TW202006153A - Austenite alloy steel including manganese, aluminum, carbon, molybdenum, and iron - Google Patents

Abstract

The present invention provides an Austenite alloy steel, which includes 25 wt% to 31 wt% of manganese, 7 wt% to 10 wt% of aluminum, 1.2 wt% to 1.6 wt% of carbon, less than 6 wt% of molybdenum, and a balanced amount of iron. The Austenite alloy steel of the present invention has high strength, high ductility and high temperature strength, and has a density of 6.8 g/cm 3, which is 14% lighter than traditional steel for molds. The Austenite alloy steel further includes less than 6 wt% chromium, and less than 5 wt% cobalt, the elongation rate is 20% to 40% and the ultimate tensile strength is higher than 1250 MPa at 25 DEG C, and the ultimate tensile strength is higher than 1000 MPa at 300 DEG C.

Description

Vostian alloy steel

The invention relates to a Vostian alloy steel, in particular to a Vostian alloy steel suitable for making hot working tools.

Ma Tian loose steel has excellent mechanical properties such as hardness and toughness, so it is often used as a material for hot working tools. However, the ductility of Ma Tian loose steel is not good, which may cause the hot tool to crack.

AISI H13 steel is one of the Ma Tian loose steel used for making hot working tools, including 0.32wt% to 0.45wt% carbon, 0.8wt% to 1.2wt% silicon, 0.20wt% to 0.50wt% manganese, 4.75wt % To 5.5wt% chromium, 1.10wt% to 1.75wt% molybdenum, 0.8wt% to 1.2wt% vanadium, no more than 0.03wt% phosphorus, no more than 0.03wt% sulfur, and a balanced amount of iron. The room temperature hardness of the AISI H13 steel is up to 55 to 58, and the elongation is between 3% and 5%. Because of the low elongation, it is easy to crack when used, so the hardness of the steel will be reduced to 42 during general use. To 50, the elongation is increased to 5% to 8%, the impact toughness is between 5 Joules to 10 Joules, and the high temperature hardness (Rockwell C hardness, HRc) is 33 to 41.

QRO 90 steel is another Ma Tian bulk steel used for making hot working tools, including 0.38wt% carbon, 0.30wt% silicon, 0.75wt% manganese, 2.60wt% chromium, 2.25wt% molybdenum, 0.9wt % Vanadium, and a balanced amount of iron. The QRO 90 steel has a room temperature hardness of 45, an elongation of 11%, an impact toughness of 10 joules, and a high temperature hardness (Rockwell C hardness, HRc) of 26 to 41.

On the other hand, iron-manganese-aluminum-carbon Austenite steels have application potential because of their high mechanical strength and high ductility, and therefore have been extensively studied in the past few decades.

It is known that when the carbon content in a steel alloy exceeds about 1.2 wt.%, the ductility of the alloy will be seriously deteriorated or embrittled. Therefore, in the prior art of studying the Vostian body alloy system, the amount of carbon in the alloy will be controlled between 0.54-1.3wt.%. The iron-manganese-aluminum-carbon steel with this carbon content is to increase the mechanical strength by adding molybdenum, niobium, and/or tungsten. However, the addition of the above elements can increase the machinery of the conventional iron-manganese-aluminum-carbon Voss steel Strength, but also because such alloys tend to precipitate coarse carbides on the grain boundary of the Wust body during the aging process, resulting in the problem of reduced ductility (ie, elongation), making hot working tools made of such steel materials It is easy to crack during use.

