CN112301193B - Thermomechanical treatment method for preparing rare earth bearing steel - Google Patents
Thermomechanical treatment method for preparing rare earth bearing steel Download PDFInfo
- Publication number
- CN112301193B CN112301193B CN202011054655.9A CN202011054655A CN112301193B CN 112301193 B CN112301193 B CN 112301193B CN 202011054655 A CN202011054655 A CN 202011054655A CN 112301193 B CN112301193 B CN 112301193B
- Authority
- CN
- China
- Prior art keywords
- rolling
- rare earth
- bearing steel
- earth bearing
- steel
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Classifications
-
- 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
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/26—Methods of annealing
- C21D1/32—Soft annealing, e.g. spheroidising
-
- 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
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/84—Controlled slow cooling
-
- 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
- C21D6/00—Heat treatment of ferrous alloys
- C21D6/002—Heat treatment of ferrous alloys containing Cr
-
- 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
- C21D6/00—Heat treatment of ferrous alloys
- C21D6/005—Heat treatment of ferrous alloys containing Mn
-
- 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
- C21D6/00—Heat treatment of ferrous alloys
- C21D6/008—Heat treatment of ferrous alloys containing Si
-
- 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
- C21D8/06—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of rods or wires
- C21D8/065—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of rods or wires of ferrous alloys
-
- 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
- C21D9/0075—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for rods of limited length
-
- 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
- C22C38/005—Ferrous alloys, e.g. steel alloys containing rare earths, i.e. Sc, Y, Lanthanides
-
- 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
-
- 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
-
- 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
- C22C38/28—Ferrous alloys, e.g. steel alloys containing chromium with titanium or zirconium
-
- 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
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/009—Pearlite
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Abstract
The application provides a thermomechanical treatment method for preparing rare earth bearing steel, measures such as controlled rolling and cooling in a two-phase region, slow cooling pit slow cooling, isothermal spheroidizing annealing and the like are adopted, the net shape and the band shape of carbide of the rare earth bearing steel can be effectively controlled to be not higher than 2.0 grade, and a microstructure is a fine, uniform and completely spheroidized pearlite structure which is not higher than 3.0 grade, so that the structure and the carbide uniformity of the rare earth bearing steel are improved, and a good base material is provided for forging heat treatment of downstream users.
Description
Technical Field
The invention relates to the technical field of rolling and heat treatment of rare earth bearing steel, in particular to a thermomechanical treatment method for preparing rare earth bearing steel.
Background
Rare earth resources are commonly called industrial vitamins, are important strategic resources in the world and are also dominant resources in China. China is the first in the world in the rare earth resource reserves, production, export and consumption. The rare earth bearing steel is developed, so that the balanced utilization of rare earth resources can be realized, the healthy development of the rare earth industry is promoted, the quality level of the rare earth bearing steel in China can be improved, the product quality level of foreign advanced enterprises is reached or exceeded, and the limitation of foreign countries on key materials of high-end equipment in China is broken.
A large number of researches and practices prove that the steel can be effectively purified and the inclusions can be spheroidized by adding the rare earth into the steel, and the rare earth added into the steel also has a certain microalloying effect.
The improvement of the cleanliness of the rare earth bearing steel and the reduction of the nonuniformity of carbide are two major prerequisites for prolonging the service life of the bearing. The rare earth added into the steel can effectively aggregate and remove large inclusions and spheroidized small inclusions, thereby improving the cleanliness of the steel. The carbides in the rare earth bearing steel are brittle phases and are often the origins of cracks, and the smaller, more uniform and more round carbides contribute more to the improvement of the service life of the bearing, which has become a consensus in the domestic bearing industry.
How to systematically control the P, S, N, H, O content of EH36 molten steel and improve the cleanliness of the molten steel and the qualified rate of casting blanks is urgent to develop a thermomechanical treatment method for preparing rare earth bearing steel.
Disclosure of Invention
The embodiment of the invention aims to provide a thermomechanical treatment method for preparing rare earth bearing steel.
