CN113881899B - Preparation method of high-strength and high-toughness steel for hot forging die - Google Patents
Preparation method of high-strength and high-toughness steel for hot forging die Download PDFInfo
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21J—FORGING; HAMMERING; PRESSING METAL; RIVETING; FORGE FURNACES
- B21J13/00—Details of machines for forging, pressing, or hammering
- B21J13/02—Dies or mountings therefor
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/10—Handling in a vacuum
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
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- C21D1/26—Methods of annealing
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- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/26—Methods of annealing
- C21D1/32—Soft annealing, e.g. spheroidising
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- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/005—Modifying the physical properties by deformation combined with, or followed by, heat treatment of ferrous alloys
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- C22B9/00—General processes of refining or remelting of metals; Apparatus for electroslag or arc remelting of metals
- C22B9/16—Remelting metals
- C22B9/18—Electroslag remelting
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- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
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- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
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- C22C38/24—Ferrous alloys, e.g. steel alloys containing chromium with vanadium
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- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
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- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/009—Pearlite
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Abstract
The invention discloses a preparation method of high-strength and high-toughness steel for a hot forging die, which comprises the steps of electric furnace smelting of pig iron, LF furnace refining and VD vacuum degassing; die casting is carried out under the protection of argon, and shot blasting or grinding treatment is carried out on the electrode blank; carrying out electroslag remelting on a casting blank under a protective atmosphere; annealing the electroslag ingot, homogenizing the electroslag ingot at high temperature, forging and forming, performing heat treatment after forging, machining a die and performing ultrasonic flaw detection to obtain the high-strength and high-toughness steel for the hot forging die. The high-toughness hot forging die steel ensures the high toughness of the hot working die steel, obviously improves the room temperature strength, has the hardness of more than 50-56HRC and the tensile strength of about 2000MPa, keeps the unnotched impact energy of more than 300J and has excellent comprehensive performance.
Description
Technical Field
The invention belongs to the technical field of ferrous metallurgy, and particularly relates to a preparation method of high-toughness steel for a hot forging die.
Background
With the continuous development of the mold manufacturing industry, the requirements on the metallurgical quality and the performance of the mold steel are continuously improved, the mold material is continuously developed from low grade to high grade, a series of novel mold materials appear in succession, and the alloying degree is also gradually improved. The research and development and production of die steel in China are rapidly developing towards the directions of multiple varieties, large sections and refinement, and high-performance and long-life die materials must be continuously developed to occupy a place in the future die steel market.
The hot forging die is a die used in a high-temperature forging process, and has extremely high requirements on die materials due to the fact that the die needs to bear severe conditions such as high temperature, heavy load and the like in the working process, good high-temperature strength needs to be achieved, good toughness needs to be achieved, and the production technology is extremely difficult, so that the hot forging die almost depends on import at present although the market demand is huge. Under the background, the high-strength and high-toughness hot forging die steel with various performance indexes reaching the international advanced level becomes a difficult problem to be solved urgently in the field of domestic metallurgy.
Disclosure of Invention
The invention aims to provide a preparation method of high-toughness hot forging die steel, which ensures the high toughness of hot die steel, remarkably improves the room temperature strength, has the hardness of more than 50 to 56HRC and the tensile strength of about 2000MPa, keeps the unnotched impact energy of more than 300J and has excellent comprehensive performance.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
in a first aspect, the present invention provides a high strength and toughness hot forging die steel, the high strength and toughness hot forging die comprising at least the following types of components: C. any one or a mixture of at least two of the elements Si, mn, cr, mo or V, for example, a combination of C, si, mn, cr, mo and V, or the like.
Preferably, the high-strength and high-toughness hot forging die steel at least comprises the following components in percentage by mass:
C： 0.45~0.60%
Si： 0.10~0.30%
Mn： 0.40~0.60%
Cr： 4.50~5.50%
Mo： 2.00~3.00%
V： 0.30~0.60%，
the balance of Fe and inevitable impurities.
