Heat treatment method for column nail roller sleeve

Abstract

A heat treatment method for a stud roller sleeve belongs to the field of metallurgy. The specific operation is to place the stud roller sleeve in a low-temperature resistance furnace and maintain it at 250-300°C for 0.5-1.0h / 100mm, then heat it to 550-570°C and maintain it for ≥1.5h / 100mm. Then, transfer it to a high-temperature resistance furnace and quickly heat it to 900-960°C, maintain it for 0.5-1.0h, and then remove it from the furnace for water cooling. Water is sprayed on the outer diameter until its surface temperature is ≤400°C, then switched to spraying, and spraying is stopped when the spraying reaches a surface temperature of ≤100°C. Water is sprayed on the inner hole until the surface temperature maintains at 600-650°C and stops rising. After water cooling, the sleeve is air-cooled on a preheated pad iron to return the outer diameter to a temperature of 300-350°C, and then placed in a furnace for tempering. The tempering temperature is 500-540°C, and the holding time is ≥4h / 100mm. The present invention realizes one-time heat treatment through process control to achieve different hardness requirements of the inner and outer sides of the stud roller sleeve, and various performance indicators meet the requirements.

Description

Technical Field

[0001] The invention belongs to the technical field of metallurgy, and in particular relates to a heat treatment method for a column nail roller sleeve. Background Art

[0002] The spike roller sleeve (hereafter referred to as the roller sleeve) is a key component of cement roller press equipment. During operation, its outer surface must withstand the shear stress from the carbide pins and the extrusion and grinding forces of the powder. The transition layer and core must have good impact toughness, while the inner hole requires a certain degree of wear resistance to ensure smooth assembly with the roller shaft. Based on its operating conditions, the basic requirements are an outer hardness between 42 and 54 HRC, an outer hardened layer depth of ≥40mm, an inner hole hardness of 260-320 HB, and core performance (at 1 / 2 the wall thickness) of σb > 750 MPa, σs > 500 MPa, δ5 > 16%, ψ > 40%, and AkU > 40J.

[0003] In order to meet the technical indicators of roller sleeves, the following two heat treatment methods are generally adopted in China: one is to make special auxiliary tools, place a sleeve in the inner hole of the roller sleeve before it enters the furnace, and install cover plates on both end faces. During the heating process, a temperature difference is formed between the outer circle and the inner hole, and then the whole is cooled. The other is to use tempering + induction quenching, with tempering as the preliminary heat treatment, and use a resistance furnace for overall heating. After burning through, it is spray cooled after being taken out of the furnace. The workpiece surface is cooled to ≤100℃, and then it is put into the resistance furnace for high-temperature tempering to make the outer circle and the inner hole reach the same hardness. In this sequence, the hardness of the inner hole is adjusted to the qualified range. The hardness of the inner hole is tested after the roller sleeve is taken out of the furnace. If it is qualified, the outer circle is semi-finished. After semi-finishing, the outer circle of the roller sleeve is induction heated. After heating, the outer circle is separately sprayed with water for cooling.

[0004] The above two heat treatment methods have their own disadvantages. The first method of making auxiliary tools requires making corresponding auxiliary tools according to the size of different roller sleeves, and the auxiliary tools cannot completely guarantee that the inner hole temperature does not exceed the austenitizing temperature. After the furnace is taken out, the inner hole is quenched during the overall cooling process to obtain martensite structure, which leads to ultra-high hardness of the inner hole. Repairs are often required, and the execution operation is complicated and requires strong on-site experience. The second method of tempering + induction quenching has a higher quality control capability, but the depth of the hardened layer generally does not exceed 50mm. At the same time, special heat treatment equipment is required, and the construction period and cost are relatively high. It is about 10 days longer than the one-time heat treatment period, and it is necessary to add a semi-finishing process of outer cylindrical processing after tempering, and then perform surface quenching. The cost is about 800 yuan / ton higher than the one-time heat treatment. Summary of the Invention