In order to solve the technical problems, the technical scheme provided by the invention is as follows:
a thermomechanical treatment method for preparing rare earth bearing steel comprises the following steps of: 1) putting a rectangular blank prepared by casting into a furnace for heating, 2) rough rolling, 3) medium rolling, 4) finish rolling, 5) first-stage water cooling, 6) size reducing and sizing, 7) second-stage water cooling, 8) segmenting, 9) collecting, 10) slow cooling and 11) isothermal spheroidizing annealing;
wherein, the three stages of rough rolling, intermediate rolling and finish rolling adopt temperature-controlled rolling;
in the step 4), the alpha + gamma two-phase region rolling is adopted in the finish rolling, the initial rolling temperature in the finish rolling stage is controlled to be in the two-phase region of the eutectoid carbide and the austenite, and the final rolling temperature is controlled to be 750-850 ℃;
in the step 7), controlling the surface re-reddening temperature of the steel bar after the second-stage water cooling to be 570-650 ℃;
in the step 10), slow cooling is carried out in a slow cooling pit, the temperature of the steel bar is 510-630 ℃ when the steel bar enters the slow cooling pit, and the temperature of the steel bar is not higher than 150 ℃ when the steel bar is discharged from the slow cooling pit;
step 11), the isothermal spheroidizing annealing specifically comprises the following steps: heating the steel bar to 780-810 ℃, then preserving heat for 3-6 hours, then slowly cooling with the furnace at a cooling rate of 10-25 ℃/h until the furnace is cooled to 690-750 ℃, then preserving heat for 4-6 hours, and then taking the steel bar out of the furnace for air cooling.
Preferably, the outer diameter of the finished product of the rare earth bearing steel after isothermal spheroidizing annealing is 30-70 mm;
the rare earth bearing steel comprises the following components in percentage by mass: 0.95 to 1.05 percent of C, 0.15 to 0.35 percent of Si, 0.25 to 0.45 percent of Mn, 1.40 to 1.65 percent of Cr, less than or equal to 0.0015 percent of Ti, less than or equal to 0.0008 percent of O, 0.0010 to 0.0030 percent of RE, and the balance of Fe and inevitable impurities;
the RE element is lanthanum and/or cerium.
Preferably, the microstructure in the finished rare earth bearing steel prepared after isothermal spheroidizing annealing is a fine, uniform and completely spheroidized pearlite structure which is not higher than 3.0 grade, and the network shape and the belt shape of carbides in the rare earth bearing steel are not higher than 2.0 grade.
The application obtains the following beneficial technical effects:
1) the method adopts controlled rolling and controlled cooling, the three stages of rough rolling, intermediate rolling and finish rolling all adopt controlled rolling, and the finish rolling in the two-phase region is divided into two sections of controlled cooling before and after the reduction sizing mill group; a large number of researches show that the cooling speed after rolling is a main factor influencing the rare earth bearing steel structure; in the cooling process after the finish rolling deformation, the diameter of the pearlite pellets and the interlayer spacing are reduced along with the increase of the cooling speed; the temperature range of the rare earth bearing steel reticular carbide precipitation is 650-850 ℃, and a large amount of precipitation is concentrated at 700-750 ℃;
the influence of the controlled cooling process on the spheroidization of the rare earth bearing steel can be summarized as follows:
(1.1) the austenitizing temperature can be reduced, and the layered pearlite breaking time is shortened, so that the spheroidization is accelerated, the isothermal spheroidization annealing period is shortened, and the energy consumption is reduced;
(1.2) improving the isothermal spheroidizing annealing quality, so that the particle size of carbides and the average carbide spacing MSP (mixed-stress relief) are reduced, and the sphericity is improved, thereby prolonging the contact fatigue life of the rare earth bearing steel;
