SE459504B - SINTRAD BORID BASED HAIR ALLOY - Google Patents

Description

459 504 z improved by regulating the levels of Al, Si and 0.

It is a principal object of the present invention to provide a sintered hard alloy that has very good mechanical strength firmness and toughness as well as stability and maintains it a lot good corrosion resistance, oxidation resistance and wear which characterizes the above-mentioned conventional sintered the hard alloys.

According to the present invention, there is provided in particular one sintered hard alloy with very good mechanical strength and toughness, which comprises 40-95% by weight of a hard phase combined set of multiple borides containing at least 10% by weight Fe and a binder phase for bonding this hard phase, each at the content of B is 3-8%, the content of Cr is up to 35% by weight cents, the Ni content is up to 35% by weight, the Al content is up to 2.85% by weight, the Si content is 0.03 - 4.75% by weight, The C content is up to 0.95% by weight, the O content is up to 2.3% by weight, the content of Mo and / or W is such that the atomic the ratio (Mo and / or W) / B is in the range from 0.75 to 1.25 and the rest consists of Fe and unavoidable nings.

The present invention is described in detail below.

All percentages given below refer to weight.

The sintered hard alloy (often referred to as "sintered alloy" hereinafter) according to the present invention contains constituent elements in the above-mentioned concentrations and atomic the holding state (Mo and / or W) / B is kept in the range from 0.75 to 1.25. Due to these structural properties, the centrifugal the alloy according to the invention so high cross-breaking limit as 175-300 kp / mmz stable at Rockewell_A shell hardness (HRA) is in the range of 80-93. The reason for the cross- the limit is high and its deviation is reduced by the atomic ratio (Mo and / or W) / B adjusted to approx. 1 has not been fully clarified.

As the result of the detailed investigation showed it the Fe-containing multiple boride that forms the hard phase comprises a Mo2FeB2 or WFeB type boride or a mixture and smaller amounts of such borides as MB, M2B and MXNYB. It was also confirmed that if the W ~ content is high it is present a double boride of the type W2FeB2.

In the multiple boride of the type Mo2FeB2, WFeB or W2FeB2 it turns out that Mo and W are partially exchanged for each other and Fe is partially substituted with such elements as Cr, Ni and Co. The aforementioned three multiple borides, including including those in which Mo and W are partially substituted each other and Fe is partially substituted with Cr, Ni and Co, are mentioned in the following multiple borides of Mo2FeB2, WFeB and W2FeB2 ~ typ.

For the production of a hard phase composed mainly of these multiple borides of the types Mo2FeB2, WFeB or W FeB 2 2 it is necessary that at least 10% Fe is included in the hard phase.

In the sintered alloy of the present invention, Fe and the Fe-containing multiple boride were reversed for the following reasons.

A sintered body of a boride containing Fe has enough high hardness and toughness and if an appropriate amount of Cr or Ni very good corrosion resistance, heat resistance durability and oxidation resistance comparable to these properties of stainless steel. Furthermore, a powder of one boride of Fe is easily produced on an industrial scale and the Fe source is easily accessible and Fe is cheap.

The hardness of the sintered alloy according to the invention depends on the amount of the multiple boride forming the hard phase, the amount of the binder phase and the hardness of the binder phase.

The Rockwell A shell hardness of the sintered alloy according to the finding is in the range from 80-93. To obtain 1 a Rockwell A shell hardness of at least 80, it is necessary to: the amount of the hard phase should be at least 40%. About the amount of the hard phase exceeds 95%, the Rockwell A shell hardness is 93 or higher but the transverse breaking limit is lower than l75 kp / mmz. Multi- that of the hard phase is therefore adjusted to 40-95%. 459 504 The content of B, which is the hard phase-forming element, should be 3% to give the minimum hard phase content of 40%, and the content of B 8% is necessary to give the maximum hard phase content of 95%. The content of B is therefore adjusted to 3-8%.