[0005] To address the above technical issues, the present invention provides a heat treatment method for a stud roller sleeve. This method eliminates the need for extensive specialized equipment and tooling, yet achieves the required performance for the sleeve's outer diameter, inner bore, and core through a single heat treatment. The stud roller sleeve production process in the present invention is as follows: converter steelmaking—LF refining—VD refining—VC ingot casting—forging—post-forging heat treatment—rough machining—final heat treatment—in-process inspection—finished product—and factory inspection. The heat treatment described in the present invention refers to the final heat treatment step.

[0006] The technical solution adopted in the present invention is:

[0007] A heat treatment method for a column nail roller sleeve includes the steps of heating in a low-temperature resistance furnace, heating in a high-temperature resistance furnace, water cooling, air cooling, and tempering;

[0008] (1) Low temperature resistance furnace heating process: put the pin roller into the low temperature resistance furnace and keep it at 250-300℃ for 0.5-1.0h / 100mm, then heat it to 550-570℃ and keep it for ≥1.5h / 100mm;

[0009] (2) High temperature resistance furnace heating process: put the column nail roller sleeve into the high temperature resistance furnace and quickly heat it to 900-960℃ and keep it at this temperature for 0.5-1.0h before taking it out of the furnace and cooling it with water;

[0010] (3) Water cooling process: Spray water on the outer circle and inner hole simultaneously. After spraying water on the outer circle until its surface temperature is ≤400℃, switch to spraying. Stop spraying when the spraying reaches its surface temperature ≤100℃. Stop spraying when the inner hole surface temperature is maintained at 600~650℃ and no longer rises.

[0011] (4) Air cooling process: After water cooling, air cool on the preheated pad to return the temperature to the outer circle temperature of 300-350℃ and then put into the furnace for tempering;

[0012] (5) Tempering process: Tempering temperature 500-540℃, holding time ≥4h / 100mm.

[0013] The low-temperature resistance furnace heating process is to keep the temperature at 250-300°C and then increase the temperature to 550-570°C at a speed of ≤30°C / h.

[0014] The high-temperature resistance furnace heating process is carried out at least 2 hours before the column nail roller sleeve is turned in, and the temperature of the high-temperature resistance furnace is set to ≥980℃ and the empty furnace is heated to wait for the material.

[0015] In the water cooling process, the outer circle water spraying time is 25 to 35 minutes, and the water pressure drops from 0.40 MPa to 0.15 MPa during the water spraying process; the spraying is 0.10±0.02 MPa water pressure + wind pressure of the same pressure, and the spraying time is 30 to 40 minutes.

[0016] In the water cooling process, the specific operation of reducing the water pressure from 0.40Mpa to 0.15Mpa during the outer circle water spraying process is: water spraying at a water pressure of 0.40Mpa for ≥5min; water spraying at a water pressure of 0.25Mpa for ≥10min, and water spraying at a water pressure of 0.15Mpa for ≥10min.

[0017] In the water cooling process, the water pressure of the inner hole water spraying is 0.35-0.40 MPa, and the water spraying time is 5-15 minutes.

[0018] In the air cooling process, the temperature of the preheated pad is 150-300°C.

[0019] The tempering process is specifically as follows: after the spike roller is put into the furnace, it is first kept at 250-300°C for ≥1h / 100mm, then heated to the tempering temperature and kept warm, and then cooled to ≤150°C before being taken out of the furnace.

[0020] The tempering process comprises the following steps: keeping the temperature at 250-300°C, then heating the temperature to the tempering temperature at a rate of ≤30°C / h, and then cooling the temperature to ≤150°C at a rate of ≤20°C / h.

[0021] The outer diameter of the column nail roller sleeve ranges from 1000 to 2200 mm, and the inner hole diameter ranges from 500 to 1500 mm.

