DE1806224C3 - Use of an austenitic, solution-annealed, hardenable manganese-nickel-chromium steel as a material for hot work tools that are stressed up to 700 degrees C. - Google Patents

Description

The remainder is iron and the usual impurities as a material for hot work tools which, like extrusion tools which are stressed at high temperatures, must have high tensile strength, hardness and toughness ^{in the range from 20 to 700 ° C.}

2. Use of a steel according to claim 1, the boron content of which is 0.01%, for said Purpose.

0.40 until 0.60% Carbon, Max 0.5% Silicon, 8th until 12% Manganese, 3 until 6% Chrome, 6th until 9% Nickel, 1.0 until 1.5% Vanadium, 0.8 until 1.8% Molybdenum, 1.2 until 2.5% Tungsten, 0 until 0.3% Niobium, 0 until 0.02% Boron,

The invention relates to the use of an austenitic, solution-annealed, hardening manganese-nickel-chromium steel as a material for such hot work tools, such as extrusion tools stressed at high temperatures, in the range of Must have high tensile strength, hardness and toughness between 20 and 700 ° C.

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Extrusion dies consists in the fact that they are in the surface area of the high temperature of the extruded Strands are exposed and at this temperature a high hardness and thus great wear resistance must have, but on the other hand also more distant and therefore cooler ones from the surface Areas must have sufficient strength and toughness to ensure the transmission of the deformation forces.

So far, martensitic steels have generally been used as hot-work steels, in which a sufficiently high room temperature hardness can be achieved through hardening and tempering. However, the hardness of this type of steel shows a relatively rapid decrease at temperatures exceeding approximately 600 ° C. This temperature range over 600 ⁰ C for many hot working purposes such. B. Extrusion of copper, important; therefore, these martensitic steels for use as a material for hot work tools have insufficient hot hardness and thus poor wear resistance.

Austenitic steels are also used for applications that require high-temperature strength used. However, they have a low hardness at room temperature, which is due to it. Cold working increased must be, which is particularly unfavorable when used as a material for hot work tools. In addition, austenitic steels generally have a higher temperature at room temperature and higher

Remaining iron and the usual impurities, as a material for such hot work tools, which, like extrusion tools stressed at high temperatures, in the range of 20 to 700 ⁰ C high tensile

must have strength, hardness and toughness.

Steels, the compositions of which are those mentioned

Ranges of alloy ingredients are on known (see. DT-AS 10 32 296). From this

Document shows that these steels can be formed by solution annealing from 1000 to 1300 ° C to objects and then cured by annealing at temperatures between 300 and 900 ⁰ C and dsrüi one SircckTcnz? vnn minrWtpns 60 kg / mm ^s at room temperature.

A similar steel, which however does not contain tungsten and whose molybdenum and chromium contents are not critical, is known for use in particular for generator rings (cf. US Pat. No. 2,865,740). This known steel is hardenable and can have a high hardness of over 430 Vickers units at room temperature. However, the cited publications contain no information on the hardness, tensile strength and toughness of these alloys at higher temperatures up to 700 ° C., in particular also on the stability of the structure achieved during precipitation hardening when working in this temperature range. These known steels can therefore not suggest their use for such hot work tools that are ^{stressed up to 700 ° C.} The use of the manganese-nickel-chromium steel proposed according to the invention advantageously eliminates the disadvantages of the steels previously used for hot work tools, which have areas of insufficient hardness, strength or toughness either at room temperature or at working temperature or the temperatures in between. In the steel to be used according to the invention, the stable austenite structure is ensured by the addition of manganese and nickel. Aging tests at 700 ° C. and 2.5 hours are made with one made of 0.4% silicon, 4.5% chromium, 1.0% vanadium, 1.5% molybdenum, 1.5% tungsten and with a carbon content of 0.3 and 0.8% and varying amount of manganese and

Nod! existing ice knuckle have been carried out, and Table 2 shows the hardness values for the. In the case of the steel type containing 0.8% carbon at room temperature for these steel alloys, it was shown that this was even without the addition of various heat treatments. Table 3 gives manganese and nickel as well as with the addition of 2 or the hardness at temperatures from 20 to 700 ⁰ C and 4% manganese had strong magnetic properties, see Table 4 the strength properties for some of the resulting alloy, but with 4% Manganese examined steel alloys. Table S contains the and 1% nods! or 4% manganese and 2% nickel grain size for some of the steels examined,
still has weak magnetic properties, As can be seen from Table 1, steels 1 fall, while additions of 6% manganese and 2% nickel, 2 and 3 from the prescribed Aualysengreazen 6% Maagsn and 4% nickel, 8% manganese and 4 ° / j »faera-js, and in Cbefeiaaüounung with Tabeiie 2 result in nickel as well as iuy _o manganese and 6% nickel, all of which also result in a much lower hardness in non-magnetic steels. A 0.8% carbon temperature than the other steels and therefore does not meet the requirements that are made of material containing 3.9% siangan and 2.3% nickel.
Alloy gave a ferrite content (martensite content) when comparing steels 3, 4 and 5 in Table 2 of about 10%. _l3 one can clearly see the effect of the change in

For steel alloys containing 0.3% carbon, see the vanadium content and the very strong effect

it was found that with a content of 4% of this alloy component they solidify during hardening.