ensuring that the structure is fine flaky pearlite, avoiding the generation of quenched martensite and inhibiting the precipitation of net-shaped carbide, wherein the reasonable process is that after the final rolling deformation, the cooling speed is controlled to be 5-10 ℃/s, and the temperature range of the net-shaped carbide in which a large amount of net-shaped carbide is precipitated is avoided as much as possible by cooling after the final rolling;
the deformation of austenite grains can be effectively increased by rolling in a two-phase region, and dispersed carbides are separated out;
after rolling, water cooling is accelerated, the steel rapidly passes through a sensitive temperature range where a large amount of carbide is separated out, the kinetic and thermodynamic conditions of carbide separation are inhibited, and the separation of the net-shaped carbide can be effectively reduced;
the water cooling area is divided into two sections, one section is arranged between the finishing mill group and the reducing and sizing mill group, and the other section is arranged after the finishing mill group comes out of the reducing and sizing mill group;
controlling the surface red returning temperature of the steel bar after the two-stage water cooling to be not more than 650 ℃, wherein the red returning temperature range is 570-650 ℃, and at the moment, the center part of the rare earth bearing steel round bar is about 600-700 ℃, which is just a temperature region for converting austenite into pearlite;
2) quickly feeding the rare earth bearing steel into a slow cooling pit for slow cooling, after controlled rolling and controlled cooling, performing segmentation, quick collection and sizing on the rare earth bearing steel, then performing slow cooling on the rare earth bearing steel in the slow cooling pit, wherein the temperature of the rare earth bearing steel fed into the slow cooling pit is about 600 ℃, and the temperature of the rare earth bearing steel discharged from the slow cooling pit is not higher than 150 ℃;
after rolling, slow cooling can greatly reduce the structural stress and the thermal stress generated in the accelerated cooling process of the rare earth bearing steel, can prevent white spots, can effectively promote pearlite transformation and prevent the super-cooling from generating a martensite structure.
3) Isothermal spheroidizing annealing, wherein isothermal spheroidizing annealing is carried out on the rare earth bearing steel after the slow cooling pit is formed, and the rare earth bearing steel is in an optimal spheroidizing heating temperature range of 790-800 ℃ by considering the influence of rare earth on tissue transformation; if the heating temperature is too high, a large amount of carbide is dissolved, the core serving as spheroidizing crystal is small, and the spheroidized crystal is coarse spherical pearlite or a part of lamellar structure; if the heating temperature is lower, flaky pearlite which is not transformed can still be remained in the structure after isothermal spheroidizing annealing;
the main purposes of isothermal spheroidizing annealing are to reduce the hardness, facilitate cutting processing, improve the comprehensive mechanical property of heat treatment, eliminate work hardening and increase the plasticity; secondly, fine particle pearlite which is uniformly distributed is obtained and is ready for quenching; the optimal treatment process is isothermal spheroidizing annealing;
in the rare earth bearing steel, the shape, size, quantity and distribution of carbide have great influence on the final service performance, and the structure form of the carbide after isothermal spheroidizing annealing is difficult to change through quenching and tempering; therefore, the isothermal spheroidizing annealing process should be strictly controlled to completely spheroidize the carbide, so as to promote the carbide to be in smaller spherical particles and be uniformly distributed on the ferrite matrix, and the structure has the characteristics of good machinability, and fine and uniformly distributed residual carbide after quenching and tempering.
