A cold working die steel material and preparation method thereof

Abstract

The invention discloses a cold working die steel material and a preparation method thereof. The cold working die steel material comprises, by mass percentage, 0.90% to 1.20% Si: 0.80% to 1.20%; Cr: 7.50% to 8.50%; Mn: 0.40% to 0.65%; Mo: 1.0% to 1.5%; V: 0.30% to 0.60%; Nb: 0.10% to 0.30%; W: 0.30% to 0.60%; P≤0.020%; S≤0.015%; Al: 0.60% to 1.00%; Co: 0.05% to 0.08%; Nd: 0.02% to 0.04%; the remainder is iron and unavoidable impurities. The present invention refers to the formula of Cr8 and introduces appropriate amounts of Al and Co, as well as the rare metal element Nd by improving the ratio of alloy elements such as Mo, V, Nb, and W. When the contents of other components are constant, the introduction of Co and Nd has a synergistic effect, which can refine the size of carbides and enhance the uniformity of carbides, while improving the stability and hardness of carbides, enhancing the resistance of carbides to peeling off from the matrix, and improving the service life of the mold steel.

Description

Technical Field

[0001] The invention relates to the technical field of cold working die steel, and in particular to a cold working die steel material and a preparation method thereof. Background Art

[0002] The use of cold stamping dies has increased year by year, and has become an important process equipment for the production of various types of sheet parts. The metal materials used as cold stamping dies are greatly affected by cold extrusion forming and blanking force during use, especially the convex and concave dies of important components. The most widely used cold working die steel materials on the current market are mainly high-carbon and high-chromium cold working die steels Cr12, Cr12MoV, Cr8 or Cr5, etc., which have high hardenability, hardenability, wear resistance, and good high-temperature oxidation resistance. Therefore, as a general-purpose cold working die steel material, it is widely used in the manufacture of cold working dies for various purposes. However, this type of cold working die steel belongs to ledeburite steel, which has high hardness, strength and wear resistance; but because the steel contains a large amount of carbide-forming elements such as Cr, Mo, and V, a large amount of eutectic carbides will be formed during solidification and eutectoid transformation, resulting in poor thermoplasticity of the steel, and surface cracks are prone to occur during forging, and the toughness is insufficient.

[0003] In order to ensure the strength, wear resistance, thermal stability of cold working die steel while improving its toughness, it can be achieved by adding transition metal elements and improving the raw material ratio. For example, CN116411220A discloses a high-toughness, low-cost cold working die steel and its preparation method, the mass ratio of which includes: C: 0.75-1.05%; Si: 0.20-0.40%; Cr: 11.5-14.5%; Mn: 0.45-0.75%, Mo: 1.0-1.5%, V: 0.30-0.60%; P≤0.020%; S≤0.020%, Nb: 0.20-0.50%, Ti: 0.01-0.15%, W: 1.0-1.6%, Y: 0.02-0.04%; the rest is Fe and other unavoidable elements. This invention improves the microstructure refinement in the steel liquid by adding titanium, tungsten and yttrium elements, increases the hardenability of the steel, increases the strength and hardness of the steel, and improves the wear resistance and toughness of the steel. CN110016617A discloses a cold working die steel and a preparation method thereof, wherein the mass ratio is: C 0.90-1.20%, Si 0.90-1.20%, Mn 0.30-0.60%, Cr7.00-9.00%, W 0.20-0.60%, Mo 0.60-1.20%, Ni 0.40-1.20%, S0.05-0.15%, Cu 0.20-0.60%, Al 0.20-0.50%, P≤0.02%, and the balance is Fe. The cold working die steel of this invention reduces the heat treatment deformation of the material while ensuring an extremely high strength and toughness ratio. The cutting performance and service life are improved.

[0004] It is still necessary to obtain cold working die steel materials with excellent performance by improving the composition. Summary of the invention

[0005] In order to overcome the problems existing in the prior art, the present invention provides a cold working die steel material, the components of which, in terms of mass percentage, include:

[0006] C: 0.90% ~ 1.20%; Si: 0.80% ~ 1.20%; Cr: 7.50% ~ 8.50%; Mn: 0.40% ~ 0.65%, Mo: 1.0% ~ 1.5%; V: 0.30% ~ 0.60%; Nb: 0.10% ~ 0.30%; W: 0.30% ~ 0.60%; P ≤ 0.020%; S ≤ 0.015%; Al: 0.60% ~ 1.00%; Co: 0.05% ~ 0.08%; Nd: 0.02% ~ 0.04%; the balance is iron and unavoidable impurities.

