A heat treatment method for high-carbon steel and high-carbon steel
Through multiple deformation annealing treatment and controlling spherical annealing parameters, the wire breaking problem of high-carbon steel strips in the process of making thin wires is solved, and a low-cost and efficient heat treatment method is realized.
Patent Information
- Application Number
- CN202211345148.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-10-31
- Publication Date
- 2025-07-18
- Estimated Expiration
- 2042-10-31
AI Technical Summary
High-carbon steel strips are prone to wire breakage problems during the process of making thin wires, and the existing heat treatment methods are costly and difficult to meet processing needs.
Multiple deformation annealing treatment is used to control the drawing deformation rate ≤60%, the spheroidization annealing temperature is <760℃, and the spheroidization annealing time is 2-5h. By controlling the spheroidization degree of carbides, the risk of wire breaking is reduced.
It reduces the rate of wire-breaking, reduces the number of annealings, saves costs, and is easy to promote and apply.
Smart Images
Figure FT_1
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of heat treatment of high-carbon steel wire rods, and particularly relates to a heat treatment method for high-carbon steel and high-carbon steel. Background Art
[0002] The carbon content in high-carbon steel wire rods is generally 0.6 - 1.7%, and it can be applied to the production of products such as prestressed steel strands, galvanized steel wires, aluminum conductor steel-reinforced wires, steel wire ropes, spring steel wires, and piano wires. Due to the high C content of high-carbon steel, its cutting performance is poor. After adding easy-cutting elements (such as S, Pb, etc.) to high-carbon steel and performing reasonable heat treatment to make it into fine wires, the easy-cutting performance and mechanical properties can be taken into account to meet the processing requirements.
[0003] Currently, in the process of making hot-rolled high-carbon steel wire rods into fine wires, 7 times of drawing and annealing are required, that is, drawing first and then annealing, and then drawing and annealing again. After repeating 5 times, fine wires are obtained. However, wire breakage problems are extremely likely to occur during the drawing process, affecting production. Summary of the Invention
[0004] In order to solve the above technical problems, the present invention provides a heat treatment method for high-carbon steel and high-carbon steel, which has a low wire breakage rate, low cost, and is easy to promote.
[0005] On the one hand, the present invention provides a heat treatment method for high-carbon steel, including the following steps:
[0006] Obtain a high-carbon steel wire rod with a carbon mass fraction of 0.6 - 1.7%;
[0007] Perform multiple deformation and annealing treatments on the high-carbon steel wire rod to obtain steel wires;
[0008] Perform tempering treatment on the steel wires to complete the heat treatment;
[0009] Among them, the deformation and annealing treatment includes drawing deformation first and then spheroidizing annealing treatment. The drawing deformation rate ≤ 60%, the temperature of the spheroidizing annealing < 760°C, and the time of the spheroidizing annealing is 2 - 5 h.
[0010] In some embodiments, in the multiple deformation and annealing treatments, the reduction rate of the first deformation and annealing treatment is 8 - 15%, and the reduction rate of the last deformation and annealing treatment is 25 - 60%.
[0011] In some embodiments, the reduction rate of the last deformation and annealing treatment is 30 - 50%.
[0012] In some embodiments, the temperature of the spheroidizing annealing is not lower than 700°C.
[0013] In some embodiments, the temperature of the spheroidizing annealing is 710 - 730°C.
[0014] In some embodiments, the number of times of the deformation annealing treatment is less than 5 times.
[0015] In some embodiments, the diameter of the high-carbon steel wire rod is 5-7 mm, and the diameter of the steel wire is 0.5-2 mm.
[0016] In some embodiments, the tempering temperature is 360-400 °C.
[0017] In some embodiments, the multiple deformation annealing treatments performed on the high-carbon steel wire rod specifically include:
[0018] After annealing the high-carbon steel wire rod at a temperature of 750-770 °C for 3-5 h, multiple deformation annealing treatments are performed.