Applicant's US Patent No. 9,528,177 discloses an iron, manganese, aluminum, and carbon quaternary alloy with a specific content of iron, manganese, aluminum, and carbon. The iron, manganese, aluminum, and carbon quaternary alloy utilizes the carbon content to be controlled between 1.4wt. % To 2.2wt.% and the iron-manganese-aluminum-carbon quaternary alloy can form a high density in the base phase of the Vostian body through the spinodal decomposition phase transformation mechanism during the quenching after solid solution treatment (SHT) And the delicate κ'-carbide makes the iron-manganese-aluminum-carbon quaternary alloy have excellent ductility and high mechanical strength. However, the addition of strong carbide-forming elements, such as chromium, titanium, and molybdenum, to this iron-manganese-aluminum-carbon quaternary alloy does not significantly affect the formation of high-density and fine κ'-carbides in the base phase of the Vostian body It is therefore not recommended to add the strong carbide forming elements to the iron-manganese-aluminum-carbon quaternary alloy.

Therefore, the object of the present invention is to provide an Austenite alloy steel which has excellent mechanical properties at room temperature without affecting ductility and excellent strength at high temperatures.

Therefore, the Vostian alloy steel of the present invention contains 25 wt% to 31 wt% manganese, 7 wt% to 10 wt% aluminum, 1.2 wt% to 1.6 wt% carbon, more than 0 wt% and less than 6 wt% molybdenum, and the balance amount Iron.

The effect of the present invention is: by adding less than 6wt% of molybdenum to a specific composition of iron, aluminum, manganese, carbon, and field alloy steel, the field alloy steel has excellent mechanical properties at room temperature, and the limit Tensile strength, and can have good strength performance at high temperature (~500℃).

The invention discloses an Austenite alloy steel with high strength and high ductility. The Austenite alloy steel can be applied to general steel plates (such as automobile steel plates), parts (such as gears) or hot die steels.

The alloy composition of the Vostian body alloy steel includes 25wt% to 31wt% manganese, 7wt% to 10wt% aluminum, 1.2wt% to 1.6wt% carbon, more than 0wt% and less than 6wt% molybdenum, and the balance amount Iron.

Manganese is a Vostian body strengthening element. Since the Vostian body phase is face-center-cubic (FCC) structure and has more slip systems, it is compared to body-center cubic (body-center-cubic). cubic (BCC) structure or hexagonal close packed (HCP) structure has better ductility. In order to obtain a complete Voss field structure at room temperature, the manganese content in the Voss field alloy steel of the present invention is 25 wt% to 31 wt%. In some embodiments, the manganese content of the Vostian alloy steel is between 26 wt% and 30 wt%. In some embodiments, the manganese content of the Vostian alloy steel is between 27 wt% and 29 wt%.

Aluminum is not only the strengthening element of the Vostian body, but also the main element forming (Fe, Mn) ₃ AlC _x carbide (ie κ'-carbide). The aluminum content in the Vostian body alloy steel of the present invention is 7 wt% Up to 10wt%. In some embodiments, the aluminum content of the Vostian alloy steel is between 8 wt% and 10 wt%. In some embodiments, the aluminum content of the Vostian alloy steel is between 8 wt% and 9 wt%.

The carbon content of the Vostian body alloy steel of the present invention is 1.2 wt% to 1.6 wt%, which is higher than that of the conventional ferromanganese aluminum carbon Vostian body steels containing molybdenum, niobium, and/or tungsten (i.e. the highest 1.0wt%). In some embodiments, the carbon content of the Vostian alloy steel is 1.3 wt% to 1.6 wt%.

Molybdenum is a strong carbide-forming element. In the Wustfield alloy steel of the present invention, the content of molybdenum is greater than 0 wt% and less than 6 wt%. In some embodiments, the molybdenum content of the Vostian alloy steel is between 2 wt% and 6 wt%.

In some embodiments, the Vostian alloy steel also contains chromium, which is also a strong carbide forming element, and the content of chromium is less than 6 wt%.

In some embodiments, the Vostian alloy steel also contains cobalt element, which is also a strong carbide forming element, and the content of the cobalt element is less than 5 wt%.

