Heat treatment box-type furnace

Abstract

The utility model relates to the technical field of bearing ring heat treatment process, in particular to a heat treatment box-type furnace which comprises a furnace shell, a first grating, a second grating, a third grating, a fourth grating and an observation hole, a furnace door is arranged on one side of the furnace shell, and an access door is arranged on the other side of the furnace shell; the first grating and the second grating are arranged on the furnace walls on the two sides respectively, the first grating and the second grating are arranged along the axial symmetry center line of the furnace shell, and the first grating and the second grating are a set of first correlation gratings. Through the design of the heat preservation observation hole of the box-type furnace production line, the product quality is optimized, and the heat preservation time can be precisely controlled without opening a door.

Description

TECHNICAL FIELD

[0001] The utility model relates to bearing ring heat treatment process technical field, concretely is a kind of heat treatment box type furnace. BACKGROUND

[0002] Heat treatment observation insulation is important characteristic in heat treatment process, and the difference between box type furnace and main furnace of through type roller bar furnace is that box type furnace only has one area, such as for large spherical bearing ring material selection GCr15SiMn, diameter 1200-1500mm, generally adopt box type furnace combined with salt bath quenching to process in line, since the past heating insulation observation hole of box type furnace is placed on rear wall, increase heating furnace insulation time confirmation difficulty, cannot determine total heating time, finally through planing assay to find that surface organization overheats, when observing bearing ring insulation through the insulation hole of box type furnace, find that heating 2 hours and 6 hours insulation color state are same, so cannot accurately determine product insulation, further cannot meet technical requirement.

[0003] Traditional box type furnace production line cannot determine insulation time, further cannot accurately control process insulation time, finally lead to insufficient insulation time or too long insulation time of ring in heating process, and there is organization underheating or organization overheating, further lead to internal grain size coarse, reduce the fatigue life of bearing ring. UTILITY MODEL CONTENTS

[0004] In view of the defects of prior art, the utility model provides a kind of heat treatment box type furnace, and the quality of product is optimized by the design of insulation observation hole of box type furnace production line, and accurate control can be carried out on insulation time without opening door.

[0005] In order to achieve the above purpose, the technical scheme provided by the utility model is a kind of heat treatment box type furnace, including furnace shell, first grating and second grating, third grating and fourth grating and observation hole, the furnace door is arranged on one side of the furnace shell, and the maintenance door is arranged on the other side;The first grating and the second grating are arranged on the furnace wall on both sides respectively, the first grating and the second grating are arranged along the axial symmetry center line of the furnace shell, the first grating and the second grating are a pair of emitting gratings one;The third grating and the fourth grating are arranged on the furnace wall on both sides respectively, the third grating and the fourth grating are arranged along the axial symmetry center line of the furnace shell, the third grating and the fourth grating are a pair of emitting gratings two;Material tray moves back and forth in furnace shell, the range of back and forth movement of material tray is the range of the detection range of the pair of emitting gratings one and the detection range of the pair of emitting gratings two;The observation hole is obliquely arranged on the furnace wall on one side, and the range of overlap and the furnace wall on the other side is observed through the observation hole.

[0006] Further, the detection range of the pair of emitting gratings one is less than the distance between the pair of emitting gratings one and the pair of emitting gratings two.

[0007] Further, the detection range of the second pair of light barriers is less than the distance between the first pair of light barriers and the second pair of light barriers.

[0008] Further, the observation hole comprises a protective tube, a protective cover, a hole sleeve and a glass mirror, one end of the protective cover is arranged with the protective tube, the other end of the protective cover is operatively associated with the hole sleeve, and the hole sleeve is provided with the glass mirror away from one end of the protective cover.

[0009] Further, the inner wall of the protective tube is provided with thermal insulation cotton, the outer side of the protective cover is provided with an exhaust pipe, the pipe opening of the exhaust pipe is provided with a pipe cap, the hole sleeve is provided with a heat insulation steel plate, the heat insulation steel plate is controlled by a connecting rod, one end of the connecting rod is inserted into the hole sleeve and connected with the heat insulation steel plate, and the other end of the connecting rod is extended out of the hole sleeve.

[0010] Further, the hole sleeve is provided with a sealing ring near one end of the glass mirror.

[0011] Further, the inclination angle of the observation hole and the furnace wall is 72°, the visual angle of the observation hole is 45°, and the diameter of the observation hole is 65mm.