[0019] On the other hand, the present invention also provides a high-carbon steel obtained by using the foregoing heat treatment method.
[0020] One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:
[0021] The heat treatment method for high-carbon steel provided by the present invention includes the following steps: obtaining a high-carbon steel wire rod with a carbon mass fraction of 0.6-1.7%; performing multiple deformation annealing treatments on the high-carbon steel wire rod to obtain a steel wire; performing a tempering treatment on the steel wire to complete the heat treatment; wherein, the deformation annealing treatment includes first drawing deformation and then spheroidizing annealing treatment, the drawing deformation rate ≤ 60%, the temperature of the spheroidizing annealing < 760 °C, and the time of the spheroidizing annealing is 2-5 h. By controlling the deformation rate, spheroidizing annealing temperature, and spheroidizing annealing time of the deformation annealing treatment of the high-carbon steel wire rod, and utilizing the spheroidizing driving effect of both drawing deformation and annealing on carbides, the spheroidizing degree of carbides is controlled. While ensuring that the high-carbon steel wire rod is rolled to the target size, the wire breakage rate during drawing is reduced, the number of annealing times is also reduced, the cost is saved, and it is convenient for popularization. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.
[0023] Figure 1 It is a process step diagram of a heat treatment method for high-carbon steel provided by the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0024] The present invention will be specifically described below in conjunction with specific embodiments and examples, and the advantages and various effects of the present invention will be presented more clearly thereby. Those skilled in the art should understand that these specific embodiments and examples are used to illustrate the present invention, rather than limiting the present invention.
[0025] Throughout the specification, unless otherwise specifically stated, the terms used herein should be understood as having the meanings as commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as the general understanding of those skilled in the art to which the present invention pertains. In case of contradiction, this specification shall prevail.
[0026] Unless otherwise specifically stated, various raw materials, reagents, instruments, and equipment used in the present invention can be obtained through market purchase or can be prepared by existing methods.
[0027] For hot-rolled wire rods of high-carbon steel, a heat treatment process of annealing - drawing - annealing - drawing - annealing... - drawing - tempering is generally adopted. Among them, the first annealing is to first anneal the hot-rolled wire rod, and then perform repeated treatments of drawing and annealing until the hot-rolled wire rod is drawn to the target size, and then it can be subjected to cutting processing after tempering. Due to the high carbon content in the high-carbon steel wire rod, the phenomenon of carbide spheroidization will occur during annealing, so this annealing is also called spheroidizing annealing. Spheroidizing annealing will promote the growth of carbides, and large-sized carbides are prone to cause fracture, that is, wire breakage problems, during the drawing process.
[0028] The technical solution provided by the embodiments of the present invention to solve the above technical problem of easy wire breakage during the drawing process is generally as follows:
[0029] Please refer to Figure 1 , on the one hand, the embodiments of the present application provide a heat treatment method for high-carbon steel, including the following steps:
[0030] S1, obtaining a high-carbon steel wire rod with a carbon mass fraction of 0.6 - 1.7%;
[0031] The high-carbon steel wire rod here can be a wire rod after hot-rolled annealing or a wire rod after cold-rolled annealing, and there is no work hardening inside, or only a small amount of work hardening, and specific restrictions are not made. The carbon content of the high-carbon steel wire rod is 0.6 - 1.7%, and the carbon content of some high-carbon steels is 0.7 - 1.1%. Due to the high carbon content of high-carbon steel, the phenomenon of carbide spheroidization is prone to occur during spheroidizing annealing, and the spheroidized carbides will gradually grow with the increase of the number of annealing times, forming large-sized spherical carbides. When the size of the spherical carbides reaches more than 1 / 10 of the wire diameter, during the drawing process, fractures, that is, wire breakage problems, are extremely likely to occur at the large-sized carbides.
