CN111172373A - Low-carbon steel heat treatment process - Google Patents
Low-carbon steel heat treatment process Download PDFInfo
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- CN111172373A CN111172373A CN202010118010.0A CN202010118010A CN111172373A CN 111172373 A CN111172373 A CN 111172373A CN 202010118010 A CN202010118010 A CN 202010118010A CN 111172373 A CN111172373 A CN 111172373A
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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
- 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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- 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
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/70—Furnaces for ingots, i.e. soaking pits
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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
- C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
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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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- 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
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
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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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/20—Ferrous alloys, e.g. steel alloys containing chromium with copper
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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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/22—Ferrous alloys, e.g. steel alloys containing chromium with molybdenum or tungsten
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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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/34—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of silicon
Abstract
The invention discloses a heat treatment process for low-carbon steel, and relates to the technical field of heat treatment. The low-carbon steel heat treatment process comprises the following steps: s10, smelting and casting a low-carbon steel material to prepare a first steel ingot, and heating the first steel ingot to 750-800 ℃; s20, placing the first steel ingot into a high-temperature smelting furnace, and preserving heat for 2-4 hours at 820-880 ℃ to obtain a second steel ingot; s30, heating the high-temperature smelting furnace to 950-1000 ℃, and preserving heat of the second steel ingot for 2-4 hours at the temperature to obtain a third steel ingot; s40, heating the high-temperature smelting furnace to 1100-1240 ℃, preserving the heat of the third steel ingot for 5-8 hours, then forging the third steel ingot for multiple times at the temperature, and finally air-cooling to room temperature; wherein the forging process comprises upsetting along the first direction and then drawing or flattening along the second direction. By adopting the low-carbon steel heat treatment process to carry out heat treatment on the low-carbon steel material, the crystal grains can be obviously refined, so that the mechanical property of the low-carbon steel is obviously improved.
Description
Technical Field
The invention relates to the technical field of heat treatment, in particular to a heat treatment process for low-carbon steel.
Background
And after finishing forging the low-carbon steel large forging material at home and abroad, carrying out Ac3+ 30-50 ℃ complete austenitizing temperature normalizing treatment for 16-48 h, and then air cooling. In the heat treatment process, particularly, the large forged material can grow grains due to overlong heat preservation time, and phenomena such as a network structure, coarse crystals or mixed crystals are easy to generate, so that the mechanical property of the low-carbon steel is reduced and unstable, and the requirements of related standards or users cannot be met.
Disclosure of Invention
The invention mainly aims to provide a low-carbon steel heat treatment process, and aims to solve the problems that the mechanical property of low-carbon steel is reduced and unstable due to overlong heat preservation time in the conventional heat treatment process.
In order to achieve the aim, the invention provides a low-carbon steel heat treatment process, which comprises the following steps:
s10, smelting and casting a low-carbon steel material to prepare a first steel ingot, and heating the first steel ingot to 750-800 ℃;
s20, placing the first steel ingot into a high-temperature smelting furnace, and preserving heat for 2-4 hours at 820-880 ℃ to obtain a second steel ingot;
s30, heating the high-temperature smelting furnace to 950-1000 ℃, and preserving heat of the second steel ingot for 2-4 hours at the temperature to obtain a third steel ingot;
s40, heating the high-temperature smelting furnace to 1100-1240 ℃, preserving the heat of the third steel ingot for 5-8 hours, then forging the third steel ingot for multiple times, and finally air-cooling to room temperature;
wherein the forging process comprises upsetting along the first direction and then drawing or flattening along the second direction.
Optionally, in step S10, the low-carbon steel material includes the following components by mass percent: 0.14 to 0.21% of C, 1.2 to 1.6% of Si, 0.45 to 0.65% of Mn, 0.50 to 0.70% of Cr, 0.05 to 0.15% of P, 0.005 to 0.015% of S, 0.12 to 0.18% of Mo, 0.15 to 0.3% of Cu, and the balance of Fe and inevitable impurities.
Optionally, step S20 includes: and (3) putting the first steel ingot into a high-temperature smelting furnace, maintaining weak flame at 820-880 ℃, and keeping the temperature for 2-4 h to avoid the flame from directly burning the surface of the first steel ingot in a spraying manner to obtain a second steel ingot.