[0007] Further, its components include, by mass percentage,

[0008] C: 0.95% ~ 1.10%; Si: 0.90% ~ 1.10%; Cr: 7.80% ~ 8.20%; Mn: 0.50% ~ 0.60%, Mo: 1.2% ~ 1.4%; V: 0.40% ~ 0.50%; Nb: 0.15% ~ 0.25%; W: 0.40% ~ 0.50%; P ≤ 0.015%; S ≤ 0.012%; Al: 0.70% ~ 0.90%; Co: 0.06% ~ 0.075%; Nd: 0.025% ~ 0.035%; the balance is iron and unavoidable impurities.

[0009] The present invention also provides a method for preparing the above-mentioned cold working die steel material, comprising:

[0010] S1. Batching materials according to components and tapping steel after melting;

[0011] S2, putting the smelted molten steel into a refining furnace for oxygen and argon blowing refining, and then casting to obtain an ingot;

[0012] S3, raising the ingot to a first temperature and keeping the temperature, then forging to obtain a steel billet;

[0013] S4, heating the steel billet to the second temperature and keeping it at the second temperature for annealing, and then taking it out of the furnace and air cooling it:

[0014] S5. After air cooling, the temperature is raised to the third temperature for quenching and tempering to obtain cold working die steel.

[0015] Furthermore, the steel tapping temperature in S1 is 1600-1650°C.

[0016] Further, the flow rate of argon in S2 is 80 to 200 L / min;

[0017] The casting temperature is 1700-1750°C.

[0018] In S1 and S2 of the present invention, an electric arc furnace and a ladle refining furnace (LF furnace) are used respectively. The LF furnace is the main off-furnace refining equipment in steel production. Its working principle is mainly to use the white slag in the barrel, in a low-oxygen atmosphere (oxygen content is 5%), blow argon into the barrel for stirring, and use graphite electrodes to heat the molten steel that has passed through the primary refining furnace for refining. The chemical reaction between the slag and the steel is accelerated by argon stirring, and the temperature compensation is performed by electric arc heating, which can ensure a longer refining time, thereby reducing the oxygen, sulfur content and inclusion content in the steel, and at the same time, the composition of the molten steel can be more accurately controlled during the refining process.

[0019] Furthermore, in S3, the first temperature is 1200-1400° C. and the temperature is kept for 2-5 hours;

[0020] The initial forging temperature of the forging is 1100-1200° C., the final forging temperature is 850-950° C., and the forging ratio is >3.

[0021] Furthermore, the second temperature in S4 is 750-900° C. and is kept for 2-5 hours.

[0022] Furthermore, the third temperature in S5 is 950-1050°C.

[0023] Furthermore, the tempering in S5 adopts low temperature tempering or high temperature tempering.

[0024] Furthermore, the low temperature tempering temperature is 150-250°C;

[0025] The high temperature tempering temperature is 450-600°C.

[0026] Cold working die steel basically belongs to hypereutectoid steel or ledeburite steel. This type of steel will produce a segregation zone of alloy elements when the steel liquid solidifies, forming a coarse-grained structure with carbides between dendrites. In order to improve the strength and toughness of this type of steel, a forging deformation process is usually used to break the coarse-grained structure of carbides in the organization, and finally improve the performance of the steel. Subsequently, the organization structure of the die steel is controlled by adjusting the heat treatment process method or parameters, and the favorable factors for strengthening and toughening the steel are used as much as possible to make the die steel have a good combination of high strength and high toughness. It is also an effective method to adjust the chemical composition of the steel by alloying, thereby regulating the organization structure of the die steel to obtain excellent strength and toughness. Cr8 series cold working die steel reduces the content of C and Cr elements on the basis of Cr12 series die steel, and correspondingly increases the content of alloying elements such as Mo, V, Nb, and W. It belongs to high-toughness and high-wear-resistant cold working die steel. The present invention refers to the formula of Cr8 and introduces appropriate amounts of Al and Co, as well as the rare metal element Nd through improved proportions of alloy elements such as Mo, V, Nb, and W, so as to improve the strength, wear resistance, stability, toughness and service life of cold working die steel.