[0032] S2. Perform multi-pass deformation annealing on the high-carbon steel wire rod to obtain steel wires. Among them, the deformation annealing treatment includes wire drawing deformation followed by spheroidizing annealing. The reduction ratio is ≤60%, the temperature of the spheroidizing annealing is <760°C, and the time of the spheroidizing annealing is 2 - 5 h.
[0033] The reduction ratio refers to the percentage of the difference between the size after wire drawing and the size before wire drawing to the size before wire drawing. During the wire drawing process, plastic deformation occurs in the high-carbon steel. Plastic deformation increases the dislocation density and the number of sub-grain boundaries of ferrite and cementite in sorbite. During the subsequent heating of spheroidizing annealing, cementite gradually dissolves into ferrite at the sub-grain boundaries, thereby making the carbide gradually spheroidize. That is to say, wire drawing generates the distortion energy that drives the spheroidization of carbide. Therefore, by controlling the wire drawing deformation rate, excessive distortion energy generated by work hardening can be avoided. And the distortion energy will drive the growth of spheroidized carbide during annealing. Therefore, controlling the wire drawing deformation rate can avoid the growth of spheroidized carbide, thereby ensuring that no wire breakage occurs during the wire drawing process. Under the action of multiple annealing treatments, small-sized carbide particles gradually dissolve into the matrix. Under the action of the concentration gradient of carbides of different sizes, carbon atoms diffuse, and large-sized carbides aggregate with the dissolved carbon atoms and gradually grow, with their morphology tending to be round. Moreover, the large-sized carbides coarsen and grow, and the particle spacing increases. Controlling a lower spheroidizing annealing temperature and a lower annealing time can avoid the growth of spherical carbides. In this application, by controlling a lower wire drawing deformation rate, a lower spheroidizing annealing temperature, and the spheroidizing annealing time, the excessive growth of spheroidized carbide is avoided, thereby reducing the risk of wire breakage. If the wire drawing deformation rate is too large, excessive distortion energy will be caused, which will promote the growth of spherical carbide and increase the risk of wire breakage during the wire drawing process. If the spheroidizing annealing temperature is too high, it is easy to promote the growth of spheroidized carbide and increase the risk of wire breakage during the wire drawing process. In some embodiments, in the multi-pass deformation annealing treatment, the reduction ratio of the first deformation annealing treatment is 8 - 15%, and the reduction ratio of the last deformation annealing treatment is 25 - 60%. The reduction ratio of the first deformation annealing treatment is less than that of the last deformation annealing treatment, which is related to the gradual decrease in the diameter size of the wire rod. In addition, in each deformation annealing treatment, the number of wire drawing passes can be one or multiple, such as two consecutive wire drawing passes, or three consecutive wire drawing passes, or four consecutive wire drawing passes, which is not specifically limited. That is to say, annealing treatment is carried out after multiple wire drawing passes. The number of wire drawing passes is related to the target cross-sectional shape of the fine wire. After multiple wire drawing passes, the cross-section of the fine wire can be adjusted without additional pass adjustment. In addition, a larger number of wire drawing passes between two annealings can effectively avoid wire breakage caused by excessive stress during wire drawing. However, too many wire drawing passes will affect production efficiency.
[0034] In some embodiments, the reduction ratio of the last deformation annealing treatment is 30 - 50%.
[0035] In some embodiments, the spheroidizing annealing temperature is not less than 700°C. If the spheroidizing annealing temperature is too low, it is difficult to remove the work hardening. Preferably, in some embodiments, the spheroidizing annealing temperature is 710-730°C. More preferably, the spheroidizing annealing temperature is 720°C. In some embodiments, the spheroidizing annealing process is: enter the annealing furnace at a temperature of 500-530°C, heat to 710-730°C and keep warm for 2-3h, then cool to 500-600°C and exit the furnace.