* Mo and W are elements that form the hard phase multiple boride '30O kp / mmz in the sintered alloy according to preface together with B, and if these elements are included in such quantities that the atomic ratio (Mo and / or W) / B is within the range from 0.75 to 1.25, a cross-breaking limit as high as 175- rising finning while the Rockwell A shell hardness is within range from 80-93. About the atomic ratio (Mo and / or W) / B adjusted to the range from 0.90 to 1.20, a higher cross-section breaking limit is reached. The content of Mo and / or W is therefore adjusted so that the atomic ratio (Mo and / or W) / B is within the range range from 0.75 to 1.25, preferably from 0.90 to 1.20.

Cr improves corrosion resistance, heat resistance and the oxidation resistance of the sintered alloy according to the invention and when Cr is used in combination with Ni exercise Cr action to make the sintered alloy of the invention non-magnetic by austenitization of the binder phase.

When the sintered alloy of the invention is used within the area where high mechanical strength and abrasion resistance heat is required but corrosion resistance is not required, Cr does not need to be added separately. In many cases required however, high corrosion resistance as well as those listed above properties, and it is therefore preferred that the content of Cr is at least 0.5%. If the Cr content exceeds 35%, the corrosion resistance, heat resistance and oxidation resistance durability but the mechanical strength is lowered and the breaking point is lower than 175 kp / mmz. The chromium content is adjusted accordingly for up to 35%, preferably 0.5-35%.

You are an element that is effective in improving the corrosion resistance and oxidation resistance, as well as Cr, and You are required to transform the structure of the binder phase s 459 504 to an austenitic non-magnetic material. If you are included in a content of up to 35% these purposes can be achieved.

Co is an element that can essentially replace Fe in borid of Mo2FeB2-, WFeB- or W2 and if the binder phase is a ferritic phase, Co has such as FeB2 ~ type that forms the hard phase, effect of increasing the red hardness of the binder phase. About Co- the content exceeds 35%, however, the cross-breaking limit is lowered below 175 kp / mmz. The upper limit for the Co content is therefore set to 35%.

Cu is an element that is added to improve thermal conductivity. and the corrosion resistance of the sintered the alloy of the invention. However, if the Cu content exceeds rises 35%, the hardness and the breaking strength limit are lowered. Cu content is therefore regulated up to 35%.

Ti, Zr and Hf belong to group Iva of the periodic table and V, Nb and Ta belong to group Va of the periodic table and replaces Mo or W in the multiple boride of type Mo2FeB2, WFeB or W2FeB2, and some of this metal is consumed for alloy in the binder phase. These metals belong to the group IVa and Va have the effect of improving the hardness of it sintered alloy according to the invention and prevent crystal grains at the liquid phase sintering. Although these metals are generally expensive, high effects can be achieved through incorporation of small amounts of these metals. About these metals of group Iva or Va are included in a total amount of up to 15% given the cost of these metals, both and the cross-breaking limit are maintained at satisfactory levels. The total content of these elements is therefore adjusted to up to 15%.

C is an element that is effective in reducing the oxides and increase the hardness of the binder phase and through these effects the total hardness of the sintered alloy is increased according to the invention. However, if the content of C exceeds 0.95%, the hardness is not further improved but the cross-breaking limit is lowered. 459 504 6 .L The C content is therefore regulated to up to 0.95%.

Al is derived from the starting powder and tends to react with B and O to form aluminum boride and alumina.

Alumina has an unfavorable effect by deteriorating the sintering properties of the sintered alloy according to the invention. It is therefore appropriate that the Al content is so low as possible. However, if the Al content is lower than 1% the adverse effect of Al is substantially neglected and in the sintered alloy according to the invention is at Al content up to 2.85%, if the incorporation of O is regulated in the largest to the extent possible, the adverse effect of Al significantly row. The Al content is therefore regulated to up to 2.85%.

O reacts with B, Cr, Al and Si to form oxides which impairs the sintering ability or sintering properties and lowers the cross-breaking limit and increases the deviation of this. It is therefore appropriate that the O content is as low as possible. However, if the 0 content is up to 2.3%, impact may occur of 0 is substantially neglected. The O content is therefore regulated up to 2.3%.

