High-performance tough hot-work die steel and preparation method thereof

Abstract

The application relates to the technical field of die steel, and particularly discloses a high-performance strong and tough hot work die steel and a preparation method thereof. The high-performance strong and tough hot work die steel comprises the following raw materials: C 0.3-0.5%, Si 0.3-0.8%, Co 0.2-0.3%, Mg 0.1-0.14%, Ti 0.23-0.35%, V 0.38-0.56%, Al 0.08-0.14%, Mn 0.1-0.18%, NiCrMo alloy powder 7-10%, P<=0.05%, S<=0.02%, and the balance of Fe and inevitable impurities. The raw materials are sequentially put into a vacuum induction furnace for smelting and poured into a steel ingot; the steel ingot is annealed and hot-rolled and then air-cooled to room temperature, and then heat treatment is carried out; the preparation method is simple and the preparation conditions are mild; the obtained hot work die steel is excellent in hot strength, toughness and wear resistance, and can meet the market application requirements.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of die steel, in particular to a high-performance strong and tough hot work die steel and a preparation method thereof. BACKGROUND

[0002] Die steel is a basic material for equipment manufacturing industry and is widely used in the fields of hot extrusion, hot forging and die casting. The performance of die steel directly affects the production efficiency, cost and product quality of enterprises. With the rapid development of industrial production and the increasing concern of people for product quality, modern industry has higher requirements for the performance and service life of dies.

[0003] Hot work die steel is mainly used in the fields of hot forming, hot extrusion and pressure casting of metals. The hot work die is repeatedly subjected to high temperature, large load impact and repeated cyclic heating and cooling during service. Although the most widely used hot work die steel H13 has good thermal stability and thermal fatigue resistance, it is brittle and has poor thermal strength, and the harsh service environment easily causes the die to deform and crack, thereby reducing the service life of the die. Based on this, the application provides a high-performance strong and tough hot work die steel and a preparation method thereof. SUMMARY

[0004] In order to improve the thermal strength and toughness of the hot work die steel, the application provides a high-performance strong and tough hot work die steel and a preparation method thereof.

[0005] In the first aspect, the application provides a high-performance strong and tough hot work die steel, which adopts the following technical scheme:

[0006] The high-performance strong and tough hot work die steel comprises the following raw materials in percentage by weight: C 0.3-0.5%, Si 0.3-0.8%, Co 0.2-0.3%, Mg 0.1-0.14%, Ti 0.23-0.35%, V 0.38-0.56%, Al 0.08-0.14%, Mn 0.1-0.18%, NiCrMo alloy powder 7-10%, P≤0.05%, S≤0.02%, and the balance of Fe and inevitable impurities.

[0007] Preferably, the high-performance strong and tough hot work die steel comprises the following raw materials in percentage by weight: C 0.4%, Si 0.6%, Co 0.25%, Mg 0.12%, Ti 0.29%, V 0.47%, Al 0.11%, Mn 0.14%, NiCrMo alloy powder 8.5%, P 0.03%, S 0.01%, and the balance of Fe and inevitable impurities.

[0008] By adopting the technical scheme, the raw material dosage and ratio are controlled, so that the hot work die steel prepared can have excellent hardness, grain size, toughness and impact resistance, and the segregation level is reduced; by adding the NiCrMo alloy powder in the formula, the uniform distribution of elements can be effectively ensured, so that the microstructure uniformity of the hot work die steel is ensured, and the hot strength, thermal stability and thermal fatigue resistance of the hot work die steel are significantly improved; meanwhile, the NiCrMo alloy powder can reduce the melting temperature of high melting point elements and reduce the burning loss of low melting point elements, so that the comprehensive mechanical properties of the hot work die steel are improved.

[0009] Preferably, the NiCrMo alloy powder is prepared by the following method:

[0010] The Ni powder, Cr powder and Mo powder are added into a grinder together to grind the mixed powder;

[0011] The mixed powder, ethanol, amino silane coupling agent and maleic anhydride are added into a ball mill together, and after ball milling, vacuum drying is performed to obtain the NiCrMo alloy powder.