[0036] In some embodiments, the high carbon steel wire rod is subjected to multiple deformation annealing treatments, specifically comprising: annealing the high carbon steel wire rod at a temperature of 750-770°C for 3-5h, and then subjected to multiple deformation annealing treatments. As can be seen from the foregoing, the high carbon steel wire rod may be a hot rolled wire rod or a cold rolled wire rod, which has a large amount of work hardening inside. For high carbon steel wire rods that have a large amount of work hardening, an annealing treatment is required first to facilitate drawing.
[0037] In some embodiments, the deformation annealing treatment is performed less than 5 times, which can reduce the heat treatment cost and avoid the problem of wire breakage caused by excessive growth of spheroidized carbides.
[0038] In some embodiments, the diameter of the high carbon steel wire rod is 5-7 mm, for example, the diameter of the high carbon steel wire rod is 5 mm, 5.5 mm, 6 mm, etc.; the diameter of the steel wire is 0.5-2 mm.
[0039] S3, tempering the steel wire to complete the heat treatment;
[0040] In some embodiments, the tempering temperature is 360-400° C. Tempering is a stress relief annealing operation that reduces the heat treatment temperature, and aims to restore the dislocations of work hardening. When the product is subsequently cut, the hardness is reduced, thereby increasing the service life of the workpiece, such as a tool.
[0041] In a second aspect, an embodiment of the present invention further provides a high carbon steel obtained by the aforementioned heat treatment method.
[0042] The heat treatment method for high carbon steel of the present application will be described in detail below in combination with embodiments, comparative examples and experimental data.
[0043] Example 1
[0044] Example 1 provides a heat treatment process for high carbon steel, the high carbon steel is 82B steel with a carbon content of 0.81%, the high carbon steel is a hot-rolled wire rod with a diameter of 6.5 mm, and the specific heat treatment process is:
[0045] Step 1: Anneal the hot-rolled wire rod first. The annealing process is as follows: The hot-rolled wire rod is put into the furnace at 500°C, heated to 760°C, held for 2 hours, and then cooled to 500°C and taken out of the furnace.
[0046] Step 2: Mechanically remove the shell of the wire rod annealed in the first step, then cold draw it to φ5.8mm, and then spheroidize and anneal it; the drawing ratio of this step is 10.7%.
[0047] Step 3: Cold draw the wire rod after spheroidizing annealing in the second step from 5.8mm through two cold drawing processes. First, draw it to 5.1mm, then draw it to 4.5mm, and finally spheroidize and anneal it. The drawing ratio of this step is 22.4%.
[0048] Step 4: Cold draw the wire rod after spheroidizing annealing in the third step from 4.5mm through two cold drawing processes. First, draw it to 3.8mm, then draw it to 3.2mm, and finally spheroidize and anneal it. The drawing ratio of this step is 29%.
[0049] Step 5: Cold draw the wire rod after spheroidizing annealing in the fourth step from 3.2mm through two cold drawing processes. First, draw it to 2.5mm, then draw it to 2mm, and finally spheroidize and anneal it. The drawing ratio of this step is 37.5%.
[0050] Step 6: Cold draw the wire rod after spheroidizing annealing in the fifth step from 2mm to 1.5mm, and then temper it to complete the heat treatment. The drawing ratio of this step is 25%.
[0051] The spheroidizing annealing process in the second to fifth steps above is as follows: Put it into the furnace at 500°C, heat it to 730°C, hold for 2 hours, and then cool it to 550°C and take it out of the furnace.
[0052] The above high-carbon steel undergoes four deformation and annealing treatments.
[0053] Example 2
[0054] Example 2 provides a heat treatment process for high-carbon steel. The high-carbon steel is Y100Pb steel with a carbon content of 0.98%. The high-carbon steel is a hot-rolled wire rod with a diameter of 6.5mm. The specific heat treatment process is as follows:
[0055] Step 1: Anneal the hot-rolled wire rod first. The annealing process is as follows: The hot-rolled wire rod is put into the furnace at 500°C, heated to 760°C, held for 2 hours, and then cooled to 500°C and taken out of the furnace.