Manganese and 0.5% nickel, 4% manganese and 2% represent.

Nickel 6% manganese and 2% nickel strongly magnetic. The action of molybdenum and tungsten goes

was. The corresponding steel yield with 8% 20 from a comparison ia in Table 2 between the

Manganese and 2% nickel were magnetic and steels 1, 4 and 2, 6 showed up and here you can see that

8/0 manganese and 4% nickel are weakly magnetic, these components also have a very beneficial effect

while having an addition of 10% manganese and 6% nickel on hardening.

resulted in a non-magnetic Suhl. A 0.3% carbon The effect of the niobium additive on hardening

as containing 7.3% manganese and 4.7% nickel results from steels 6 to 9. In steels 8 and 9

Steel alloy resulted in a ferrite content (martensite - the niobium content is higher than the permissible upper one

content) of about 10%. Limit and, it seems, has a discount

From these experiments it can be seen that the hardness results.

Steel types to be used according to the invention with In investigations in practical operation with 0.8% carbon, contents below 4% manganese and 30 steels to be used according to the invention have proven to be useful 2% nickel and 0.3% carbon under 7% Man- turned out to be a die for extrusion Gan and below 5% nickel no stable austenite structure of a nickel alloy, consisting of 0.12% carbon, 0.35% silicon, 0.03% copper, 0.21% iron,

The hardening decisive for the hardness is in 0.26% manganese, 15.1% chromium, 1.18% titanium, 4.71% causes significant levels of vanadium addition, and 35 aluminum, 20.1% cobalt, 4.93% molybdenum, 0.009% in this case, the precipitation of vanadium carbides boron, the remainder nickel for 130 operations as an average have great importance. These vanadium carbides and can be used by six different pressing media especially those who did not know about solution annealing. At vvähicini of the years ivoo / iyö / completely dissolved also have a particularly beneficial effect, with two studies that are often used on the wear resistance of the steel. Under- 40 martensitic steels, containing 0.36% coal exploration have shown that the vanadium content, 0.3% silicon, 2.8% chromium, 2.8% molybdenum, be at least 0.6%, 1.6% but not more than 2.8% cobalt, 0.5% vanadium or 0.4% carbon, should, since this reduces deformability 0.3% silicon, 2.8% chromium, 1.5% molybdenum, 5.0% at high temperature brings with it. Tungsten, 2.2% cobalt, 1% vanadium, were the

The addition of chromium is beneficial for hardening 45 corresponding averages only 80 operations each

and also has a beneficial effect on the die.

Resistance to oxidation. When extruding with dies from the last

Molybdenum and tungsten also have a favorable name

Effect on the Aüaliäiicn and also improve the pressed semi-finished product after approximately

obviously the wear resistance of the steel. There have been observed 5 ° 10 work cycles while at

has therefore proven necessary to extrude molybdenum with dies from the invention

Bring tungsten in the specified amounts. steel to be used scratches only after about

The addition of niobium has a very beneficial effect. 100 operations began to occur. This shows

on the fine grain and verily also on the clear superiority in the wear resistance

Toughness minimum at 500 to 700 ° C. A niobium content 55 of the steel to be used according to the invention. Cracks

0.2% seems to be the cheapest. in the extrusion dies were often

As far as boron is concerned, the addition of this static steel has been observed, but in no way contributes

Alloy material to the emergence of toughness - the steels to be used according to the invention,

at least at 500 to 70O ⁰ C and is at the same time. The steel to be used according to the invention has there-

particularly favorable in terms of constriction. The 60 shown in these operational tests that he is a

However, the boron content should not exceed 0.02%. significantly higher resistance to wear and tear

A boron content of about 0.01% has proven to be more resistant than that previously used for this purpose

most proven. types of steel normally used.

The invention is now to be described with reference to some of the Tables 2, 3 and 4 in more detail in the tables containing steel alloys that a according to the present invention is to be described. Table 1 shows the cooperation of applicable steel after solution annealing at 1150 ⁰ C reduction of 12 different steel alloys in and curing at 70o ⁰ C a 420 Vickers units connection with the present invention tested in excess of room temperature hardness is obtained and outside

which has good strength at high temperature, satisfactory toughness and good wear resistance. Furthermore, a hot hardness of at least 240 Vickers units at 700 ^° C. was achieved. Foregoing

In the past, a good combination could not be achieved with the martcnsitischen hot-work steels or non-cold-working ausienitic hot-work steels can be achieved.