[0012] The mass ratio of the Ni powder, Cr powder and Mo powder is 1-1.2:22-24:5-7.

[0013] Preferably, the mass ratio of the mixed powder, ethanol, amino silane coupling agent and maleic anhydride is 1:0.1-0.2:0.003-0.005:0.0001-0.0003.

[0014] Preferably, the vacuum drying temperature is 220-280℃.

[0015] By adopting the technical scheme, the Ni powder, Cr powder and Mo powder are blended and ground, and then ethanol, amino silane coupling agent and maleic anhydride are added for ball milling, so that the powder is modified by wrapping and the required NiCrMo alloy powder is obtained; the obtained NiCrMo alloy powder is used for formula addition, so that the mechanical properties such as hot strength, thermal stability and thermal fatigue resistance of the hot work die steel are significantly improved.

[0016] In a second aspect, the application also provides a preparation method of a high-performance and high-toughness hot work die steel, which adopts the following technical scheme:

[0017] The preparation method of the high-performance and high-toughness hot work die steel comprises the following preparation steps:

[0018] S1, raw materials are weighed according to a formula, and the raw materials are sequentially put into a vacuum induction furnace for melting and poured into a steel ingot;

[0019] S2, the steel ingot obtained in step S1 is annealed, hot rolled and air cooled to room temperature, and then heat treated to obtain the required die steel.

[0020] Preferably, the annealing treatment in step S2 specifically refers to: placing the ingot obtained in step S1 in a heating furnace, heating to 910-970℃, holding for 0.3-1h, then cooling to 520-540℃ at a rate of 3-5℃ / min, holding for 1-2h.

[0021] Preferably, the heat treatment in step S2 specifically refers to: heating to 480-550℃ at a rate of 7-12℃ / min, holding for 2-4h, then continuously heating to 1050-1100℃, holding for 0.5-1h, and oil cooling to room temperature.

[0022] By adopting the above technical solution, the raw materials are mixed and smelted and then cast into shape, the uniformity and mechanical properties of the hot work die steel are improved by controlling the annealing and heat treatment process parameters, the mechanical strength, wear resistance and high temperature crack resistance are improved, the preparation method is simple, the preparation conditions are mild, the preparation cost is low, it is efficient and pollution-free, the hot work die steel obtained has excellent hot strength, toughness and wear resistance, and meets the market application requirements.

[0023] In summary, the present application has the following beneficial effects:

[0024] The present application controls the amount and ratio of raw materials, which can effectively ensure that the hot work die steel prepared has excellent hardness, grain size, toughness and impact resistance, and reduces the segregation level; by adding NiCrMo alloy powder in the formula, the uniform distribution of elements can be effectively ensured, thereby ensuring the uniformity of the hot work die steel, and significantly improving the hot strength, thermal stability and thermal fatigue resistance of the hot work die steel; at the same time, the NiCrMo alloy powder can reduce the melting temperature of high melting point elements and reduce the burning loss of low melting point elements, thereby improving the comprehensive mechanical properties of the hot work die steel.

[0025] The present application mixes and smelts the raw materials and then casts them into shape, improves the uniformity and mechanical properties of the hot work die steel by controlling the annealing and heat treatment process parameters, improves the mechanical strength, wear resistance and high temperature crack resistance, the preparation method is simple, the preparation conditions are mild, the preparation cost is low, it is efficient and pollution-free, the hot work die steel obtained has excellent hot strength, toughness and wear resistance, and meets the market application requirements. Embodiment

[0026] The present application will be further illustrated below in combination with specific examples.

[0027] Preparation Examples 1-3 and Comparative Preparation Example 1-4 provide a preparation method of NiCrMo alloy powder.