[0056] Step 2: Mechanically remove the shell of the wire rod annealed in the first step, then cold draw it through two processes, successively draw it to φ5.5mm and 4.5mm, and then spheroidize and anneal it; the drawing ratio of this step is 18%;
[0057] Step 3: The wire rod after spheroidizing annealing in Step 2 is cold drawn twice from 4.5 mm, first to 3.5 mm, then to 2.5 mm, and finally spheroidizing annealing is carried out. The drawing rate of this step is 44%.
[0058] Step 4: The wire rod after spheroidizing annealing in Step 3 is cold drawn from 2.5 mm to 1.5 mm, and finally spheroidizing annealing is carried out. The drawing rate of this step is 40%.
[0059] Step 5: The wire rod after spheroidizing annealing in Step 4 is cold drawn from 1.5 mm to 1 mm, and then tempered to complete the heat treatment. The drawing rate of this step is 33%.
[0060] The spheroidizing annealing process in the above Step 2 to Step 5 is to heat the furnace to 720 °C at 530 °C, hold for 2.5 h, and then cool to 570 °C and take out of the furnace.
[0061] The above high-carbon steel has undergone three deformation annealing treatments.
[0062] Example 3
[0063] Example 3 takes Example 2 as a reference. The difference between Example 3 and Example 2 is that the high-carbon steel is GCr15 steel with a carbon content of 1.3%. In Steps 2 to 5, the spheroidizing annealing process is to heat the furnace to 725 °C at 520 °C, hold for 3 h, and then cool to 560 °C and take out of the furnace. The rest of Example 3 is the same as Example 2.
[0064] Example 4
[0065] Example 4 takes Example 2 as a reference. The difference between Example 4 and Example 2 is that the high-carbon steel is GCr15 steel with a carbon content of 1.5%. In Steps 2 to 5, the spheroidizing annealing process is to heat the furnace to 710 °C at 510 °C, hold for 3.5 h, and then cool to 580 °C and take out of the furnace. The rest of Example 4 is the same as Example 2.
[0066] Example 5
[0067] Example 5 takes Example 2 as a reference. The difference between Example 5 and Example 2 is that the high-carbon steel is GCr15 steel with a carbon content of 1.65%. In Steps 2 to 5, the spheroidizing annealing process is to heat the furnace to 700 °C at 500 °C, hold for 4 h, and then cool to 570 °C and take out of the furnace. The rest of Example 5 is the same as Example 2.
[0068] Example 6
[0069] Example 6 provides a heat treatment process for high-carbon steel. The high-carbon steel is WN85Pb steel (grade), with a carbon content of 0.85%. The high-carbon steel is a hot-rolled wire rod with a diameter of 5.5 mm. The specific heat treatment process is as follows:
[0070] First step: Anneal the hot-rolled wire rod first. The annealing process is as follows: The hot-rolled wire rod is put into the furnace at 500 °C and heated to 760 °C, held for 2 h, and then cooled to 500 °C and taken out of the furnace.
[0071] Second step: Mechanically remove the shell of the wire rod annealed in the first step, and then perform two cold drawing operations, drawing to φ4.8 mm and 4.0 mm in sequence, and then spheroidize and anneal;
[0072] Third step: The wire rod spheroidized and annealed in the second step is cold drawn twice from 4.0 mm, first drawn to 3.3 mm, then drawn to 2.7 mm, and finally spheroidized and annealed.
[0073] Fourth step: The wire rod spheroidized and annealed in the third step is cold drawn from 2.7 mm to 2 mm, and finally spheroidized and annealed.
[0074] Fifth step: The wire rod spheroidized and annealed in the fourth step is cold drawn from 2 mm to 1.3 mm, and then tempered to complete the heat treatment.
[0075] The spheroidizing annealing process in the second to fifth steps above is to put it into the furnace at 500 °C and heat it to 720 °C, hold for 2.5 h, and then cool to 560 °C and take it out of the furnace.
