阅读说明：本技术 双层u型退火炉及退火方法 (Double-layer U-shaped annealing furnace and annealing method ) 是由 孙钦贺 于 2021-07-26 设计创作，主要内容包括：本发明涉及一种双层U型退火炉,包括：设有由隔热隔板分隔构成的下层炉膛和设有加热器的上层炉膛的炉体,两个分设于上层炉膛两端的隔热门,与上层炉膛右端、下层炉膛右端分别连通且设有右门和左门的双层真空室,置于双层真空室右侧的进料台、出料台,装于炉体左端的双层升降室,穿设于上层炉膛、双层真空室、进料台中的上电动辊筒组,穿设于下层炉膛、双层真空室、出料台中的下电动辊筒组,其特征是,所述的双层U型退火炉还包括：两个一一对应设于下层炉膛的两个侧板上的通气门组,多个设于隔热隔板上,两侧端与下层炉膛的两个侧板通过左右向滑轨一一对应滑动连接的隔热滑板,设于隔热滑板上的个数与上通孔个数相同的下通孔,滑板驱动装置。(The invention relates to a double-layer U-shaped annealing furnace, which comprises: furnace body with be equipped with by the upper furnace of the lower floor furnace that thermal-insulated baffle partition constitutes and be equipped with the heater, the insulated door at upper furnace both ends is located to two branches, with the upper furnace right-hand member, the double-deck real empty room that the lower floor furnace right-hand member communicates respectively and is equipped with right door and left door, arrange the feed table on double-deck real empty room right side in, go out the material platform, adorn in the double-deck lift room of furnace body left end, wear to locate upper furnace, double-deck real empty room, last electric roller group in the feed table, wear to locate lower floor furnace, double-deck real empty room, lower electric roller group in the material platform, characterized by, double-deck U type annealing stove still include: two one-to-one ventilation door groups are arranged on two side plates of the lower-layer hearth, a plurality of thermal insulation partition plates are arranged on the thermal insulation partition plates, two side ends and the two side plates of the lower-layer hearth are connected with thermal insulation sliding plates in a sliding mode through left and right sliding rails in one-to-one correspondence, lower through holes and sliding plate driving devices are arranged on the thermal insulation sliding plates, the number of the lower through holes is the same as that of the upper through holes, and the number of the lower through holes is the same as that of the upper through holes.)

1. A double-layer U-shaped annealing furnace comprising: furnace body with be equipped with by the upper furnace of the lower floor furnace that thermal-insulated baffle partition constitutes and be equipped with the heater, the insulated door at upper furnace both ends is located to two branches, with the upper furnace right-hand member, the double-deck real empty room that the lower floor furnace right-hand member communicates respectively and is equipped with right door and left door, arrange the feed table on double-deck real empty room right side in, go out the material platform, adorn in the double-deck lift room of furnace body left end, wear to locate upper furnace, double-deck real empty room, last electric roller group in the feed table, wear to locate lower floor furnace, double-deck real empty room, lower electric roller group in the material platform, characterized by, double-deck U type annealing stove still include: two one-to-one ventilation door groups are arranged on two side plates of the lower-layer hearth, a plurality of thermal insulation partition plates are arranged on the thermal insulation partition plates, two side ends and the two side plates of the lower-layer hearth are connected with thermal insulation sliding plates in a sliding mode through left and right sliding rails in one-to-one correspondence, lower through holes and sliding plate driving devices are arranged on the thermal insulation sliding plates, the number of the lower through holes is the same as that of the upper through holes, and the number of the lower through holes is the same as that of the upper through holes.

2. The double-layer U-shaped annealing furnace of claim 1, further comprising a furnace gas heat exchange device; the burner gas heat transfer device includes: the plurality of hot air circulating fans are provided with a plurality of heat exchange pipes penetrating through a top plate arranged on the upper-layer hearth and connected with the top plate.

3. The double-layer U-shaped annealing furnace according to claim 1, further comprising a protective atmosphere control device; the protective atmosphere control device comprises: a plurality of nitrogen pipes arranged in one side plate in a penetrating way, and a plurality of nitrogen concentration detectors arranged on the top plate.

4. The double-layer U-shaped annealing furnace according to claim 1, wherein a plurality of cooling fans are installed on the top plate of the upper hearth and the bottom plate of the lower hearth.

5. The double-layer U-shaped annealing furnace according to claim 1, wherein the upper hearth has a top plate and the lower hearth has a bottom plate, and a plurality of thermocouples are installed on the top plate and the bottom plate.