It should be noted that the content of low melting point elements (such as manganese and aluminum) in the Vostian body alloy steel will be caused by volatilization during the smelting process. The amount of addition during smelting is different, however, the difference between the two is not large, and it is within the allowable error range without affecting the properties of the finally produced Vostian body alloy.

Referring to FIG. 1, the manufacturing method of the Vostian alloy steel includes steps 91 to 95.

The step 91 is to smelt the aforementioned alloy composition of the Vostian body alloy steel into a casting in a high frequency melting furnace under the atmosphere.

Then, step 92 is performed, and the casting is hot-worked (for example: hot rolling, hot forging, etc.) at 1100°C to 950°C to a predetermined shape to become a hot work.

Next, step 93 is performed, and the hot work is water quenched for the first time and cooled to room temperature.

Then proceed to step 94. The step 94 is to perform aging treatment on the hot work piece after the first water quenching treatment at 480°C to 600°C.

In detail, when the temperature of the aging treatment is between 480°C and 500°C, the aging time is 5 to 12 hours; when the temperature of the aging treatment is greater than 500°C, the aging time is 1 to 4 hours.

Finally, step 95 is performed, and the hot work piece after aging treatment is subjected to second water quenching and cooled to room temperature, that is, the production of the Vostian body alloy steel is completed.

The manufacturing process of the Vostian body alloy steel of the present invention is different from the conventional iron-manganese-aluminum-carbon alloy steel with low carbon content and containing strong carbide-forming elements, and the conventional iron-manganese-aluminum steel with low carbon content and containing strong carbide-forming elements is known. After hot working, the carbon alloy steel needs to be subjected to solution heat treatment, and the coarse carbides precipitated on the grain boundary will be re-dissolved in the base phase to improve the ductility of the iron manganese aluminum carbon alloy steel. The field alloy steel composition, although it has a relatively high content of carbon and strong carbide forming elements, however, the present invention utilizes the temperature control (1100°C to 950°C) of the hot working process (hot rolling or hot forging), so it can be avoided The iron-manganese-aluminum-carbon alloy is composed of precipitated coarse carbides on the grain boundaries during the hot working process. Therefore, after the hot working process, the conventional solid solution heat treatment step is not required to make the Vostian body obtained Alloy steel has both strength and ductility.

In addition, it should be noted that the aforementioned step 95 can also be performed without a process, that is, the hot work piece can also be selected to be naturally cooled to room temperature after aging treatment without performing a second water quenching. In addition, the present invention uses heat as the control of the treatment temperature, which can effectively prevent the precipitation of coarse carbides and affect the ductility of the alloy steel. Therefore, it is possible to effectively reduce the overall process time without performing the conventional heat solution step. However, after the hot working treatment and the first water quenching, you can also choose to carry out the hot solution step. This process does not affect the overall characteristics of the alloy steel in this case.

In particular, the Vostian body alloy steel prepared by using the Vostian iron alloy composition of the present invention and the manufacturing method of this case is a complete Vostian body phase, and its room temperature (25°C) yield strength (YS) is between 1200 MPa To 1400MPa, Rockwell C hardness (HRc) between 45 and 55, ultimate tensile strength between 1200MPa and 1500MPa, and elongation (El) between 20% and 40%, and at the same time can be at high temperature (< 700℃) has good yield strength (YS) and ultimate tensile strength (UTS). Therefore, in addition to being used as general steel plates (such as automobile steel plates) and parts (such as gears), the Vostian body alloy steel in this case is more suitable for hot work die steel.

In addition, it should be noted that the density of the general iron-aluminum-manganese-carbon alloy is about 6.6~6.8g/cm ³ , which is 14% lighter than that of the general mold steel (density about 7.8~7.9g/cm ³ ). Therefore, in addition to high strength and high ductility, the Vostian body alloy steel of the present invention can also have the advantages of light weight.