[0076] The above high-carbon steel undergoes three deformation and annealing treatments.
[0077] Comparative Example 1
[0078] Comparative Example 1 provides a heat treatment method for high-carbon steel. The high-carbon steel is Y100Pb steel (grade), with a carbon content of 0.98%. The high-carbon steel is a hot-rolled wire rod with a diameter of 6.5 mm. The specific heat treatment process is as follows:
[0079] First step: Spheroidize and anneal the Φ6.5 mm hot-rolled high-carbon steel. The annealing process: Put it into the furnace at 500 °C and heat it to 760 °C × 2 h, and cool to 500 - 550 °C and take it out of the furnace.
[0080] Second step: Mechanically remove the shell of the wire rod annealed in the first step to form a wire rod with a diameter of φ6.4 mm, and then perform two cold drawing operations, drawing to φ5.8 mm and φ5.4 mm in sequence, and then spheroidize and anneal;
[0081] Third step: The wire rod spheroidized and annealed in the second step is cold drawn twice, drawing to φ4.8 mm and φ4.5 mm in sequence, and finally spheroidize and anneal;
[0082] The fourth step is to cold draw the wire rod after spheroidizing annealing in the third step twice, drawing it to φ4.0mm and φ3.5mm respectively, and finally spheroidizing annealing;
[0083] Step 5: After the spheroidizing annealing in step 4, the wire rod is cold drawn twice, and is drawn to φ3.0mm and φ2.5mm respectively, and finally spheroidizing annealing is performed;
[0084] Step 6: After the spheroidizing annealing in step 5, the wire rod is cold drawn twice, drawn to φ2.0mm and φ1.5mm respectively, and finally spheroidizing annealing is performed;
[0085] In the seventh step, the wire rod after spheroidizing annealing in the sixth step is cold drawn to φ1.0mm, and then tempered at 380℃ for 2h.
[0086] The spheroidizing annealing process from the second step to the sixth step is: enter the furnace at 500℃, heat up to 760℃×4h, and cool down to 500-550℃ before leaving the furnace.
[0087] The heat treatment process provided in Comparative Example 1 underwent 5 deformation annealing treatments.
[0088] Comparative Example 2
[0089] Comparative Example 2 is taken as a reference to Example 2. The difference between Comparative Example 5 and Example 2 is that in the second to fifth steps, the spheroidizing annealing temperature is 770°C and the heat preservation time is 3h. The rest of Comparative Example 5 is the same as Example 2.
[0090] Table 1
[0091] Number Wire breakage rate during drawing Proportion of carbides with size > 10μm Spheroidization rating Example 1 3.6‰ 1.6％ 2 Example 2 2.7‰ 1.5％ 2 Example 3 3.1‰ 1.5％ 2 Example 4 3.3‰ 1.4％ 2 Example 5 2.9‰ 1.5％ 2 Example 6 3.0‰ 1.6％ 2 Comparative Example 1 2.4％ 5.8％ 4 Comparative Example 2 3.9％ 6.7％ 3
[0092] The production process was statistically analyzed, and the proportion of carbides with a size greater than 10 μm in the filaments was calculated by sampling and statistics. The spheroidization of the filaments was rated (according to the national standard GB / T 18254-2016). The results are shown in Table 1.