6. The double-deck U-shaped annealing furnace according to any one of claims 1 to 5, wherein said double-deck elevating chamber comprises: the transfer device comprises a chamber body, transfer baskets, a winch and a transfer cylinder, wherein the right end of the chamber body is respectively communicated with the left end of an upper-layer hearth and the left end of a lower-layer hearth; the piston rod of the transfer cylinder is opposite to the left end of the lower hearth.

7. The double-layered U-shaped annealing furnace according to any one of claims 1 to 5, wherein the slide plate driving means comprises: a driving cylinder which is provided with an electromagnetic directional valve and is connected with the lower end of the heat insulation partition plate, and a connecting plate which is respectively connected with the right end of the heat insulation sliding plate and a piston rod of the driving cylinder.

8. A double-layer U-shaped annealing furnace annealing method is disclosed, the double-layer U-shaped annealing furnace is the double-layer U-shaped annealing furnace disclosed by any one of claims 1 to 7, and is characterized in that in the first step, workpieces to be annealed are stacked in a charging basket and lifted to a feeding table; step two, the charging basket moves from right to left according to a set beat under the drive of an upper electric roller group, a right door is opened, the discharging basket enters a double-layer vacuum chamber, the right door is closed, the left door is opened after the double-layer vacuum chamber is vacuumized, the charging basket enters an upper hearth, the charging basket is arranged in the upper hearth one by one after the actions are repeated, a heat insulation door is closed, nitrogen is filled from a nitrogen pipe, and the workpiece is heated and insulated according to the requirement of an annealing process under the nitrogen protection atmosphere; step three, opening a heat insulation door, enabling the charging basket in the upper-layer hearth to enter a transfer basket and descend along with the transfer basket, pushing the charging basket into the lower-layer hearth by a piston rod of a transfer cylinder, driving the charging basket to move from left to right according to a set beat under the driving of a lower electric roller group, and repeating the actions to push the charging basket into the lower-layer hearth one by one; meanwhile, according to the second step, the charging baskets are arranged into the upper-layer hearth one by one, the heat insulation door is closed, the piston rod of the driving cylinder drives the heat insulation sliding plate to move, the lower through hole is communicated with the upper through hole, and after the heat emitted by the workpiece and the charging basket in the lower-layer hearth preheats the workpiece and the charging basket in the upper-layer hearth, the heat insulation sliding plate is reset; cooling the workpiece in the lower hearth according to the requirement of an annealing process; when the annealing process is needed, the ventilating door set and/or a cooling fan arranged on a bottom plate arranged on the lower hearth can be started to accelerate the cooling speed; filling nitrogen from a nitrogen pipe, and heating and insulating the workpiece in the upper hearth under the nitrogen protective atmosphere according to the requirement of an annealing process; opening a left door and a right door, and moving the charging baskets filled with the annealed workpieces in the lower hearth from left to right to a discharging table one by one according to a set beat under the driving of a lower electric roller group and lifting the charging baskets; and repeating the third step and the fourth step until the annealing is finished.

9. The annealing method of the double-layer U-shaped annealing furnace according to claim 8, wherein the workpiece to be annealed is a high-carbon chromium bearing steel workpiece; the annealing process comprises the following steps: (1) heating the workpiece to 780 ℃ in an upper hearth under the nitrogen protection atmosphere, heating for 250min, and keeping the temperature for 360min after heating; (2) in thatOn the upper partIn the hearth of the layer, the workpiece is quickly cooled to 730 ℃ within 60min, then is sequentially and slowly cooled to 725 ℃, and is slowly cooled for 120min, 715 ℃, and is slowly cooled for 120min, then is slowly cooled to 580 ℃, and is slowly cooled for 180min, and then is cooled to 500 ℃ within 150 min; (3) the annealed workpiece is evaluated by a metallographic analysis system under (1000 x), reaches grade 3 of the metallographic examination atlas standard of the high-carbon chromium bearing steel, and the microstructure is fine and uniformly distributed spherical pearlite; the hardness of the work piece after annealing is 179 HBW-207 HBW (indentation diameter is 4.5 mm-4.2 mm) or HRB 88-94.

Technical Field

The invention relates to the technical field of heat treatment, in particular to a double-layer U-shaped annealing furnace and an annealing method.