Alternatively, in step S30: and heating the high-temperature smelting furnace to 950-1000 ℃ at a heating rate of 50-80 ℃/h.
Optionally, in step S40, the temperature of the high-temperature smelting furnace is raised to 1100 to 1240 ℃ at a rate of 100 to 150 ℃/h.
Optionally, in step S40, the number of the multiple forging processes is 20 to 30.
Optionally, in step S40, the finish forging temperature of the forging process is 800 to 850 ℃, and the total deformation amount reaches 20 to 25%.
Alternatively, in step S40, the forging process includes: carrying out upsetting along a first direction, and then carrying out drawing-out along a second direction, wherein the first direction and the second direction are opposite; and/or the presence of a gas in the gas,
after upsetting is carried out along a first direction, flattening is carried out along a second direction, and the first direction and the second direction are vertical directions.
The invention provides a low-carbon steel heat treatment process, which comprises the steps of firstly smelting and casting a low-carbon steel material to prepare a first steel ingot, and heating the first steel ingot to 750-800 ℃; then, preserving the heat of the first steel ingot at 820-880 ℃ for 2-4 h to obtain a second steel ingot; heating the second steel ingot to 950-1000 ℃, and preserving heat for 2-4 hours to obtain a third steel ingot; and finally, preserving the heat of the third steel ingot at 1100-1240 ℃ for 5-7 h, then forging the third steel ingot for multiple times, and finally air-cooling to room temperature. By controlling proper temperature and time parameters and forging treatment of drawing out after upsetting or flattening after upsetting for multiple times, large blocky carbides can be crushed and refined, grains of the low-carbon steel material are obviously refined, and the mechanical properties such as plasticity, toughness and the like of the low-carbon steel material are improved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other related drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is an electron micrograph of a comparative example treated low carbon steel;
FIG. 2 is an electron micrograph of a low carbon steel treated in example 1;
FIG. 3 is an electron micrograph of a low carbon steel treated in example 2.
The implementation, functional features and advantages of the objects of the present invention will be further explained with reference to the accompanying drawings.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. It is to be understood that the described embodiments are merely a few embodiments of the invention, and not all embodiments.
It should be noted that those whose specific conditions are not specified in the examples were performed according to the conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially. In addition, the meaning of "and/or" appearing throughout includes three juxtapositions, exemplified by "A and/or B" including either A or B or both A and B. In addition, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The existing heat treatment for large low-carbon steel forgings has long heat preservation time, so that crystal grains grow up, and phenomena such as a network structure, coarse crystals or mixed crystals are easy to generate, so that the mechanical property of the low-carbon steel is reduced and unstable.
In view of the above, the invention provides a low-carbon steel heat treatment process, and the low-carbon steel material is subjected to heat treatment by adopting the low-carbon steel heat treatment process provided by the invention, so that large blocky carbides can be crushed and refined, and grains of the low-carbon steel material are obviously refined, and the mechanical properties such as plasticity, toughness and the like of the low-carbon steel material are improved. The low-carbon steel heat treatment process comprises the following steps:
s10, smelting and casting the low-carbon steel material to prepare a first steel ingot, and heating the first steel ingot to 750-800 ℃.
In the technical scheme of the invention, the low-carbon steel material comprises the following components in percentage by mass: 0.14 to 0.21% of C, 1.2 to 1.6% of Si, 0.45 to 0.65% of Mn, 0.50 to 0.70% of Cr, 0.05 to 0.15% of P, 0.005 to 0.015% of S, 0.12 to 0.18% of Mo0.15 to 0.3% of Cu, and the balance of Fe and inevitable impurities. The high C content is advantageous for strength, hardness and the like of the low carbon steel, but is extremely disadvantageous for plasticity and toughness of the low carbon steel, and decreases the yield ratio, increases decarburization sensitivity, and deteriorates fatigue resistance, workability and high temperature plasticity of the low carbon steel, so that the C content in the low carbon steel should be appropriately reduced to 0.21% or less. However, the C content after quenching and high-temperature tempering should not be too low to obtain the desired high strength, and thus the C content is preferably controlled to 0.14 to 0.21%. S is an inevitable impurity, forms MnS inclusions, and segregates at grain boundaries to deteriorate toughness of the low carbon steel, thereby reducing toughness and plasticity of the low carbon steel. Therefore, the S content should be controlled to 0.015% or less. The Cu realizes precipitation strengthening by precipitating epsilon-Cu, the strength of the low-carbon steel is improved, in addition, the proper amount of Cu element is added, and the atmospheric corrosion resistance of the low-carbon steel can be improved, so the Cu content is controlled to be 0.15-0.3%.