[0028] Preparation Example 1

[0029] The NiCrMo alloy powder is prepared by the following method:

[0030] The Ni powder, the Cr powder and the Mo powder are added into a grinder in a mass ratio of 1:22:5, and the mixture is ground to a particle size of 1 μm to obtain a mixed powder;

[0031] The mixed powder, ethanol, aminopropyltrimethoxysilane and maleic anhydride are added into a ball mill in a mass ratio of 1:0.1:0.003:0.0001, and the mixture is ball-milled for 3 h, and then vacuum dried at a temperature of 280°C to obtain a NiCrMo alloy powder.

[0032] Preparation Example 2

[0033] The NiCrMo alloy powder is prepared by the following method:

[0034] The Ni powder, the Cr powder and the Mo powder are added into a grinder in a mass ratio of 1.1:23:6, and the mixture is ground to a particle size of 5 μm to obtain a mixed powder;

[0035] The mixed powder, ethanol, aminopropyltrimethoxysilane and maleic anhydride are added into a ball mill in a mass ratio of 1:0.15:0.004:0.0002, and the mixture is ball-milled for 4 h, and then vacuum dried at a temperature of 250°C to obtain a NiCrMo alloy powder.

[0036] Preparation Example 3

[0037] The NiCrMo alloy powder is prepared by the following method:

[0038] The Ni powder, the Cr powder and the Mo powder are added into a grinder in a mass ratio of 1.2:24:7, and the mixture is ground to a particle size of 10 μm to obtain a mixed powder;

[0039] The mixed powder, ethanol, aminopropyltrimethoxysilane and maleic anhydride are added into a ball mill in a mass ratio of 1:0.2:0.005:0.0003, and the mixture is ball-milled for 5 h, and then vacuum dried at a temperature of 220°C to obtain a NiCrMo alloy powder.

[0040] Comparative Preparation Example 1

[0041] Comparative Preparation Example 1 is the same as Preparation Example 1, except that the mass ratio of the Ni powder, the Cr powder and the Mo powder is 5:22:1.

[0042] Comparative Preparation Example 2

[0043] Comparative Preparation Example 2 is the same as Preparation Example 1, except that the mass ratio of the Ni powder, the Cr powder and the Mo powder is 22:1:5.

[0044] Comparative Preparation Example 3

[0045] Comparative Preparation Example 3 is the same as Preparation Example 1, except that the aminopropyltrimethoxysilane is replaced by vinyltrimethoxysilane.

[0046] Comparative Preparation Example 4

[0047] Comparative Preparation Example 4 is the same as Preparation Example 1, except that the maleic anhydride is replaced by an equal mass of aminopropyltrimethoxysilane. Example 1

[0048] The application provides a high-performance strong and tough hot work die steel, which comprises the following raw materials in percentage by weight: C 0.3%, Si 0.3%, Co 0.2%, Mg 0.1%, Ti 0.23%, V 0.38%, Al 0.08%, Mn 0.1%, NiCrMo alloy powder 7%, P 0.05%, S 0.02%, and the balance of Fe and inevitable impurities.

[0049] The NiCrMo alloy powder is prepared according to Preparation Example 1.

[0050] The application further provides a preparation method of the high-performance strong and tough hot work die steel, which comprises the following steps:

[0051] S1, the raw materials are weighed according to the formula, and the raw materials are sequentially put into a vacuum induction furnace for smelting and poured into a steel ingot;

[0052] S2, the steel ingot obtained in the step S1 is annealed, hot-rolled and air-cooled to room temperature, and then subjected to heat treatment to obtain the required die steel;

[0053] The annealing treatment specifically refers to that the steel ingot obtained in the step S1 is placed in a heating furnace, heated to 910 DEG C, and kept for 1 h, then cooled to 520 DEG C at a rate of 5 DEG C / min, and kept for 2 h;

[0054] The heat treatment specifically refers to that the temperature is increased to 480 DEG C at a rate of 7 DEG C / min, kept for 4 h, then continuously increased to 1050 DEG C, kept for 1 h, and oil-cooled to room temperature. Example 2

[0055] The application provides a high-performance strong and tough hot work die steel, which comprises the following raw materials in percentage by weight: C 0.4%, Si 0.6%, Co 0.25%, Mg 0.12%, Ti 0.29%, V 0.47%, Al 0.11%, Mn 0.14%, NiCrMo alloy powder 8.5%, P 0.03%, S 0.01%, and the balance of Fe and inevitable impurities.

