JPS6067638A - Cermet for cutting tool and hot processing tool - Google Patents

Abstract

PURPOSE:To provide the titled cermet enhanced in plastic deformation resistance and impact resistance, obtained by forming a hard phase from a composition of (Ti, W) CN, (Ti, W, Group 5a element) CN, metal boride and MgO while constituting the remainder from a bonding phase of a W-component. CONSTITUTION:A cermet contains one or more of 10-65wt% (Ti, W) CN and (Ti, W, M) CN (wherein M is a metal belonging to the Groups 4a, 5a except Ti), 0.1-5wt% boride of a metal selected from metals belonging to Groups 4a, 5a, 6a and 0.01-1wt% MgO as hard phase forming components and comprises the remainder of bonding phase forming components consisting of W and inevitable impurities. By this composition, sintering property is enhanced as well as excellent toughness, that is, impact resistance is obtained and, in addition, high hardness, that is, excellent wear resistance property and plastic deformation resistance are obtained. Therefore, when this cermet is used as a cutting tool and a hot processing tool, excellent properties are developed.

Description

Detailed Description of the Invention The present invention has high toughness and high hardness, as well as excellent wear resistance, plastic deformation resistance, and impact resistance. Cutting tools used for cutting and heavy cutting such as high-feed cutting and deep 9-in cutting, as well as hot rolling rolls, hot drawing rolls, hot compression dies, hot forging dies, and hot extrusion bunches. The present invention relates to a metal whose binder phase is composed of W and exhibits excellent performance when used as a hot working tool exposed to high temperatures for a relatively long period of time.

In recent years, 1'+'iJ speed cutting and multi-feed cutting have been tested to improve machining efficiency, but increasing the cutting speed at full speed or increasing the feed rate will cause the temperature of the cutting tool's edge to decrease. increases, and the cutting edge often reaches Q before use due to plastic deformation caused by high temperature rather than wear.

However, the hard phases currently in practical use are mainly tungsten carbide (hereinafter referred to as wc) and titanium carbide (
The WCC cemented carbide (hereinafter referred to as TiC) is composed of Ti (hereinafter referred to as TiC), while the binder phase is mainly composed of iron group metals. In addition, not only these WCC cemented carbide TiC1 cermets, but also those with a hard coating layer formed on their surfaces, are used under conditions where the cutting edge temperature is slightly above 1000°C.

Therefore, from the above-mentioned viewpoint, the present inventors have developed a cutting tool that can be used as a cutting tool for high-speed cutting and heavy-duty cutting of steel, etc., which requires particularly excellent plastic deformation resistance, impact resistance, and wear distribution. 4'Af suitable for! As a result of all the research conducted to develop No. 4, a composite metal carbonitride solid solution of T] and W (hereinafter referred to as (T1゜W)CN) powder, T
48 and 5a of the periodic table of elements excluding i, W, and Ti
Composite metal carbonitride solid solution (hereinafter referred to as (Ti, W, M)ON) powder with one or more of group metals, as well as metals of groups 4a, 5a, and 6a of the periodic table of elements. powder, boron powder, boride powder of these metals, and magnesium oxide (hereinafter referred to as MgO) powder.

and W powder were prepared, all of these raw material powders were blended into a predetermined composition, and thereafter manufactured by a normal powder metallurgy method.
In terms of weight (% indicates weight% below) ゛), (Ti, W)C
One or two of N and (Ti, W, M)ON = lO~65, borides of metals from groups 4a, 5a, and 6a of the periodic table of the elements (hereinafter collectively referred to as One or more of the metal e1 urides): 0.1 to 5 ratios, MgO: 0.01 to 1 ratios.

In a cermet with a composition in which all of MgO is present and the remainder is W and unavoidable impurities, most of the MgO is (
Since (Ti, W) ON and (Ti, W, M) react with C in CN and reduce its Oik, (T
i, W)C! The sinterability of N and (Ti, W, M)ON is improved, and the boron in the metal boride or the boron filler combines with oxygen dissolved in W or oxygen in the oxide film. Volatile boron oxide is completely formed, and by removing it, the surface of W is activated and the sinterability becomes VC, which further improves the sinterability. So, 1C7Z has excellent toughness, that is, impact resistance! 7. Furthermore, (T1゜W)ON, (Ti, W,
We found that the presence of M)ON, metal hydrides, ν, and MgO results in high hardness, that is, excellent surface I abrasion resistance and surface J plastic deformability.

This invention was made based on the findings described in section 1, and the reasons for limiting the component composition as described above will be fully explained below.

(a) (Ti,w)cN and (Ti,W,M)
CN These components are mainly hard phase forming components.

It has the effect of improving the surface corrosion resistance and plastic deformation resistance of cermet, but if its content is less than 10%, it will be uniformly dispersed in the idW substrate without forming a skeleton entirely, and the desired effect will not be achieved. On the other hand, if the content exceeds 65%, the amount of W that forms the matrix will be relatively reduced and the toughness will deteriorate, so the content of G:
'r: Defined as 10th to 65th section.

(b) Metal borides These components include oxygen that dissolves solidly in W during sintering, or volatile compounds that react with oxygen in the oxide film formed on the W surface. Forming boron oxide1. As a result, the W surface is activated, which further improves the sinterability and gives the cermet excellent toughness and impact resistance.It also forms a hard phase and hardens the cermet. It has the effect of improving hardness and wear resistance, but
If the content HL is less than 0.1%, the desired effect will not be achieved in the above action, whereas if the content exceeds 5%, the metal buride itself will become VC, causing significant grain growth. The content k O
, Sections 1 to 5.