S20, placing the first steel ingot into a high-temperature smelting furnace, and preserving heat for 2-4 hours at 820-880 ℃ to obtain a second steel ingot.
After the steel ingot is cast, the steel ingot is drawn in a red hot state, and the steel ingot is sent to a steel rolling mill by a red sending process to be charged and reheated for rolling, so that the energy can be obviously saved, the production flow is simplified, and the production cost is reduced. In order to reduce or even avoid cracks, the cast first steel ingot is placed into a high-temperature smelting furnace for heating, the temperature of the furnace when the first steel ingot is placed into the high-temperature smelting furnace is not higher than the surface temperature of the first steel ingot by 70-80 ℃, namely the temperature of the furnace is 820-880 ℃, and the temperature is kept for 2-4 hours at the temperature. In addition, in order to ensure that the effect of preventing the cracks is better, the heat preservation is carried out for maintaining fine flame during the heat preservation, and the flame is prevented from directly burning the surface of the first steel ingot to obtain the second steel ingot. And the first steel ingot is kept red all the time by adopting the indirect heating mode, so that the temperature of the first steel ingot is required to be kept above 600 ℃, and is preferably 600-700 ℃.
And S30, heating the high-temperature smelting furnace to 950-1000 ℃, and preserving the heat of the second steel ingot for 2-4 hours at the temperature to obtain a third steel ingot.
Specifically, the high-temperature smelting furnace is heated to 950-1000 ℃ at the speed of 50-80 ℃/h, and the second steel ingot is kept at the temperature for 2-4 h to obtain a third steel ingot.
And S40, heating the high-temperature smelting furnace to 1100-1240 ℃, preserving the heat of the third steel ingot for 5-7 hours, then forging the third steel ingot for multiple times, and finally air-cooling to room temperature.
Specifically, the high-temperature smelting furnace is heated to 1100-1240 ℃ at the speed of 100-150 ℃/h, heat preservation is carried out for 5-7 h, then the third steel ingot is forged for multiple times, and finally air cooling is carried out to the room temperature. Wherein, the times of multiple forging treatment are 20-30, the temperature can continuously drop in the forging process, and in order to ensure that the forging effect is better, the final forging temperature needs to be maintained at 800-850 ℃. The forging treatment can make the crystal grains finer, so that the plasticity and the toughness of the low-carbon steel material are improved, and in order to make the forging effect better, the total deformation amount of the forging is required to reach 20-25%. Preferably, the single deformation of each upsetting or drawing is 20-25%, and the internal defects of the low-carbon steel material can be effectively eliminated.
In addition, the primary forging treatment comprises upsetting along a first direction and then drawing along a second direction, wherein the first direction and the second direction are opposite; or flattening along a second direction after upsetting is carried out along a first direction, wherein the first direction and the second direction are vertical directions. Upsetting is a process of reducing the height of a billet by pressure and increasing the diameter (or transverse dimension), and is the most basic forming method in a plastic forming process. In the heat treatment, the third steel ingot is subjected to upsetting deformation for one time, and then is subjected to flattening or drawing deformation, so that continuous forging and extrusion are realized, the strain accumulated twice is obtained, the accumulated deformation degree of the third steel ingot is improved, the crystal grains are effectively refined, and the comprehensive mechanical property of the treated low-carbon steel is improved.
Wherein, in order to make the forging effect better, the accumulated forging ratio after one-time forging treatment
The temperature is controlled to be between 1.8 and 2.5. The cumulative forging ratio is defined as follows:
Li-1is the cross-sectional area of the third ingot before upsetting or flattening or elongation treatment, LíFor the cross-sectional area through the upset or flatten or draw out long processing back third steel ingot, n is total forging and handles the number of times, and i is that the primary is handled. Further, the single forging ratio: l isí-1/Lí>0.5。
Furthermore, stretching or flattening after upsetting can be performed simultaneously or alternatively, and the stretching or flattening can be performed according to actual needs. Example (c): multiple forging treatment protocol 1: upsetting downwards, and drawing upwards; then flattening along the side surface (along the vertical direction) after upsetting downwards; the cycle is repeated 10 times, namely 20 times. Multiple forging treatment protocol 2: upsetting downwards, and drawing upwards; the process is circulated for 25 times. Multiple forging treatment protocol 3: flattening along the side surface (along the vertical direction) after upsetting downwards; the process is circulated 30 times.
