Rolling method for h13 die cast steel ingot

Abstract

This invention discloses a rolling method for H13 die-cast steel ingots, belonging to the technical field of die steel rolling production processes. It provides a rolling method for H13 die-cast steel ingots that significantly reduces production costs, effectively breaks and welds the core carbides of the ingot, and improves the rolling flaw detection pass rate. The rolling method includes H13 die-cast steel ingots with carbide-forming elements Cr, Mo, and V content not exceeding 9%. The rolling method involves first obtaining a heated H13 die-cast steel ingot through high-temperature short-time heating, then subjecting the high-temperature H13 die-cast steel ingot to carbide-breaking rolling and tempering compaction rolling to obtain a fully carbide-broken H13 die-cast steel initial rolled billet. Next, the H13 die-cast steel initial rolled billet undergoes high-temperature homogenization treatment to obtain a fully and uniformly diffused H13 die-cast steel initial rolled billet. Finally, continuous rolling and annealing treatment are performed to obtain H13 round bars with uniform composition, fully broken and welded core carbides, and a flaw detection pass rate meeting requirements.

Description

Technical Field

[0001] This invention relates to a rolling method, and more particularly to a rolling method for H13 die-cast steel ingots, belonging to the technical field of die steel rolling production process. Background Technology

[0002] H13 is a high-alloy tool steel containing approximately 8% carbide-forming elements such as Cr, Mo, and V. During the casting and solidification process, the core of the ingot cools the slowest, causing severe segregation of alloying elements in the last solidified regions, such as between dendrites and grain boundaries. This results in the enrichment of high-melting-point liquid carbides distributed in a network, chain, or blocky pattern at the original austenite grain boundaries. These carbides are large, hard, and brittle. When distributed in a network structure along the grain boundaries, they severely disrupt the continuity of the matrix. During the rolling process, under the rolling force, they easily become crack initiation points, leading to intergranular cracking at the core and ultimately resulting in the finished product failing inspection.

[0003] To address the above issues, most manufacturers currently employ continuous casting and powder metallurgy to fundamentally resolve carbide segregation, thereby avoiding rolling cracking problems caused by liquefied carbides. For H13 products produced by ingot casting, prolonged high-temperature homogenization is often used to fully dissolve and diffuse the liquefied carbides, supplemented by repeated upsetting and forging to ensure thorough breakage and welding with the base material. However, due to the unique deformation characteristics of rolling production, repeated upsetting and forging cannot be performed as effectively as in forging, thus significantly limiting the breakage and welding of carbides, especially in areas with severe carbide segregation in the ingot core. Furthermore, prolonged high-temperature homogenization not only significantly increases energy costs but also drastically increases the oxidation loss of the steel. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a rolling method for H13 die-cast steel ingots that significantly reduces production costs, effectively breaks and welds the core carbides of steel ingots, and improves the rolling flaw detection pass rate.

[0005] The technical solution adopted to solve the above-mentioned technical problems is: a rolling method for H13 ingot casting, including H13 ingot casting with carbide-forming elements Cr, Mo and V content not exceeding 9%. The rolling method is as follows: first, a heated H13 ingot casting is obtained by high-temperature short-time heating; then, the high-temperature H13 ingot casting is subjected to carbide crushing rolling and tempering compaction rolling to obtain a fully crushed H13 ingot casting steel initial rolled billet; next, the H13 ingot casting steel initial rolled billet is subjected to high-temperature homogenization treatment to obtain a fully and uniformly diffused H13 ingot casting steel initial rolled billet; finally, continuous rolling and annealing are performed to obtain H13 round bars with uniform composition, fully crushed and welded core carbides, and a flaw detection pass rate that meets the requirements.

[0006] Furthermore, the high-temperature short-time heating is carried out using a red-hot method. Before entering the furnace, the surface temperature of the H13 ingot is not lower than 400°C. After entering the furnace, it is held at 600°C for 2 hours, then heated to 850°C at a rate of 100°C / h, held for 2 hours, and then heated to 1200°C at a rate of 100°C / h, and held for 3 hours to complete the high-temperature short-time heating of the H13 ingot.