[0012] Further, the furnace shell is provided with a thermocouple and a waste combustion pipeline system, the thermocouple is arranged on one side of the access door, and the waste combustion pipeline system is arranged on the other side of the access door.

[0013] Further, the furnace wall in the furnace shell is provided with thermal insulation bricks and thermal insulation cotton, the thermal insulation bricks are provided with the thermal insulation cotton outside, and the thermal insulation cotton is provided with the furnace shell outside.

[0014] The bearing ring heat treatment process of the heat treatment box-type furnace comprises the following steps

[0015] S100, pre-cleaning, including cleaning and drying, the bearing ring is first cleaned and then dried;

[0016] The cleaning temperature is 30-40℃, and the time is 20-30min;

[0017] The drying temperature is 110℃, and the time is 20-30min;

[0018] S200, heating and holding, the bearing ring is first heated and then held;

[0019] The bearing ring is heated to 820-860℃, and the heating time is 2h, then the holding starts, the color contrast between the workpiece in high temperature state and the furnace wall is observed through the observation hole, when the color of the workpiece in high temperature state is consistent with the color of the furnace wall, it is confirmed that the holding time of the workpiece is terminated;

[0020] S300, quenching, cooling the bearing ring to 175℃;

[0021] S400, post-cleaning, including air cooling, cleaning and blow-drying, air cooling for 20-60min, cleaning for 10-40min, and blow-drying for 10-30min;

[0022] S500, deep cooling, cooling the bearing ring to 0-7℃ and keeping the temperature, and the processing time is 50min;

[0023] S600, high-temperature tempering the bearing ring to 180-200℃ and keeping the temperature, and the processing time is 8h.

[0024] The utility model discloses a solidification heat treatment heating holding time process parameter and accurate control to product organization level, grain size after heat treatment, and the utility model relates to the design of the heat preservation observation hole of box type furnace production line, and the accurate control of the heat preservation time of product in the furnace is realized without opening the furnace door, and further through the statistical analysis, the heat preservation time of martensite product of box type furnace production line is quantitatively managed. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 It is structural schematic diagram of an embodiment of the utility model;

[0026] Figure 2 It is structural schematic diagram of observation hole of the utility model;

[0027] Figure 3 It is process flow diagram of bearing ring heat treatment process of the utility model;

[0028] In the drawing: 100, furnace shell, 110, furnace door, 120, maintenance door, 130, furnace wall, 131, first grating, 132, second grating, 133, third grating, 134, fourth grating,

[0029] 300, observation hole, 310, protective tube, 320, protective cover, 321, exhaust pipe, 330, hole sleeve, 331, heat insulation steel sheet, 332, connecting rod, 333, sealing ring, 340, glass mirror,

[0030] 400, thermocouple installation place 400,

[0031] 500, waste gas combustion pipeline system,

[0032] 600, heat preservation brick,

[0033] 700, heat preservation cotton,

[0034] A. Detection range of through-beam grating one, B. Detection range of through-beam grating two, C. Overlapping range, D. Field of view. Detailed Implementation

[0035] To make the above-mentioned objects, features, and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a full understanding of this utility model. However, this utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this utility model. Therefore, this utility model is not limited to the specific embodiments disclosed below.

[0036] like Figure 1 , Figure 2 As shown, an embodiment of the present invention discloses a heat treatment box furnace, comprising a furnace shell 100, a first grating 131, a second grating 132, a third grating 133, a fourth grating 134, and an observation hole 300. A furnace door 110 is provided on one side of the furnace shell 100, and a maintenance door 120 is provided on the other side. The first grating 131 and the second grating 132 are respectively disposed on the furnace walls 130 on both sides, and are arranged along the axis of symmetry of the furnace shell 100. The first grating 131 and the second grating 132 form a set of through-beam gratings (photoelectric switches). The third grating 133 and... The fourth grating 134 is respectively set on the furnace walls 130 on both sides. The third grating 133 and the fourth grating 134 are set along the axis of symmetry of the furnace shell 100. The third grating 133 and the fourth grating 134 are a set of two-way gratings (photoelectric switches). The material tray is moved back and forth in the furnace shell 100 through rollers and transmission system. The range of the material tray moving back and forth is the range C that overlaps with the detection range A of the first-way grating and the detection range B of the second-way grating. The observation hole 300 is set at an angle on one side of the furnace wall 130. The overlapping range C and the furnace wall 130 on the other side can be observed through the observation hole 300.