Si is an element derived mainly from the starting the powder. Si has the effect of improving the sintering the mass or sintering properties of the sintered alloy according to the invention and increases the density and thus improves the mechanical properties of the sintered alloy according to the invention. However, if the Si content is lower than 0.03% is the effects are not significant, and if the Si content exceeds 4.75%, the sintered alloy according to the invention becomes brittle.

The Si content is therefore adjusted to 0.03 to 4.75%.

As set forth in the aforementioned Japanese Patent Publication a Fe-B powder or an Fe-B type alloy was used, obtained by water or gas atomization, such as drilling source, or in some cases a powder of ferrobor, a powder was used of a boride of Ni, Cr, W, Ti or Mo or a powder of a single substance of B as a boron source. Such a drilling source mixes powdered with individual substances of Mo, W, Ti, V, Fe, Cr, Ni, Co and Cu or alloys containing two or more of these metals, and, if necessary, carbon powder is added or carbide. The resulting mixed powder is subjected to wet pulverization in an organic solvent in a vibrating ball mill and then subjected to drying, granulation and pressing. Then it is subjected to the green or unsintered the compact liquid phase sintering in a non-oxidizing atmosphere.

The sintered alloy according to the invention is thus prepared In this way. By using the liquid phase sintering method the density can be increased to substantially 100% in the sintered alloy. the ring according to the invention. To prevent oxidation at the sintering step, it is important that the sintering is carried out carried out in a non-oxidizing atmosphere, such as vacuum, or reducing gas or an inert gas. Usually, liquid phase sintering at 110 DEG to 140 DEG C. for 5-90 minutes. If the sintering temperature is lower than 100 ° C, no additional sufficient amount of the liquid phase and the sintering does not proceed to a sufficient degree which results in the formation of a sintered body which is full of cavities. If the sintering temperature is higher than 140,000, the liquid phase sintering becomes sufficiently advanced, however coarsening of crystal grains is achieved and the transverse breaking limit lowered. If the sintering time is shorter than 5 minutes, it is not increased density to a desired satisfactory level, and also if the sintering time is longer than 90 minutes can not be achieved any improvement in strength corresponding to elongation of the sintering time, and in some cases a reduction of durability. A sintering time exceeding 90 minutes is therefore not required.

The liquid phase sintering method which is effective in reducing the formation of cavities to as low a level as possible in it the sintered alloy of the invention has been described. The however, it must be noted that the same effect can on similar is achieved by other sintering methods, for example static hot pressing, hot pressing and electric sintering.

The present invention is described in detail below 459 504 8 with reference to the following examples which are not intended to: limit the scope of the invention.

The composition of materials used in the following examples and comparative examples are those given in Tables 1, 2 and 3 in the following.

Example 1 A mixture of 20.2% ferroboron powder A, 69.2% ferrous tungsten powder powder, 2.1% Cr powder, 1.1% Ni powder, 7.1% carbonyl-Fe powder and 0.3% C powder were wet powdered in a vibrating ball mill with steel grinding cup (vibration ball mills with steel grinder beaker was used in the following examples) 28 hours, and the the powdered mixture was dried, granulated, pressed and sintered in vacuo at 1300 ° C.

Example 2 A mixture of 9.3% ferroboron powder B, 22.2% ferrous tungsten powder, 27.4% W powder, 1.1% Cr powder, 2.0% Ni powder, 25.0% WB powder, 12.7% carbonyl-Fe powder and 0.3% C- powder was wet powdered in a vibrating ball mill for 28 hours, and the powdered mixture was dried, granulated, was pressed and sintered in vacuo at 127503.

Example 3 A mixture of 31.1% B-containing alloy powder A, 35.5% Mo powder, 2.1% Ni powder, 31.0% carbonyl-Fe powder and 0.3% C powder was wet powdered in a vibrating ball mill 28 hours and the powdered mixture was dried, granulated was pressed, pressed and sintered in vacuo at 225 ° C.