Wherein the content of C can be 0.45%, 0.46%, 0.47%, 0.48%, 0.49%, 0.5%, 0.51%, 0.52%, 0.53%, 0.54%, 0.55%, 0.56%, 0.57%, 0.58%, 0.59%, 0.6% and all values in the range, which are not described again due to space limitation;
the content of Si may be 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.19%, 0.20%, 0.21%, 0.22%, 0.23%, 0.24%, 0.25%, 0.26%, 0.27%, 0.28%, 0.29%, 0.3% and all values within the range, which will not be described again due to space limitation;
the content of Mn may be 0.41%, 0.42%, 0.43%, 0.44%, 0.45%, 0.46%, 0.47%, 0.48%, 0.49%, 0.50%, 0.51%, 0.52%, 0.53%, 0.54%, 0.55%, 0.56%, 0.57%, 0.58%, 0.59%, 0.6%, and all values within the ranges, which will not be described herein due to space limitations;
the content of Cr may be 0.45%, 0.46%, 0.47%, 0.48%, 0.49%, 0.50%, 0.51%, 0.52%, 0.53%, 0.54%, 0.55% and all values within the ranges, which are not described again due to space limitation;
the content of Mo may be 2.00%, 2.10%, 2.20%, 2.30%, 2.40%, 2.50%, 2.60%, 2.70%, 2.80%, 2.90%, 3.00% and all values within the ranges, which are not described in detail due to space limitations;
the content of V may be 0.30%, 0.35%, 0.40%, 0.45%, 0.50%, 0.55%, 0.60% and all values within the stated ranges, which will not be described again due to space limitations.
In a second aspect, the present invention provides a method for producing a high-toughness hot forging die steel according to the first aspect, including at least the steps of:
1) Electric furnace smelting of pig iron, LF furnace refining and VD (ladle refining furnace) vacuum degassing; 2) Carrying out die casting under the protection of argon, and carrying out shot blasting or grinding treatment on the electrode blank; 3) Carrying out electroslag remelting on a casting blank under a protective atmosphere; 4) Annealing the electroslag ingot; 5) Carrying out high-temperature homogenization treatment on the electroslag ingot; 6) Forging and forming; 7) Heat treatment after forging; 8) Die machining and ultrasonic inspection.
Preferably, in the step 1), pig iron is added into an electric furnace, the content of C is kept to be more than or equal to 0.10 percent before tapping of the electric furnace, and molten metal is prevented from being oxidized; and controlling the contents of P, S and C in the steel and the tapping temperature in real time before tapping of the electric furnace.
Preferably, in step 1), during tapping, a carburant is added (in the ratio of example: for example, 15 to 20 tons of pig iron, and about 50kg of recarburizer) to deoxidize carbon.
Preferably, in the step 1), in the refining process of the molten steel in the LF furnace, any one or a mixture of at least two of Al powder, C powder and calcium carbide is adopted for diffusion deoxidation; alloy raw materials containing Mn, V, cr and Mo are added into the molten steel, and elements of Mn, V, cr and Mo are supplemented into the molten steel.
Preferably, in the step 1), before VD vacuum degassing, the FeO content is ensured to be less than or equal to 0.50% (for example, 0.45%, 0.40%, 0.35%, 0.30% and the like can be ensured), and the white slag is kept for more than 20 min; in the VD vacuum treatment process, the maintaining time of the vacuum degree (Torr =0.5,1 Torr 8194; 133.322= Pa) is more than 20min.
Preferably, in step 1), the molten steel is vacuum degassed in VD to ensure that the H content is less than or equal to 2.0ppm (and may be, for example, 1.5ppm, 1.0 ppm, 0.5 ppm, etc.) and the free oxygen content is less than or equal to 5ppm (and may be, for example, 4 ppm, 3 ppm, 2 ppm, 1 ppm, etc.).