[0037] It should be noted that the maintenance door 120 is closed and sealed during normal production. When the equipment is under maintenance, the maintenance door is opened, and the material tray moves back and forth inside the furnace shell 100 via rollers and a transmission system.

[0038] In one embodiment, the detection range A of the first through-beam grating is smaller than the distance between the first through-beam grating and the second through-beam grating.

[0039] In one embodiment, the detection range B of the second through-beam grating is smaller than the distance between the first through-beam grating and the second through-beam grating.

[0040] In an embodiment, the observation hole 300 comprises a protective tube 310, a protective cover 320, a hole sleeve 330 and a glass mirror 340, one end of the protective cover 320 is arranged with the protective tube 310, the other end of the protective cover 320 is operatively associated with the hole sleeve 330, and the glass mirror 340 is arranged at the end of the hole sleeve 330 away from the protective cover 320, wherein the glass mirror 340 is made of high-temperature-resistant glass and is used for the observation hole 300 of the heat treatment furnace with a temperature of 300-1200℃.

[0041] In an embodiment, the inner wall of the protective tube 310 is provided with heat preservation cotton 700, which prevents heat loss in the furnace, the outer side of the protective cover 320 is provided with an exhaust pipe 321, the pipe opening of the exhaust pipe 321 is provided with a pipe cap, the exhaust pipe 321 is not used in normal state, and can be opened for maintenance, the hole sleeve 330 is provided with a heat insulation steel plate 331, which is also used to prevent heat loss in the furnace, and the heat insulation steel plate 331 is controlled by a connecting rod 332, one end of the connecting rod 332 is inserted into the hole sleeve 330 and connected with the heat insulation steel plate 331, and the other end of the connecting rod 332 extends out of the hole sleeve 330, when the product needs to be observed, the connecting rod 332 is lifted to open the heat insulation steel plate 331; when the product does not need to be observed, the connecting rod 332 is lowered to close the heat insulation steel plate 331.

[0042] Further, the end of the hole sleeve 330 close to the glass mirror 340 is provided with a sealing ring 333, which is a high-temperature-resistant sealing ring 333 and is used for sealing the observation hole 300 of the heat treatment furnace with a temperature of 300-1200℃.

[0043] Further, the inclination angle between the observation hole 300 and the furnace wall 130 is 72°, the visual angle of the observation hole 300 is 45°, and the diameter of the observation hole 300 is 65mm.

[0044] It should be noted that the height of the furnace wall 130 of the heat treatment box furnace is 2960mm, and the observation hole 300 is located at 1 / 2 of the furnace wall 130.

[0045] In an embodiment, the furnace shell 100 is provided with a thermocouple installation position 400 and a waste combustion pipeline system, the thermocouple installation position 400 is arranged on one side of the maintenance door 120, and the waste combustion pipeline system is arranged on the other side of the maintenance door 120, the waste combustion pipeline system is used to burn and volatilize the waste replaced from the heating furnace by open flame, and the thermocouple installation position 400 is used to detect the temperature in the heating furnace.

[0046] In an embodiment, the furnace wall in the furnace shell 100 is provided with heat preservation bricks 600 and heat preservation cotton 700, the heat preservation cotton 700 is arranged outside the heat preservation bricks 600, and the furnace shell 100 is arranged outside the heat preservation cotton 700.

[0047] Referring to the drawings Figure 1When loading, the ring or workpiece is loaded on the tray, the tray is 1800mm long*1800mm wide*10mm high, and the grating is used to detect the tray to determine its position; the tray is driven by the roller bar from left to right, and after entering the heating furnace, it is detected by the grating 3 and the grating 4 to be in the detection range B of the second light barrier, and then stopped, and after a delay of 2 seconds, the roller bar is reversed, and after being detected by the grating 1 and the grating 2, it is stopped, and after a delay of 2 seconds, it is reversed, and so on, until the heating time is completed and the material is discharged. The repeated transmission is to protect the roller bar from bending in a high temperature state, so that the workpiece moves between the detection range C of the detection range A of the first light barrier and the detection range B of the second light barrier in the furnace, and the visual field range D of the observation hole 300 includes the detection range A of the first light barrier and the detection range B of the second light barrier. During the movement of the tray, the furnace wall (equipment furnace wall 130) can be seen at the same time, and the color of the workpiece in a high temperature state is observed to confirm the holding time of the workpiece, so as to avoid overheating of the bearing ring due to too long holding time.