[0022] The column nail roller sleeve is usually made of medium carbon high alloy steel, and edge chipping and cracking are prone to occur during the heat treatment cooling process. The main purpose of the present invention is to effectively avoid edge chipping while ensuring the cooling effect by using the method of spraying water first and then spraying (similar to the process of simulating water quenching + oil cooling). The water spraying section uses high water pressure to fully break the steam film, so that the workpiece surface is quickly cooled; the spraying section uses air jets to atomize and spray water, reducing the cooling intensity, so that the surface is slowly cooled and the heat exchange is gentle.

[0023] After the spraying is stopped, the roller sleeve is not completely cooled. There is a large temperature difference between the outer circle and the inner hole. Placing it on the pad is a process of temperature equalization. It is required to use a preheated pad (150-300℃) to prevent the pad temperature from being too low or too high, affecting the heat return of the contact surface, avoiding uneven stress distribution and insufficient structural transformation.

[0024] The beneficial effects of adopting the above technical solution are: the present invention can achieve different hardness requirements of the outer circle and the inner hole through one heat treatment, eliminating the tempering process and the semi-finishing process; there is no need to add special heating equipment or make insulating tooling, and a temperature difference is formed between the outer circle and the inner hole by combining low-temperature preheating and high-temperature rapid heating. The outer circle is then fully cooled by graded cooling to obtain a martensitic structure, and the inner hole is self-tempered and returned to the temperature after cooling to obtain tempered bainite. Finally, the entire part is tempered in the furnace to obtain a tempered martensitic structure on the outer circle, thereby achieving different hardness requirements of the outer circle and the inner hole through one heat treatment, while ensuring that the core has good comprehensive mechanical properties.

[0025] The outer circle hardness of the column nail roller sleeve of the present invention can be controlled at 42-54HRC, the outer circle hardness uniformity is ≤3HRC, the hardened layer depth is ≥40mm (single side), the inner hole hardness is 260-320HB, the inner hole hardness uniformity is ≤30HB, the core performance σb>780MPa, σs>510MPa, δ5>16%, ψ>40%, AkU>40J, and various performance indicators meet the design requirements, with high hardness uniformity, improved fatigue resistance, maintenance-free during the product life cycle, and no peeling or accidents have occurred after more than 20,000 hours of continuous use, and the service life is extended by more than 20%.

[0026] Figures in the specification

[0027] Figure 1 This is a process curve diagram of Example 1 of the present invention;

[0028] Figure 2 This is a physical picture of the column nail roller sleeve after heat treatment in Example 1 of the present invention. DETAILED DESCRIPTION

[0029] The present invention will be further described in detail below with reference to specific embodiments.

[0030] The heat treatment method of the stud roller sleeve of the present invention is applicable to stud roller sleeves with an outer diameter of φ1000-2200 mm and an inner hole of φ500-1500 mm. The method includes heating in a low-temperature resistance furnace, heating in a high-temperature resistance furnace, water cooling, air cooling, and tempering. The specific operations are as follows:

[0031] (1) Low-temperature resistance furnace heating process: put the pin roller into the low-temperature resistance furnace and keep it at 250-300℃ for 0.5-1.0h / 100mm, then heat it to 550-570℃ at a rate of ≤30℃ / h and keep it at ≥1.5h / 100mm;

[0032] (2) High-temperature resistance furnace heating process: put the column nail roller sleeve into the high-temperature resistance furnace and quickly heat it to 900-960℃ and keep it warm for 0.5-1.0h before taking it out of the furnace and cooling it with water; at least 2h before the column nail roller sleeve is put into the furnace, the temperature of the high-temperature resistance furnace should be set to ≥980℃ and the empty furnace should be heated to wait for the material.