Preferably, in the step 3), pseudo-ginseng slag is used for electroslag remelting; in the pseudo-ginseng slag, caF 2 And Al 2 O 3 The mass ratio of (A) to (B) is 7:3; steel scraps and/or fluorite powder are/is adopted as a slagging and arc striking agent so as to avoid titanium increase. The slagging and arc striking agent does not allow the use of titanium-containing conductive slag and steel scrap arc striking to take preventive measures (such as increasing the thickness of a dummy bar, broken steel scrap and the like)。
Preferably, in step 6), the ingot is forged after being diffused at a high temperature of 1270 ℃, the ingot is forged by using a one-shot ingot with integral upsetting of an inter-plate cylinder, the height-to-edge ratio after upsetting is 0.8 to 1.0 (for example, 0.82, 0.84, 0.86, 0.88, 0.90, 0.92, 0.94, 0.96, 0.98, etc.), and the ingot is drawn out by using an FM method (forging method without mannesmann effect) for the purpose of breaking up coarse cast structures and massive carbides; the second fire blank is subjected to integral upsetting, the height and the edge-to-width ratio after upsetting are 0.8-1.0 (for example, 0.82, 0.84, 0.86, 0.88, 0.90, 0.92, 0.94, 0.96, 0.98 and the like), and a WHF method (Wide Die gravity blow) is adopted for drawing and blanking, so that the compactness of the structure is ensured; the final furnace temperature is 1230-1250 ℃, and the height-to-width ratio after upsetting is 1.8-2.2 (for example, 1.82, 1.84, 1.86, 1.88, 1.90, 1.92, 1.94, 1.96, 1.98, 2.00, 2.10, etc.).
Preferably, in step 7), after forging, the blank is put into an annealing furnace to be fed in at least 700 ℃ (830 to 850 ℃) as soon as possible, then the temperature is raised (the heating rate is at least 100 ℃/h) to 1000-1040 ℃ (for example, 1000 ℃, 1005 ℃, 1010 ℃, 1015 ℃, 1020 ℃, 1025 ℃, 1030 ℃, 1035 ℃ and 1040 ℃) and is preserved for 8 to 10 hours, the austenite structure is homogenized, and then the blank is slowly cooled to 700-760 ℃ (for example, 700 ℃, 710 ℃, 720 ℃, 730 ℃, 740 ℃, 750 ℃ and 760 ℃) and is preserved for 15 to 20 hours, so that the pearlite transformation of the structure is generated; then heating (heating rate is more than or equal to 100 ℃/h) to 1000-1040 ℃ (for example, 1000 ℃, 1005 ℃, 1010 ℃, 1015 ℃, 1020 ℃, 1025 ℃, 1030 ℃, 1035 ℃ and 1040 ℃) (10-15 hours), re-nucleating and austenitizing again to refine grains and homogenize the structure; then, water-air alternate cooling is carried out to avoid the precipitation of the net-shaped carbide; finally, spheroidizing annealing is carried out to spheroidize the structure, so as to obtain a uniform structure of granular pearlite and granular carbide.
Preferably, in the water-air alternative cooling process in the step 7), water-air alternative rapid cooling is adopted to reduce the surface temperature of the forge piece to 250-300 ℃, then the temperature is kept in a low-temperature furnace at 300-350 ℃ for 8-10 hours, then the temperature is rapidly increased (more than or equal to 100 ℃/h) to about 750 ℃ and kept for 3 hours, then the temperature is rapidly increased (more than or equal to 100 ℃/h) again to about 830 ℃ and kept for 20-25 hours, and finally the furnace is cooled to about 500 ℃ and is taken out of the furnace for air cooling.
Preferably, the uniform structure obtained in the step 7) is subjected to die machining and ultrasonic flaw detection to obtain the high-strength and high-toughness steel for the hot forging die.
The technical effects of the invention include:
1. the high-toughness hot forging die steel provided by the invention not only ensures the high toughness of the existing hot forging die steel, but also obviously improves the room temperature strength, and through detection, the hardness can reach 50-56HRC, the tensile strength is about 2000MPa, the unnotched impact energy is kept above 300J, and the comprehensive performance is excellent. Compared with the prior heat treatment process after forging, the process can avoid the rework heat treatment process, the one-time qualification rate of the product is 100 percent, the stability of the product quality is obviously improved, the production cost is reduced, and the process has good popularization and application prospects.
2. The process can effectively refine the uniform structure of the crystal grains, obtain the ideal structure of uniform and fine granular pearlite and the dispersed and distributed point-shaped carbide, eliminate structural stress and thermal stress, reduce the hydrogen content in the steel, avoid the defects of white spots, hydrogen embrittlement and the like, obviously improve the comprehensive mechanical property and prolong the service life.