Background

A bearing workpiece made of the high-carbon chromium bearing steel needs to be annealed after forging; the structure of the bearing steel annealing furnace is known from a bearing steel annealing furnace disclosed in the utility model of the chinese patent application No. 202020642750. X; the traditional bearing steel annealing furnace has the defects of low annealing efficiency, unstable annealing quality and non-utilization of annealing waste heat; therefore, it is an urgent problem to design a double-layer U-shaped annealing furnace and an annealing method that have high annealing efficiency and stable annealing quality and utilize annealing waste heat to preheat a workpiece.

Disclosure of Invention

The invention aims to overcome the defects of low annealing efficiency, unstable annealing quality and non-utilization of annealing waste heat of the conventional bearing steel annealing furnace, and provides a double-layer U-shaped annealing furnace and an annealing method which have high annealing efficiency and stable annealing quality and utilize the annealing waste heat to preheat a workpiece.

The specific technical scheme of the invention is as follows:

a double-layer U-shaped annealing furnace comprising: a controller, a furnace body provided with a lower hearth and an upper hearth, wherein the lower hearth is formed by separating a heat insulation partition plate, the upper hearth is provided with a heater, the two heat insulation doors are respectively arranged at two ends of the upper hearth, the double-layer vacuum chamber is respectively communicated with the right end of the upper hearth and the right end of the lower hearth and is provided with a right door and a left door, a feeding table arranged at the right side of the double-layer vacuum chamber, a discharging table positioned at the lower side of the feeding table, a double-layer lifting chamber arranged at the left end of the furnace body, an upper electric roller set arranged in the upper hearth, the double-layer vacuum chamber and the feeding table, a lower electric roller set arranged in the lower hearth, two ventilation door sets arranged on two side plates arranged on the lower hearth in a one-to-one correspondence manner, a plurality of upper through holes arranged on the heat insulation partition plate and arranged on the left and right, and heat insulation sliding plates which are arranged at the lower side of the heat insulation partition plate and are in one-to-one correspondence with the two side plates of the lower hearth through left and right sliding rails, the number of the lower through holes which are arranged on the heat insulation sliding plate is the same as that of the upper through holes and corresponds to the upper through holes one by one, and the sliding plate driving device; the heater is an electric heater; the lower through hole is not communicated with the upper through hole at the initial position.

Preferably, the double-layer U-shaped annealing furnace further comprises a furnace gas heat exchange device; the burner gas heat transfer device includes: the plurality of hot air circulating fans are provided with a plurality of heat exchange pipes penetrating through a top plate arranged on the upper-layer hearth and connected with the top plate.

Preferably, the double-layer U-shaped annealing furnace further comprises a protective atmosphere control device; the protective atmosphere control device comprises: a plurality of nitrogen pipes arranged in one side plate in a penetrating way, and a plurality of nitrogen concentration detectors arranged on the top plate.

Preferably, a plurality of cooling fans are arranged on the top plate arranged on the upper-layer hearth and the bottom plate arranged on the lower-layer hearth.

Preferably, a plurality of thermocouples are arranged on the top plate arranged on the upper-layer hearth and the bottom plate arranged on the lower-layer hearth.

Preferably, the double-deck lift chamber includes: the transfer device comprises a chamber body, transfer baskets, a winch and a transfer cylinder, wherein the right end of the chamber body is respectively communicated with the left end of an upper-layer hearth and the left end of a lower-layer hearth; the piston rod of the transfer cylinder is opposite to the left end of the lower hearth.

Preferably, the slide plate driving device includes: a driving cylinder which is provided with an electromagnetic directional valve and is connected with the lower end of the heat insulation partition plate, and a connecting plate which is respectively connected with the right end of the heat insulation sliding plate and a piston rod of the driving cylinder.

