DE1558477B1 - Highly wear-resistant, machinable and hardenable sintered steel alloy - Google Patents

Description

1 2

The invention relates to a highly wear-resistant, perforated sheet metal. The alloy according to the invention is in

solution annealed condition machinable and through 'solution annealed condition machinable, for which the

Tempering precipitation-hardenable sintered steel alloy not too high a carbide content as well as the

according to patent 1,257,440.! Character of the steel matrix are responsible. To the

Hardenable sintered steel alloys, which are made from another 5, the said alloy according to the Pa-

Carbide and steel components combined and Tent 1257 440 precipitation hardenable by tempering,

into bodies using powder metallurgy, which is particularly due to the fact that they are completely free from warpage

are already known. The carbide has an extremely beneficial effect on hardening. There-

component, which has amounts of 25 to 75% of the weight with this sintered steel alloy with carbide component

velvet alloy may be present, the steel io ponente will have properties that were not previously known

base material to increase the wear resistance alloy of the same type combined,

admitted. It also has another favorable

There are basically two manufacturing processes permanent property, namely a high heat resistance, Such sintered steel alloys with contents of hard - what they for tools, tool parts and machine materials, like carbides ,. Bonds or nitrides, common. 15 elements that are subject to heavy wear and tear at the same time Once the alloy can be exposed to the high temperature by mixing, e.g. B. Tools powdery starting components, pressing and for pressing plastics, matrices and Sintering, or you first produce punches for the hot forming of steel, light, a hard material, in particular carbide skeleton and impregnates heavy and non-ferrous metals with advantage this skeleton with the desired steel base mass. 20 makes.

The subject of patent 1 257 440 is a new object of the present invention is now that Alloy of the sintered steel alloy type with sintered steel alloy according to patent 1257440 embedded carbide, which makes it highly wear-resistant, in still corrosion-resistant. This will be glowing with redemption Condition can be worked on and also in accordance with the method by replacing up to 60Vo des is cash. The new sintered steel alloy meets 25 nickel content achieved through chromium. Corresponding In particular, the important requirement that the percentage mentioned from it should be chromium in the quantity Objects in the finishing work from 7 to 16% of the total weight of the invention following hardening do not suffer any delay. appropriate alloy can be added.

Sintered steel alloys with a carbide content, in which the sintered steel alloy according to the invention can

the steel matrix can be hardened by conversion, even small amounts of nitrogen up to

due to the 0.04% occurring during the conversion, boron up to 0.01% and zirconium up to 0.05%

Changes in volume often cause cracks in the microstructure to be added. The addition of these elements

which during the stress, in particular due to chromium-nitrogen, ferroboron or co-

Impact, starting point for fatigue fractures in the bait, boron or zirconium metal.

Represent the parts used in the operation. 35 Below is an example of manufacture

It is true that objects have already been separated from an alloy with
hardenable sintered steel alloys with embedded

Hard material components (carbides, nitrides, borides) - 33.0% titanium carbide,

knows, which as a result of their different behavior -γχ ^ y ₀ chromium

not so susceptible to 4 ° distortion during the hardening process. '

are like the alloys hardenable by transformation 7.5% nickel,

However, the previously known, 5.5% cobalt,

by precipitation hardenable hard alloys / ion / λ / γ 1 ua-

with a steel matrix due to its high proportion of hard material ⁴ ' ^{3 h} molybdenum,

not editable. 45 0.85% titanium,

To solve the problem mentioned, 0 l ^fl / aluminum

Patent 1,257,440 proposed a sintered alloy, ''

those of 0.02o / o nitrogen,

0.01% zirconium, ⁵⁰ 0.003% boron,

Remainder iron

given.

55 A mixture of the individual alloy components of the steel alloy with the titanium carbide was ground to a grain size of on average 3 to 5 μΐη, pressed into molded parts and between

1340 and 1380 ⁰ C, preferably 136O ⁰ C in Va- ^ mi _Sf u _S uwi _C UUVC1U1WUU.UO _{6o kuum of Μείη6Γ sintered as 10} _ ₂ J _{111n H. the}

yerunremigungenan phosphorus, _{sintered] inge were then incubated at} 820 to 86o ⁰ C a b ht ^ cüwetel and Müzmm solution treatment with a 4-hour hold time, and ^e "followed by air cooling, subjected. DiegenannteLegierungistzurpulvermetallurgischen The hardness then was 45 H _RC. In this state, in the manufacturing, ie Mixing, pressing and sintering of the intermetallic phases formed in the powder-form starting materials, from tools and stalls, could determine the parts by machining-machine parts that are not processed at all during hardening, as a result of which they suffer their final shape, e.g. Dies for punching held.

27 to 35% Titanium carbide with less than 0.1% of free carbon, 12 to 26% Nickel, 5 to 11% Cobalt, 3 to 7% Molybdenum, 0.15 to 2.4% Titanium, 0.05 to 0.6% Aluminum, 0.03% Carbon, Remainder iron as well as unavoidable

The hardening of the finished parts took place, depending on the hardness required for the intended use, by tempering at 480 ° C. for a holding time of 6 hours at this temperature and subsequent air cooling. The alloy then had a hardness of 62 to 65 H _RC .

Both the solution heat treatment and the hardening by tempering should be carried out in completely neutral media or inert atmospheres to avoid any absorption of undesirable substances, ζ. B. Coal ίο substance and oxygen.

After the moldings had hardened by tempering, there was no distortion whatsoever, leading to dimensional inaccuracy which could give rise to parts or stress cracks. The parts possessed besides the high hardness and heat resistance also have good corrosion resistance, making them more wear-resistant Makes tools and parts that are exposed to a corrosive atmosphere suitable.

20th

Claims (3)

Patent claims: 1. Highly wear-resistant, machinable in the solution-annealed condition and precipitation hardenable by tempering Sintered steel alloy, consisting of 27 to 35 ° / o titanium carbide with less than
0.1% of free carbon,
12 to 26% nickel,
5 to 11% cobalt,
3 to 7% molybdenum,
0.15 to 2.4% titanium,
0.05 to 0.6% aluminum,
0.03% carbon, Remainder iron as well as unavoidable impurities like phosphorus, sulfur and silicon, according to patent 1257440, characterized in that up to 60% of the nickel content is replaced by chrome. 2. Alloy according to claim 1, characterized in that it 0 to 0.04% nitrogen, 0 to 0.05% zirconium and 0 to 0.01% boron contains. 3. Use of an alloy according to one of claims 1 and 2 for tools, tool parts and machine elements that, in addition to strong wear and tear and high temperature, also withstand corrosion attacks.