[0007] The preferred method for the above scheme is to control the number of rolling passes and the corresponding reduction rate of carbide crushing rolling according to the following table.

[0008] .

[0009] Furthermore, in the tempering process of compaction rolling, the H13 die-cast steel ingot, after the carbides are fully crushed, is placed in a high-temperature heating furnace and held at 1200℃ for 3 hours before being compacted and rolled.

[0010] The preferred method for the above scheme is to control the number of rolling passes and the corresponding reduction rate in the compaction rolling process according to the table below.

[0011] , The cross-sectional dimensions of the H13 die-cast steel initial rolled square billet obtained after initial rolling are 220×220 mm.

[0012] Furthermore, the high-temperature homogenization treatment of the crushed carbides was carried out according to the following steps:

[0013] First, the H13 die-cast steel initial rolled square billet is cut into the specified size that meets the requirements of the heating furnace. Then, it is placed in the high-temperature heating furnace and held at 1250℃ for 5 hours before being taken out of the furnace for continuous rolling.

[0014] The preferred method of the above scheme is that the continuous rolling of finished products is carried out on a six-stand round steel continuous rolling mill, the rolling method is six-pass diameter reduction rolling, the final rolling temperature is not lower than 880℃, and finally the continuous rolled material with a diameter of φ80-φ180 mm is obtained.

[0015] Furthermore, the annealing process is carried out in an annealing furnace. Specifically, the rolled H13 round bars are fed into the annealing furnace, heated to 870°C at a heating rate of 100°C / h and held for 6 hours, then cooled to 710°C at a cooling rate of 50°C / h and held for 10 hours, and finally cooled to below 350°C at a cooling rate of 100°C / h before being removed from the furnace and air-cooled.

[0016] The beneficial effects of this invention are as follows: The technical solution provided in this application first performs carbide crushing rolling and tempering compaction rolling on a red-charged H13 die-cast steel ingot to obtain a fully crushed H13 die-cast steel initial rolled billet. Then, the H13 die-cast steel initial rolled billet undergoes high-temperature homogenization treatment to obtain a fully and uniformly diffused H13 die-cast steel initial rolled billet. Finally, continuous rolling and annealing treatment are performed to obtain H13 round bars with uniform composition, fully crushed and welded core carbides, and a qualified inspection rate that meets requirements. This solves the problem of high production costs associated with the long-term high-temperature homogenization treatment for dissolving and precipitating carbides in the prior art, thereby significantly reducing the production cost of H13 die-cast high-alloy tool steel and achieving the goal of effectively crushing and welding the core carbides of the steel ingot, thus improving the rolling and inspection qualification rate. Attached Figure Description

[0017] Figure 1 This is the core microstructure of an H13 round bar sample produced in Example 1 of the rolling method for H13 die-cast steel ingots according to the present invention.

[0018] Figure 2 This refers to the core structure of a non-conforming H13 round bar sample produced in the comparative production of the rolling method for H13 die-cast steel ingots according to the present invention. Detailed Implementation

[0019] like Figure 1 , Figure 2This invention illustrates a rolling method for H13 ingot casting, which significantly reduces production costs, effectively breaks and welds core carbides in steel ingots, and improves the rolling flaw detection pass rate. The rolling method involves H13 ingot casting with carbide-forming elements Cr, Mo, and V content not exceeding 9%. The method first obtains a heated H13 ingot casting through high-temperature short-time heating. Then, the high-temperature H13 ingot casting undergoes carbide-breaking rolling and tempering compaction rolling to obtain a fully carbide-broken H13 ingot casting initial billet. Next, the H13 ingot casting initial billet undergoes high-temperature homogenization treatment to obtain a fully and uniformly diffused H13 ingot casting initial billet casting. Finally, continuous rolling and annealing are performed to obtain H13 round bars with uniform composition, fully broken and welded core carbides, and a flaw detection pass rate meeting requirements. The technical solution provided in this application involves first subjecting a red-fired H13 die-cast steel ingot to carbide crushing rolling and tempering compaction rolling to obtain a fully crushed H13 die-cast steel billet. Next, the billet undergoes high-temperature homogenization treatment to obtain a fully and uniformly diffused H13 die-cast steel billet. Finally, continuous rolling and annealing are performed to obtain H13 round bars with uniform composition, fully crushed and welded core carbides, and a qualified inspection rate meeting requirements. This solves the problem of high production costs associated with prolonged high-temperature homogenization treatment to dissolve and precipitate carbides in existing technologies, thereby significantly reducing the production cost of H13 die-cast high-alloy tool steel and achieving the goals of effectively crushing and welding core carbides in the ingot, thus improving the rolling and inspection qualification rate.