[0056] The NiCrMo alloy powder is prepared according to Preparation Example 1.

[0057] The application further provides a preparation method of the high-performance strong and tough hot work die steel, which comprises the following steps:

[0058] S1, the raw materials are weighed according to the formula, and the raw materials are sequentially put into a vacuum induction furnace for smelting and poured into a steel ingot;

[0059] S2, the steel ingot obtained in step S1 is annealed, hot-rolled and air-cooled to room temperature, and then heat-treated to obtain the required die steel;

[0060] The annealing treatment specifically refers to: the steel ingot obtained in step S1 is placed in a heating furnace, heated to 940 DEG C, and held for 0.6 h, then cooled to 530 DEG C at a rate of 4 DEG C / min, and held for 1.5 h;

[0061] The heat treatment specifically refers to: heating to 510 DEG C at a rate of 10 DEG C / min, holding for 3 h, then continuing to heat to 1080 DEG C, holding for 0.8 h, and oil cooling to room temperature. Example 3

[0062] The application provides a high-performance strong and tough hot work die steel, which comprises the following raw materials in percentage by weight: C 0.5%, Si 0.8%, Co 0.3%, Mg 0.14%, Ti 0.35%, V 0.56%, Al 0.14%, Mn 0.18%, NiCrMo alloy powder 10%, P 0.05%, S 0.02%, and the balance of Fe and inevitable impurities.

[0063] The NiCrMo alloy powder is prepared by the preparation example 1.

[0064] The application further provides a preparation method of the high-performance strong and tough hot work die steel, which comprises the following steps:

[0065] S1, the raw materials are weighed according to the formula, and the raw materials are sequentially put into a vacuum induction furnace for smelting and poured into a steel ingot;

[0066] S2, the steel ingot obtained in step S1 is annealed, hot-rolled and air-cooled to room temperature, and then heat-treated to obtain the required die steel;

[0067] The annealing treatment specifically refers to: the steel ingot obtained in step S1 is placed in a heating furnace, heated to 970 DEG C, and held for 0.3 h, then cooled to 540 DEG C at a rate of 3 DEG C / min, and held for 1 h;

[0068] The heat treatment specifically refers to: heating to 550 DEG C at a rate of 12 DEG C / min, holding for 2 h, then continuing to heat to 1100 DEG C, holding for 0.5 h, and oil cooling to room temperature. Example 4

[0069] The high-performance strong and tough hot work die steel provided in the application comprises the following raw materials in percentage by weight: C 0.3%, Si 0.3%, Co 0.2%, Mg 0.1%, Ti 0.23%, V 0.38%, Al 0.08%, Mn 0.1%, NiCrMo alloy powder 7%, P 0.05%, S 0.02%, and the balance of Fe and inevitable impurities.

[0070] The NiCrMo alloy powder is prepared according to Preparation Example 2.