The annealing method of the double-layer U-shaped annealing furnace is characterized in that the double-layer U-shaped annealing furnace is the double-layer U-shaped annealing furnace, and comprises the following steps of firstly, stacking workpieces to be annealed in a charging basket and hoisting the workpieces to a feeding table; step two, the charging basket moves from right to left according to a set beat under the drive of an upper electric roller group, a right door is opened, the discharging basket enters a double-layer vacuum chamber, the right door is closed, the left door is opened after the double-layer vacuum chamber is vacuumized, the charging basket enters an upper hearth, the charging basket is arranged in the upper hearth one by one after the actions are repeated, a heat insulation door is closed, nitrogen is filled from a nitrogen pipe, and the workpiece is heated and insulated according to the requirement of an annealing process under the nitrogen protection atmosphere; step three, opening a heat insulation door, enabling the charging basket in the upper-layer hearth to enter a transfer basket and descend along with the transfer basket, pushing the charging basket into the lower-layer hearth by a piston rod of a transfer cylinder, driving the charging basket to move from left to right according to a set beat under the driving of a lower electric roller group, and repeating the actions to push the charging basket into the lower-layer hearth one by one; meanwhile, according to the second step, the charging baskets are arranged into the upper-layer hearth one by one, the heat insulation door is closed, the piston rod of the driving cylinder drives the heat insulation sliding plate to move, the lower through hole is communicated with the upper through hole, and after the heat emitted by the workpiece and the charging basket in the lower-layer hearth preheats the workpiece and the charging basket in the upper-layer hearth, the heat insulation sliding plate is reset; cooling the workpiece in the lower hearth according to the requirement of an annealing process; when the annealing process is needed, the ventilating door set and/or a cooling fan arranged on a bottom plate arranged on the lower hearth can be started to accelerate the cooling speed; filling nitrogen from a nitrogen pipe, and heating and insulating the workpiece in the upper hearth under the nitrogen protective atmosphere according to the requirement of an annealing process; opening a left door and a right door, and moving the charging baskets filled with the annealed workpieces in the lower hearth from left to right to a discharging table one by one according to a set beat under the driving of a lower electric roller group and lifting the charging baskets; and repeating the third step and the fourth step until the annealing is finished.

Preferably, the workpiece needing annealing is a high-carbon chromium bearing steel workpiece; the annealing process comprises the following steps: (1) heating the workpiece to 780 ℃ in an upper hearth under the nitrogen protection atmosphere, heating for 250min, and keeping the temperature for 360min after heating; (2) in the upper hearth, quickly cooling the workpiece to 730 ℃ within 60min, then sequentially slowly cooling to 725 ℃, slowly cooling for 120min, slowly cooling to 715 ℃, slowly cooling for 120min, then slowly cooling to 580 ℃, slowly cooling for 180min, and then cooling to 500 ℃ within 150 min; (3) the annealed workpiece is evaluated by a metallographic analysis system under (1000 x), reaches grade 3 of the metallographic examination atlas standard of the high-carbon chromium bearing steel, and the microstructure is fine and uniformly distributed spherical pearlite; the hardness of the annealed workpiece is 179 HBW-207 HBW (with the diameter of an indentation of 4.5 mm-4.2 mm) or HRB88-94, so that the quality of the annealed bearing forging can meet the national standard of GB/T34891-2017 technical conditions for heat treatment of high-carbon chromium bearing steel bearing parts of rolling bearings, and the annealing quality requirement of the workpiece can be met.

Compared with the prior art, the invention has the beneficial effects that: the double-layer U-shaped annealing furnace is characterized in that workpieces are stacked in a charging basket, the workpieces in an upper-layer hearth are heated and insulated according to the requirement of an annealing process, meanwhile, the workpieces in the upper-layer hearth are cooled according to the requirement of the annealing process, a piston rod of a driving cylinder drives a heat insulation sliding plate to move, a lower through hole is communicated with an upper through hole, the workpieces and the charging basket in a lower-layer hearth are preheated by heat emitted by the workpieces and the charging basket in the upper-layer hearth, the temperature in the upper-layer hearth is uniform through a hot air circulating fan, the furnace temperatures of the upper-layer hearth and the lower-layer hearth are monitored through a thermocouple, the annealing efficiency is high, the annealing quality is stable, and the workpieces are preheated by using annealing waste heat. Dry nitrogen is filled into a nitrogen pipe of the protective atmosphere control device, the nitrogen concentration is detected by a nitrogen concentration detector, and the workpiece is heated and insulated according to the requirement of an annealing process under the protective atmosphere of nitrogen, so that the oxidation is prevented, and the quality of the workpiece is prevented from being influenced by water vapor. The cooling fan is beneficial to quickly cooling the furnace body after the annealing is finished; when the annealing process is needed, the ventilating door set and/or the cooling fan arranged on the bottom plate arranged on the lower hearth can be started to accelerate the cooling speed. The double-layer lifting chamber is simple and practical in structure, and is beneficial to the charging basket to be quickly and conveniently transported to the upper-layer hearth from the lower-layer hearth.

Drawings

FIG. 1 is a schematic view showing a structure of a double-layer U-shaped annealing furnace of the present invention.