[0027] The main function of Al in steel is to refine the grains and fix the nitrogen in the steel. At the same time, it is also added as a deoxidizer during the smelting process. Some studies have also shown that Al also affects the pearlite morphology in the cast structure of steel. The present invention increases the proportion of Al. Adding an appropriate amount of rare earth elements during the smelting process of steel can effectively play the role of deoxidation and desulfurization, and at the same time can improve the morphology of inclusions in the steel and improve the toughness of the steel. The present invention found that the introduction of Co can improve the morphology and type of inclusions, refine the structure of the steel, and improve the martensitic substructure and the number and distribution of secondary precipitated carbides to a certain extent. The results show that the introduction of Co and Nd can refine the size of carbides and enhance the uniformity of carbides, while enhancing the stability and hardness of carbides, enhancing the resistance of carbides to peeling off from the matrix, and improving the service life of mold steel.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] The present invention refers to the formula of Cr8 and introduces appropriate amounts of Al and Co, as well as the rare metal element Nd by improving the ratio of alloy elements such as Mo, V, Nb, and W. When the contents of other components are constant, the introduction of Co and Nd has a synergistic effect, which can refine the size of carbides and enhance the uniformity of carbides, while improving the stability and hardness of carbides, enhancing the resistance of carbides to peeling off from the matrix, and improving the service life of the mold steel. DETAILED DESCRIPTION

[0030] The endpoints and any values ​​of the ranges disclosed in the present invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be regarded as specifically disclosed in the present invention.

[0031] The following will be combined with the specific embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] Example 1

[0033] A method for preparing cold working die steel material, the steps are as follows:

[0034] S1. The ingredients are prepared according to the components in Table 1, wherein iron and unavoidable impurities are residual materials and are not listed, and then the raw materials are put into an electric arc furnace for melting and steel is tapped at 1635°C;

[0035] Table 1 Mass percentage of components in Example 1

[0036] C Si Cr Mn Mo V Nb W P S Al Co Nd 0.98 1.05 8.15 0.55 1.35 0.43 0.22 0.47 0.012 0.011 0.78 0.05 0.020

[0037] S2, putting the molten steel into the LF furnace, blowing argon at an argon flow rate of 115L / min for refining, and when the temperature rises to 1720°C, putting it into a mold for casting to obtain an ingot;

[0038] S3, heating the ingot to 1350°C and keeping it warm for 3.5h, then forging, with the initial forging temperature being 1150°C, the final forging temperature being 880°C, and the forging ratio being 4, and obtaining a steel billet after the forging is completed;

[0039] S4, heating the steel billet to 850°C and keeping it at that temperature for 5 hours for annealing, and then taking it out of the furnace and air cooling it;

[0040] S5. After cooling to 25°C, heat to 1030°C and keep warm for 30 minutes, then oil cool and temper at 200°C. Temper twice to obtain cold working die steel material.

[0041] Example 2

[0042] A method for preparing cold working die steel material, the steps are as follows:

[0043] S1. The ingredients are prepared according to the components in Table 2, wherein iron and unavoidable impurities are residual materials and are not listed. The raw materials are then put into an electric arc furnace for melting and steel is tapped at 1635°C.

[0044] Table 2 Mass percentage of components in Example 2

[0045] C Si Cr Mn Mo V Nb W P S Al Co Nd 0.98 1.05 8.15 0.55 1.35 0.43 0.22 0.47 0.012 0.011 0.78 0.07 0.030

[0046] S2, putting the molten steel into the LF furnace, blowing argon at an argon flow rate of 115L / min for refining, and when the temperature rises to 1720°C, putting it into a mold for casting to obtain an ingot;

[0047] S3, heating the ingot to 1350°C and keeping it warm for 3.5h, then forging, with the initial forging temperature being 1150°C, the final forging temperature being 880°C, and the forging ratio being 4, and obtaining a steel billet after the forging is completed;

[0048] S4, heating the steel billet to 850°C and keeping it at that temperature for 5 hours for annealing, and then taking it out of the furnace and air cooling it;

[0049] S5. After cooling to 25°C, heat to 1030°C and keep warm for 30 minutes, then oil cool and temper at 200°C. Temper twice to obtain cold working die steel material.