Example 4 A mixture of 44.6% B-containing alloy powder C, 51.2% Mo powder, 1.1% Ni powder, 2.8% carbonyl-Fe powder and 0.3% C-powder was wet powdered in a vibrating ball mill for 28 hours. and the powdered mixture was dried, granulated, pressed and sintered in vacuo at 225 ° C. 9 459 04 Example 5 A mixture of 27.0% ferroboron powder A, 39.1% Mo powder, 3.1% Cr powder, 1.1% Ni powder, 29.1% MoB powder, 0.3% carbonyl-Fe powder and 0.3% C-powder were wet powdered in a vibration ball mill 28 hours and the powdered mixture dried, granulated, pressed and sintered in vacuo at 1275 ° C.

Example 6 A mixture of 28.1% B-containing alloy powder C, 38.0% ferrous tungsten powder, 16.7% Mo powder, 0.5% Cr powder, 0.5% Ni powder, 16.0% MoB powder and 0.2% C powder wet powdered was placed in a vibratory ball mill for 28 hours and pulverized the mixture was dried, granulated, pressed and sintered in vacuo at 127 ° C.

Exemgel 7 '_ A mixture of 32.3% B-containing alloy powder-C, 28.0% Mo- powder, 0.6% Cr powder, 2.1% Ni powder, 36.7% carbonyl Fe powder and 0.3% C powder were wet powdered in a vibrating ball mill for 28 hours and the powdered mixture was dried, granulated, pressed and sintered in vacuo at 220 ° C.

Exemgel 8 A mixture of 44.6% B-containing alloy powder C, 47.1% Mo powder, 2.1% Ni powder, 5.9% carbonyl-Fe powder and 0.3% C-powder was wet powdered in a vibrating ball mill for 28 hours and the powdered mixture was dried, granulated, was pressed and sintered in vacuo at 225 ° C.

Example 9 A mixture of 32.3% B-containing alloy powder C, 44.8% Mo powder, 0.6% Cr powder, 2.1% Ni powder, 19.9% carbonyl Fe powder and 0.3% C powder were wet powdered in a vibrating medium. ball mill for 28 hours and the powdered mixture is dried. were granulated, pressed and sintered in vacuo at 225 ° C. 459 504 10 Example 10 A mixture of 27.6% ferroboron powder A, 50.6% Mo powder, 2; 3% Cr powder, 2.0% Ni powder, 15.0% MoB powder, 2.2% carbonyl-Fe powder and 0.3% C-powder were wet powdered in a vibratory ball mill for 28 hours and the powdered mixture The mixture was dried, granulated, pressed and sintered vacuum via 127 ° C.

Exemgël ll A mixture of 32.0% B-containing alloy powder A, 39.0% Mo powder, 6.5% Cr powder, 2.0% Ni ~ powder, 20.2% carbonyl Fe powder and 0.3% C powder were wet powdered in a vibrating medium. ball mill for 28 hours and the powdered mixture is dried. were granulated, pressed and sintered in vacuo at 127,500.

Example l2 A mixture of 43.4% B-containing alloy powder B, 34.3% Mo- powder, 21.0% Cr powder, 1.0% Ni powder and 0.3% C powder wet pulverized in a vibrating ball mill for 28 hours and the the powdered mixture was dried, granulated, pressed and sintered in vacuo at 127,500.

Example 13 A mixture of 30.3% ferroboron powder A, 41.9% Mo powder, 2.1% Cr powder, 25.4% Ni powder and 0.3% fC powder wet powder in a vibrating ball mill for 28 hours and the powdered The mixture was dried, granulated, pressed and concentrated. in vacuo at 1200 ° C.