(c) MgO Most of the MgO components are (Ti, V/) during sintering.
Reacts with the C component in ON and (Ti, W, M)ON to completely reduce the C content in the components, thereby improving the sinterability of these components and giving the cermet vCj superior toughness and In addition to providing impact resistance, M
gO himself also (Ti, W) CN O':bi (T l
l It precipitates as a hard phase-forming component within the WIM)ON grains and at the grain boundaries with W of these grains, and has the effect of suppressing grain growth, but if its content is less than 0.01%, the effect described in 1. On the other hand, if the content exceeds 1%, the plastic deformation resistance of the cermet will decrease [and the impact resistance will also deteriorate as cavities are more likely to form in the cermet]. Since the content ff1t
o, o1-1 section.

(a) Part of w and the unavoidable impurity W component dissolves in the hard phase, but most of it exists as a binder phase and is strongly bonded to the hard phase, giving the cermet excellent toughness and impact resistance. It has the effect of applying force. Also MO as an impurity.

It may contain one or more of Or, Fe, Ni, Co, Re, Pt, and Pd, but if the content is less than one thread each, the cermet properties will not be impaired in any way. It's nothing special.

Next, all embodiments of the cermet of this invention will be explained in detail.

Example 1 Complete solid solution ('ri, w)cNN powders (Ti, W) with an average particle size of 15 μm'f were used as raw material powders.
.

Zr) ON powder, (Ti, W, Hf) ON powder, (Ti, W.

V) ON powder, (Ti, W, Nb) ON powder, (T
i,W.

Ta) aN powder, and (Ti, W, Zr, Ta
) C”N powder, TiBz powder, ZrB2 powder, and HfB2, all of which also contain an average particle size of 1.2 μm.
Powder Song, 'VB2 powder, Ta132 powder/powder, N1)B
2 powder, OrB powder, MOB powder, and WB powder, as well as MgO powder with an average particle size of 0.8 μm and N powder with the same 0.8 μm, and all these raw material powders were blended into a predetermined composition and milled in a ball mill. After 72 hours of pulverization and mixing in a chamber, after drying, it was press-molded at a pressure of 1 ton to form a compact, and then the compact was pressed under pressure.
The cermets 1 to 15 of the present invention and the comparative tool each having the component compositions shown in Table 1 were sintered in a nitrogen atmosphere at a predetermined temperature within the range of 1800 to 2200°C for 1 hour. - knots 1-6
was manufactured.

It should be noted that Comparative Cermets 1 to 6 all have compositions in which the content of any one of the constituent components (as shown in Table 1) is outside the scope of the present invention.

Next, the resultant sermeno of the present invention I-1 to 15
For comparison cermets 1 to 6, the hardness (Rockwell hardness) and transverse rupture strength were measured, and J
The entire cutting boot tab has the shape of IS-8NP433.

Workpiece gy3::rxs-8NcM-8C Hardness: H (12
(30mm cutting speed: I 8 G m/min.

High-speed continuous cutting test under the conditions of feed: 0.3 am/rev, depth of cut: 2 degrees, cutting time: 10 min, and work material: JI
S-8NCM-8 (hardness: HR290).

All interrupted cutting tests were conducted under the following conditions: cutting speed: 100 m/cm, feed: 0.5 mm/rev, %, depth of cut: 3 mm, cutting time: 3 mm. The face wear width and the rake face wear depth were measured, and in the above-mentioned interrupted cutting test, the total number of cutting edges in which chipping occurred at the cutting edge among the 10 test cutting edges was measured. These measurement results are also shown in Table 1. For comparison purposes, % ISO PLO grade WCC cemented carbide cutting insert (hereinafter referred to as conventional insert 1), and Tie
- TiC-based Zanonoto cutting tip having a composition of Mo 10 and IJi 15 (hereinafter referred to as conventional cutting tip 2)
A cutting test was also conducted for VC under the above cutting conditions, and the results are also shown in Table 1.

From the results shown in Table 1, the present invention Sarnono)・1 to 1
No. 5 has high hardness and high toughness.

In all cutting tests, 11it HM' shows excellent corrosion resistance and bonding resistance, whereas comparative cermets 1 to 1
As seen in No. 6, if any of the ICB components is contained outside the scope of the present invention, at least one of hardness and toughness will be inferior, and the wear resistance will be poor in the cutting test. It is clear that at least one of (plastic deformation resistance) and impact resistance shows poor results. Furthermore, since the conventional cutting tip 1.2 has inferior hardness and toughness compared to the cermet of the present invention, it was found to be 1liJ in the cutting test.
It is clear that No. 19 showed poor results in toughness and surface 1 impact properties.

The cermet of the present invention has high hardness and high toughness, and has a wear resistance of 196. It has excellent plastic deformation resistance and impact resistance, so it can be used as a cutting tool for high-speed cutting and heavy cutting of steel that requires properties such as stiffness.
When using C, it shows excellent cutting performance immediately, and it can also be used for relatively long periods of time at high temperatures such as hot rolling rolls, hot wire drawing rolls, hot compression dies, hot forging dies, and even hot extrusion bunches. Even when used as a hot processing tool, it exhibits excellent performance over a long period of time.
1) It has useful properties.

Applicant: Mitsubishi Metals Corporation Agent Tomi 1) Kazuo Name

Claims (1)

[Claims] (1) As a hard phase forming component, a composite metal carbonitride solid solution of Ti and W, and one or more of the group 4a and 5a metals of the periodic table of elements excluding T1, W and t Either one of the composite metal carbonitride solid solutions,
Or both: 10 to 65, and one or more borides of metals from Groups 4, A, 5a, and 6a of the Periodic Table of Elements as hard phase forming components: 0.1 to 5
Width, also as a hard phase forming component, magnesium oxide
0. A cermet for cutting tools and hot working tools, characterized in that it contains 1% to 1% of Ol, and the remainder consists of W as a binder phase forming component and unavoidable impurities.