[0020] Accordingly, in order to ensure the quality of crushing and rolling, the high-temperature short-time heating of this application is carried out by red-feeding. Before entering the furnace, the surface temperature of the H13 ingot is not lower than 400°C. After entering the furnace, it is held at 600°C for 2 hours, then heated to 850°C at a heating rate of 100°C / h, held for 2 hours, and then heated to 1200°C at a heating rate of 100°C / h, and held for 3 hours to complete the high-temperature short-time heating of the H13 ingot.

[0021] Furthermore, the number of rolling passes and the corresponding reduction rate for carbide crushing rolling are controlled according to the table below.

[0022] . The tempering process during compaction rolling involves placing the fully crushed H13 die-cast steel ingot into a high-temperature heating furnace, holding it at 1200℃ for 3 hours, and then proceeding with compaction rolling. The number of rolling passes and the corresponding reduction rates during compaction rolling are controlled according to the table below.

[0023] , The cross-sectional dimensions of the H13 die-cast steel initial rolled square billet obtained after initial rolling are 220×220 mm.

[0024] At this point, the high-temperature homogenization treatment of the crushed carbides is carried out according to the following steps:

[0025] First, the H13 die-cast steel billet is cut into the specified dimensions required by the heating furnace. Then, it is placed in a high-temperature heating furnace and held at 1250℃ for 5 hours before being removed for continuous rolling. Continuous rolling is carried out on a six-stand round bar continuous rolling mill, using a six-pass reduction rolling method. The final rolling temperature is not lower than 880℃, ultimately obtaining continuously rolled steel with a diameter of φ80-φ180 mm. Annealing is performed in an annealing furnace. Specifically, the rolled H13 round bars are fed into the annealing furnace, heated to 870℃ at a rate of 100℃ / h and held for 6 hours, then cooled to 710℃ at a rate of 50℃ / h and held for 10 hours. Finally, they are cooled to below 350℃ at a rate of 100℃ / h before being removed from the furnace and air-cooled.

[0026] In summary, the technical solution provided in this application also has the following advantages:

[0027] By improving the existing rolling process, the ingot is heated at high temperature for a short time. Combined with adjustments to the reduction regime in the initial squaring process, this allows the ingot to first fully break down the liquid carbides in the core and then compact them during the billet forming process. Further high-temperature homogenization treatment of the billet allows the already broken and compacted liquid carbides to diffuse and become uniform within a relatively short time. The continuous rolling process, due to its large diameter reduction and uniform composition, easily yields bars with good core quality. This invention solves the problem of intergranular cracking caused by the segregation of liquid carbides in the core of H13 steel ingots, without changing the process equipment or auxiliary instruments. H13 round bars with diameters of φ80-φ180 mm produced using this method have good internal quality, and their flaw detection meets the Class B requirements of GB / T 4162 "Ultrasonic Testing Method for Forged and Rolled Steel Bars". It also reduces the total heating time in the rolling process, reduces oxidation loss, improves product yield, and lowers production costs.

[0028] The technical solution of this application will be further described below through specific embodiments:

[0029] This invention provides a rolling method for H13 round bars, which solves the problem that when using die casting to roll H13 round bars in existing rolling methods, liquid carbides precipitate along the grain boundaries in the core of the ingot, and cracks easily start at the carbide locations and spread along the grains during rolling deformation, resulting in a low pass rate for flaw detection of the round bars.

[0030] To achieve the above objectives, the present invention provides the following technical solution:

[0031] A rolling method for H13 round bars, the method comprising the following steps:

[0032] Step S1: Hot-cast ingot, high-temperature heating. The hot-cast ingot is subjected to high-temperature heating treatment to obtain a heated billet.