[0093] As can be seen from the data in Table 1, when using the methods provided in Embodiments 1 to 6 of the present application, the number of deformation annealing times ≤ 4 times, the wire breakage rate during drawing is 2.7 - 3.6‰, the proportion of carbides with a size > 10μm is 1.4 - 1.6%, and the spheroidization rating is Grade 2. For the method provided in Comparative Example 1, the number of deformation annealing times is 5 times, which is more than that in Embodiments 1 to 6, and the cost is high. The wire breakage rate during drawing is 2.4%, which is higher than that in Embodiments 1 to 6. The proportion of carbides with a size > 10μm is 5.8%, and the spheroidization rating is Grade 4, which is higher than that of the present application. From a microscopic perspective, it is proved that the wire breakage rate during drawing is higher than that of the present application. For the method provided in Comparative Example 2, the annealing temperature is too high, the wire breakage rate during drawing is 3.9%, which is higher than that in Embodiments 1 to 6. The proportion of carbides with a size > 10μm is 6.7%, and the spheroidization rating is Grade 3, which is higher than that of the present application. From a microscopic perspective, it is proved that the wire breakage rate during drawing is higher than that of the present application.
[0094] The heat treatment method and high-carbon steel provided by the present invention control the deformation rate, spheroidizing annealing temperature, and spheroidizing annealing time of the deformation annealing treatment of the high-carbon steel wire rod, utilize the spheroidizing driving effect of drawing deformation and annealing on carbides, control the spheroidization degree of carbides, reduce the wire breakage rate during drawing while ensuring that the high-carbon steel wire rod is rolled to the target size, reduce the number of annealing times, save costs, and are convenient for popularization. For the heat treatment method provided by the present invention, the wire breakage rate during drawing is 2.7 - 3.6‰, the wire breakage rate is low, the number of deformation annealing times is small, and the cost is low.
[0095] Finally, it should also be noted that the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or elements inherent to such process, method, article or device.
[0096] Although the preferred embodiments of the present invention have been described, those skilled in the art can make additional changes and modifications once they know the basic creative concept. Therefore, the appended claims are intended to be construed to include the preferred embodiments and all changes and modifications falling within the scope of the present invention.
[0097] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention also intends to include these modifications and variations.
Claims
1. A heat treatment method for high carbon steel, characterized in that, It includes the following steps: Obtain a high-carbon steel wire rod with a carbon mass fraction of 0.6 to 1.7%; Perform multiple deformation annealing treatments on the high-carbon steel wire rod to obtain a steel wire; Temper the steel wire, complete the heat treatment, and then perform machining; Among them, the deformation annealing treatment includes first drawing deformation and then spheroidizing annealing treatment. The drawing deformation rate ≤ 60%, the diameter reduction rate of the first deformation annealing treatment is 8 - 15%, the diameter reduction rate of the last deformation annealing treatment is 25 - 60%, the temperature of the spheroidizing annealing is < 760 °C and not lower than 700 °C, and the time of the spheroidizing annealing is 2 - 4 h to avoid the growth of spherical carbides.
2. The heat treatment method of high carbon steel according to claim 1, characterized in that, The diameter reduction rate of the last deformation annealing treatment is 30 - 50%.
3. The heat treatment method of high carbon steel according to claim 2, characterized in that, The spheroidizing annealing temperature is 710 - 730 °C.
4. The heat treatment method of high carbon steel according to any one of claims 1-3, characterized in that, The number of times of the deformation annealing treatment is less than 5 times.
5. The heat treatment method of high carbon steel according to any one of claims 1 - 3, characterized in that, The diameter of the high-carbon steel wire rod is 5 - 7 mm, and the diameter of the steel wire is 0.5 - 2 mm.
6. The heat treatment method of high carbon steel according to any one of claims 1-3, characterized in that, The tempering temperature is 360 - 400 °C.
7. The heat treatment method of high carbon steel according to any one of claims 1 - 3, characterized in that, The multiple deformation annealing treatments performed on the high-carbon steel wire rod specifically include: After annealing the high-carbon steel wire rod at a temperature of 750 - 770 °C for 3 - 5 h, perform multiple deformation annealing treatments.
8. A high-carbon steel, characterized in that, Obtained by using the heat treatment method according to any one of claims 1 - 7.
Citation Information
Patent Citations
Manufacturing process of screw wires
CN102861782A
High-performance reinforcing steel bar and preparation method thereof
CN104372895A