In the figure: the device comprises a controller 1, a heat insulation partition plate 2, a lower-layer hearth 3, an upper-layer hearth 4, a furnace body 5, a heat insulation door 6, a right door 7, a double-layer vacuum chamber 9 of a left door 8, a charging basket 10, a feeding table 11, a discharging table 12, a double-layer lifting chamber 13, an upper electric roller group 14, a lower electric roller group 15, a side plate 16, a ventilation door group 17, an upper through hole 18, a left-right slide rail 19, a heat insulation slide plate 20, a lower through hole 21, a top plate 22, a heat exchange tube 23, a hot air circulating fan 24, a nitrogen tube 25, a nitrogen concentration detector 26, a bottom plate 27, a cooling fan 28, a thermocouple 29, a chamber body 30, a vertical guide rail 31, a transfer basket 32, a winch 33, a transfer cylinder 34, a driving cylinder 35 and a connecting plate 36.

Detailed Description

The invention will be further described with reference to the drawings.

As shown in figure 1: a double-layer U-shaped annealing furnace comprising: a controller 1, a furnace body 5 provided with a lower hearth 3 formed by separating a heat insulation partition plate 2 and an upper hearth 4 provided with a heater (not shown), two heat insulation doors 6 respectively arranged at both ends of the upper hearth 4, a double-layer vacuum chamber 9 respectively communicated with the right end of the upper hearth 4 and the right end of the lower hearth 3 and provided with a right door 7 and a left door 8, a feeding table 11 arranged at the right side of the double-layer vacuum chamber 9, a discharging table 12 positioned at the lower side of the feeding table 11, a double-layer lifting chamber 13 arranged at the left end of the furnace body 5, an upper electric roller set 14 arranged in the upper hearth 4, the double-layer vacuum chamber 9 and the feeding table 11, a lower electric roller set 15 arranged in the lower hearth 3, the double-layer vacuum chamber 9 and the discharging table 12, two ventilation door sets 17 arranged on two side plates 16 arranged on the lower hearth 3 one by one, a plurality of upper through holes 18 arranged on the heat insulation partition plate 2 and arranged left and right, two side plates 19 arranged at both side ends of the lower side of the heat insulation partition plate 2 and the lower hearth 3 The heat insulation sliding plates 20 are in one-to-one corresponding sliding connection, the lower through holes 21 are arranged on the heat insulation sliding plates 20, the number of the lower through holes is the same as that of the upper through holes 18, and the lower through holes correspond to one; the heater is an electric heater; in the initial position, the lower through hole 21 is not communicated with the upper through hole 18.

The double-layer U-shaped annealing furnace also comprises a furnace gas heat exchange device; the burner gas heat transfer device includes: seven hot air circulating fans 24 which are provided with a plurality of heat exchange pipes 23 penetrating through the top plate 22 arranged on the upper hearth 4 and are screwed with the top plate 22.

The double-layer U-shaped annealing furnace also comprises a protective atmosphere control device; the protective atmosphere control device comprises: a plurality of nitrogen gas pipes 25 penetrating one side plate 16, and a nitrogen gas concentration detector 26 mounted on the top plate 22.

And a plurality of cooling fans 28 are arranged on the top plate 22 arranged on the upper-layer hearth 4 and the bottom plate 27 arranged on the lower-layer hearth 3.

The top plate 22 arranged on the upper hearth 4 and the bottom plate 27 arranged on the lower hearth 3 are both provided with a plurality of thermocouples 29.

The double-deck lift chamber 13 includes: a chamber body 30 with the right end communicated with the left end of the upper hearth 4 and the left end of the lower hearth 3 respectively, transfer baskets 32 in one-to-one corresponding sliding connection with the two side ends of the chamber body 30 through vertical guide rails 31, a winch 33 installed at the upper end of the chamber body 30 and connected with the upper end of the transfer baskets 32 through slings, and a transfer cylinder 34 installed with an electromagnetic directional valve (not shown) and connected with the left end of the chamber body 30 in a threaded manner; the piston rod of the transfer cylinder 34 is opposite to the left end of the lower hearth 3.

The slide plate driving device comprises: a driving cylinder 35 provided with a solenoid directional valve (not shown) and screwed with the lower end of the heat insulation partition plate 2, and a connecting plate 36 screwed with the right end of the heat insulation slide plate 20 and the piston rod of the driving cylinder 35.