[0033] The red-feeding ingot refers to the process of sending a 3.5-ton die-cast flat ingot to the heating furnace while maintaining its temperature, ensuring that the surface temperature of the ingot is ≥400℃ before entering the furnace.

[0034] The high-temperature heating treatment involves placing the red-hot ingot into a high-temperature heating furnace, holding it at 600°C for 2 hours, then raising the temperature to 850°C at a rate of 100°C / hour and holding it for 2 hours, followed by raising the temperature to 1200°C at a rate of 100°C / hour and holding it for 3 hours.

[0035] Step S2: Initial rolling of the square billet. The heated ingot is rolled to obtain the initial rolled square billet.

[0036] The initial rolling process for the squaring billet is as follows: crushed carbide rolling → reheating in the furnace → compaction rolling;

[0037] The number of rolling passes and reduction rate of the crushed carbides:

[0038]

[0039] The reheating process involves placing the initial rolled intermediate billet, which has already been rolled with crushed carbides, into a high-temperature heating furnace, holding it at 1200°C for 3 hours, and then removing it from the furnace for compaction rolling.

[0040] The number of compaction rolling passes and the reduction rate:

[0041] , After initial rolling, a square billet with a cross-sectional dimension of 220×220 mm is obtained.

[0042] Step S3: High-temperature homogenization. The above-mentioned primary rolled billet is cut into appropriate lengths and placed in a heating furnace for reheating to obtain a heated primary rolled billet.

[0043] The high-temperature homogenization process involves placing the square billet obtained from the initial rolling into a high-temperature heating furnace, holding it at 1250°C for 5 hours, and then taking it out of the furnace for continuous rolling.

[0044] Step S4: Continuous rolling. The heated initial rolled billet is continuously rolled to obtain continuously rolled material.

[0045] The continuous rolling process involves placing the square billet, which has undergone high-temperature homogenization, onto a six-stand round steel continuous rolling mill for six passes of diameter reduction rolling, controlling the final rolling temperature to ≥880℃, and finally obtaining continuously rolled steel with a diameter of φ80-φ180 mm.

[0046] Step S5: Annealing. The above continuously rolled material is annealed to obtain H13 round bars.

[0047] The annealing process involves placing the continuously rolled material into an annealing furnace, heating it to 870°C at a rate of 100°C / h and holding it there for 6 hours, then cooling it down to 710°C at a rate of 50°C / h and holding it there for 10 hours, and finally cooling it down to below 350°C at a rate of 100°C / h before removing it from the furnace and air cooling it.

[0048] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0049] Furthermore, the flowchart shown in the accompanying drawings is merely illustrative and does not necessarily include all steps. For example, some steps may be broken down, while others may be combined or partially combined; therefore, the actual execution order may change depending on the specific circumstances.

[0050] Furthermore, the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented, for example, in orders other than those illustrated or described herein.

[0051] Furthermore, the terms “comprising” and “having”, and any variations thereof, are intended to cover non-exclusive inclusion, such that a process, method, system, product, or device that includes a series of steps or sub-modules is not necessarily limited to those steps or sub-modules that are explicitly listed, but may include other steps or sub-modules that are not explicitly listed or that are inherent to such process, method, product, or device.

[0052] Example 1

[0053] Step S1: Hot-cast ingot, high-temperature heating. The hot-cast ingot is subjected to high-temperature heating treatment to obtain a heated billet.

[0054] The 3.5 t ingot casting flat ingot was heated and sent to the heating furnace. The surface temperature of the ingot was 510℃ before entering the furnace.

[0055] The red-hot ingot is placed in a high-temperature heating furnace and held at 600℃ for 2 hours. Then, the temperature is increased to 850℃ at a rate of 100℃ / h and held for 2 hours. Finally, the temperature is increased to 1200℃ at a rate of 100℃ / h and held for 3 hours.

[0056] Step S2: Initial rolling of the square billet. The heated ingot is rolled to obtain the initial rolled square billet.