It is known that iron, aluminum, manganese and carbon alloys with high carbon content (1.4wt.% to 2.2wt.%) can be obtained through the process control (heat treatment/solid solution/quenching water) to obtain a microstructure of complete Vostian body phase, and in There are very dense and fine nano-sized (Fe, Mn) ₃ AlC _x carbides (κ′-carbide) in the Vostian body phase base, and the precipitation of coarse carbides on the grain boundaries can be avoided. Therefore, the The iron-aluminum-manganese-carbon alloy can have basically good mechanical properties and elongation at room temperature. However, the present invention found that it can be effective when further adding carbide strengthening elements (molybdenum, chromium, cobalt) with a content of 2-6 wt% to the composition of the iron-manganese-aluminum-carbon alloy in a specific ratio, together with the control of heat treatment temperature It avoids the disadvantages of coarse carbide precipitation that will reduce the ductility of the material on the grain boundary. Therefore, in addition to the ductility of the iron-aluminum-manganese-carbon alloy steel produced at room temperature, it can be further improved at the same time. The room temperature and high temperature strength of the iron-aluminum-manganese-carbon alloy steel made in this case, in addition, because the iron-aluminum-manganese-carbon alloy steel in this case does not require a solution treatment step, it can also effectively reduce the overall process time.

The physical properties of the test specimens are made using the alloy compositions of the following specific examples 1 to 11 and comparative examples 1 to 3, and then tested to more specifically describe the characteristics of the Vostian body alloy steel of the present invention.

It should be noted that the following specific examples are intended to illustrate the Vostian body alloy steel that exemplifies the present invention, but it cannot be used to limit the scope of the present invention.

Specific example 1

1. An alloy composition containing 30wt% manganese, 8.5wt% aluminum, 1.45wt% carbon, 6% molybdenum, and a balanced amount of iron is melted in the atmosphere in a high-frequency melting furnace to a thickness of 2cm casting.

2. The casting is heated in a furnace at 1100°C for 20 minutes, and then hot rolled at 1100°C to 950°C to a thickness of at least less than 25% of the thickness of the casting to obtain a test piece.

3. Perform the first water quenching of the test piece to room temperature, then grind to remove the oxide layer, then perform aging treatment at 500°C (Aging), and finally perform the second water quenching of the test piece to room temperature stand-by.

Specific examples 2 to 11

The test specimens of the specific examples 2 to 11 are made in the same way as the test specimen of the specific example 1, except for the content of each element in the alloy.

Comparative examples 1~3

The test specimens of the comparative examples 1 to 3 are made in the same way as the specific example 1, except for the content of each element in the alloy.

The content of alloy constituent elements of these specific examples and comparative examples is summarized in Table 1.

Table 1

Next, the test specimens prepared by the foregoing specific examples and comparative examples are tested for yield strength (YS), ultimate tensile strength (UTS), elongation (El), and hardness (HRc).

The yield strength, ultimate tensile strength, elongation, and hardness of the test specimens were measured at room temperature using the following test methods. The measurement results are shown in Table 2.

In addition, the test specimens of the specific examples 4, 7 and 9 and comparative examples 1 to 3 were tested at 300°C, 500°C and 700°C for yield strength and ultimate tensile strength. The results are shown in Table 3.

Test method of each feature:

1. Tensile test

Yield Strength (YS): The stress when the tensile curve is parallel to the elastic line by 0.2% strain.

Ultimate Tensile Strength (UTS): The maximum stress in the tensile curve.

Elongation (Elongation, El): The tensile curve plots the amount of strain parallel to the elastic line at the break point.

The aforementioned yield strength, ultimate tensile strength, and elongation are measured using an Instron tensile testing machine at room temperature (25°C) at a tensile rate of ^10-3 /sec to obtain a tensile curve. Among them, the specifications of the test specimens refer to ASTM E8/E8M specifications. During high temperature testing, a high temperature furnace is installed in a tensile testing machine, and the tensile test is performed after heating to a predetermined temperature.