[0071] The application further provides a preparation method of the high-performance strong and tough hot work die steel, comprising the following steps:

[0072] S1, raw materials are weighed according to a formula, and the raw materials are sequentially put into a vacuum induction furnace for smelting and poured into a steel ingot;

[0073] S2, the steel ingot obtained in step S1 is annealed, hot-rolled, and then air-cooled to room temperature, and then heat-treated to obtain the required die steel;

[0074] The annealing treatment specifically refers to: the steel ingot obtained in step S1 is placed in a heating furnace, heated to 910 DEG C, and kept for 1 h, then cooled to 520 DEG C at a rate of 5 DEG C / min, and kept for 2 h;

[0075] The heat treatment specifically refers to: heating to 480 DEG C at a rate of 7 DEG C / min, keeping for 4 h, then continuously heating to 1050 DEG C, keeping for 1 h, and oil cooling to room temperature. Example 5

[0076] The high-performance strong and tough hot work die steel provided in the application comprises the following raw materials in percentage by weight: C 0.3%, Si 0.3%, Co 0.2%, Mg 0.1%, Ti 0.23%, V 0.38%, Al 0.08%, Mn 0.1%, NiCrMo alloy powder 7%, P 0.05%, S 0.02%, and the balance of Fe and inevitable impurities.

[0077] The NiCrMo alloy powder is prepared according to Preparation Example 3.

[0078] The application further provides a preparation method of the high-performance strong and tough hot work die steel, comprising the following steps:

[0079] S1, raw materials are weighed according to a formula, and the raw materials are sequentially put into a vacuum induction furnace for smelting and poured into a steel ingot;

[0080] S2, the steel ingot obtained in step S1 is annealed, hot-rolled, and then air-cooled to room temperature, and then heat-treated to obtain the required die steel;

[0081] The annealing treatment specifically refers to: placing the ingot obtained in step S1 in a heating furnace, heating to 910 DEG C, keeping for 1h, then cooling to 520 DEG C at a rate of 5 DEG C / min, keeping for 2h;

[0082] The heat treatment specifically refers to: heating to 480 DEG C at a rate of 7 DEG C / min, keeping for 4h, then continuously heating to 1050 DEG C, keeping for 1h, and oil cooling to room temperature.

[0083] Comparative Example 1

[0084] The high-performance strong and tough hot work die steel provided in the application comprises the following raw materials in percentage by weight: C 0.3%, Si 0.3%, Co 0.2%, Mg 0.1%, Ti 0.23%, V 0.38%, Al 0.08%, Mn 0.1%, Ni 0.25%, Cr 5.5%, Mo 1.25%, P 0.05%, S 0.02%, and the balance of Fe and inevitable impurities.

[0085] The application further provides a preparation method of the high-performance strong and tough hot work die steel, comprising the following steps:

[0086] S1, the raw materials are weighed according to the formula, and the raw materials are sequentially put into a vacuum induction furnace for smelting and poured into an ingot;

[0087] S2, the ingot obtained in step S1 is annealed, hot-rolled and air-cooled to room temperature, and then heat-treated to obtain the required die steel;

[0088] The annealing treatment specifically refers to: placing the ingot obtained in step S1 in a heating furnace, heating to 910 DEG C, keeping for 1h, then cooling to 520 DEG C at a rate of 5 DEG C / min, keeping for 2h;

[0089] The heat treatment specifically refers to: heating to 480 DEG C at a rate of 7 DEG C / min, keeping for 4h, then continuously heating to 1050 DEG C, keeping for 1h, and oil cooling to room temperature.

[0090] Comparative Example 2

[0091] The high-performance strong and tough hot work die steel provided in the application comprises the following raw materials in percentage by weight: C 0.3%, Si 0.3%, Co 0.2%, Mg 0.1%, Ti 0.23%, V 0.38%, Al 0.08%, Mn 0.1%, NiCrMo alloy powder 7%, P 0.05%, S 0.02%, and the balance of Fe and inevitable impurities;

[0092] The NiCrMo alloy powder is prepared by Comparative Preparation Example 1.

[0093] The application further provides a preparation method of the high-performance strong and tough hot work die steel.

[0094] S1, ingredients are weighed according to a formula, and the ingredients are sequentially put into a vacuum induction furnace for smelting and pouring into a steel ingot;

[0095] S2, the steel ingot obtained in step S1 is annealed, hot-rolled and air-cooled to room temperature, and then heat-treated to obtain the required die steel.

