FR2616447A1 - COPPER-BASED METAL BINDER FOR THE FABRICATION OF THE ACTIVE LAYER OF AN ABRASIVE TOOL - Google Patents

Abstract

The invention relates to a metal binder for an abrasive tool. The composition of the metal binder in% by weight is as follows: tin 13 to 17; cobalt 2 to 9.9; titanium hydride 7 to 10; lanthanum hexaboride 0.01 to 0.09; copper making the complement to 100%. The invention applies in particular to the manufacture of abrasive tools for machining natural building materials and other non-metallic materials that are difficult to work.

Description

The present invention relates to the manufacture of abrasive tools used

to machine materials

  natural building materials and other non-metallic

  difficult to work with, for example, copper-based metal binders for the manufacture of

  the active layer of an abrasive tool.

  A copper-based metallic binder is known for the manufacture of the active layer of an abrasive tool, whose composition in% by weight is as follows: Tin 8 to 12% Iron 8.5 to 12% Cobalt - 13 to 28 % Mixture of titanium diboride or titanium-chromium double boride and titanium hydride in a weight ratio of 1-2 / 1 respectively 4.5 to 24% Copper complementing 100

(SU, A, 985 111).

  The active layer of an abrasive tool based on the binder

  indicated metal is characterized by a low resistance

  wear when the tool is used at a

  high level. Thus, for example, the active layer of a diamond saw with a diameter of 320 mm, used to cut granite and having a feed rate of 1000 mm / min, has a wear resistance of 7 mm. , 4 m2 of granite, the

  specific consumption of synthetic diamonds -

  grain size of 400/315 being 3.2 carats per meter

square of granite.

  It was therefore proposed to develop a

  copper-based metallic binder which would increase the wear resistance of the active layer of the abrasive tool in the case of its use for

machining at high efficiency.

  The problem thus posed is solved with the aid of a copper-based metal binder for the manufacture of the active layer of an abrasive tool comprising tin, cobalt, titanium hydride, characterized in that it contains additionally lanthanum hexaboride, the ratio of the constituents being as follows, in% by weight: Tin 13 to 17% Cobalt 2 to 9.9% Titanium hydride 7 to 10% Lanthanum hexaboride 0.01 The introduction of lanthanum hexaboride into the metal binder claimed provides an active layer of an abrasive tool with a fine grain structure which contributes, in turn, to to raise the strength properties of the active layer and, therefore, its wear resistance. Thus, for example, the limit of the bending strength of the active layer based on the metal binder claimed reaches 589 MPa for a temperature of 4000C and 461 MPa for a temperature of 500 C, which means that it is 1 , 8 to 2.5 times greater than the limit of the bending strength of the active layer based on the known metal binder. In the case of a diamond saw (disc 320 mm in diameter) used to cut the granite and having a feed rate of 1000 mm / min, the strength of the active layer based on the metal binder claimed reached 25.1 m2 of granite, this

  which means that it is 3 times greater than the resistance

  wear of the active layer of a diamond saw based on the known metal binder and that the specific consumption of synthetic diamonds having a grain size of 400/315 does not exceed 1.47 carats per square meter

of granite.

26 16447

  As stated above, the claimed metal binder contains tin in an amount of 13 to 17%

  in weight. The reduction of the tin binder content beyond

  Below 13% by weight results in a higher porosity of the active layer, which results in the decrease of the strength of said layer and, consequently, the decrease of its wear resistance. When the content of the tin binder exceeds 17% by weight, fragile chemical combinations are formed in a high amount during the process of manufacturing the active layer of an abrasion tool, which

  which also leads to the decrease of its resistance to wear.

  When the content of cobalt claimed metal binder is less than 2% by weight, there is an increase in shrinkage of the active layer during the process of its manufacture. The increase of the content

  above 9.9% by weight of cobalt leads to an increase in

  tion of the binder concretion temperature during the manufacture of the active layer of an abrasive tool, which

  night to the resistance of the diamond grains.

  When the content of the claimed metal titanium hydride binder is less than 7% by weight, this results in a decrease in the holding strength of the diamond grains in the active layer of an abrasive tool, which is

  harmful to the wear resistance of said active layer.

  When the content of titanium hydride is greater than 10% by weight, this causes the withdrawal of the active layer and its

  cracking during the process of its manufacture.

  When the content of the metal binder claimed in lanthanum hexaboride is less than 0.01% by weight or greater than 0.09% by weight, it proves impossible to obtain an active layer of an abrasive tool characterized by a structure fine grained, which results in a decrease in

  resistance properties of the active layer and, in particular

bind, of its resistance to wear.