[0048] It should be noted that a conventional heat treatment box furnace has a heat treatment process flow for large spherical bearing ring, which is loading-previous cleaning-heating and holding-quenching-post cleaning-deep cooling-tempering-unloading. In the heating and holding process, the austenitizing treatment is at 860-880℃, the carbon potential is 0.70%-0.90%, the total heating time of austenitizing is 6 hours, the salt bath quenching is at 170-180℃ for 15-45 minutes, the cold treatment is at 0-7℃, the tempering is at 180-200℃ for 8-10 hours. The post cleaning includes air cooling, cleaning and drying, wherein the air cooling is for 20-60 minutes, the cleaning is for 10-40 minutes, and the drying is for 10-30 minutes. In order to observe the state of the bearing ring during holding, the furnace door 110 or the maintenance opening behind the furnace door 110 is used for observation.

[0049] After the machining is completed, it is found through disassembling and testing the above-mentioned physical ring that the surface organization is overheated. Through the maintenance opening hole of the box furnace, it is found that the color state of the heating for 2 hours and the heating for 6 hours is the same during holding, so the precise holding of the product cannot be determined through the maintenance opening. In addition, the heating of the bearing ring is affected by the way of opening the furnace door 110.

[0050] As shown in Figure 3 , the bearing ring heat treatment process using the heat treatment box furnace in the above-mentioned embodiment includes

[0051] S100, previous cleaning, including cleaning and drying, the bearing ring is cleaned first and then dried;

[0052] The cleaning temperature is 40℃, and the time is 20-30min; the cleaning method is spraying, and the cleaning liquid is a metal cleaner.

[0053] The drying temperature is 110℃, and the time is 20-30min; the drying is performed by electric heating.

[0054] S200, heating and holding, the bearing ring is heated and then held;

[0055] The bearing ring is heated to 860℃, the heating time is 2h, and the holding time is 1h; the heating furnace is heated to 10-15L / h of process nitrogen and 0.4-0.8m3 / h of propane in the heating stage, and is heated to 5-10L / h of process nitrogen and 0.8-1.2m3 / h of propane in the holding stage;

[0056] It should be noted that in the bearing ring feeding-heating-holding, the holding time of the box furnace heating furnace is the martensite holding time = product effective wall thickness*0.7-1.2.

[0057] S300, quenching, the bearing ring is cooled to 175℃ and held, the quenching time is 20min in the first stage, the stirring speed is 1600r / min, and the quenching time is 10min in the second stage, and the stirring speed is 400r / min; the quenching is performed by quenching nitrate, and the composition of the quenching nitrate is (50%KNO3+50%NaNO2)±5%.

[0058] S400, post-cleaning, including air cooling, cleaning and drying, air cooling for 40min, cleaning for 25min, and drying for 20min; after quenching, the product surface temperature is 175℃, and the product surface is cooled by a fan to 40-50℃, and then the product surface is cleaned by foaming to remove salt deposits, and finally the product surface is dried by a fan.

[0059] S500, cryogenic treatment, the bearing ring is cooled to 7℃ and held, and the processing time is 50min; the cryogenic treatment is performed by liquid nitrogen.

[0060] S600, the bearing ring is high-temperature tempered to 200℃ and held, and the processing time is 8h; the tempering is performed by salt bath, and the salt bath medium is the same as the quenching nitrate in the quenching tank, and the tempering time is generally 8-10h.

[0061] It needs to be explained that, the utility model discloses a box -type furnace heat preservation observation hole 300 is arranged on side furnace wall 130, and the angle design of observation hole 300 and furnace wall 130 is arranged, and the observation field of vision in the furnace is enlarged to the maximum (see Figure 2 ), then the bearing ring is heat treated by the above-mentioned process route, the heating time is 2 hours, the heat preservation time is 1 hour, and after the product is discharged from the furnace, the martensite organization is found to be 3 levels, and the industry standard JB / T1255-2014 version 1-4 levels are met.

[0062] In the description of the utility model, it needs to be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the utility model and simplifying the description, and therefore cannot be understood as indicating or implying that the indicated device or element must have a particular orientation, a particular orientation and operation, and therefore cannot be understood as limiting the utility model.