In conclusion, the microstructure of the rare earth bearing steel after controlled rolling and controlled cooling, slow cooling pit slow cooling and isothermal spheroidizing annealing is a fine, uniform and completely spheroidized pearlite structure, and the qualified grade can reach the grade of 5 th grade figures 2-3 in GB/T18254-2016 high-carbon chromium rare earth bearing steel; the net shape and the strip shape of the carbide are respectively not more than 2.0 grades according to the 6 th grade and the 8 th grade, and are superior to the standard of super-grade high-quality steel; the contact fatigue life of the rare earth bearing steel after the thermomechanical treatment can reach 3-5 multiplied by 10 under the contact stress of not more than 4.5GPa7；
The rare earth bearing steel has the following main advantages: (a) based on the components of GCr15, 0.0010-0.0030 percent of RE is added, so that steel quality and spheroidized inclusions can be effectively purified, microalloying is realized, and the fatigue life is long; (b) the microstructure and carbide of the rare earth bearing steel designed and produced by adopting the components and the thermomechanical treatment process are more uniformly distributed, and the pearlite structure is fully spheroidized, fine and uniform;
the method and the device have the advantages that controlled rolling and controlled cooling, slow cooling pit slow cooling and isothermal spheroidizing annealing are carried out on the rare earth bearing steel, the uniformity of the rare earth bearing steel structure and carbide can be improved, the isothermal spheroidizing annealing qualification rate of the rare earth bearing steel bar is remarkably improved, and meanwhile, the spheroidized structure which is uniformly and finely dispersed and distributed from the center to the edge of the steel can be obtained. The combination of the processes is adopted as a main thermomechanical treatment means before supply in a steel mill, so that the carbide segregation distribution of the rare earth bearing steel can be greatly reduced, and a low-cost high-quality blank is provided for a downstream bearing processing user before forging heat treatment.
Detailed Description
For a further understanding of the invention, reference will now be made to the preferred embodiments of the invention by way of example, and it is to be understood that the description is intended to further illustrate the features and advantages of the invention and not to limit the scope of the claims.
The application provides a thermomechanical treatment method for preparing rare earth bearing steel, which comprises the following steps of: 1) putting a rectangular blank prepared by casting into a furnace for heating, 2) rough rolling, 3) medium rolling, 4) finish rolling, 5) first-stage water cooling, 6) size reducing and sizing, 7) second-stage water cooling, 8) segmenting, 9) collecting, 10) slow cooling and 11) isothermal spheroidizing annealing;
wherein, the three stages of rough rolling, intermediate rolling and finish rolling adopt temperature-controlled rolling;
in the step 4), the alpha + gamma two-phase region rolling is adopted in the finish rolling, the initial rolling temperature in the finish rolling stage is controlled to be in the two-phase region of the eutectoid carbide and the austenite, and the final rolling temperature is controlled to be 750-850 ℃;
in the step 7), controlling the surface re-reddening temperature of the steel bar after the second-stage water cooling to be 570-650 ℃;
in the step 10), slow cooling is carried out in a slow cooling pit, the temperature of the steel bar is 510-630 ℃ when the steel bar enters the slow cooling pit, and the temperature of the steel bar is not higher than 150 ℃ when the steel bar is discharged from the slow cooling pit;
step 11), the isothermal spheroidizing annealing specifically comprises the following steps: heating the steel bar to 780-810 ℃, then preserving heat for 3-6 hours, then slowly cooling with the furnace at a cooling rate of 10-25 ℃/h until the furnace is cooled to 690-750 ℃, then preserving heat for 4-6 hours, and then taking the steel bar out of the furnace for air cooling.
In one embodiment of the application, the outer diameter of the finished rare earth bearing steel prepared after isothermal spheroidizing annealing is 30-70 mm;
the rare earth bearing steel comprises the following components in percentage by mass: 0.95 to 1.05 percent of C, 0.15 to 0.35 percent of Si, 0.25 to 0.45 percent of Mn, 1.40 to 1.65 percent of Cr, less than or equal to 0.0015 percent of Ti, less than or equal to 0.0008 percent of O, 0.0010 to 0.0030 percent of RE, and the balance of Fe and inevitable impurities;
the RE element is lanthanum and/or cerium.
In one embodiment of the application, the microstructure in the finished rare earth bearing steel prepared after isothermal spheroidizing annealing is a fine, uniform and completely spheroidized pearlite structure which is not higher than 3.0 grade, and the network shape and the belt shape of carbide in the rare earth bearing steel are not higher than 2.0 grade.
