature strength.

Carbide alloys have excellent toughness and wear resistance, so they have been widely used in cutting tools. However, as machining efficiency becomes more and more important, the amount of chips discharged per hour has become an issue. As a result, cutting has been performed at higher speeds, and the high-temperature strength of the cemented carbide used as the chip material, including plastic deformation resistance, wear resistance, and chipping resistance, has become a particular problem. For this reason, TiC-based cermets have come to be used in some cases, but
In terms of toughness, it is currently still not as good as cemented carbide based on WC.

The object of the present invention is to improve the above-mentioned problems of cemented carbide and to provide a new cemented carbide that has excellent high-temperature strength and wear resistance.

The feature of the present invention is that Zr or a Zr compound, which has conventionally been harmful to cemented carbide in terms of toughness, is added, and the amount added is 1.0% by weight or more and less than 5.0% by weight. This is because the amount is extremely small.

Surprisingly, the inventors discovered that the addition of Zr or a Zr compound significantly improves the high-temperature strength compared to conventional alloys, to the point where tJ can be called revolutionary. High-temperature creep test (.) The time to break is several times longer for Zr-added materials, and the strain rate is a fraction of the conventional +2.

In addition, when cutting, the deformation of the cut section due to cutting heat is gradually reduced, so a reduction in abnormal wear, a reduction in nose sagging of the depth, and a reduction in defects caused by plastic deformation are observed. Furthermore, since the high-temperature strength is improved, the occurrence of heat cracking, which is a particularly fatal damage, is extremely reduced in the case of interrupted cutting. In addition, surprisingly, the flank section,
The amount of wear on parts of the crater and each part is extremely reduced.

Now, as mentioned above, Zr produces an epoch-making effect, but it is preferable that the addition tri is 1.0% by weight or more and less than 5.0% by weight. When it is less than 1.0%, the amount of strain at break is (ゝ)(ゝ) small.

In addition, if it exceeds 5.0%, it is not preferable because the bending angle at room temperature decreases slightly and heating occurs frequently. -(B-,1)-Co alloy also has the effect of 1u.The inventors are investigating the cause of this effect of 7-r day and night, but have not yet been able to reach a firm conclusion. do not have.

Example 1 70WC-10Ti C-101'a C-8Co -
Powder was blended into a composition of 2ZrC and sintered in vacuum at 1400° C. for 1 hour to obtain a sample (A). At the same time, a sample (B) to which ZrC was not added was prepared as a comparative material.

A stress of 65 Kg/mm2 was applied to these two types at 1000° C., and rupture time and strain rate tests were conducted using a three-point bending method. As shown in Table 1, it can be seen that the ZrC-added 1 day Δ type has significantly superior strength such as fracture resistance and deformation resistance at high temperatures.

Table 1 Example 2 73WC-7-r! C-5Ta C-3Nl) C-
The powder was blended with a composition of 9Co-3ZrO and sintered at 1390°C for 1 hour to obtain a sample (C). At the same time, a sample (D) without ZrO was prepared as a comparison material.
.

These two types are cut into the following cutting strip 4 [i.e., the work material
80M140 Cutting speed 180 m/min Feed 0.4111 m/reV depth of cut
Cutting was performed for 10 minutes with a distance of 2 mm between the cut parts.

As shown in Table 2, the grades to which 7rO is added have significantly superior wear resistance.

Table 2 Example 3 WC-6C'0-4Zr N-type 111A k-powder was fully blended and sintered at 1400°C for 1 hour. Sample (E)
And so. At the same time, a sample to which no ZrN was added (
F) was produced.

These two types are combined under the following interrupted cutting conditions, i.e., cutting speed.
150 m/min feed 0.4IIl111/'Blade depth of cut 2 n+n+ Rigid material 80M440 Work material lJ45mm Cutter body 150φ The tip of the comparison material (F) broke due to heat cracking after 30 minutes of cutting, but (E) Even after 55 minutes of cutting, the chip still suffered some heat cracking, but no breakage occurred.

By adding Zr to cemented carbide in this manner, a new cemented carbide having excellent high-temperature strength and wear resistance can be obtained.

Procedural amendment (formality) 117 (□15.7・12.I22..

Name of invention: 89 goya 11- Representative Norio Kokono Sentence/1 Description of the mountain 11 units ? Contents of +li 11' Clear copy of the statement (no changes to the contents)

Claims (1)

[Claims] 1. WC, Ti C, Ta C, Nb C, 1-IJ,
A cemented carbide containing one or more types of C and a B-1 type solid solution which is a solid solution carbide with W C as a hard phase, which is bonded with an iron group metal, further containing Zr metal, Z
A cemented carbide characterized by containing one or more of l-carbide, Zr nitride, and 7r oxide in an amount of at least 5 and less than 5% by weight. 2. One of 7r carbide, 7r nitride, and Zr oxide is added to the cemented carbide base metal, which is made by hard layering WC and bonding it with iron group metal.
Species or two or more species on the gold side i, 1% or more 15.0% by weight
Cemented carbide characterized by containing less than or equal to