[0063] In addition, the terms "first" and "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" can explicitly or implicitly include at least one of the features. In the description of the utility model, the meaning of "a plurality of" is at least two, for example, two, three, etc., unless otherwise specifically limited.

[0064] In the utility model, unless otherwise specifically defined and limited, the terms "mounting", "connection", "connection", "fixing" and the like should be understood in a broad sense, for example, can be fixedly connected, or can be detachably connected, or can be integrated, can be mechanically connected, or can be electrically connected, can be directly connected, or can be indirectly connected through an intermediate medium, can be the communication or interaction relationship between two elements, unless otherwise specifically limited. For ordinary skilled in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.

[0065] In the present application, unless otherwise explicitly specified and limited, the first feature is "on" or "under" the second feature, which can be direct contact between the first and second features, or indirect contact through an intermediate medium. Moreover, the first feature "above", "above" and "above" the second feature can be directly above or obliquely above the first feature, or only indicate that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "below" and "below" the second feature can be directly below or obliquely below the first feature, or only indicate that the horizontal height of the first feature is less than that of the second feature. It should be noted that when an element is referred to as "fixed to" or "provided on" another element, it can be directly on another element or there can be a middle element. When an element is considered to be "connected" to another element, it can be directly connected to another element or there can be a middle element. The terms "vertical", "horizontal", "up", "down", "left", "right" and similar expressions used herein are for illustrative purposes only and are not the only embodiment.

Claims

1. A heat treatment box furnace, comprising a furnace shell, a furnace door on one side, and an inspection door on the other side, characterized in that: It also includes a first grating and a second grating, which are respectively disposed on the furnace walls on both sides. The first grating and the second grating are arranged along the axisymmetric center line of the furnace shell. The first grating and the second grating are a set of through-beam gratings. The third and fourth gratings are respectively disposed on the furnace walls on both sides. The third and fourth gratings are arranged along the axisymmetric center line of the furnace shell. The third and fourth gratings are a set of two-way gratings. The material tray moves back and forth inside the furnace shell, and the range of the material tray's back and forth movement is the overlapping range of the detection range of the first through-beam grating and the second through-beam grating. An observation hole is obliquely mounted on one side of the furnace wall, through which the overlapping area and the furnace wall on the other side can be observed.

2. The heat treatment box furnace according to claim 1, characterized in that: The detection range of the first through-beam grating is smaller than the distance between the first through-beam grating and the second through-beam grating.

3. The heat treatment box furnace according to claim 1, characterized in that: The detection range of the second through-beam grating is smaller than the distance between the first through-beam grating and the second through-beam grating.

4. A heat treatment box furnace according to claim 1, characterized in that: The observation hole includes a protective tube, a protective cap, a hole sleeve, and a glass mirror. One end of the protective cap is disposed with the protective tube, and the other end of the protective cap is operably associated with the hole sleeve. The glass mirror is disposed at the end of the hole sleeve away from the protective cap.

5. A heat treatment box furnace according to claim 4, characterized in that: The inner wall of the protective pipe is provided with heat insulation cotton, the outer side of the protective cover is provided with an exhaust pipe, the pipe opening of the exhaust pipe is provided with a pipe cap, the hole sleeve is provided with a heat insulation steel plate, the heat insulation steel plate is controlled by a connecting rod, one end of the connecting rod is inserted into the hole sleeve and connected to the heat insulation steel plate, and the other end of the connecting rod extends out of the hole sleeve.

6. A heat treatment box furnace according to claim 4, characterized in that: A sealing ring is provided at one end of the sleeve near the glass mirror.

7. A heat treatment box furnace according to claim 1, characterized in that: The observation hole has an inclination angle of 72° to the furnace wall, a field of view angle of 45°, and a diameter of 65 mm.

8. A heat treatment box furnace according to claim 1, characterized in that: The furnace shell is provided with a thermocouple mounting point and a waste combustion pipeline system. The thermocouple mounting point is located on one side of the inspection door, and the waste combustion pipeline system is located on the other side of the inspection door.

9. A heat treatment box furnace according to claim 1, characterized in that: The furnace wall inside the furnace shell is provided with insulating bricks and insulating cotton, the insulating cotton is placed outside the insulating bricks, and the furnace shell is placed outside the insulating cotton.

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