Example 14 A mixture of 40.7% B-containing alloy powder C, 9.5 9 ferrotitanium powder, 46.6% Mo powder, 1.1% Ni powder, 1.8% carbonyl-Fe powder and 0.3% C-powder were wet powdered in a vibration ball mill 28 hours and the powdered mixture dried, granulated, pressed and sintered in vacuo at 13 ° C. 11> 459 504 Example 15 A mixture of 42.0% B-containing alloy powder C, 7.3% ferrovanadine powder, 50.4% Mo powder and 0.3% C powder wet powdered in a vibrating ball mill for 28 hours and the powdered mixture was dried, granulated, pressed and sintered in vacuo at 225 ° C.

Example 16 A mixture of 25.0% B-containing alloy powder C, 28.5% Mo powder, 1.1 Ni powder, 19.0% Co powder, 25.3% MOB powder powder, 0.8% carbonyl-Fe powder and 0.3% C-powder wet powder was placed in a vibrating ball mill for 28 hours and the pulverized the mixture was dried, granulated, pressed and sintered 1 vacuum via 12zs ° c.

Example 17 A mixture of 25.0% B-containing alloy powder C, 28.5% Mo powder, 0.9% Cr powder, 1.0% Ni powder, 19.0% Cu powder, 25.3% MoB powder and 0.3% C powder were wet powdered in one vibration ball mill 28 hours and the powdered mixture dried, granulated, pressed and sintered in vacuo at 12 ° C.

Comparative Example l A mixture of 35.0% ferroboron powder A, 30.0% Mo powder, 3.0% Cr powder, 3.0% Ni powder, 28.7 U carbonyl-Fe powder and Q, 3% C ~ powder was wet powdered in a vibratan ball mill 28 hours and the powdered mixture was dried, granulated clay, pressed and sintered in vacuo at 120096.

Comparative Example 2 A mixture of 42.0% B-containing alloy powder B, 54.7% Mo powder, 3.0% Ni powder and 0.3% C powder wet powder was placed in a vibrating ball mill 28 rhymes and the pulverized the mixture was dried, granulated, pressed and sintered 1 vacuum at 1215 ° C. 459 504 12 Comparative Example 3 A mixture of 43.0% B-containing alloy powder D, 16.0% B-containing alloy powder E, 25.0% Mo powder, 14.6% Cr- powder, 1.0% Ni powder and 0.4% C powder were wet powdered in a vibrating ball mill for 28 hours and the powdered mixture The mixture was dried, granulated, pressed and sintered vacuum at 225 ° C.

Chemical analysis values, (Mo and / or W) / B atomic ratios, the amounts-of the hard phases and the Rockwell A-shell hardness as well as the cross-fracture limit values for the sintered alloys which was obtained according to Example 1-17 and Comparative Example 1-3 is shown in Table 3.

Examples 1-5 show the relationship between the B content and the amount of the hard phase, the Rockwell A shell hardness and the transverse breaking limit.

Examples 6-10 show the relationships between (Mo and / or W) / B atomic the ratio and amount of the hard phase, Rockwell A scale the hardness and the breaking point.

Examples II-17 show the amount of the hard phase, Rockwell A- the shell hardness and the breaking strength when Cr, Ni, Ti are included as metal belonging to group IVa, V as metal belonging to group Va, Co resp. Cu ingick.

Example 13 is an embodiment with a non-magnetic sintered alloy.

In Comparative Examples 1 and 3, (Mo and / or W) / B atomic kept too low and was outside the area specified certified according to the invention.

