JPS59133346A - Sintered hard alloy - Google Patents

Abstract

PURPOSE:To improve the wear resistance and welding resistance of the resulting titled alloy for cutting by incorporating Co3W3C into the structure of a sintered body contg. W, Ti, Ta, Nb substituted optionally for part of Ta, carbon and an iron group metal as a binding phase. CONSTITUTION:75-95% W is blended with 0-5% Ti, Ta and Nb substituted optionally for part of Ta, 3-8% carbon and 2-20% iron group metal such as Co as a binding phase in the form of powder. The powdery blend is mixed in a wet state by means of superhard balls in a mill rotating at high speed, and the mixture is dried and press-molded in a prescribed metallic mold. The resulting green compact is heated at a high temp. in vacuum to obtain a sintered hard alloy. At this time, a Co3W3C phase is formed by controlling only the amount of carbon to be alloyed in the alloy composition.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cemented carbide, and in particular to an improved wear resistance of a superhard sintered alloy for cutting a material.

Conventionally, sintered cemented carbide for cutting metals is often made of tungsten carbide hardened with cobalt, and the alloy structure has a sound structure consisting of two phase regions: a carbide phase and a binder phase. Met.

However, in recent years, there have been many opportunities to cut difficult-to-cut materials such as nutless steel, nickel-based alloys, or titanium alloys, and when the conventional cemented carbide mentioned above is used to cut these difficult-to-cut materials, the cutting edge wears out, especially near the boundaries. The tool life was extremely short due to easy wear of the tool.

The present invention has been made in view of the above-mentioned conventional problems.
The object of the present invention is to provide an ultra-hard sintered alloy for cutting that has excellent wear resistance and welding resistance and has a long life even when cutting difficult-to-cut materials.

The present invention uses 75 to 95% tungsten, 0 to 5% titanium and tantalum, or 0 to 5% tantalum in which a part of tantalum is replaced with niobium.
This is an ultra-hard sintered body containing 003W30 in the sintered body structure, which contains 5 to 8% of carbon and 2 to 20% of iron group metal as a binder phase.

As previously mentioned, conventional cemented carbides for cutting are usually manufactured by controlling the carbon content so as not to generate free carbon or 003W30 phase in the alloy structure, and to prevent the formation of two carbide phases and a binder phase. It is common to make cemented carbide with a healthy structure consisting of phase regions, and the reason for this is that free carbon and 003W3
This is because it is said that the formation of zero phase reduces wear resistance or toughness.

However, as a result of various experiments conducted by the inventors,
The total carbon content in the cemented carbide is set to a low value, and the alloy structure contains 0
03 As a result of the cutting test on the sample in which the W2O phase was formed,
It has been discovered that a superhard sintered alloy with excellent wear resistance and adhesion resistance can be obtained without reducing toughness.

Next, the reason why this ultra-hard sintered alloy was constructed as described above will be described. Tungsten 75-95<, titanium and tantalum or tank μ partially replaced with niobium 0-5% and carbon 5-g< 2-20% iron group metal (both by weight) The person who did this was P series 9.
Compared to M series (JIS B l+ 1' 011) cemented carbide, it generally has the best alloy strength and thermal conductivity for the same binder phase volume, making it ideal for cutting difficult-to-cut materials such as those mentioned above. This is to do so. Furthermore, the reason for the formation of the Co3W30 phase in the alloy structure is that the Co3W30 phase has excellent welding resistance and wear resistance, and
This is based on the knowledge that as the phase is formed, the amount of tungsten solidly dissolved in the binder phase increases, and the binder phase is strengthened as a solid solution, thereby improving the properties of the alloy. In fact, the presence of the 003 W2O phase in the alloy structure is favorable for increasing tool boundary wear caused by difficult-to-cut materials that are easily work-hardened or have low thermal conductivity. Cutting test results have confirmed that it brings about results.

This invention will be specifically explained below.

First, the manufacturing method is to mix tungsten, titanium, tantalum, or tantalum partially replaced with niobium, raw material powder such as carbon, and bonded metal powder of CO, and then rotate this powder at high speed using a carbide po-μ. The mixture was wet mixed in a mill for about 148 hours, dried, and then press-molded in a predetermined mold to form a compact, and then 10-2 to 1O-31111
The superhard alloy of the present invention is obtained by applying a temperature of 1350 to 11150°C in a vacuum of H9 and holding it for about 60 minutes.
A W2O phase is generated.

Below, we will discuss some examples.

Diameter 251 using the ultra-hard sintered alloy obtained above as a cutting edge
An end mill tool of m was manufactured.

This end mill tool was attached to a vertical milling machine (vertical milling machine), and a cutting test was conducted.

The conditions for this test were as follows: Work material 5US3011 (HB18
0) at a cutting speed of 50 m/min, feed of 0.11 mm/
rev, depth of cut 5 strg, cutting time 20 m-*n was tested as test) A, cutting speed 145 m/min, feed 0.3 mm/r using N1 base alloy as work material.
ev, Test B was conducted under the conditions of depth of cut of 5 mm and cutting time of 15 min, and work material T was tested.
1 alloy, cutting speed lIOm/m'xn, feed 0
．． 3mm/rev.

Test C was conducted with a cutting depth of 5 mm and a cutting time of 10 mi, n.

The results of these tests are shown in Table 1. The measured values in the table are the flank wear of the cutting edge (wear and the maximum wear near the cutting boundary (wear)).The table also includes Co3 as well as each sample.
Alloys that do not generate the W30 phase are also listed, their characteristic values and test results are listed, and compared with the alloy of the present invention.

Table 1 (Wear Width = Unit + a) As shown in Table 1 above, the alloy of the present invention showed better results in terms of flank wear of the cutting edge and wear near the boundary than the comparative alloy.

In addition, the wear especially near the boundary is improved and exhibits extremely excellent wear resistance when cutting difficult-to-cut materials.

Procedural amendment (voluntary) ■、Small incident display 1981 Patent Application No. 7968 2. Name of the invention Super hard sintered alloy 3. Person who makes corrections Relationship to the case Patent applicant spontaneous correction 5. Subject of correction Claims and Detailed Description of the Invention in the Specification 7 Contents of amendment (1) Amend the claims as shown in the attached sheet.

(2) "Co3W30" in lines 16-17 and line 20 of page 2 of the specification is corrected to "C03W3C."

(3) [CO3
Corrected W30 j to "CO3W3C".

(4) "r C03Wa○" on page 4, line 2, line 3, line 4, and line 11 of page 4 of the specification is corrected to [cO3W3cJ.

(5) On page 4 of the specification, lines 14 to 17, "First, the manufacturing method is to mix the desired amount." ,Nb)(:
, 1~3μ with raw material powder such as tungsten and carbon
m of cobalt-bonded metal powder in a desired amount.''

(6) Page 6, line 3 of the specification Correct “Co3W30” to r　Co3Wa　CJ.

2. Claims (1) Tungsten 75-95%, titanium and tantalum, or tantalum partially replaced with niobium 0-5
% and carbon as a component and 2 to 20% of iron group metal as a binder phase. body.

Claims (1)

[Claims] (1) Tungsten 75-95%, titanium and tantalum, or tantalum partially replaced with niobium 0-5
% and carbon as a component and 2 to 20% of iron group metal as a binder phase. body.