The invention provides a low-carbon steel heat treatment process, which comprises the steps of firstly smelting and casting a low-carbon steel material to prepare a first steel ingot, and heating the first steel ingot to 750-800 ℃; then, preserving the heat of the first steel ingot at 820-880 ℃ for 2-4 h to obtain a second steel ingot; heating the second steel ingot to 950-1000 ℃, and preserving heat for 2-4 hours to obtain a third steel ingot; and finally, preserving the heat of the third steel ingot at 1100-1240 ℃ for 5-7 h, forging the third steel ingot for multiple times at the temperature, and finally air-cooling. By controlling proper temperature and time parameters and forging treatment of drawing out after upsetting or flattening after upsetting for multiple times, large blocky carbides can be crushed and refined, grains of the low-carbon steel material are obviously refined, and the mechanical properties such as plasticity, toughness and the like of the low-carbon steel material are improved.
The technical solutions of the present invention are further described in detail below with reference to specific examples and drawings, it should be understood that the following examples are merely illustrative of the present invention and are not intended to limit the present invention.
Example 1
(1) Smelting and casting a low-carbon steel material with the components of 0.16% of C, 1.4% of Si, 0.5% of Mn, 0.7% of Cr, 0.05% of P, 0.009% of S, 0.12% of Mo0.3% of Cu and the balance of Fe and impurities to prepare a first steel ingot, and heating the first steel ingot to 750 ℃.
(2) And (3) putting the first steel ingot into a high-temperature smelting furnace, and maintaining fine flame at 820 ℃ for heat preservation for 4h to obtain a second steel ingot.
(3) And heating the high-temperature smelting furnace to 970 ℃ at the speed of 50 ℃/h, and preserving the heat of the second steel ingot for 3h at the temperature to obtain a third steel ingot.
(4) And heating the high-temperature smelting furnace to 1100 ℃ at a speed of 100 ℃/h, preserving heat of the third steel ingot for 6h, forging the third steel ingot at 1100 ℃ (upsetting, then drawing out in the opposite direction), forging for 26 times in such a way, keeping the finish forging temperature of 800 ℃, ensuring that the total deformation reaches 22%, and finally cooling to room temperature in air. And observing the microstructure of the treated low-carbon steel material under a scanning electron microscope to obtain a graph 2.
Example 2
(1) Smelting and casting a low-carbon steel material with the components of 0.21% of C, 1.2% of Si, 0.65% of Mn, 0.58% of Cr, 0.15% of P, 0.005% of S, 0.16% of Mo, 0.22% of Cu and the balance of Fe and impurities to prepare a first steel ingot, and heating the first steel ingot to 770 ℃.
(2) And (3) putting the first steel ingot into a high-temperature smelting furnace, and maintaining fine flame at 860 ℃ for heat preservation for 3 hours to obtain a second steel ingot.
(3) And (3) heating the high-temperature smelting furnace to 950 ℃ at a speed of 70 ℃/h, and preserving the heat of the second steel ingot for 4h at the temperature to obtain a third steel ingot.
(4) And heating the high-temperature smelting furnace to 1240 ℃ at a speed of 150 ℃/h, preserving heat of the third steel ingot for 5h, forging the third steel ingot at 1240 ℃ (upsetting, then drawing out in the opposite direction), forging for 20 times in such a way, keeping the finish forging temperature of 850 ℃ and the total deformation of 20%, and finally air-cooling to room temperature. And observing the microstructure of the treated low-carbon steel material under a scanning electron microscope to obtain a graph 3.
Example 3
(1) Smelting and casting a low-carbon steel material with the components of 0.14% of C, 1.6% of Si, 0.45% of Mn, 0.5% of Cr, 0.11% of P, 0.015% of S, 0.18% of Mo0.15% of Cu and the balance of Fe and impurities to prepare a first steel ingot, and heating the first steel ingot to 800 ℃.