In Comparative Example 2, the (Mo and / or W) / B atomic ratio was too high and low outside the range specified in the invention. 13 459 5Ü4 The results shown in Table 4 show that they sintered the alloys according to the invention have very good properties compared to sintered alloys according to the comparative examples as regards the cross-breaking limit. 14 459 5-04 mcHuwwHEoumcwvum> H Hamßwä Eocmm »HHmumEmum Hm> Hsmwm: fl uwmw fl um fl uamcnm> m .u: muoumuM fl> v mc fl cuummcmëemm wcm fi mp @@. o w ~ .o m @ .o -.o Hm.o 1 m.NH o. @ N _ _ mcm fi c fi ..mN.o @ m.o @ m.H cw.ø. @ ~ .o 1 o.HH w. @ A Q W _ mcæ fifl n wm.ø om.o @@. c vo.o _ msm fifl ß mo.o @ m.o «H.q Nv.o o fi. o @. @ @. ~ fi ~. @ 2 U M mcm fifl ß dm.0 fl N.o mw.a wo.o @ ~ .o 1 m.mñ m.m fl < mm 0 o fi w fi <: z 2 Lo Q _ ucmëu fl m> oum 1 459 504 15 Ho.o mo.o 1 1 1 1 1 1 wcß fi øß 1 mo.o m.m Q: mo.o mo.o 1 1 1 1 1 1 1 wcø fi an mo.o o.oH mo: @ o.ø 1 vo.o mo.o @ o.o 1 1 @. ~> 1 1 fi cm fi ßn 1 cmu fl uounwm @ o.o 1> H.H o ~ .H 1 1 H @. ~ @ 1 1 1 wcæ fi qn 1: fl ww: m> oHH @ m -.o 1 no.o 1 ~ o.o 1 1 1 v <.ß> m>. «wcm fi mn smuwHo> ou» wm Hv.o m «.o mm.o wo.o HN.o oo.o 1 1 1 1 wcm fi øn N.w ~ m Honouuwm @ w.o om.o> m.o @ o.o wH.o Ho.o 1 1 1 1 wc flfifi ß @ .mH 4 Honouuwm U o im wa 12131. .Vw>.! ._ .., ._ å 2 m MMMHMMW> Oum mc fi cmußw Hm fifl w mc fl uwmw fl> m ^ ucmo0umuxH> V mc fl cuuwwcm fiämm N H fi wnmñ 459 504 16 Table 3 Degrees of purity (weight percent) of metal powder and carbon black Powder Purity Carbonyl-Fe 99.98 Mo 99.9 Cr 99.8 Ni 99.8 Co '99.9 W 99.9 Cu 99.9 C 99.9 17 wcm fi mn «o.H -.o ~> .o @ H.o 1 1 o.H w.o ~ 1 1 1 w.w ~ H.æ 1m1m W mcq fi mn @ o.o HH.o mv.o @ H.c 1 1 @. ~ w.H 1 1 1 o. ~ m> .m N W W wcw fl mn @ o.ø ~ H.o @ H.o ~ o.o 1 1 m. ~ m. ~ 1 1 1 m.æ ~ m.m H fi q wcm fi mn @ o.o @ o.o N ~ .o Ho.o H.w ~ 1 o.H o.N 1 1 1 æ.w <m.m ßñ wcm fifl n @ o.o> o.o m ~ .o ~ ø.o 1 H. @ H o.H m.o 1 1 1 o.Hw>. @ md mca fl mn <@. o <fi. o> «. o o ~ .o 1 1 1 @ .H @ .m 1 1 o.w <H.m m fl mcm fl øn NH.o ~ fi. o @ m.o ~ o.o 1 1 o.H m. ~ 1 m.w 1 «.« <o.m w fi wcm fi mp «o.o wH.o wN.o ~ o.o 1 1 H.w ~ o. ~ 1 1 1 @. @ m m.« mä wcm fi ßn> @. o ~ H.o @ w.o @ ~ .o 1 1 o. ~ m.vN 1 1 N. <@. «m o. <NH mcm fl mß m @ .o o fi. o m ~ .o Ho.o 1 1 @ .H m.oH 1 1 1 H.> m ~ .w H fi a mcm fi mn mo.o mo.o ßH.o ~ o.o 1 1 @ .H ~ .N 1 1 1 o.H @ m.m OH W wcm flfl n ~ o.o oH.o @ ~ .o ~ o.o 1 1 o. ~ ø.N 1 1 1 @ .m <o.q_ Q m mcm fi mn w0.o fi H.o m «.o No.o 1 1 o.N o. ~ 1 1 1 m.w« m.m um I mcß fi mn «o.o ßo.o @ ~ .o Hø.o .1 1 o.N H. ~ 1 1 1 @. @ m @.