2. Hardness test (HRc)

Rockwell Hardness machine (Rockwell Hardness machine), with a load of 150kgf for testing, the test using the indenter is a diamond cone.

Table 2

table 3

As shown in Table 2, the test specimens prepared in the specific examples 1 to 11 have a room temperature yield strength between 1230 MPa and 1350 MPa, a room temperature ultimate tensile strength between 1280 MPa and 1386 MPa, and a room temperature elongation between 20% and 37 %, and the hardness (HRc) is between 45.0 and 47.7. Compared with the characteristic data of Comparative Example 1 and Comparative Example 2, it is shown that the Vostian alloy steel of the present invention does have high strength and also has good extension. Sex. In particular, by controlling the molybdenum content in the Vostian alloy steel to 2wt% to 6wt%, compared to Comparative Examples 1 to 3, and two conventional hot working alloys of AISI H13 and QRO 90, The Voss body alloy steel of the present invention not only maintains excellent room temperature strength and room temperature elongation, but also has a certain strength at high temperatures, showing that the Voss body alloy steel of the present invention has good ductility and can also be used as The new type of hot work alloy steel is used, and it can avoid the cracking of the manufactured hot work tool during use.

Preferably, the carbon content of the Vostian body alloy steel is between 1.42wt% and 1.5wt%, the molybdenum content is between 3.5wt% and 5wt%, and the ultimate tensile strength of the Vostian body alloy steel is up to 1353MPa To 1386MPa, the yield strength can reach 1310MPa to 1340MPa, and the hardness can reach 47 to 47.7.

More preferably, the carbon content of the Vostian alloy steel is between 1.42wt% and 1.45wt%, the molybdenum content is between 3.5wt% and 4wt%, and the elongation of the Vostian alloy steel can reach 25%.

Preferably, the manganese content of the Vostian body alloy steel is between 27.7wt% and 30wt%, the aluminum content is between 8.2wt% and 8.5wt%, and the ultimate tensile strength of the Vostian body alloy steel can reach 1280MPa To 1386MPa, yield strength can reach 1250MPa to 1350MPa, hardness can reach 46.7 to 47.7, elongation can reach 20% to 32%.

Preferably, the manganese content of the Vostian body alloy steel is between 27wt% and 29wt%, the aluminum content is between 8.0wt% and 8.5% by weight, and the molybdenum content is between 3.0wt% and 6wt%. The elongation of alloy steel can be greater than 20%, the ultimate tensile strength at room temperature can be greater than 1280MPa, the yield strength can be greater than 1230MPa, and the ultimate tensile strength and yield strength at 300℃ can be greater than 1000MPa.

Preferably, the molybdenum content of the Vostian body alloy steel is 3.0 wt% and contains 3 wt% chromium or 2 wt% cobalt. The ultimate tensile strength of the Vostian body alloy steel at room temperature can reach 1280 MPa to 1344MPa, yield strength can reach 1230MPa to 1300MPa, hardness can reach 45 to 46.8, elongation can reach 24% to 37%.

In addition, it should be noted that the mechanical strength data in Table 2 shows that the aging time of the specific examples 1 to 11 between 5 and 12 hours has no significant effect on the final mechanical strength, showing that the present invention uses heat treatment temperature Control can effectively prevent the precipitation of coarse carbides. Therefore, the time for the aging treatment can be more flexible, and it will not cause the longer the aging time of the conventional iron-manganese-aluminum-carbon steel, the more obvious the appearance of coarse carbides. The problem of reduced ductility.