[0033] (3) Water cooling process: The outer circle and the inner hole are sprayed with water at the same time. After the outer circle is sprayed with water until its surface temperature is ≤400℃, it is changed to spraying. When the spraying reaches its surface temperature ≤100℃, the spraying is stopped. The total time of the outer circle water spraying is 25 to 35 minutes. During the water spraying process, the water pressure is reduced from 0.40Mpa to 0.15Mpa. The specific operation is to spray water at a water pressure of 0.40Mpa for ≥5 minutes, spray water at a water pressure of 0.25Mpa for ≥10 minutes, and spray water at a water pressure of 0.15Mpa for ≥10 minutes. The spraying is 0.10±0.02Mpa water pressure + wind pressure of the same pressure, and the spraying time is 30 to 40 minutes. When the inner hole is sprayed with water and its surface temperature is maintained at 600 to 650℃ and no longer increases, the spraying is stopped; the water pressure of the inner hole water spraying is 0.35 to 0.40Mpa, and the spraying time is 5 to 15 minutes.

[0034] (4) Air cooling process: After water cooling, air cool on a preheated iron pad at a temperature of 150-300°C until the outer circle temperature reaches 300-350°C and then put into the furnace for tempering.

[0035] (5) Tempering process: After the pin roller is put into the furnace, it is first kept at 250-300℃ for ≥1h / 100mm, then heated to the tempering temperature of 500-540℃ at a rate of ≤30℃ / h and kept at this temperature for ≥4h / 100mm, and then cooled to ≤150℃ at a rate of ≤20℃ / h before being taken out of the furnace.

[0036] Example 1

[0037] In this embodiment, the delivery dimensions of the column nail roller sleeve are outer diameter Dφ1794mm, inner hole diameter dφ1190mm, height H1220mm, and a processing allowance is left before entering the furnace for final heat treatment. Since the present invention adopts horizontal furnace loading, the deformation of the ring wall-type live parts needs to be considered. After adding the allowance, the dimensions are Dφ1810mm, inner hole diameter dφ1170mm, and height H1260mm.

[0038] The calculation method of holding time is based on the equivalent wall thickness of the workpiece, which is 1 to 1.5 times the actual wall thickness ((outer diameter - inner hole diameter) / 2). In this example, the equivalent wall thickness of the stud roller sleeve is 450mm (1.41 times the actual wall thickness).

[0039] Refer to the attached Figure 1 In this embodiment, the column nail roller sleeve is horizontally loaded into the low-temperature resistance furnace, the furnace is started and the temperature is raised to 280℃ and kept warm for 3.5h (the insulation time is calculated as 0.8h / 100mm), and then the temperature is raised to 560±10℃ at ≤30℃ / h and kept warm for 8h.

[0040] Refer to the attached Figure 1 2 hours before the column nail roller is put into the furnace, start the high-temperature resistance furnace and heat it up to 980℃ to wait for the material to ensure that the pad iron is burned through.

[0041] Refer to the attached Figure 1 The stud roller sleeve (workpiece) is transferred from the low-temperature resistance furnace to the high-temperature resistance furnace for rapid heating. Two thermocouples are applied to measure the workpiece temperature after the workpiece is transferred in. When the thermocouple temperature (workpiece temperature) reaches 900°C, the furnace temperature is lowered and the holding time begins. Finally, the furnace temperature and the thermocouple temperature (workpiece temperature) reach 930±10°C. After holding for 0.8 hours, the workpiece is removed from the furnace for spray quenching.

[0042] The outer circle of the column roller sleeve is spray quenched by a horizontal spray quenching machine. The specific parameters are 0.40MPa water pressure spray quenching for 8min, 0.25Mpa water pressure spray quenching for 12min, and 0.15Mpa water pressure spray quenching for 10min. When the spraying is stopped, the outer circle temperature can be measured to be ≤400℃. Then, 0.10Mpa water pressure and 0.10Mpa air pressure are used for spray quenching for 35min. After stopping the spraying, the outer circle temperature can be measured to be ≤100℃.