  The indicated content of the metal binder claimed in

  copper gives the physical and mechanical properties

  required for the active layer of an abrasive tool.

  The claimed copper metal binder is prepared by blending constituents into a kneader.

  powder taken to specific proportions.

  To make the active layer of an abrasive tool using the binder obtained, it is necessary to add the grains of an abrasive. The addition of the grains of abrasive material can take place during the mixing of the constituents of the binder. As abrasive, for example, diamond, cubic boron nitride, boron carbide, tungsten carbide, titanium carbide or mixtures thereof can be used. As a general rule, the abrasive is used in one

  amount equal to 5 to 40% of the mass of the metal binder.

  The mixture obtained of the metal binder with the abrasive is subjected to a treatment according to a known technology in the powder metallurgy, which consists in particular in compressing the mixture in a mold under a pressure of 4900 to 6870 bar, in removing the agglomerates from the molds. and

  to perform a thermal concretion under vacuum at a temperature of

  between 870 and 1000 ° C for 30 to 60 minutes. After that, it is necessary to cool the active layer obtained from an abrasion tool, to execute its machining

  mechanical and put it on the body of the abrasive tool.

  Table 1 which follows gives the different composi-

  of the claimed metal binder and the composition of the known metallic binder according to the author's certificate

SU, A, 985111.

Table 1

  n component content,% by weight 6 position of the binder metal-Tin Cobalt Hydride Hexabo- Iron Copper Titanium mixture Titanium lanthanum diboride titanium hydride (1: 1 weight ratio)

I 16.09 9.9 7 0.01 67 - -

II 13 2.91 10 0.09 74 - -

III 17 2 8 0.05 72.95 - -

IV 8 27 - - 40 12 13

(compliant

at SU, A,

985 111)

  Using the claimed metal binder (composi-

  tions I to III) and the known metal binder (composition IV), the active layers of diamond saws were made.

  (discs 320 mm in diameter). For that, we mixed -

  each of the binders indicated to synthetic diamonds of a grain size of 400/315, the amount of diamonds being equal to 7.5% of the mass of the metal binder. The resulting blends were subjected to pressure die-casting (5890 bar), and agglomerates representing segments having a length of 40 mm, a width of 4 mm, a height of 6 mm and a radius of 40 mm were removed from the molds. 160 mm and performed their thermal concretion in a vacuum oven at a temperature of 980 C for 40 minutes. Then, the active layers in the form of the segments were cooled, mechanically machined and fixed on the steel discs of the saws. The diameter of the discs

was-320 mm.

  The saws to which the active layers were attached were subjected to the granite sawing test using a milling machine at the following cutting speed: saw advance speed of 1000 mm / min, circumferential speed of the saw blade. saw (disc) 20.9 m / s, penetration depth per pass of 30 mm, water cooling, flow rate

water: 8 to 10 1 / min.

  The results of the tests are shown in Table 2.

Table 2

  n0 of the composi- Resistance to specific consumption

  binding of the binder the wear of the active metal diamond layer of the active layer, saw, m2 of granite carat / m2 of granite

I 16.1 1.47

II 20.3 1.15

III 25.1 0.94

IV 7.4 3.20

(in accordance with

SU, A, 985111)

  As can be seen from Table 2, the wear resistance of the active layers of the saw blades based on the claimed metal binder (compositions I to III) is 2 to 3 times greater than the wear resistance of the active layer. based on the known metal binder (composition IV). The specific consumption of the diamonds of the active layers based on the claimed metal binder is 2 to 3 times smaller compared to the specific consumption of the diamonds of the

  active layer based on the known metal binder.

  The saws whose disks had an active layer based on the claimed metal binder (compositions I to III) were tested under the conditions indicated with the only difference that the feed rate was

  1250 mm / min. The results of the tests are given in Table 3.

Table 3

  n of the compo- Resistance to wear Specific consumption

  binder active layer only metal diamonds saw blade, active layer, m2 carat granite / m2 granite

I 13.2 1.76

II 13.0 1.78

III 15.0 1.56

  Thus, the claimed metal binder makes it possible to produce an active layer of an abrasive tool characterized by a high wear resistance under the conditions of use of the tool for machining at high efficiency.

Claims (1)

CLAIM   A copper-based metallic binder for producing the active layer of an abrasive tool containing tin, cobalt, titanium hydride, characterized in that it additionally contains lanthanum hexaboride, the component ratio (in% by weight) being as follows: Tin 13 to 17% Cobalt 2 to 9.9% Titanium hydride 7 to 10% Lanthanum ester 0.01 to 0.09%   Copper making the complement to 100.