[0050] Example 3

[0051] A method for preparing cold working die steel material, the steps are as follows:

[0052] S1. The ingredients are prepared according to the components in Table 3, wherein iron and unavoidable impurities are residual materials and are not listed, and then the raw materials are put into an electric arc furnace for melting and steel is tapped at 1635°C;

[0053] Table 3 Mass percentage of components in Example 3

[0054] C Si Cr Mn Mo V Nb W P S Al Co Nd 0.98 1.05 8.15 0.55 1.35 0.43 0.22 0.47 0.012 0.011 0.78 0.075 0.035

[0055] S2, putting the molten steel into the LF furnace, blowing argon at an argon flow rate of 115L / min for refining, and when the temperature rises to 1720°C, putting it into a mold for casting to obtain an ingot;

[0056] S3, heating the ingot to 1350°C and keeping it warm for 3.5h, then forging, with the initial forging temperature being 1150°C, the final forging temperature being 880°C, and the forging ratio being 4, and obtaining a steel billet after the forging is completed;

[0057] S4, heating the steel billet to 850°C and keeping it at that temperature for 5 hours for annealing, and then taking it out of the furnace and air cooling it;

[0058] S5. After cooling to 25°C, heat to 1030°C and keep warm for 30 minutes, then oil cool and temper at 200°C. Temper twice to obtain cold working die steel material.

[0059] Example 4

[0060] A method for preparing cold working die steel material, the steps are as follows:

[0061] S1. The ingredients are prepared according to the components in Table 4, wherein iron and unavoidable impurities are residual materials and are not listed, and then the raw materials are put into an electric arc furnace for melting and steel is tapped at 1635°C;

[0062] Table 4 Mass percentage of components in Example 4

[0063] C Si Cr Mn Mo V Nb W P S Al Co Nd 0.98 1.05 8.15 0.55 1.35 0.43 0.22 0.47 0.012 0.011 0.78 0.078 0.039

[0064] S2, putting the molten steel into the LF furnace, blowing argon at an argon flow rate of 115L / min for refining, and when the temperature rises to 1720°C, putting it into a mold for casting to obtain an ingot;

[0065] S3, heating the ingot to 1350°C and keeping it warm for 3.5h, then forging, with the initial forging temperature being 1150°C, the final forging temperature being 880°C, and the forging ratio being 4, and obtaining a steel billet after the forging is completed;

[0066] S4, heating the steel billet to 850°C and keeping it at that temperature for 5 hours for annealing, and then taking it out of the furnace and air cooling it;

[0067] S5. After cooling to 25°C, heat to 1030°C and keep warm for 30 minutes, then oil cool and temper at 200°C. Temper twice to obtain cold working die steel material.

[0068] Comparative Example 1

[0069] A method for preparing cold working die steel material, the steps are as follows:

[0070] S1. The ingredients are prepared according to the components in Table 5, wherein iron and unavoidable impurities are residual materials and are not listed, and then the raw materials are put into an electric arc furnace for melting and steel is tapped at 1635°C;

[0071] Table 5 Mass percentage of components in Comparative Example 1

[0072] C Si Cr Mn Mo V Nb W P S Al 0.98 1.05 8.15 0.55 1.35 0.43 0.22 0.47 0.012 0.011 0.78

[0073] S2, putting the molten steel into the LF furnace, blowing argon at an argon flow rate of 115L / min for refining, and when the temperature rises to 1720°C, putting it into a mold for casting to obtain an ingot;

[0074] S3, heating the ingot to 1350°C and keeping it warm for 3.5h, then forging, with the initial forging temperature being 1150°C, the final forging temperature being 880°C, and the forging ratio being 4, and obtaining a steel billet after the forging is completed;

[0075] S4, heating the steel billet to 850°C and keeping it at that temperature for 5 hours for annealing, and then taking it out of the furnace and air cooling it;

[0076] S5. After cooling to 25°C, heat to 1030°C and keep warm for 30 minutes, then oil cool and temper at 200°C. Temper twice to obtain cold working die steel material.