[0043] While quenching the outer circle, use the inner hole nozzle auxiliary tool to quench the inner hole of the stud roller sleeve. Quench for 10 minutes at 0.40MPa water pressure. After stopping the spraying, the inner hole will return to the temperature and temper by itself. The returning temperature is 630-640℃. If the temperature is higher than this range, continue to spray for 1-2 minutes.

[0044] After the spray quenching is completed, the column nail roller sleeve is placed horizontally on the iron pad of the 150-300℃ low-temperature resistance furnace for air cooling and returning to temperature. No through draft is allowed in the factory. When the outer circle temperature is finally measured to drop to 300-350℃, it is put into the furnace for tempering.

[0045] Refer to the attached Figure 1 After returning to temperature, start the furnace and heat it to 280℃ and keep it for 5h, then heat it to 520±5℃ and keep it for 20h at ≤30℃ / h, then cool it to 400℃ at ≤20℃ / h, and then cool it to ≤150℃ at ≤15℃ / h before taking it out of the furnace.

[0046] The performance indicators of the spike roller sleeve after heat treatment in this embodiment are shown in Table 1.

[0047] Example 2

[0048] In this embodiment, the delivery dimensions of the column nail roller sleeve are outer diameter Dφ2180mm, inner hole diameter dφ1480mm, height H1620mm, and a processing allowance is left before entering the furnace for final heat treatment. Since the present invention adopts horizontal furnace loading, the deformation of the ring wall-type live parts needs to be considered. After adding the allowance, the dimensions are Dφ2200mm, inner hole diameter dφ1455mm, and height H1660mm.

[0049] The calculation method of holding time is based on the equivalent wall thickness of the workpiece, which is 1 to 1.5 times the actual wall thickness. In this example, the equivalent wall thickness of the stud roller sleeve is 550 mm (1.48 times the actual wall thickness).

[0050] Refer to the attached Figure 1In this embodiment, the column nail roller sleeve is horizontally loaded into a low-temperature resistance furnace, and the furnace is started to heat up to 280℃ and kept warm for 5.5h (the heat preservation time is calculated as 1.0h / 100mm), and then the temperature is raised to 560±10℃ at a rate of ≤30℃ / h and kept warm for 8h.

[0051] Refer to the attached Figure 1 2 hours before the column nail roller is put into the furnace, start the high-temperature resistance furnace and heat it up to 1000℃ to wait for the material to ensure that the pad iron is burned through.

[0052] Refer to the attached Figure 1 The stud roller sleeve (workpiece) is transferred from the low-temperature resistance furnace to the high-temperature resistance furnace for rapid heating. After the workpiece is transferred in, two thermocouples are applied to measure the workpiece temperature. When the thermocouple temperature (workpiece temperature) rises to 900°C, the furnace temperature is lowered and the holding time begins. Finally, the furnace temperature and the thermocouple temperature (workpiece temperature) reach 930±10°C. After holding for 1 hour, the workpiece is removed from the furnace and spray quenched.

[0053] The outer circle of the column roller sleeve is spray quenched by a horizontal spray quenching machine. The specific parameters are 0.40MPa water pressure spray quenching for 10min, 0.25Mpa water pressure spray quenching for 12min, and 0.15Mpa water pressure spray quenching for 13min. When the spraying is stopped, the outer circle temperature can be measured to be ≤400℃. Then, 0.12Mpa water pressure and 0.12Mpa air pressure are used for spray quenching for 40min. After stopping the spraying, the outer circle temperature can be measured to be ≤100℃.

[0054] While quenching the outer circle, use the inner hole nozzle auxiliary tool to quench the inner hole of the stud roller sleeve. Quench for 15 minutes at a water pressure of 0.40MPa. After stopping the spraying, the inner hole will return to the temperature and temper by itself. The returning temperature is 640-650℃. If the temperature is higher than this range, continue to spray for 1-2 minutes.