Referring to FIGS. 2 to 4, FIGS. 2 to 4 are optical microscope photographs of the specific examples 1, 3, and 8 after hot working, and FIGS. 5 to 7 are the specific examples 1, 3, and 8 after hot working and Photograph of optical microscope after aging treatment. It can be seen from Figures 2 to 4 that when the hot working temperature is controlled at 1100°C to 950°C, coarse carbides are not likely to precipitate at the grain boundaries after the hot working treatment. Therefore, after further processing with different aging times, and referring to Figures 5-7, it is not easy to produce coarse carbides. However, referring to Figs. 8 and 9, which are optical micrographs of Comparative Examples 1 and 2 after hot working, it can be seen from Figs. 8 and 9 that when the excessive addition of strong carbide-forming elements, the hot working is controlled longitudinally The treatment temperature will still precipitate a large amount of coarse carbides, which is not conducive to the ductility of the iron-manganese-aluminum-carbon alloy.

In addition, from the high-temperature tensile strength results in Table 3 above, it can be seen that the yield strength of the iron-aluminum-manganese-carbon Vostian alloy steel produced by the present invention at 300°C is between 970 MPa and 1030 MPa, and the ultimate tensile strength is 1022 MPa to 1070 MPa The yield strength at 500°C is between 650MPa and 700MPa, the ultimate tensile strength is between 719MPa and 786MPa, the yield strength at 700°C is between 410MPa and 420MPa, and the ultimate tensile strength is between 440MPa and 449MPa. Although Comparative Example 3 has good ductility at room temperature, the yield strength and ultimate tensile strength at room temperature and high temperature (300°C, 500°C) are still inferior to the present invention. Starfield alloy steel not only has good strength performance at room temperature, but also has good mechanical strength at 300 ℃ and 500 ℃, so it can be used as a new medium and low temperature hot working alloy steel.

In summary, according to the disclosure of the prior art, strong carbide-forming elements such as molybdenum and tungsten (eg Fe-29Mn-9Al- 0.9C-0.6Mo, Fe-29Mn-9Al-0.9C-0.4Mo-0.6W and other iron-manganese-aluminum-carbon alloys) can improve the ductility of the alloy, but it can not significantly improve the strength of the alloy, and the low-carbon iron The manganese aluminum carbon alloy contains more of these strong carbide forming elements (for example: Fe-27.9Mn-8.6Al-1.0C-0.51Mo-0.73W-0.55Nb iron manganese aluminum carbon alloy), although it can increase the alloy Strength but unable to maintain good ductility. The aforementioned US Patent No. 9,528,177 also discloses that adding these strong carbide forming elements to a high carbon content iron-manganese aluminum carbon alloy cannot effectively improve the ductility of the alloy, so it is not recommended for high carbon content iron-manganese aluminum carbon alloys Add these strong carbide forming elements. However, by controlling the content of each element in the composition of the high-carbon iron-manganese-aluminum-carbon alloy in a specific range and matching a specific heat treatment temperature, the Voss field alloy steel of the present invention makes the Voss body body finally obtained Alloy steel can have excellent mechanical strength and ductility at room temperature, while still maintaining proper strength at high temperature, and is lightweight and has good performance. It can be used as mechanical parts and steel for heat treatment tools. The invention of Vostian body alloy steel can be used not only as general steel but also as hot working alloy steel, so it can indeed achieve the purpose of cost invention.

However, the above are only examples of the present invention, and should not be used to limit the scope of the present invention. Any simple equivalent changes and modifications made according to the scope of the patent application of the present invention and the content of the patent specification are still classified as This invention covers the patent.

91~95‧‧‧Step

Other features and effects of the present invention will be clearly presented in the embodiment with reference to the drawings, in which: FIG. 1 is a block diagram of the manufacturing process of the Vossian alloy steel of the present invention; FIG. 2 is the Vossian body of the present invention Specific example 1 of alloy steel after hot working treatment; optical micrograph; Figure 3 is the photomicrograph of specific example 3 of Vostian body alloy steel of the present invention after hot working; Figure 4 is the photomicrograph of Vostian body of the present invention. Specific example 8 of alloy steel after hot work optical micrograph; FIG. 5 is specific example 1 of Vostian body alloy steel of the present invention after aging treatment; FIG. 6 is Vostian body alloy of the present invention Specific example 3 of steel after aging treatment optical micrograph; FIG. 7 is an optical microscope photo of specific example 8 of Vostian body alloy steel of the present invention after aging treatment; FIG. 8 is photograph of Vostian body alloy steel of the present invention Comparative Example 1 is an optical microscope photograph after hot working treatment; and FIG. 9 is an optical microscope photograph after comparatively hot working treatment of Comparative Example 2 of the present invention.

Claims (19)

A Vostian body alloy steel, containing 25wt% to 31wt% manganese, 7wt% to 10wt% aluminum, 1.2wt% to 1.6wt% carbon, more than 0wt% and less than 6wt% molybdenum, and a balanced amount of iron . The Vostian body alloy steel according to claim 1, wherein the proportion of the manganese is between 26wt% and 30wt%, and the proportion of the aluminum is between 8wt% and 10wt%. The Vostian body alloy steel according to claim 2, wherein the proportion of manganese is between 27wt% and 29wt%, and the proportion of molybdenum is between 2wt% and 6wt%. The Vostian body alloy steel according to claim 3, wherein the proportion of the aluminum is between 8 wt% and 9 wt%. The Vostian alloy steel according to claim 1, wherein the ratio of the carbon is 1.4 wt% to 1.6 wt%. The Vostian body alloy steel according to claim 1, wherein the proportion of the molybdenum is between 2wt% and 6wt%. The field alloy steel according to claim 1 further contains chromium in a proportion of less than 6wt%. The field alloy steel according to claim 1, further comprising cobalt in a proportion of less than 5 wt%. The Vostian body alloy steel according to claim 1, wherein the Vostian body alloy steel is a full Vostian body phase, and the elongation at 25°C is between 20 and 40%, and the ultimate tensile strength is greater than 1250MPa, and the ultimate tensile strength at 300℃ is greater than 1000MPa. A method for manufacturing Vostian body alloy steel, comprising: Step (a): melting the alloy composition as described in claim 1 into a casting; Step (b): performing heat treatment on the casting at 1100°C to 950°C It becomes a hot work piece; Step (c): The first hot work piece after the hot work treatment is water quenched; and Step (d): The hot work piece after the first water quench is at 480 ℃ Aging treatment to 600℃. The method of manufacturing a Vostian body alloy steel according to claim 10, wherein the temperature of the aging treatment is from 480°C to 500°C, the time of the aging treatment is from 5 to 12 hours, and the temperature of the aging treatment When it is greater than 500°C to 600°C, the aging treatment time is 1 to 4 hours. The manufacturing method of the Vostian body alloy steel according to claim 10, further comprising a step (e), the second water quenching of the aging-treated casting. The method for manufacturing a Vostian body alloy steel according to claim 10, wherein in step (b), the casting is hot-worked to a thickness of at least 25% of the thickness of the casting. A Vostian body alloy steel produced by the manufacturing method as described in claim 10, which has an elongation at room temperature of 20 to 40% and an ultimate tensile strength greater than 1000 MPa at 300°C . The Vossian alloy steel according to claim 14, wherein the Vossian alloy steel has a yield strength at room temperature of 1230 to 1350 MPa and an ultimate tensile strength of 1280 to 1386 MPa. The Vossian alloy steel according to claim 14, wherein the Vossian alloy steel has a Rockwell hardness of 45 to 48 at room temperature. The bulk alloy steel according to claim 14, wherein the bulk strength of the bulk alloy steel at 300°C is greater than 970 MPa. The Vossian alloy steel according to claim 14, wherein the Vossian alloy steel has a yield strength at 500° C. greater than 650 MPa and an ultimate tensile strength greater than 700 MPa. The Vossian alloy steel according to claim 14, wherein the Vossian alloy steel has a yield strength at 700°C of 410 to 420 MPa and an ultimate tensile strength of 440 to 449 MPa.

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