According to the rare earth bearing steel, molten steel is refined through LF and VD, rare earth is added into the steel before VD is vacuumized, continuous casting is carried out in a full-protection mode, a rectangular billet is manufactured through casting, the rectangular billet is 220 multiplied by 260mm, and the rare earth bearing steel with the diameter of 30 mm-70 mm is obtained through reheating and rolling after slow cooling.
The methods and devices not described in detail in the present invention are all the prior art and are not described in detail.
For further understanding of the present invention, the thermomechanical treatment method for producing a rare earth bearing steel according to the present invention is described in detail below with reference to the following examples, and the scope of the present invention is not limited by the following examples.
Example 1
The rare earth bearing steel of the embodiment 1 comprises the following components in percentage by mass: c: 0.98%, Si: 0.25%, Mn: 0.30%, Cr: 1.50%, Ti: 0.0012%, O: 0.0006%, RE: 0.0021% and the balance of Fe and inevitable impurities; the outer diameter of the prepared finished rare earth bearing steel is 30 mm.
A thermomechanical treatment method for preparing rare earth bearing steel comprises the following steps of:
1) putting a rectangular blank prepared by casting into a furnace for heating, 2) rough rolling, 3) medium rolling, 4) finish rolling, 5) first-stage water cooling, 6) reducing and sizing, 7) second-stage water cooling, 8) segmenting, 9) collecting, 10) slow cooling and 11) isothermal spheroidizing annealing;
wherein, the three stages of rough rolling, intermediate rolling and finish rolling adopt temperature-controlled rolling;
in the step 4), the alpha + gamma two-phase region is adopted for rolling in the finish rolling, the initial rolling temperature in the finish rolling stage is controlled to be in the first eutectoid carbide and austenite two-phase region, and the final rolling temperature is controlled to be 830 ℃;
in the step 7), controlling the surface re-reddening temperature of the steel bar subjected to the second-stage water cooling to be 630-650 ℃;
in the step 10), slow cooling is carried out in a slow cooling pit, the temperature of the steel bar is 510-630 ℃ when the steel bar enters the slow cooling pit, and the temperature of the steel bar is 120 ℃ when the steel bar is discharged from the slow cooling pit;
step 11), the isothermal spheroidizing annealing specifically comprises the following steps: heating the steel to 790 ℃, then preserving heat for 3 hours, then slowly cooling with the furnace at a cooling rate of 10-25 ℃/h until the furnace is cooled to 690 ℃, then preserving heat for 4 hours, and then taking out the steel from the furnace for air cooling.
Example 2
The rare earth bearing steel of the embodiment 2 comprises the following components in percentage by mass: c: 0.98%, Si: 0.25%, Mn: 0.30%, Cr: 1.50%, Ti: 0.0012%, O: 0.0006%, RE: 0.0021% and the balance of Fe and inevitable impurities; the outer diameter of the prepared finished rare earth bearing steel is 50 mm.
A thermomechanical treatment method for preparing rare earth bearing steel comprises the following steps of: 1) putting a rectangular blank prepared by casting into a furnace for heating, 2) rough rolling, 3) medium rolling, 4) finish rolling, 5) first-stage water cooling, 6) size reducing and sizing, 7) second-stage water cooling, 8) segmenting, 9) collecting, 10) slow cooling and 11) isothermal spheroidizing annealing;
wherein, the three stages of rough rolling, intermediate rolling and finish rolling adopt temperature-controlled rolling;
in the step 4), the alpha + gamma two-phase region is adopted for rolling in the finish rolling, the initial rolling temperature in the finish rolling stage is controlled to be in the two-phase region of the eutectoid carbide and the austenite, and the final rolling temperature is controlled to be 800 ℃;
in the step 7), controlling the surface re-reddening temperature of the steel bar after the second-stage water cooling to be 600-630 ℃;
in the step 10), slow cooling is carried out in a slow cooling pit, the temperature of a steel bar is 580-610 ℃ when the steel bar enters the slow cooling pit, and the temperature of the steel bar is 100 ℃ when the steel bar is discharged from the slow cooling pit;
step 11), the isothermal spheroidizing annealing specifically comprises the following steps: heating the steel to 790 ℃, then preserving heat for 4 hours, then slowly cooling along with the furnace at a cooling rate of 10-25 ℃/h until the furnace is cooled to 700 ℃, then preserving heat for 5 hours, and then taking out the steel from the furnace for air cooling.