[0096] The annealing treatment specifically refers to placing the steel ingot obtained in step S1 in a heating furnace, heating to 910 DEG C, keeping for 1 h, then cooling to 520 DEG C at a rate of 5 DEG C / min, and keeping for 2 h.

[0097] The heat treatment specifically refers to heating to 480 DEG C at a rate of 7 DEG C / min, keeping for 4 h, then continuously heating to 1050 DEG C, keeping for 1 h, and oil cooling to room temperature.

[0098] Comparative Example 3

[0099] The application provides a high-performance strong and tough hot work die steel, which comprises the following raw materials in percentage by weight: C 0.3%, Si 0.3%, Co 0.2%, Mg 0.1%, Ti 0.23%, V 0.38%, Al 0.08%, Mn 0.1%, NiCrMo alloy powder 7%, P 0.05%, S 0.02%, and the balance of Fe and inevitable impurities.

[0100] The NiCrMo alloy powder is prepared according to Comparative Preparation Example 2.

[0101] The application further provides a preparation method of the high-performance strong and tough hot work die steel, which comprises the following steps.

[0102] S1, ingredients are weighed according to a formula, and the ingredients are sequentially put into a vacuum induction furnace for smelting and pouring into a steel ingot;

[0103] S2, the steel ingot obtained in step S1 is annealed, hot-rolled and air-cooled to room temperature, and then heat-treated to obtain the required die steel.

[0104] The annealing treatment specifically refers to placing the steel ingot obtained in step S1 in a heating furnace, heating to 910 DEG C, keeping for 1 h, then cooling to 520 DEG C at a rate of 5 DEG C / min, and keeping for 2 h.

[0105] The heat treatment specifically refers to heating to 480 DEG C at a rate of 7 DEG C / min, keeping for 4 h, then continuously heating to 1050 DEG C, keeping for 1 h, and oil cooling to room temperature.

[0106] Comparative Example 4

[0107] The high-performance strong and tough hot work die steel provided in the application comprises the following raw materials in percentage by weight: C 0.3%, Si 0.3%, Co 0.2%, Mg 0.1%, Ti 0.23%, V 0.38%, Al 0.08%, Mn 0.1%, NiCrMo alloy powder 7%, P 0.05%, S 0.02%, and the balance of Fe and inevitable impurities.

[0108] The NiCrMo alloy powder is prepared according to Comparative Preparation Example 3.

[0109] The application further provides a preparation method of the high-performance strong and tough hot work die steel, comprising the following steps:

[0110] S1, the raw materials are weighed according to the formula, and the raw materials are sequentially put into a vacuum induction furnace for smelting and poured into a steel ingot;

[0111] S2, the steel ingot obtained in step S1 is annealed, hot-rolled, and then air-cooled to room temperature, and then heat-treated to obtain the required die steel;

[0112] The annealing treatment specifically refers to: the steel ingot obtained in step S1 is placed in a heating furnace, heated to 910 DEG C, and kept for 1 h, then cooled to 520 DEG C at a rate of 5 DEG C / min, and kept for 2 h;

[0113] The heat treatment specifically refers to: heating to 480 DEG C at a rate of 7 DEG C / min, keeping for 4 h, then continuously heating to 1050 DEG C, keeping for 1 h, and oil cooling to room temperature.

[0114] Comparative Example 5

[0115] The high-performance strong and tough hot work die steel provided in the application comprises the following raw materials in percentage by weight: C 0.3%, Si 0.3%, Co 0.2%, Mg 0.1%, Ti 0.23%, V 0.38%, Al 0.08%, Mn 0.1%, NiCrMo alloy powder 7%, P 0.05%, S 0.02%, and the balance of Fe and inevitable impurities;

[0116] The NiCrMo alloy powder is prepared according to Comparative Preparation Example 4.