The electric heater, the upper electric roller set 14, the lower electric roller set 15, the hot air circulating fan 24, the nitrogen concentration detector 26, the cooling fan 28, the thermocouple 29, the winch 33, the transfer cylinder 34, the driving cylinder 35 and the electromagnetic directional valve are respectively and electrically connected with the controller 1.

The annealing method of the double-layer U-shaped annealing furnace is characterized in that the double-layer U-shaped annealing furnace is the double-layer U-shaped annealing furnace, and comprises the following steps that firstly, workpieces to be annealed are stacked in a charging basket 10 and lifted to a feeding table 11; step two, the charging basket 10 moves from right to left according to a set beat under the drive of the upper electric roller group 14, the right door 7 is opened, the discharging basket 10 enters the double-layer vacuum chamber 9, the right door 7 is closed, the left door 8 is opened after the double-layer vacuum chamber 9 is vacuumized, the charging basket 10 enters the upper hearth 4, the charging basket 10 is repeatedly arranged in the upper hearth 4 one by one after the actions are repeated, the heat insulation door 6 is closed, nitrogen is filled from the nitrogen pipe 25, and the workpiece is heated and insulated according to the requirement of an annealing process under the nitrogen protection atmosphere; step three, opening the heat insulation door 6, enabling the charging basket 10 in the upper-layer hearth 4 to enter the transfer basket 32 and descend along with the transfer basket 32, pushing the charging basket 10 into the lower-layer hearth 3 by a piston rod of the transfer cylinder 34, enabling the charging basket 10 to move from left to right according to a set beat under the driving of the lower electric roller group 15, and repeating the actions to push the charging basket 10 into the lower-layer hearth 3 one by one; meanwhile, according to the second step, the charging baskets 10 are loaded into the upper-layer hearth 4 one by one, then the heat insulation door 6 is closed, the piston rod of the driving cylinder 35 drives the heat insulation sliding plate 20 to move, so that the lower through hole 21 is communicated with the upper through hole 18, and after the heat emitted by the workpieces and the charging baskets 10 in the lower-layer hearth 3 preheats the workpieces and the charging baskets 10 in the upper-layer hearth 4, the heat insulation sliding plate 20 resets; cooling the workpiece in the lower hearth 3 according to the requirement of the annealing process; when the annealing process is needed, the ventilating door group 17 and/or the cooling fan 28 arranged on the bottom plate 27 arranged on the lower hearth 3 can be started to accelerate the cooling speed; nitrogen is filled from the nitrogen pipe 25, and the workpiece in the upper hearth 4 is heated and insulated according to the requirement of the annealing process under the nitrogen protective atmosphere; opening a left door 8 and a right door 7, and moving the charging baskets 10 filled with the annealed workpieces in the lower hearth 3 to a discharging platform 12 one by one from left to right according to a set beat under the driving of a lower electric roller group 15 and lifting the charging baskets; and repeating the third step and the fourth step until the annealing is finished.

The workpiece needing annealing is a high-carbon chromium bearing steel workpiece; the annealing process comprises the following steps: (1) heating the workpiece to 780 ℃ in the upper hearth 4 under the nitrogen protection atmosphere, heating for 250min, and keeping the temperature for 360min after heating; (2) in the upper hearth 3, the workpiece is quickly cooled to 730 ℃ within 60min, then is gradually cooled to 725 ℃ in sequence, is slowly cooled for 120min, is slowly cooled to 715 ℃, is slowly cooled for 120min, is slowly cooled to 580 ℃, is slowly cooled for 180min, and is then cooled to 500 ℃ within 150 min; (3) the annealed workpiece is evaluated by a metallographic analysis system under (1000 x), reaches grade 3 of the metallographic examination atlas standard of the high-carbon chromium bearing steel, and the microstructure is fine and uniformly distributed spherical pearlite; the hardness of the annealed workpiece is 179 HBW-207 HBW (with the diameter of an indentation of 4.5 mm-4.2 mm) or HRB88-94, so that the quality of the annealed bearing forging can meet the national standard of GB/T34891-2017 technical conditions for heat treatment of high-carbon chromium bearing steel bearing parts of rolling bearings, and the annealing quality requirement of the workpiece can be met.

In addition to the above embodiments, the technical features or technical data of the present invention may be reselected and combined to form new embodiments within the scope of the claims and the specification of the present invention, which are all realized by those skilled in the art without creative efforts, and thus, the embodiments of the present invention not described in detail should be regarded as specific embodiments of the present invention and are within the protection scope of the present invention.