[0077] Comparative Example 2

[0078] A method for preparing cold working die steel material, the steps are as follows:

[0079] S1. The ingredients are prepared according to the components in Table 6, wherein iron and unavoidable impurities are residual materials and are not listed, and then the raw materials are put into an electric arc furnace for melting and steel is tapped at 1635°C;

[0080] Table 6 Comparative Example 2 Component Mass Percentage

[0081] C Si Cr Mn Mo V Nb W P S Al Co 0.98 1.05 8.15 0.55 1.35 0.43 0.22 0.47 0.012 0.011 0.78 0.07

[0082] S2, putting the molten steel into the LF furnace, blowing argon at an argon flow rate of 115L / min for refining, and when the temperature rises to 1720°C, putting it into a mold for casting to obtain an ingot;

[0083] S3, heating the ingot to 1350°C and keeping it warm for 3.5h, then forging, with the initial forging temperature being 1150°C, the final forging temperature being 880°C, and the forging ratio being 4, and obtaining a steel billet after the forging is completed;

[0084] S4, heating the steel billet to 850°C and keeping it at that temperature for 5 hours for annealing, and then taking it out of the furnace and air cooling it;

[0085] S5. After cooling to 25°C, heat to 1030°C and keep warm for 30 minutes, then oil cool and temper at 200°C. Temper twice to obtain cold working die steel material.

[0086] Comparative Example 3

[0087] A method for preparing cold working die steel material, the steps are as follows:

[0088] S1. The ingredients are prepared according to the components in Table 7, wherein iron and unavoidable impurities are residual materials and are not listed, and then the raw materials are put into an electric arc furnace for melting and steel is tapped at 1635°C;

[0089] Table 7 Comparative Example 3 Component Mass Percentage

[0090] C Si Cr Mn Mo V Nb W P S Al Nd 0.98 1.05 8.15 0.55 1.35 0.43 0.22 0.47 0.012 0.011 0.78 0.030

[0091] S2, putting the molten steel into the LF furnace, blowing argon at an argon flow rate of 115L / min for refining, and when the temperature rises to 1720°C, putting it into a mold for casting to obtain an ingot;

[0092] S3, heating the ingot to 1350°C and keeping it warm for 3.5h, then forging, with the initial forging temperature being 1150°C, the final forging temperature being 880°C, and the forging ratio being 4, and obtaining a steel billet after the forging is completed;

[0093] S4, heating the steel billet to 850°C and keeping it at that temperature for 5 hours for annealing, and then taking it out of the furnace and air cooling it;

[0094] S5. After cooling to 25°C, heat to 1030°C and keep warm for 30 minutes, then oil cool and temper at 200°C. Temper twice to obtain cold working die steel material.

[0095] Comparative Example 4

[0096] A method for preparing cold working die steel material, the steps are as follows:

[0097] S1. The ingredients are prepared according to the components in Table 8, wherein iron and unavoidable impurities are residual materials and are not listed, and then the raw materials are put into an electric arc furnace for melting and steel is tapped at 1635°C;

[0098] Table 8 Comparative Example 4 Component Mass Percentage

[0099] C Si Cr Mn Mo V Nb W P S Co Nd 0.98 1.05 8.15 0.55 1.35 0.43 0.22 0.47 0.012 0.011 0.07 0.030

[0100] S2, putting the molten steel into the LF furnace, blowing argon at an argon flow rate of 115L / min for refining, and when the temperature rises to 1720°C, putting it into a mold for casting to obtain an ingot;

[0101] S3, heating the ingot to 1350°C and keeping it warm for 3.5h, then forging, with the initial forging temperature being 1150°C, the final forging temperature being 880°C, and the forging ratio being 4, and obtaining a steel billet after the forging is completed;

[0102] S4, heating the steel billet to 850°C and keeping it at that temperature for 5 hours for annealing, and then taking it out of the furnace and air cooling it;

[0103] S5. After cooling to 25°C, heat to 1030°C and keep warm for 30 minutes, then oil cool and temper at 200°C. Temper twice to obtain cold working die steel material.

[0104] Test Case

[0105] The eutectic carbide inhomogeneity rating was performed with reference to the standard GB / T 14979-1994 “Evaluation Method for Eutectic Carbide Inhomogeneity of Steel”. The results are shown in Table 9. Generally speaking, the lower the rating, the more uniform the eutectic carbide.

[0106] Table 9 Eutectic carbide unevenness rating results

[0107] Eutectic Carbide Inhomogeneity Rating Example 1 Level 1 Example 2 Level 1 Example 3 Level 1 Example 4 Level 2 Comparative Example 1 Level 3 Comparative Example 2 Level 3 Comparative Example 3 Level 3 Comparative Example 4 Level 4

[0108] It can be seen from the results in Table 9 that, compared with the comparative example, the cold working die steel material prepared in the embodiment of the present invention has better eutectic carbide uniformity. This is because the presence of higher Al in the formula can refine the grains and fix nitrogen, and the introduction of Co and Nd can refine the size of carbides and enhance the uniformity of carbides.