(2) And (3) putting the first steel ingot into a high-temperature smelting furnace, and maintaining fine flame at 880 ℃ for heat preservation for 2 hours to obtain a second steel ingot.
(3) And (3) heating the high-temperature smelting furnace to 1000 ℃ at the speed of 80 ℃/h, and preserving the heat of the second steel ingot for 2h at the temperature to obtain a third steel ingot.
(4) And heating the high-temperature smelting furnace to 1200 ℃ at a speed of 120 ℃/h, preserving heat of the third steel ingot for 6h, forging the third steel ingot at 1200 ℃ (upsetting, then flattening along the vertical direction), forging for 30 times in such a way, keeping the finish forging temperature at 830 ℃, ensuring that the total deformation reaches 25%, and finally cooling to room temperature in air.
Example 4
(1) Smelting and casting a low-carbon steel material with the components of 0.17% of C, 1.5% of Si, 0.49% of Mn, 0.58% of Cr, 0.15% of P, 0.005% of S, 0.16% of Mo, 0.25% of Cu and the balance of Fe and impurities to prepare a first steel ingot, and heating the first steel ingot to 770 ℃.
(2) And (3) putting the first steel ingot into a high-temperature smelting furnace, and maintaining fine flame at 850 ℃ for heat preservation for 3h to obtain a second steel ingot.
(3) And (3) heating the high-temperature smelting furnace to 1000 ℃ at the speed of 80 ℃/h, and preserving the heat of the second steel ingot for 2h at the temperature to obtain a third steel ingot.
(4) And heating the high-temperature smelting furnace to 1240 ℃ at a speed of 150 ℃/h, preserving heat of the third steel ingot for 5h, forging the third steel ingot at 1240 ℃ (upsetting, then flattening along the vertical direction), forging for 20 times in this way, keeping the finish forging temperature at 800 ℃, ensuring that the total deformation reaches 20%, and finally cooling to room temperature in the air.
Comparative example
The low carbon steel material with the components of C0.16%, Si 1.4%, Mn 0.5%, Cr 0.7%, P0.05%, S0.009%, Mo0.12%, Cu 0.3% and the balance of Fe and impurities is subjected to full austenitizing temperature normalizing treatment at 860 ℃ for 24h and then air-cooled to room temperature. And observing the microstructure of the treated low-carbon steel material under a scanning electron microscope to obtain a graph 1.
The low carbon steel materials treated in the above examples 1 to 4 and the low carbon steel material treated in the above proportion 1 were made into sample strips by an injection molding machine, and the sampling part: the mechanical property data of the product at a position 12.5mm away from the surface are shown in Table 1.
TABLE 1 mechanical Property test results
Yield strength is the yield limit at which the metal material yields, i.e., the stress that resists a slight amount of plastic deformation. The tensile strength is a critical value of the transition of the metal from uniform plastic deformation to local concentrated plastic deformation, and is also the maximum bearing capacity of the metal under a static stretching condition, and the tensile strength is the resistance representing the maximum uniform plastic deformation of the material. As can be seen from Table 1, compared with the low-carbon steel material treated by the comparative example, the low-carbon steel material treated by the embodiment of the invention has finer grains and better mechanical properties such as yield strength, tensile strength, hardness and the like, i.e. the plasticity and toughness of the low-carbon steel material are obviously improved, so that the low-carbon steel treated by the low-carbon steel heat treatment process of the invention can be used as a large forging material.
The grain structures of fig. 2 and 3 are significantly finer in fig. 2 and 3 of the microstructure of the low carbon steel material treated in the examples than in fig. 1 of the microstructure of the low carbon steel material in the comparative examples.
In conclusion, the low-carbon steel material is subjected to heat treatment by adopting the low-carbon steel refined structure heat treatment process, so that the crystal grains can be obviously refined, the mechanical properties such as plasticity, toughness and the like of the low-carbon steel material are obviously improved, and the low-carbon steel treated by the low-carbon steel heat treatment process can be used as a large forging material.
The above is only a preferred embodiment of the present invention, and it is not intended to limit the scope of the invention, and various modifications and changes will occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention shall be included in the scope of the present invention.