[0055] After the spray quenching is completed, the column nail roller sleeve is placed horizontally on the iron pad of the 150-300℃ low-temperature resistance furnace for air cooling and returning to temperature. No through draft is allowed in the factory. When the outer circle temperature is finally measured to drop to 300-350℃, it is put into the furnace for tempering.

[0056] Refer to the attached Figure 1 After returning to temperature, start the furnace and heat it to 280℃ and keep it for 6h, then heat it to 510±5℃ at ≤30℃ / h and keep it for 25h, then cool it down to 400℃ at ≤20℃ / h, and then cool it down to ≤150℃ at ≤15℃ / h before taking it out of the furnace.

[0057] The performance indicators of the spike roller sleeve after heat treatment in this embodiment are shown in Table 1.

[0058] Example 3

[0059] In this embodiment, the delivery dimensions of the column nail roller sleeve are outer diameter Dφ1405mm, inner hole diameter dφ840mm, and height H1000mm. A processing allowance is left before entering the furnace for final heat treatment. Since the present invention adopts horizontal furnace loading, the deformation of the ring wall-type live parts needs to be considered. After adding the allowance, the dimensions are Dφ1415mm, inner hole diameter dφ825mm, and height H1040mm.

[0060] The calculation method of holding time is based on the equivalent wall thickness of the workpiece, which is 1 to 1.5 times the actual wall thickness. In this example, the equivalent wall thickness of the stud roller sleeve is 400 mm (1.42 times the actual wall thickness).

[0061] Refer to the attached Figure 1 In this embodiment, the column nail roller sleeve is horizontally loaded into a low-temperature resistance furnace, the furnace is started and the temperature is raised to 280℃ and kept warm for 2 hours (the insulation time is calculated as 0.5h / 100mm), and then the temperature is raised to 560±10℃ at a rate of ≤30℃ / h and kept warm for 8 hours.

[0062] Refer to the attached Figure 1 2 hours before the column nail roller is put into the furnace, start the high-temperature resistance furnace and heat it up to 980℃ to wait for the material to ensure that the pad iron is burned through.

[0063] Refer to the attached Figure 1 The stud roller sleeve (workpiece) is transferred from the low-temperature resistance furnace to the high-temperature resistance furnace for rapid heating. Two thermocouples are applied to measure the workpiece temperature after the workpiece is transferred in. When the thermocouple temperature (workpiece temperature) reaches 900°C, the furnace temperature is lowered and the holding period begins. Finally, the furnace temperature and the thermocouple temperature (workpiece temperature) reach 930±10°C. After holding for 0.6 hours, the workpiece is removed from the furnace for spray quenching.

[0064] The outer circle of the column roller sleeve is spray quenched by a horizontal spray quenching machine. The specific parameters are 0.40MPa water pressure spray quenching for 7min, 0.25Mpa water pressure spray quenching for 11min, and 0.15Mpa water pressure spray quenching for 11min. At this time, when the spraying is stopped, the outer circle temperature can be measured to be ≤400℃. Then, 0.10Mpa water pressure and 0.10Mpa air pressure are used for spray quenching for 33 min. After stopping the spraying, the outer circle temperature can be measured to be ≤100℃.

[0065] While quenching the outer circle, use the inner hole nozzle auxiliary tool to quench the inner hole of the stud roller sleeve. Quench at 0.35MPa water pressure for 7 minutes. After stopping the spraying, the inner hole will return to the temperature and temper by itself. The returning temperature is 610-620℃. If the temperature is higher than this range, continue to spray for 1-2 minutes.

[0066] After the spray quenching is completed, the column nail roller sleeve is placed horizontally on the iron pad of the 150-300℃ low-temperature resistance furnace for air cooling and returning to temperature. No through draft is allowed in the factory. When the outer circle temperature is finally measured to drop to 300-350℃, it is put into the furnace for tempering.

[0067] Refer to the attached Figure 1After returning to temperature, start the furnace and heat it to 280℃ and keep it for 4h, then heat it to 530±5℃ and keep it for 16h at ≤30℃ / h, then cool it to 400℃ at ≤20℃ / h, and then cool it to ≤150℃ at ≤15℃ / h before taking it out of the furnace.