[0057] The initial rolling process for squaring billets is as follows: crushing carbides and rolling → reheating in the furnace → compaction rolling;

[0058] Crushed carbide rolling passes and reduction rate:

[0059]

[0060] The intermediate billet that has been rolled by crushing carbides is placed into a high-temperature heating furnace and held at 1200℃ for 3 hours before being taken out of the furnace for compaction rolling.

[0061] Compaction rolling passes and reduction rate:

[0062] , After initial rolling, a square billet with a cross-sectional dimension of 220×220 mm is obtained.

[0063] Step S3: High-temperature homogenization. The above-mentioned primary rolled billet is cut into appropriate lengths and placed in a heating furnace for reheating to obtain a heated primary rolled billet.

[0064] The square billet obtained from the initial rolling is placed in a high-temperature heating furnace and held at 1250℃ for 5 hours before being taken out of the furnace for continuous rolling.

[0065] Step S4: Continuous rolling. The heated initial rolled billet is continuously rolled to obtain continuously rolled material.

[0066] The square billet, after being homogenized at high temperature, is placed on a six-stand round steel continuous rolling mill for six passes of diameter reduction rolling. The final rolling temperature is 890℃, resulting in a continuously rolled product with a diameter of φ180 mm.

[0067] Step S5: Annealing. The above continuously rolled material is annealed to obtain H13 round bars.

[0068] The continuously rolled material is placed in an annealing furnace and heated to 870℃ at a heating rate of 100℃ / h and held for 6 hours. Then it is cooled to 710℃ at a cooling rate of 50℃ / h and held for 10 hours. Finally, it is cooled to 350℃ at a cooling rate of 100℃ / h and then removed from the furnace and air-cooled.

[0069] Using the above method, H13 round bars with a diameter of φ180 mm were obtained, and the flaw detection pass rate was 98.15%.

[0070] Example 2

[0071] Step S1: Hot-cast ingot, high-temperature heating. The hot-cast ingot is subjected to high-temperature heating treatment to obtain a heated billet.

[0072] The 3.5 t ingot casting flat ingot was heated and sent to the heating furnace. The surface temperature of the ingot was 450℃ before it entered the furnace.

[0073] The red-hot ingot is placed in a high-temperature heating furnace and held at 600℃ for 2 hours. Then, the temperature is increased to 850℃ at a rate of 100℃ / h and held for 2 hours. Finally, the temperature is increased to 1200℃ at a rate of 100℃ / h and held for 3 hours.

[0074] Step S2: Initial rolling of the square billet. The heated ingot is rolled to obtain the initial rolled square billet.

[0075] The initial rolling process for squaring billets is as follows: crushing carbides and rolling → reheating in the furnace → compaction rolling;

[0076] Crushed carbide rolling passes and reduction rate:

[0077]

[0078] The intermediate billet that has been rolled by crushing carbides is placed into a high-temperature heating furnace and held at 1200℃ for 3 hours before being taken out of the furnace for compaction rolling.

[0079] Compaction rolling passes and reduction rate:

[0080] , After initial rolling, a square billet with a cross-sectional dimension of 220×220 mm is obtained.

[0081] Step S3: High-temperature homogenization. The above-mentioned primary rolled billet is cut into appropriate lengths and placed in a heating furnace for reheating to obtain a heated primary rolled billet.

[0082] The square billet obtained from the initial rolling is placed in a high-temperature heating furnace and held at 1250℃ for 5 hours before being taken out of the furnace for continuous rolling.

[0083] Step S4: Continuous rolling. The heated initial rolled billet is continuously rolled to obtain continuously rolled material.

[0084] The square billet, after being homogenized at high temperature, is placed on a six-stand round steel continuous rolling mill for six passes of diameter reduction rolling. The final rolling temperature is 880℃, resulting in a continuously rolled product with a diameter of φ80 mm.

[0085] Step S5: Annealing. The above continuously rolled material is annealed to obtain H13 round bars.

[0086] The continuously rolled material is placed in an annealing furnace and heated to 870℃ at a heating rate of 100℃ / h and held for 6 hours. Then it is cooled to 710℃ at a cooling rate of 50℃ / h and held for 10 hours. Finally, it is cooled to 350℃ at a cooling rate of 100℃ / h and then removed from the furnace and air-cooled.