« _ ß, wcm fi mn mo.o mo.o æm.o H0.0 1 1 w.O ß.H 1 1 m æw w.mm o.m_ o mcw fl wn mo.o mo. @ @ H.o Nø.o 1 1 o.H o.m 1 1 1 H.w @ ß. @ @ wca fi mß wo.o mH.o m ~ .o Ho.o 1 1 o.H o. ~ 1 1 1 w.ww m.m W wcø fi ßn m @ .o wH.o <~ .o Ho.o 1 1 o. ~ o. «1 1 1 m.mm: .w m mcm fl mn @ o.o mo.o æo.o Ho.o 1 1 @. ~ o.H 1 1 o.m @ 1 o. «W wcmñmß @ Q.o mH.o mH.o fi o.o 1 1 o.H o. ~ 1 1 o.Hm 1 o.m H um o U fi w fl <: O oo fi z Lo> Ha 2 os m .Hz _ Avcmuoumux fl> v Cwvumbwm fl mcm mxm fl ëmz .cw fl mëmxmmm fl wnmmëmf: oo cw fi n fi unu umw fl cw cwwuw> mcwumuuounHm> u uåmw uwnwnmz fl mxm 14 Hawšxuom: oo uwmmw mmums> m Hmwmcwë.: W @ cm fi HwLunwEoum1m \ ^ 3 uwHHm \: uo oz. w Hamnmà ~ cwmuw> mæ fi m: m mxm fl ëmm 18 459 5.04 Hwmåmxm w fi um> um flfifl m mwwm> OHm Hw> oHm O fl a «.Ec4 ww wow H.ww ww ww.m w X M _ www www w.ww ww ww.H_ w w. ww www w.ww ww ww.o w www www w.ww ww oo.H ww www www w.ww ww Ho.w ww www www> .ww ww wo.w ww www www w.ww ww oo.H vw www www w.ww ww oo.w ww www www w.ww ww ww.o .w fi www www w.ww Hw wo.wH w. m www www w.ow ww ww.w o fi m www www W o.ww ow ww.w_ w W www www w.ww ww ww.oM w www www o.ww ww ww.o w www www w.Hw ww oo.w w www www w.ww ww vo.w w www .www w.ow ww oo.w w www www w. «w ww oo.w w www wow w.ww ww ww.o w oww www o.ww ow oo.w H lwvum> m © uw> u fl wwwz .KMS ^ | »Xw> w | eo» w ^ NO \ mxw mmm m \ ^> f.o: «W = www» wa wwwz ww \; Uo wøuounuw> H n fl uwm Uwcwz oïv ^ .wwwoww w wwwnma

Claims (4)

”IQ J: - U1 \ () 01 C) .Its PATENTKRAV Sintered hard alloy with very good mechanical strength and toughness, characterized in that it comprises 40-95% by weight of a hard phase consisting of multiple bores containing at least 10% by weight of Fe and a binder phase for bonding this hard phase, wherein the B content is 3-8%, the Cr content is up to 35% by weight, the Ni content is up to 35% by weight, the Al content is up to 2.85% by weight, the Si content is 0.03 to 4% by weight. , 75% by weight, the C content is up to 0.95% by weight, the O content is up to 2.3% by weight, the content of Mo and / or W is such that the (Mo and / or W) / B atomic ratio is within the range from 0.75 to 1.25 and the rest consists of Fe and unavoidable impurities. Sintered hard alloy according to claim 1, characterized in that the content of Mo and / or W is such that the (Mo and / or W) / B atomic ratio is in the range from 0.90 to 1.20. Sintered hard alloy according to Claim 1 or 2, characterized in that the Cu or Co content is up to 35%. Sintered hard alloy according to one of Claims 1 to 3, characterized in that the total content of at least one of the elements Ti, V, Nb, Ta, Hf and Zr is up to 15% f. ... F-lan -...