[0109] Referring to the standard GB / T 229-2020 “Charpy Pendulum Impact Test Method for Metallic Materials”, the room temperature impact energy values ​​of the cold working die steel materials prepared in the embodiments and comparative examples were tested. The size of the sample was 10 mm × 10 mm × 55 mm, and there was a V-notch in the middle of the sample. The results are shown in Table 10.

[0110] Table 10 Transverse impact energy value results at room temperature

[0111] Transverse impact energy value at room temperature (J) Example 1 4.95 Example 2 5.23 Example 3 5.08 Example 4 4.98 Comparative Example 1 3.96 Comparative Example 2 4.05 Comparative Example 3 4.23 Comparative Example 4 2.87

[0112] From the results in Table 10, it can be seen that the cold-working die steel material prepared in the embodiment of the present invention also has stronger toughness, because the introduction of Nd has the effect of deoxidation and desulfurization and improves the morphology of inclusions in the steel; the introduction of Co can improve the morphology and type of inclusions, refine the organization of steel, improve the number and distribution of martensitic substructure and secondary precipitation carbides to a certain extent, and the introduction of Co and Nd has a synergistic effect, which can refine the size of carbides and enhance the uniformity of carbides, while improving the stability and hardness of carbides, enhancing the resistance of carbides to peeling off from the matrix, and refining the organization of steel, thereby improving the toughness of the material. At the same time, the different impact energies of Examples 1 to 4 also show that appropriate Co and Nd doping can further optimize toughness.

[0113] The wear resistance of the cold working die steel materials prepared in the embodiments and comparative examples was tested using a pin-on-disc friction and wear tester. The samples were discs with a diameter of 20 mm and a thickness of 3 mm. The grinding material was a SiC steel ball with a diameter of 5 mm. The grinding was carried out without lubrication at a load of 60 N and a speed of 500 rpm for 1 h. The grinding volume is shown in Table 11.

[0114] Table 11 Grinding volume results

[0115]

[0116]

[0117] It can also be seen from the test results in Table 11 that the embodiments of the present invention also have stronger wear resistance.

[0118] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A cold working die steel material, characterized in that: The components in mass percentage include: C: 0.90%~1.20%; Si: 0.80%~1.20%; Cr: 7.50%~8.50%; Mn: 0.40%~0.65%, Mo: 1.0%~1.5%; V: 0.30%~0.60%; Nb: 0.10%~0.30%; W: 0.30%~0.60%; P≤0.020%; S≤0.015%; Al：0.70%~0.90%； Co: 0.06%~0.075%; Nd: 0.025%~0.035%; the balance is iron and inevitable impurities.

2. A method for preparing a cold working die steel material as claimed in claim 1, characterized in that: include, S1. Batching materials according to components and tapping steel after melting; S2, putting the smelted molten steel into a refining furnace for argon blowing refining, and then casting to obtain an ingot; S3, raising the ingot to a first temperature and keeping the temperature, then forging to obtain a steel billet; S4, heating the steel billet to the second temperature and keeping it at the second temperature for annealing, and then taking it out of the furnace and air cooling it: S5. After air cooling, the temperature is raised to the third temperature for quenching and tempering to obtain cold working die steel.

3. The method for preparing cold working die steel material according to claim 2, characterized in that: The tapping temperature in S1 is 1600-1650°C.

4. The method for preparing cold working die steel material according to claim 2, characterized in that: The flow rate of argon in S2 is 80-200 L / min; The casting temperature is 1700-1750°C.

5. The method for preparing cold working die steel material according to claim 2, characterized in that: In S3, the first temperature is 1200-1400° C. and the temperature is kept for 2-5 hours; The initial forging temperature of the forging is 1100-1200°C, the final forging temperature is 850-950°C, and the forging ratio is >3.

6. The method for preparing cold working die steel material according to claim 2, characterized in that: The second temperature in S4 is 750-900° C. and is kept for 2-5 hours.

7. The method for preparing cold working die steel material according to claim 2, characterized in that: The third temperature in S5 is 950-1050°C.

8. The method for preparing cold working die steel material according to claim 2, characterized in that: The tempering in S5 may be low temperature tempering or high temperature tempering.

9. The method for preparing cold working die steel material according to claim 8, characterized in that: The low temperature tempering temperature is 150~250℃; The high temperature tempering temperature is 450-600°C.

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