Detailed Description
The following describes embodiments of the present invention in detail.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples described in this specification can be combined and combined by those skilled in the art.
Example 1
1) Electric furnace smelting, LF furnace refining and VD vacuum degassing;
in the step 1), before tapping of the electric furnace, the content of C is kept to be more than or equal to 0.10 percent; adding pig iron into an electric furnace, and keeping the content of C to be more than or equal to 0.10% before tapping of the electric furnace, so as to prevent molten metal from being oxidized; controlling the contents of P, S and C in steel and the tapping temperature in real time before tapping of the electric furnace;
during the tapping process, firstly adding a carburant for carbon deoxidation, and then adding alloy elements. During the tapping process, firstly adding carburant (the adding proportion is for example 15-20 tons of pig iron, and the carburant is added by about 50 kg) for carbon deoxidation; in the process of refining molten steel in an LF (ladle furnace), any one or a mixture of at least two of Al powder, C powder and calcium carbide is adopted for diffusion deoxidation; adding alloy raw materials containing Mn, V, cr and Mo into the molten steel, and supplementing Mn, V, cr and Mo into the molten steel.
Before VD vacuum degassing, the FeO content is ensured to be less than or equal to 0.50 percent, and the white slag is kept for more than 20 min; in the VD vacuum processing, the vacuum degree (Torr) = 0.5) is maintained for more than 20min.
After VD vacuum degassing, the H content is ensured to be less than or equal to 2.0ppm, and the free oxygen content is ensured to be less than or equal to 5ppm.
2) Carrying out die casting, electrode blank shot blasting or grinding under the protection of argon;
3) Carrying out electroslag remelting in a protective atmosphere;
carrying out electroslag remelting on pseudo-ginseng slag containing CaF 2 And Al 2 O 3 The mass ratio of (A) to (B) is 7: and 3, adopting steel scraps and/or fluorite powder as a slagging and arc striking agent.
The slagging and arc striking agent does not allow the use of titanium-containing conductive slag, and steel scrap arc striking needs to take preventive measures (such as increasing the thickness of a dummy plate and crushing steel scraps), and steel scrap and fluorite powder are adopted to avoid titanium increase.
4) Annealing the electroslag ingot;
5) Homogenizing the steel ingot at high temperature;
6) Forging and forming;
the steel ingot is forged after high-temperature diffusion at 1270 ℃, the steel ingot is upset integrally by adopting a cylinder between flat plates, the height-diameter ratio after upset is controlled to be 0.8-1.0, and the steel ingot is drawn and blanked by adopting an FM (forging method without Mannesmann effect) method, so as to break up coarse cast structures and massive carbides. The second fire blank is subjected to integral upsetting, the height-to-side width ratio after upsetting is controlled to be 0.8-1.0, and a WHF (Wide Die gravity Blow forming) method is adopted for drawing and blanking to ensure the compactness of the structure. The temperature of the last furnace is 1230-1250 ℃, and the forging ratio is controlled between 1.8-2.2.
7) Heat treatment after forging;
and (3) putting the forged blank into an annealing furnace to be fed at the temperature of more than or equal to 700 ℃ as soon as possible after forging, heating to the temperature of between 1000 and 1040 ℃, keeping the temperature, homogenizing the austenite structure, slowly cooling to the temperature of between 700 and 760 ℃, and keeping the temperature to ensure that the structure generates pearlite transformation. According to the invention, starting from the structure transformation rule of the steel, after forging, the temperature is quickly raised to A cm （A cm : the final temperature of the secondary cementite completely dissolved into austenite during heating) above 80 ℃ for a long time, the network carbide precipitated in the forging process can be fully dissolved, the original coarse grains are eliminated, and a fine and small austenite structure is obtained.
Then heating to 1000-1040 ℃, preserving heat, re-nucleating austenitizing to refine grains and uniform structure, and then performing water-air alternate cooling to avoid the precipitation of net-shaped carbide. Then rapidly heating to A again C3 （A c3 : the final temperature at which the proeutectoid ferrite is completely converted into austenite during heating) above 30 ℃ for a long time, more uniform and fine austenite and a large amount of dispersed undissolved cementite crystal nuclei can be obtained.