Claims (7)
1. The low-carbon steel heat treatment process is characterized by comprising the following steps of:
s10, smelting and casting a low-carbon steel material to prepare a first steel ingot, and heating the first steel ingot to 750-800 ℃;
s20, placing the first steel ingot into a high-temperature smelting furnace, and preserving heat for 2-4 hours at 820-880 ℃ to obtain a second steel ingot;
s30, heating the high-temperature smelting furnace to 950-1000 ℃, and preserving heat of the second steel ingot for 2-4 hours at the temperature to obtain a third steel ingot;
s40, heating the high-temperature smelting furnace to 1100-1240 ℃, preserving the heat of the third steel ingot for 5-7 hours, then forging the third steel ingot for multiple times, and finally air-cooling to room temperature;
wherein the forging process comprises upsetting along the first direction and then drawing or flattening along the second direction.
2. The heat treatment process for the low carbon steel as claimed in claim 1, wherein in the step S10, the low carbon steel material comprises the following components in percentage by mass: 0.14 to 0.21% of C, 1.2 to 1.6% of Si, 0.45 to 0.65% of Mn, 0.50 to 0.70% of Cr, 0.05 to 0.15% of P, 0.005 to 0.015% of S, 0.12 to 0.18% of Mo, 0.15 to 0.3% of Cu, and the balance of Fe and inevitable impurities.
3. The heat treatment process for low carbon steel according to claim 1, wherein in step S30: and heating the high-temperature smelting furnace to 950-1000 ℃ at a heating rate of 50-80 ℃/h.
4. The heat treatment process for the low carbon steel according to claim 1, wherein in step S40, the temperature of the high temperature melting furnace is raised to 1100 to 1240 ℃ at a temperature raising rate of 100 to 150 ℃/h.
5. The heat treatment process for the low carbon steel according to claim 1, wherein the number of the multiple forging treatments in step S40 is 20 to 30.
6. The heat treatment process for the low carbon steel according to claim 5, wherein in step S40, the finish forging temperature of the forging treatment is 800-850 ℃, and the total deformation amount reaches 20-25%.
7. The low carbon steel heat treatment process of claim 1, wherein the forging process in step S40 includes: carrying out upsetting along a first direction, and then carrying out drawing-out along a second direction, wherein the first direction and the second direction are opposite; and/or the presence of a gas in the gas,
after upsetting is carried out along a first direction, flattening is carried out along a second direction, and the first direction and the second direction are vertical directions.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112359293A (en) * | 2020-11-23 | 2021-02-12 | 武汉轻工大学 | Mo-V series high-speed steel roll collar for KOCKS bar mill and preparation method thereof |
| CN113403568A (en) * | 2021-06-01 | 2021-09-17 | 温岭市云福热处理厂 | Low-carbon steel and heat treatment process thereof |
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| CN1255949A (en) * | 1998-01-14 | 2000-06-07 | 新日本制铁株式会社 | Bainite type rail excellent in surface fatigue damage resistance and wear resistance |
| CN1800427A (en) * | 2004-12-31 | 2006-07-12 | 马鞍山钢铁股份有限公司 | Bainite steel for railroad carriage wheel |
| JP5135557B2 (en) * | 2010-03-11 | 2013-02-06 | 新日鐵住金株式会社 | High-strength steel material and high-strength bolt excellent in delayed fracture resistance |
| CN104722702A (en) * | 2014-11-14 | 2015-06-24 | 上海新闵（东台）重型锻造有限公司 | Forging forming technology for high-temperature steam pipeline of supercritical unit |
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| CN108453202A (en) * | 2018-02-13 | 2018-08-28 | 无锡宏达重工股份有限公司 | A kind of manufacturing process of large marine shafting forging manufacture |
| CN109622836A (en) * | 2018-12-05 | 2019-04-16 | 无锡继平锻造有限公司 | A kind of forging and heat treatment process of Shell Forging Parts |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112359293A (en) * | 2020-11-23 | 2021-02-12 | 武汉轻工大学 | Mo-V series high-speed steel roll collar for KOCKS bar mill and preparation method thereof |
| CN113403568A (en) * | 2021-06-01 | 2021-09-17 | 温岭市云福热处理厂 | Low-carbon steel and heat treatment process thereof |
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