[0068] The performance indicators of the spike roller sleeve after heat treatment in this embodiment are shown in Table 1.

[0069] Example 4

[0070] In this embodiment, the delivery dimensions of the column nail roller sleeve are outer diameter Dφ1000mm, inner hole diameter dφ500mm, height H800mm, and a processing allowance is left before entering the furnace for final heat treatment. Since the present invention adopts horizontal furnace loading, the deformation of the ring wall-type live parts needs to be considered. After adding the allowance, the dimensions are Dφ1010mm, inner hole diameter dφ485mm, and height H840mm.

[0071] The calculation method of holding time is based on the equivalent wall thickness of the workpiece, which is 1 to 1.5 times the actual wall thickness. In this example, the equivalent wall thickness of the stud roller sleeve is 350mm (1.33 times the actual wall thickness).

[0072] Refer to the attached Figure 1 In this embodiment, the column nail roller sleeve is horizontally loaded into a low-temperature resistance furnace, and the furnace is started to heat up to 250℃ and kept warm for 2 hours (the insulation time is calculated as 0.6h / 100mm), and then the temperature is raised to 550℃ at a rate of ≤30℃ / h and kept warm for 5.5 hours.

[0073] Refer to the attached Figure 1 2 hours before the column nail roller is put into the furnace, start the high-temperature resistance furnace and heat it up to 980℃ to wait for the material to ensure that the pad iron is burned through.

[0074] Refer to the attached Figure 1 The stud roller sleeve (workpiece) is transferred from the low-temperature resistance furnace to the high-temperature resistance furnace for rapid heating. After the workpiece is transferred in, two thermocouples are applied to measure the workpiece temperature. When the thermocouple temperature (workpiece temperature) rises to 900°C, the furnace temperature is lowered and the holding time begins. Finally, the furnace temperature and the thermocouple temperature (workpiece temperature) reach 910±10°C. After holding for 0.5 hours, the workpiece is removed from the furnace and spray quenched.

[0075] Use a horizontal spray quenching machine to spray quench the outer circle of the column roller sleeve. The specific parameters are 0.40MPa water pressure spray quenching for 5min, 0.25Mpa water pressure spray quenching for 10min, and 0.15Mpa water pressure spray quenching for 10min. When the spraying is stopped, the outer circle temperature can be measured to be ≤400℃. Then use 0.08Mpa water pressure and 0.08Mpa wind pressure to spray quench for 30min. After stopping the spraying, the outer circle temperature can be measured to be ≤100℃.

[0076] While quenching the outer circle, use the inner hole nozzle auxiliary tool to quench the inner hole of the stud roller sleeve. Quench at 0.35MPa water pressure for 5 minutes. After stopping the spraying, the inner hole will return to the temperature and temper by itself. The returning temperature is 600-610℃. If the temperature is higher than this range, continue to spray for 1-2 minutes.

[0077] After the spray quenching is completed, the column nail roller sleeve is placed horizontally on the iron pad of the 150-300℃ low-temperature resistance furnace for air cooling and returning to temperature. No through draft is allowed in the factory. When the outer circle temperature is finally measured to drop to 300-350℃, it is put into the furnace for tempering.

[0078] Refer to the attached Figure 1 After returning to temperature, start the furnace and heat it to 250℃ and keep it for 3.5h, then heat it to 500±5℃ at ≤30℃ / h and keep it for 14h, then cool it down to 400℃ at ≤20℃ / h, and then cool it down to ≤150℃ at ≤15℃ / h before taking it out of the furnace.

[0079] The performance indicators of the spike roller sleeve after heat treatment in this embodiment are shown in Table 1.