Then the temperature is kept at the low temperature of 300 to 350 ℃, the quenching stress is eliminated, the generation of quenching cracks is avoided, and finally the temperature is quickly raised to A again C1 （A C1 : the initial temperature of pearlite transformed into austenite during heating) is kept at about 30 ℃, martensite, bainite and residual austenite are gradually decomposed, and carbide is largely precipitated, aggregated and spheroidized by taking a cementite crystal nucleus as a core, so that uniform and fine granular pearlite and dispersed distribution are finally obtainedGranular carbide structure. Through the process of water-air alternating rapid cooling, secondary carbides are prevented from being separated out along a grain boundary, and an integrated structure of martensite, lower bainite, cementite crystal nucleus and a small amount of residual austenite is obtained. And finally, spheroidizing the structure by spheroidizing annealing to obtain a uniform structure of granular pearlite and granular carbide, and preparing the structure for machining a die and final heat treatment.
8) Mould machining and ultrasonic flaw detection.
And carrying out die machining and ultrasonic flaw detection on the obtained uniform structure to obtain the high-strength and high-toughness steel for the hot forging die.
Comparative example 1
Hot work die steel 5CrNiMo produced by certain metal materials (shanghai) limited.
Comparative example 2
Hot work die steel 4Cr produced by certain metallic Material (Dongguan) Co., ltd 5 MoSiV。
And (3) performance testing:
example 1, comparative example 1 and comparative example 2 were subjected to various performance tests at room temperature (25. + -. 1 ℃ C.) and the results are shown in Table 1, each of which was repeated 10 times. As can be seen from Table 1, compared with comparative example 1 and comparative example 2, the high-toughness hot forging die steel of example 1 not only ensures the high toughness of the hot die steel, but also obviously improves the room temperature strength, the hardness reaches more than 50-56HRC, the tensile strength is about 2000MPa, the unnotched impact energy is kept more than 300J, and the comprehensive performance is excellent; the one-time qualification rate of the product is 100 percent, the stability of the product quality is obviously improved, the production cost is reduced, and the method has good popularization and application prospects. The comparative examples 1 and 2 belong to the prior art, the hardness, the tensile strength and the unnotched impact energy are obviously lower than those of the invention, and the product percent of pass is also obviously lower than 100%.
TABLE 1 Performance test results
| Hardness (HRC) | Tensile strength (MPa) | Retention of unnotched ballistic work (J) | First pass percent of product (%) | |
| Example 1 | 50-56 | 2000-2021 | 300-350 | 100 |
| Comparative example 1 | 40-45 | 1500-1600 | 250-300 | 90 |
| Comparative example 2 | 40-50 | 1600-1750 | 250-300 | 80 |
It is to be noted and understood that various modifications and improvements can be made to the invention described in detail above without departing from the spirit and scope of the invention as claimed in the appended claims. Accordingly, the scope of the claimed subject matter is not limited by any of the specific exemplary teachings provided.
The applicants hereby give notice that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. For those skilled in the art to which the invention pertains, numerous simple deductions or substitutions may be made without departing from the spirit of the invention, which shall be deemed to belong to the scope of the invention.
Claims (1)
1. The preparation method of the steel for the high-strength and high-toughness hot forging die is characterized in that the steel is smelted in an electric furnace by pig iron, the content of C is kept to be more than or equal to 0.10 percent before the steel is tapped from the electric furnace, molten metal is prevented from being oxidized, and the content of P, S and C in the steel and the tapping temperature are controlled in real time before the steel is tapped from the electric furnace; refining in an LF furnace and vacuum degassing by VD, wherein in the refining process of the LF furnace, any one or a mixture of at least two of Al powder, C powder or calcium carbide is adopted for diffusion deoxidation; adding alloy raw materials containing Mn, V, cr and Mo into the molten steel, and supplementing Mn, V, cr and Mo into the molten steel; before VD vacuum degassing, the content of FeO is ensured to be less than or equal to 0.50 percent, and the white slag is kept for more than 20 min; after VD vacuum degassing, ensuring that the H content is less than or equal to 2.0ppm and the free oxygen content is less than or equal to 5ppm, and performing die casting under the protection of argon;
carrying out electroslag remelting on the steel ingot in a protective atmosphere by using pseudo-ginseng slag, wherein CaF in the pseudo-ginseng slag 2 And Al 2 O 3 The mass ratio of (A) to (B) is 7:3;
steel scraps and/or fluorite powder are/is adopted as a slagging and arc striking agent; annealing an electroslag ingot, performing high-temperature homogenization treatment, forging and forming, and performing heat treatment after forging; the steel ingot is forged after high-temperature diffusion at 1270 ℃, the steel ingot of the first heating adopts a cylinder between flat plates to carry out integral upsetting, the height-to-edge ratio after upsetting is 0.8-1.0, and the forging method without Mannesmann effect is adopted to carry out drawing blanking so as to break coarse cast-state tissues and massive carbides; the second-fire blank is subjected to integral upsetting, the height-to-edge width ratio after upsetting is 0.8-1.0, and the blank is drawn and blanked by adopting a wide anvil strong pressing forging method, so that the compactness of the texture is ensured; the temperature of the last furnace is 1230-1250 ℃, and the height and the edge width ratio after upsetting are 1.8-2.2;
after forging, putting the material into an annealing furnace at 830-850 ℃ for feeding, heating to 1000-1040 ℃, keeping the temperature for 8-10 hours, wherein the heating rate is more than 100 ℃/h, homogenizing an austenite structure, slowly cooling to 700-760 ℃, keeping the temperature for 15-20 hours, and enabling the structure to generate pearlite transformation; then heating to 1000-1040 ℃ and preserving heat for 10-15 hours, wherein the heating rate is more than 100 ℃/h, and re-austenitizing to refine grains and uniform tissues; then, alternately cooling in water and air to avoid the precipitation of the net-shaped carbide, and in the alternately cooling in water and air, reducing the surface temperature of the forge piece to 250 to 300 ℃ by alternately cooling in water and air, and then keeping the temperature in a low-temperature furnace at 300 to 350 ℃ for 8 to 10 hours to eliminate the quenching stress; then heating to 740 to 760 ℃ again at the heating rate of more than 100 ℃/h, preserving the heat for 2 to 4 hours, then heating to 820 to 840 ℃ again at the heating rate of more than 100 ℃/h, preserving the heat for 20 to 25 hours, and finally cooling the furnace to below 500 ℃ and taking out the furnace for air cooling; finally, spheroidizing annealing is carried out to spheroidize the structure to obtain a uniform structure of granular pearlite and granular carbide;
the electroslag ingot is processed by a die machine and subjected to ultrasonic flaw detection to obtain the high-strength and high-toughness steel for the hot forging die, and the high-strength and high-toughness steel for the hot forging die at least comprises the following components in percentage by mass: c: 0.45 to 0.60%, si: 0.10 to 0.30%, mn: 0.40 to 0.60%, cr: 4.50 to 5.50 percent, mo: 2.00 to 3.00%, V: 0.30 to 0.60 percent, and the balance of Fe and inevitable impurities.
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| CN104046915A (en) * | 2014-04-28 | 2014-09-17 | 如皋市宏茂重型锻压有限公司 | Large-section high-performance hot work die steel for die casting and preparation technology thereof |
| CN108193023A (en) * | 2017-12-01 | 2018-06-22 | 内蒙古北方重工业集团有限公司 | The method for eliminating net carbide in H13 mould steel annealing microscopic structure |
| CN109468537A (en) * | 2018-12-25 | 2019-03-15 | 上海合毓模具技术有限公司 | A kind of novel advanced hot stamping die steel HS8 and preparation method thereof |
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| CN104046915A (en) * | 2014-04-28 | 2014-09-17 | 如皋市宏茂重型锻压有限公司 | Large-section high-performance hot work die steel for die casting and preparation technology thereof |
| CN108193023A (en) * | 2017-12-01 | 2018-06-22 | 内蒙古北方重工业集团有限公司 | The method for eliminating net carbide in H13 mould steel annealing microscopic structure |
| CN109468537A (en) * | 2018-12-25 | 2019-03-15 | 上海合毓模具技术有限公司 | A kind of novel advanced hot stamping die steel HS8 and preparation method thereof |
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