Example 3
The rare earth bearing steel of the embodiment 3 comprises the following components in percentage by mass: c: 1.00%, Si: 0.27%, Mn: 0.35%, Cr: 1.55%, Ti: 0.0011%, O: 0.0005%, RE: 0.0025%, the balance being Fe and inevitable impurities; the outer diameter of the prepared finished rare earth bearing steel is 70 mm.
A thermomechanical treatment method for preparing rare earth bearing steel comprises the following steps of: 1) putting a rectangular blank prepared by casting into a furnace for heating, 2) rough rolling, 3) medium rolling, 4) finish rolling, 5) first-stage water cooling, 6) size reducing and sizing, 7) second-stage water cooling, 8) segmenting, 9) collecting, 10) slow cooling and 11) isothermal spheroidizing annealing;
wherein, the three stages of rough rolling, intermediate rolling and finish rolling adopt temperature-controlled rolling;
in the step 4), the alpha + gamma two-phase region is adopted for rolling in the finish rolling, the initial rolling temperature in the finish rolling stage is controlled to be in the two-phase region of the eutectoid carbide and the austenite, and the final rolling temperature is controlled to be 780 ℃;
in the step 7), controlling the surface re-reddening temperature of the steel bar after the second-stage water cooling to be 580-610 ℃;
in the step 10), slow cooling is carried out in a slow cooling pit, the temperature of the steel bar is 560-600 ℃ when the steel bar enters the slow cooling pit, and the temperature of the steel bar is 110 ℃ when the steel bar is discharged from the slow cooling pit;
step 11), the isothermal spheroidizing annealing specifically comprises the following steps: heating the steel to 790 ℃, then preserving heat for 6 hours, then slowly cooling with the furnace at a cooling rate of 10-25 ℃/h until the furnace is cooled to 710 ℃, then preserving heat for 5 hours, and then taking out the steel from the furnace for air cooling.
The results of microstructure and carbide network strip tests on the rare earth bearing steels prepared in examples 1 to 3 are shown in tables 1, 2 and 3.
TABLE 1 acceptable grade of microstructure of rare earth bearing steel prepared in example
TABLE 2 acceptable grade of carbide reticulation in rare earth bearing steels prepared in examples
TABLE 3 acceptable grade of carbide ribbon in rare earth bearing steels prepared in examples
The principles and embodiments of the present invention are explained herein using specific examples, which are set forth only to help understand the method and its core ideas of the present invention. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.
Claims (2)
1. A thermomechanical treatment method for preparing rare earth bearing steel is characterized in that,
the rare earth bearing steel comprises the following components in percentage by mass: 0.95 to 1.05 percent of C, 0.15 to 0.35 percent of Si, 0.25 to 0.45 percent of Mn, 1.40 to 1.65 percent of Cr, less than or equal to 0.0015 percent of Ti, less than or equal to 0.0008 percent of O, 0.0010 to 0.0025 percent of RE, and the balance of Fe and inevitable impurities; RE element is lanthanum and/or cerium;
the thermomechanical treatment method comprises the following steps of: 1) putting a rectangular blank prepared by casting into a furnace for heating, 2) rough rolling, 3) medium rolling, 4) finish rolling, 5) first-stage water cooling, 6) size reducing and sizing, 7) second-stage water cooling, 8) segmenting, 9) collecting, 10) slow cooling and 11) isothermal spheroidizing annealing;
wherein, the three stages of rough rolling, intermediate rolling and finish rolling adopt temperature-controlled rolling;
in the step 4), the alpha + gamma two-phase region rolling is adopted in the finish rolling, the initial rolling temperature in the finish rolling stage is controlled to be in the two-phase region of the eutectoid carbide and the austenite, and the final rolling temperature is controlled to be 750-850 ℃;
in the step 7), controlling the surface re-reddening temperature of the steel bar after the second-stage water cooling to be 570-650 ℃;
in the step 10), slow cooling is carried out in a slow cooling pit, the temperature of the steel bar is 510-630 ℃ when the steel bar enters the slow cooling pit, and the temperature of the steel bar is not higher than 150 ℃ when the steel bar is discharged from the slow cooling pit;
step 11), the isothermal spheroidizing annealing specifically comprises the following steps: heating the steel bar to 780-810 ℃, then preserving heat for 3-6 hours, then slowly cooling with the furnace at a cooling rate of 10-25 ℃/h until the furnace is cooled to 690-750 ℃, then preserving heat for 4-6 hours, and then taking the steel bar out of the furnace for air cooling;
the outer diameter of the finished product of the rare earth bearing steel after isothermal spheroidizing annealing is 30-70 mm.