[0117] The application further provides a preparation method of the high-performance strong and tough hot work die steel, comprising the following steps:

[0118] S1, the raw materials are weighed according to the formula, and the raw materials are sequentially put into a vacuum induction furnace for smelting and poured into a steel ingot;

[0119] S2, the steel ingot obtained in step S1 is annealed, hot-rolled, and then air-cooled to room temperature, and then heat-treated to obtain the required die steel;

[0120] The annealing treatment specifically refers to: placing the ingot obtained in step S1 in a heating furnace, heating to 910 DEG C, keeping for 1 h, then cooling to 520 DEG C at a rate of 5 DEG C / min, keeping for 2 h;

[0121] The heat treatment specifically refers to: heating to 480 DEG C at a rate of 7 DEG C / min, keeping for 4 h, then continuously heating to 1050 DEG C, keeping for 1 h, and oil cooling to room temperature.

[0122] Comparative Example 6

[0123] The high-performance strong and tough hot work die steel provided in the application comprises the following raw materials in percentage by weight: C 0.3%, Si 0.3%, Co 0.2%, Mg 0.1%, Ti 0.23%, V 0.38%, Al 0.08%, Mn 0.1%, NiCrMo alloy powder 7%, P 0.05%, S 0.02%, and the balance of Fe and inevitable impurities.

[0124] The NiCrMo alloy powder is prepared by the preparation example 1.

[0125] The application further provides a preparation method of the high-performance strong and tough hot work die steel, comprising the following steps:

[0126] S1, the raw materials are weighed according to the formula, and the raw materials are sequentially put into a vacuum induction furnace for smelting and poured into an ingot;

[0127] S2, the ingot obtained in step S1 is annealed, hot-rolled and air-cooled to room temperature, and then heat-treated to obtain the required die steel;

[0128] The annealing treatment specifically refers to: placing the ingot obtained in step S1 in a heating furnace, heating to 910 DEG C, keeping for 1 h, then cooling to 520 DEG C at a rate of 5 DEG C / min, keeping for 2 h;

[0129] The heat treatment specifically refers to: heating to 480 DEG C at a rate of 7 DEG C / min, keeping for 4 h, then continuously heating to 1050 DEG C, keeping for 1 h, and oil cooling to room temperature.

[0130] Comparative Example 7

[0131] The high-performance strong and tough hot work die steel provided in the application comprises the following raw materials in percentage by weight: C 0.3%, Si 0.3%, Co 0.2%, Mg 0.1%, Ti 0.23%, V 0.38%, Al 0.08%, Mn 0.1%, NiCrMo alloy powder 7%, P 0.05%, S 0.02%, and the balance of Fe and inevitable impurities.

[0132] The NiCrMo alloy powder is prepared by the preparation example 1.

[0133] The application further provides a preparation method of the high-performance and strong and tough hot work die steel.

[0134] S1, ingredients are weighed according to a formula, and the ingredients are sequentially put into a vacuum induction furnace for smelting and poured into a steel ingot;

[0135] S2, the steel ingot obtained in step S1 is annealed, hot-rolled and air-cooled to room temperature, and then heat-treated to obtain the required die steel;

[0136] The annealing treatment specifically refers to: the steel ingot obtained in step S1 is placed in a heating furnace, heated to 910℃, and kept for 1h, then cooled to 520℃ at a rate of 5℃ / min, and kept for 2h;

[0137] The heat treatment specifically refers to: heated to 1050℃ at a rate of 7℃ / min, kept for 5h, and oil-cooled to room temperature.

[0138] Comparative Example 8 (H13 type hot work die steel)

[0139] Performance test

[0140] The hot work die steels in Examples 1-5 and Comparative Examples 1-8 of the application are made into samples with a specification of 1000*300*19*36 (mm); the comprehensive performance of the high-performance and strong and tough hot work die steels prepared in Examples 1-5 and Comparative Examples 1-8 of the application is tested respectively;

[0141] The V-type impact toughness at -40℃ is determined according to the standard HB 5278-1984; the tensile strength and yield strength at 700℃ are determined according to the standard GB / T4338-2006; the mechanical properties at room temperature are determined according to the standard GB / T 228.1-2010, and the test results are shown in Table 1:

[0142] Table 1:

[0143]

[0144] As shown by the data in Table 1, the performance of the hot work die steels prepared in Examples 1-5 of the application is obviously improved compared with the comprehensive performance of the hot work die steels in Comparative Examples 1-4.