Table 1

Composition of investigated steel alloys

steel Percentage of Si Mn Cr Ni Mon W. V Nb B. No. C. 0.46 11.5 4.9 9.0 _ _ 0.92 - 1 0.42 0.48 10.1 4.4 8.0 - - 1.55 - 0.011 2 0.48 0.44 10.5 4.8 8.5 1.41 1.9 - - 0.009 3 0.46 0.40 9.0 4.3 8.1 1.45 1.6 1.03 - 0.010 4th 0.44 0.41 9.8 4.3 8.0 1.44 1.5 1.36 - 0.012 5 0.46 0.47 9.8 4.3 7.9 1.24 1.4 1.42 - 0.010 6th 0.47 0.36 8.9 4.6 8.2 1.52 1.9 1.22 0.17 0.007 7th 0.49 0.42 9.6 4.3 7.9 1.41 1.5 1.31 0.44 0.013 8th 0.45 0.39 8.9 4.6 8.2 1.53 1.9 1.20 0.68 0.009 9 0.49 0.40 9.6 4.3 8.5 0.80 2.4 1.12 - 0.011 10 0.45 0.40 11.0 5.0 8.5 1.50 1.8 1.01 - - Il 0.42 0.37 10.6 5.2 8.5 1.51 1.7 1.05 - 0.013 12th 0.42

Table 2

Hardness according to V i c k e r s (HV 30) at room temperature for the steels specified in Table 1 according to

Table 4

Fcstigkeitseigenschafien at 600 ⁰ C for some of the steels shown in Table 1

I. Out Aiis- C, 700 ° C, Out 1 specified 12 h) 1150 ³ C, Steels (Heat treatment: 500 ⁰ C 600'C IdLiIb icnenuei Harden 700 ° C 35 steel
No. Yield strength tensile strength elongation i *) (ινμ / liill 6.0 A
lacing steel
No. Solution heat treatment 1150 ⁰ C.
1 h, water as well harden harden 12 h harden Solution heat treatment 1 h, water as well 306 293 650-C 271 8.0 V Lh, off , 700 ° 387 700 ⁰ C, 700 ⁰ C, 328 300 286 255 32.0 (7o) harden 6h 412 24 hours steel H3rtp ηJioh Vi rk <» ^rc Kj *; γ 296 295 291 1 259 65.0 4.3 700 ⁰ C 356 383 No. Temperatures 283 273 273 244 73.9 5.2 3h 408 438 406 20 ° C 317 298 267 254 40 1 58.6 58.6 5.7 24.5 1 283 205 443 240 4th 438 279 2 67.5 89.2 4.0
s *
n, t 48.2 2 445 443 440 5 443 3 26.7 87.9 37.7 3 453 447
420
418 453 6th 443 45 4th 81.5 85.4 26.2 4th 454 466 450 8th 420 6th 82.8 85.4
ου, υ 36.0 5- 454 454
430 438 425 10 466 8th 79.0 45.3 6th 446 445 428 457 11th
12th 71.3 in table 1 13.5
27.9 7th
8th
ο 455
432 435 441 10 451 434 437 5 ° 11 324 at 2O ⁰ C some of the according to ASTM 12th 335 table 5 after solution annealing (HV 30 and HV 5 Grain size for 1150 ° C specified table at the elevated temperatures) for tiniee of in Steels Grain size _ Hardness ι c ker s table 55 IiVlJ VV Ui steel 4.5 Solution
glow No. 4 ^ 5 1150 ° C, 1 7th 1200 ⁰ C water 6o 6.5 8.5 1 9 <3 170 4th <3 198 5 3 208 7th 5.5 202 8th 6.5 215 9 8th 212 230
214 221 185 178 3 according to V i t iuwisviiaii

Claims (1)

Patent claims: 1. Use of an austenitic, solution-annealed, hardenable manganese-nickel-chromium steel, consisting of 0.40 to until 0.60% Carbon, maj until 0.5% Silicon, 8th until 12% Manganese, 3 until 6% Chrome, 6th until 9% Nickel, 1.0 until 1.5% Vanadium, 0.8 until 1.8% Molybdenum, 1.2 until 2.5% Tungsten, 0 0.3% Niobium, 0 0.02% Boron, Temperatures but rapidly sinking toughness with toughness minimum at ungefänr 600 to 700 ⁰ C, which is in turn in the meaningful for many hot-work steels temperature range. The invention has the object of providing a material for use in such WarmarbeitswerJczeuge that as Strangpreßwerkzeuge in the temperature range from 20 to 700 ⁰ C and at appropriate temperature gradient high Zugfcsd "k; it must have hardness and toughness. Open solution to this problem "exists according to the invention in the use of an austenitic, solution-annealed, hardenable manganese-nickel-chromium steel, consisting of