2. The thermomechanical treatment method for producing a rare-earth bearing steel, according to claim 1, wherein the microstructure of the finished rare-earth bearing steel after isothermal spheroidizing annealing is a fine, uniform and completely spheroidized pearlite structure of not higher than 3.0 grade, and the network shape and the band shape of carbides in the rare-earth bearing steel are not higher than 2.0 grade.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011054655.9A CN112301193B (en) | 2020-09-30 | 2020-09-30 | Thermomechanical treatment method for preparing rare earth bearing steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011054655.9A CN112301193B (en) | 2020-09-30 | 2020-09-30 | Thermomechanical treatment method for preparing rare earth bearing steel |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112301193A CN112301193A (en) | 2021-02-02 |
| CN112301193B true CN112301193B (en) | 2022-07-05 |
Family
ID=74488550
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011054655.9A Active CN112301193B (en) | 2020-09-30 | 2020-09-30 | Thermomechanical treatment method for preparing rare earth bearing steel |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112301193B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114134403B (en) * | 2021-05-19 | 2023-01-13 | 江阴兴澄特种钢铁有限公司 | Steel for large-specification wind power bearing rolling body and production method thereof |
| CN113337693B (en) * | 2021-06-28 | 2023-05-26 | 建龙北满特殊钢有限责任公司 | Heat treatment method for reducing grade of large-size bearing steel net-shaped carbide |
| CN114015927B (en) * | 2022-01-07 | 2022-04-22 | 北京科技大学 | Rare earth-containing high-carbon chromium bearing steel and preparation method thereof |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5440226A (en) * | 1977-09-05 | 1979-03-29 | Sumitomo Metal Ind Ltd | Spheroidizing heat treatment method for high carbon- chromium-molybdenum bearing steel |
| JP2011208209A (en) * | 2010-03-29 | 2011-10-20 | Jfe Steel Corp | Method for manufacturing bearing steel having excellent rolling fatigue characteristic, and bearing steel |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106636591B (en) * | 2015-11-03 | 2018-09-25 | 北京京诚瑞信长材工程技术有限公司 | A kind of controlled rolling and controlled cooling method of big specification high-carbon-chromium bearing steel |
| CN106086353B (en) * | 2016-08-29 | 2018-06-01 | 大冶特殊钢股份有限公司 | The milling method that big cross section GCr15 bearing steels net carbide is controlled to be precipitated |
| CN107502825B (en) * | 2017-07-27 | 2019-04-23 | 抚顺特殊钢股份有限公司 | A kind of high-speed EMUs high-carbon-chromium bearing steel manufacturing process |
| CN109055707A (en) * | 2018-10-26 | 2018-12-21 | 苏州轴承厂股份有限公司 | The heat treatment process of high-carbon-chromium bearing steel part |
| CN109338035B (en) * | 2018-11-08 | 2020-08-18 | 江阴兴澄特种钢铁有限公司 | Steel for wind driven generator gear box bearing and production method thereof |
| CN110016541B (en) * | 2019-05-24 | 2020-10-23 | 东北大学 | Method for shortening spheroidizing annealing time of GCr15 bearing steel through controlled rolling and controlled cooling process |
| CN110129540A (en) * | 2019-06-10 | 2019-08-16 | 南京钢铁股份有限公司 | Improvement bearing steel surface, which is quenched, is tempered the process of line and staff control |
| CN111254359A (en) * | 2020-03-25 | 2020-06-09 | 山东钢铁股份有限公司 | Corrosion-resistant rare earth bearing steel and preparation method thereof |