[0145] Compared with Example 1, no NiCrMo alloy powder is added in Comparative Example 1, and Ni, Cr and Mo are added respectively; in Comparative Examples 2-5, the NiCrMo alloy powder is selected from the NiCrMo alloy powder prepared in Comparative Preparation Examples 1-4; in Comparative Example 6, no step annealing is adopted, and only holding at 910℃ for 3h and then decreasing to room temperature; in Comparative Example 7, no step heat treatment is adopted, and only holding at 1050℃ for 5h and then oil cooling to room temperature; in Comparative Example 8, it is H13 type hot work die steel; the test results show that the hot strength and toughness of the hot work die steel prepared in the application are significantly improved.

[0146] The specific embodiments are only an explanation of the application, and are not a limitation of the application, and those skilled in the art can make modifications to the embodiments without creative contribution according to the needs after reading the specification, but as long as the modifications are within the scope of the claims of the application, they are protected by the patent law.

Claims

1. A high-performance, strong and tough hot work die steel, characterized in that, The raw materials include the following weight percentages: C 0.3-0.5%, Si 0.3-0.8%, Co 0.2-0.3%, Mg 0.1-0.14%, Ti 0.23-0.35%, V 0.38-0.56%, Al 0.08-0.14%, Mn 0.1-0.18%, NiCrMo alloy powder 7-10%, P≤0.05%, S≤0.02%, with the balance being Fe and unavoidable impurities; The NiCrMo alloy powder is prepared by the following method: Ni powder, Cr powder and Mo powder are added together to a grinder and ground to obtain a mixed powder; The mixed powder, ethanol, aminosilane coupling agent and maleic anhydride were added together into a ball mill, ball milled and mixed, and then vacuum dried to obtain NiCrMo alloy powder. The mass ratio of Ni powder, Cr powder and Mo powder is 1-1.2:22-24:5-7; The mass ratio of the mixed powder, ethanol, aminosilane coupling agent, and maleic anhydride is 1:0.1-0.2:0.003-0.005:0.0001-0.0003; The preparation method of the high-performance, high-toughness hot work die steel includes the following preparation steps: S1. Weigh the raw materials according to the formula ratio, put the raw materials into the vacuum induction furnace in sequence for melting and casting into steel ingots; S2. Anneal the steel ingot obtained in step S1, hot roll it, air cool it to room temperature, and then perform heat treatment to obtain the required mold steel. The annealing process in step S2 specifically refers to: placing the steel ingot obtained in step S1 in a heating furnace, heating it to 910-970℃, holding it at that temperature for 0.3-1h, and then cooling it down to 520-540℃ at a rate of 3-5℃ / min, holding it at that temperature for 1-2h. The heat treatment in step S2 specifically refers to: heating to 480-550℃ at a rate of 7-12℃ / min, holding at that temperature for 2-4 hours, then continuing to heat to 1050-1100℃, holding at that temperature for 0.5-1 hours, and then oil cooling to room temperature.

2. The high-performance, strong and tough hot work die steel according to claim 1, characterized in that, The raw materials include the following weight percentages: C 0.4%, Si 0.6%, Co 0.25%, Mg 0.12%, Ti 0.29%, V 0.47%, Al 0.11%, Mn 0.14%, NiCrMo alloy powder 8.5%, P 0.03%, S 0.01%, with the balance being Fe and unavoidable impurities.

3. The high-performance, strong and tough hot work die steel according to claim 1, characterized in that, The vacuum drying temperature is 220-280℃.

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