[0087] Using the above method, H13 round bars with a diameter of φ80 mm were obtained, and the flaw detection pass rate was 98.00%.

[0088] Example 3

[0089] Step S1: Hot-cast ingot, high-temperature heating. The hot-cast ingot is subjected to high-temperature heating treatment to obtain a heated billet.

[0090] The 3.5 t ingot casting flat ingot was heated and sent to the heating furnace. The surface temperature of the ingot was 480℃ before entering the furnace.

[0091] The red-hot ingot is placed in a high-temperature heating furnace and held at 600℃ for 2 hours. Then, the temperature is increased to 850℃ at a rate of 100℃ / h and held for 2 hours. Finally, the temperature is increased to 1200℃ at a rate of 100℃ / h and held for 3 hours.

[0092] Step S2: Initial rolling of the square billet. The heated ingot is rolled to obtain the initial rolled square billet.

[0093] The initial rolling process for squaring billets is as follows: crushing carbides and rolling → reheating in the furnace → compaction rolling;

[0094] Crushed carbide rolling passes and reduction rate:

[0095]

[0096] The reheating process involves placing the initial rolled intermediate billet, which has already been rolled with crushed carbides, into a high-temperature heating furnace, holding it at 1200℃ for 3 hours, and then removing it from the furnace for compaction rolling.

[0097] Compaction rolling passes and reduction rate:

[0098] , After initial rolling, a square billet with a cross-sectional dimension of 220×220 mm is obtained.

[0099] Step S3: High-temperature homogenization. The above-mentioned primary rolled billet is cut into appropriate lengths and placed in a heating furnace for reheating to obtain a heated primary rolled billet.

[0100] The square billet obtained from the initial rolling is placed in a high-temperature heating furnace and held at 1250℃ for 5 hours before being taken out of the furnace for continuous rolling.

[0101] Step S4: Continuous rolling. The heated initial rolled billet is continuously rolled to obtain continuously rolled material.

[0102] The square billet, after being homogenized at high temperature, is placed on a six-stand round steel continuous rolling mill for six passes of diameter reduction rolling. The final rolling temperature is 895℃, resulting in a continuously rolled product with a diameter of φ130 mm.

[0103] Step S5: Annealing. The above continuously rolled material is annealed to obtain H13 round bars.

[0104] The continuously rolled material is placed in an annealing furnace and heated to 870℃ at a heating rate of 100℃ / h and held for 6 hours. Then it is cooled to 710℃ at a cooling rate of 50℃ / h and held for 10 hours. Finally, it is cooled to 350℃ at a cooling rate of 100℃ / h and then removed from the furnace and air-cooled.

[0105] Using the above method, H13 round bars with a diameter of φ130 mm were obtained, and the flaw detection pass rate was 97.79%.

[0106] Comparative Example

[0107] The comparative model is produced using conventional methods, which are completed in four steps.

[0108] Step S1: Hot-rolled ingots undergo high-temperature homogenization. The hot-rolled ingots are subjected to high-temperature homogenization treatment to obtain a cast billet after high-temperature homogenization treatment.

[0109] The 3.5 t ingot casting flat ingot was heated and sent to the heating furnace. The surface temperature of the ingot was 505℃ before entering the furnace.

[0110] The red-hot ingot is placed in a high-temperature heating furnace and held at 600℃ for 2 hours. Then, the temperature is increased to 850℃ at a rate of 100℃ / h and held for 2 hours. Finally, the temperature is increased to 1250℃ at a rate of 100℃ / h and held for 20 hours.

[0111] Step S2: Initial rolling of the square billet. The heated ingot is rolled to obtain the initial rolled square billet.

[0112] The initial rolling and squaring process is as follows:

[0113] , After initial rolling, a square billet with a cross-sectional dimension of 220×220 mm is obtained.

[0114] Step S3: Continuous rolling, the above-mentioned initial rolled billet is continuously rolled to obtain continuously rolled material.

[0115] The initial rolled billet is placed on a six-stand round steel continuous rolling mill for six passes of diameter reduction rolling, with a final rolling temperature of 850℃, to obtain a continuous rolled material with a diameter of φ130 mm.

[0116] Step S4: Annealing. The above continuously rolled material is annealed to obtain H13 round bars.

[0117] The continuously rolled material is placed in an annealing furnace and heated to 870℃ at a heating rate of 100℃ / h and held for 6 hours. Then it is cooled to 710℃ at a cooling rate of 50℃ / h and held for 10 hours. Finally, it is cooled to 350℃ at a cooling rate of 100℃ / h and then removed from the furnace and air-cooled.

[0118] Using the above method, H13 round bars with a diameter of φ130 mm were obtained, and the flaw detection pass rate was 77.61%.

[0119] Finally, it should be noted that the above description 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 foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A rolling method for H13 ingot casting, comprising H13 ingot casting with carbide-forming elements Cr, Mo, and V content not exceeding 9%, characterized in that: The rolling method involves first obtaining a heated H13 die-cast steel ingot through high-temperature short-time heating, then subjecting the high-temperature H13 die-cast steel ingot to carbide crushing rolling and tempering compaction rolling to obtain a fully crushed H13 die-cast steel initial rolled billet, followed by high-temperature homogenization treatment of the crushed carbides to obtain a fully and uniformly diffused H13 die-cast steel initial rolled billet, and finally performing continuous rolling and annealing treatment to obtain H13 round bars with uniform composition, fully crushed and welded core carbides, and a flaw detection pass rate that meets the requirements.

2. The rolling method for H13 die-cast steel ingots according to claim 1, characterized in that: High-temperature short-time heating is carried out using the red-feeding method. Before entering the furnace, the surface temperature of the H13 ingot is not lower than 400℃. After entering the furnace, it is held at 600℃ for 2 hours, then heated to 850℃ at a rate of 100℃ / h, held for 2 hours, and then heated to 1200℃ at a rate of 100℃ / h, and held for 3 hours to complete the high-temperature short-time heating of the H13 ingot.

3. The rolling method for H13 die-cast steel ingots according to claim 1, characterized in that: The number of rolling passes and the corresponding reduction rate for carbide crushing rolling are controlled according to the table below. 。 4. The rolling method for H13 die-cast steel ingots according to claim 3, characterized in that: The tempering process of compaction rolling involves placing the H13 die-cast steel ingot, after the carbides are fully crushed, into a high-temperature heating furnace, holding it at 1200℃ for 3 hours, and then removing it from the furnace for compaction rolling.

5. The rolling method for H13 die-cast steel ingots according to claim 4, characterized in that: The number of rolling passes and the corresponding reduction rate in compaction rolling are controlled according to the table below. ， The cross-sectional dimensions of the H13 die-cast steel initial rolled square billet obtained after initial rolling are 220×220 mm.

6. The rolling method for H13 die-cast steel ingots according to claim 1, characterized in that: The high-temperature homogenization treatment of the crushed carbides was carried out according to the following steps. First, the H13 die-cast steel initial rolled square billet is cut into the specified size that meets the requirements of the heating furnace. Then, it is placed in the high-temperature heating furnace and held at 1250℃ for 5 hours before being taken out of the furnace for continuous rolling.

7. The rolling method for H13 die-cast steel ingots according to claim 6, characterized in that: The continuous rolling of finished products is carried out on a six-stand round steel continuous rolling mill. The rolling method is six-pass diameter reduction rolling, and the final rolling temperature is not lower than 880℃, finally obtaining continuously rolled products with a diameter of φ80-φ180 mm.

8. The rolling method for H13 die-cast steel ingots according to claim 7, characterized in that: The annealing process is carried out in an annealing furnace. Specifically, the rolled H13 round bars are fed into the annealing furnace, heated to 870℃ at a heating rate of 100℃ / h and held for 6 hours, then cooled to 710℃ at a cooling rate of 50℃ / h and held for 10 hours, and finally cooled to below 350℃ at a cooling rate of 100℃ / h before being taken out of the furnace and air-cooled.

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