-
2020
- 2020-09-30 CN CN202011054655.9A patent/CN112301193B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5440226A (en) * | 1977-09-05 | 1979-03-29 | Sumitomo Metal Ind Ltd | Spheroidizing heat treatment method for high carbon- chromium-molybdenum bearing steel |
| JP2011208209A (en) * | 2010-03-29 | 2011-10-20 | Jfe Steel Corp | Method for manufacturing bearing steel having excellent rolling fatigue characteristic, and bearing steel |
Also Published As
| Publication number | Publication date |
|---|---|
| CN112301193A (en) | 2021-02-02 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN112301193B (en) | Thermomechanical treatment method for preparing rare earth bearing steel | |
| CN110438310B (en) | Hot work die steel and heat treatment method thereof | |
| CN103215516B (en) | A kind of 700MPa grade high-strength hot-rolled Q & P steel and manufacture method thereof | |
| CN105525078A (en) | Preparation method for improving performance of 4Cr5MoSiV1 hot work die steel | |
| CN102899460A (en) | Heat treatment method for martensitic stainless steel forging module | |
| CN112981239B (en) | Quenched and tempered low-carbon alloy steel and manufacturing method thereof | |
| CN108950385A (en) | Forge the big specification abrading-ball steel of low-cost and high-performance and its production method | |
| CN108611563A (en) | A kind of CSP flows excellent formability energy mild steel steel plate and its manufacturing method | |
| CN112090956B (en) | Production control method of wire rod for low-segregation high-torsion bridge cable | |
| CN102899589A (en) | High-strength non-tempered bainite steel and preparation method thereof | |
| CN108085591A (en) | A kind of steel plate HTNM400 and its production method with low-welding crack-sensitive energy | |
| CN107604248A (en) | A kind of high intensity Q500GJD quenched and tempered states steel plate for building structure and its manufacture method | |
| CN105002434A (en) | Hot-rolled steel for steel disc of vehicle driven plate and preparation method of hot-rolled steel | |
| CN109695003B (en) | High-wear-resistance steel ball with excellent toughness and manufacturing method thereof | |
| CN109112391B (en) | Hot work die steel and preparation method thereof | |
| CN113737099A (en) | Tool steel suitable for large-deformation cold machining forming and preparation method thereof, and sleeve and preparation method thereof | |
| CN109628833B (en) | Cr-Mo-Si-V cold-work die steel and preparation method thereof | |
| CN109136757B (en) | Production method of medium-carbon cold heading steel wire and medium-carbon cold heading steel wire | |
| CN114000068B (en) | Low-nitrogen ultrahigh-strength hot-rolled steel strip with thickness of 4-10mm and production method thereof | |
| JPH03146618A (en) | Production of cold forging steel | |
| CN111101077B (en) | Low-cost high-wear-resistance stretch reducing roller and heat treatment process thereof | |
| CN111118276A (en) | Heat treatment process for ultra-deep quench-hardened cold roll | |
| CN107227393B (en) | Production method for reducing fatigue crack propagation rate of bainite steel rail | |
| CN109694994B (en) | Corrosion-resistant high-wear-resistant steel ball and manufacturing method thereof | |
| KR101253807B1 (en) | High Silicon Bearing Steel And Spheroidizing Annealing Method for High Silicon Bearing Steel |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |