DE2035226C - Use of a sintered metal alloy for wear-resistant, mechanically and corrosion-chemically highly stressed objects with low density - Google Patents

Description

0 until 0.08% Carbon, 0.2 until 1.8% Copper, 0.2 until 1.2% Niobium / tantalum and / or titanium, 0.5 until 29% Molybdenum, 0.005 until 0.1% Boron, 0 until 23% Chrome, 0 until 1.7% Aluminum, 0 until 1.9% Manganese, 0 until 6.8% Tungsten, 0 until 68% Iron, 10 until 66% nickel

As a material for objects which, like bearing materials used at high temperatures and grinding balls, must have high hardness, compressive strength and toughness, high wear resistance, good oxidation and corrosion resistance and low density.
2. Use of a sintered metal alloy according to J consisting of 70 percent by weight ffiwbW with less than 0.01% free carbon and 30 percent by weight of an austenitic alloy with

16.8% chromium,

Molybdenum,
Tungsten,
Copper,
Niobium,

16.8%
4.7%
0.8%

0.3% niobium,

less than 0.03% carbon,
0.02% boron,
Remainder nickel

for the purpose of claim i.

Use of a sintered melal alloy according to claim 1, consisting of; 70Gewichtsprozent titanium carbide with less than 0.01% free carbon and 30 weight percent of an austenitic ^Leg: Irung mil

less than 0.03% carbon,
18.0% chromium,
12.0% nickel,
1.0% molybdenum.
0.8% copper,
0.3% titanium,
0.01% boron,
Remainder iron

for the purpose of claim 1.

The invention relates to the use of a single metal alloy as a material for objects, the liohe hardness, compressive strength and toughness, great Wear resistance, good oxidation and corrosion resistance, must have low density.

The object of the present invention is to find an alloy which has in addition a large Verschleißfyiderstand a high degree of toughness, good oxy- (dütions- and corrosion resistance and low Fichte Further demands are high compressive strength and had. Such demands are Z, B. to bearing materials that are used at high temperatures, or on materials for grinding balls, "·.

Ceramic materials made from oxides, e.g. B. aluminum oxide, silicon oxide, metal carbides, /. B. tungsten-tantalum, niobium, titanium or molybdenum carbide, or borides, nitrides and suicides meet / was part of the above-mentioned requirements, but are too brittle, splinter easily, and their compressive strength and wear resistance are insufficient. Pure carbides are also too brittle, and in most cases their density is too high. Hard metals, consisting of metal carbides with metallic binders, have in de; Usually too high a density and insufficient corrosion resistance. Borides, nitrides and suicides as fincelial components are brittle like glass and therefore also unsuitable for the purpose of the present invention. Conclusions Metallcgi reach (dog too low Druckfe.tigkeit and Hard not the desired properties.

from 25 to 75% titanium carbide and 15 to 75% of an austeii'tischen or by conversion and / or Precipitation of intermetallic phases of hardenable steel containing 1.2 to 15% manganese, the high

ήο has wear resistance, in particular friction and erosion wear-resistant wedge, with high hardness, does not meet all of the requirements mentioned above, above all it has insufficient resistance to oxidation and corrosion and does not have a sufficiently low density.

To solve the problem on which the invention is based, when using a sintered metal alloy, consisting of 55 to 80 percent by weight of one or more carbides of titanium, chromium, vanadium, as single or mixed carbides

and 20 to 45 percent by weight of an austenitic metal alloy with

up to 0.08% carbon,

0.2 until 1.8% Copper, Titanium, 0.2 until 1.2% Niobium / tantalum and / or ' 0.5 until 29% Molybdenum, 0.005 until 0.1% Boron, U until 23% Chrome, 0 until 1.7% Aluminum, 0 until 1.9% Manganese, 0 until 6.8% Tungsten, 0 until 68% Iron, 10 until 66% nickel

$ 6 suggested for the aforementioned purpose. The above area becomes the use an alloy of the following composition is preferred! ^ sintered carbide hard alloy, consisting of: 70 weight percent titanium carbide with less

Also the United States patent specification 3,450,511

035 2 * 26

as 0.01% free carbon and 30% by weight of an austenitic alloy

16.8% chromium,

16.8% molybdiine,

4.7% tungsten,

0.8% copper,

0.3% niobium,

less than 0.03% carbon,

0.02% boron,

Remainder nickel.

IO

Another preferred alloy to be used consists of 70 percent by weight of titanium carbide less than 0.01% free carbon and 30% by weight an austenitic alloy with

less than 0.03% carbon,
18.0% chromium,
12.0% nickel,

Molybdenum,

Copper,

Titanium,

1.0%
0.8%
0.3%
0.01% boron,
Remainder iron.

20th

The density of the aforementioned preferred alloy is 5.80 g / cm ³ , the hardness 70 to 72 HR _£ , the compressive strength 300 to 350 kp / mm ² , and the corrosion resistance, especially under reducing conditions, that is to halides, to acidic chloride solutions and Salic acid was present. The toughness of the sintered metal alloy to be used according to the invention was tested on sintered balls which were thrown or hurled onto a concrete slab from a height of 10 m. It was found that the balls, without showing the slightest tendency to splinter, jumped back to the starting height.

The sintered metal alloy to be used according to the invention is produced in a manner known per se by mixing the alloy components ground to a maximum of 6 μm, i.e. the carbide components and the individual elements or master alloys of the binding metal alloy, wet grinding, for example in attritors, to a particle size of at most 3 μm with a large Finest grain fraction and subsequent drying and expulsion of the grinding liquid in a vacuum dryer. After kneading the mixture again with the addition of additives that facilitate the pressing, which are also sufficient to granulate the finest powder for better flowability, the granulate is pressed into shaped bodies on mechanical or isostatic presses, which are then vacuum- Sintering furnace under a pressure of less than) 0 ~ ² Torr at a temperature of about 1250 to 135O ° C for a time sufficient for heating, holding and cooling vr.i about 8 to 48 hours with alloy and mixed crystal formation.

Due to the aforementioned good properties of the sintered metal alloy of the above composition, it is suitable, for example, as a material for grinding balls that are used in a neutral, oxidizing or corrosive atmosphere, also under the influence of heat up to about 800 ^° C., and also as a material for parts that are used at high temperature, e.g. B. ball bearings, roller bearings, thrust bearings, slide rails, gas bearings, Due to the austeni'isi-hen structure of the binding metal alloy, it can also be used for parts that do not have to be magnetizable, e.g. B. for punches or dies of presses that are used in a magnetic field.

Claims (1)

Claims; 1, using a sintered alloy, consisting of from 55 to 80 percent by weight of one or several of the carbides of titanium, chromium, vanadium as single or mixed carbides and 45 bis 20 percent by weight of an austenitic metal alloy with