[0080] Example 5

[0081] In this embodiment, the delivery dimensions of the column nail roller sleeve are outer diameter Dφ1200mm, inner hole diameter dφ550mm, and height H1000mm. A processing allowance is left before entering the furnace for final heat treatment. Since the present invention adopts horizontal furnace loading, the deformation of the ring wall-type live parts needs to be considered. After adding the allowance, the dimensions are Dφ1210mm, inner hole diameter dφ535mm, and height H1040mm.

[0082] The calculation method of holding time is based on the equivalent wall thickness of the workpiece, which is 1 to 1.5 times the actual wall thickness. In this example, the equivalent wall thickness of the stud roller sleeve is 500 mm (1.48 times the actual wall thickness).

[0083] Refer to the attached Figure 1 In this embodiment, the column nail roller sleeve is horizontally loaded into a low-temperature resistance furnace, and the furnace is started to heat up to 260℃ and kept warm for 3 hours (the insulation time is calculated as 0.6h / 100mm), and then the temperature is raised to 550℃ at a rate of ≤30℃ / h and kept warm for 5.5 hours.

[0084] Refer to the attached Figure 1 2 hours before the column nail roller is put into the furnace, start the high-temperature resistance furnace and heat it up to 980℃ to wait for the material to ensure that the pad iron is burned through.

[0085] Refer to the attached Figure 1 The stud roller sleeve (workpiece) is transferred from the low-temperature resistance furnace to the high-temperature resistance furnace for rapid heating. Two thermocouples are applied to measure the workpiece temperature after the workpiece is transferred in. When the thermocouple temperature (workpiece temperature) reaches 900°C, the furnace temperature is lowered and the holding period begins. Finally, the furnace temperature and the thermocouple temperature (workpiece temperature) reach 910±10°C. After holding for 0.6 hours, the workpiece is removed from the furnace for spray quenching.

[0086] The outer circle of the column roller sleeve is spray quenched by a horizontal spray quenching machine. The specific parameters are 0.40MPa water pressure spray quenching for 6min, 0.25Mpa water pressure spray quenching for 10min, and 0.15Mpa water pressure spray quenching for 10min. When the spraying is stopped, the outer circle temperature can be measured to be ≤400℃. Then, 0.10Mpa water pressure and 0.10Mpa air pressure are used for spray quenching for 32 min. After stopping the spraying, the outer circle temperature can be measured to be ≤100℃.

[0087] While quenching the outer circle, use the inner hole nozzle auxiliary tool to quench the inner hole of the stud roller sleeve. Quench at 0.35MPa water pressure for 6 minutes. After stopping the spraying, the inner hole will return to the temperature and temper by itself. The returning temperature is 620-630℃. If the temperature is higher than this range, continue to spray for 1-2 minutes.

[0088] After the spray quenching is completed, the column nail roller sleeve is placed horizontally on the iron pad of the 150-300℃ low-temperature resistance furnace for air cooling and returning to temperature. No through draft is allowed in the factory. When the outer circle temperature is finally measured to drop to 300-350℃, it is put into the furnace for tempering.

[0089] Refer to the attached Figure 1 After returning to temperature, start the furnace and heat it to 250℃ and keep it for 5h, then heat it to 540±5℃ at ≤30℃ / h and keep it for 20h, then cool it down to 400℃ at ≤20℃ / h, and then cool it down to ≤150℃ at ≤15℃ / h before taking it out of the furnace.

[0090] The performance indicators of the spike roller sleeve after heat treatment in this embodiment are shown in Table 1.

[0091] Example 6

[0092] In this embodiment, the delivery dimensions of the column nail roller sleeve are outer diameter Dφ2000mm, inner hole diameter dφ1260mm, height H1600mm, and processing allowance is left before entering the furnace for final heat treatment. Since the present invention adopts horizontal furnace loading, the deformation of the ring wall-type live parts needs to be considered. After adding the allowance, the dimensions are Dφ2016mm, inner hole diameter dφ1240mm, and height H1640mm.

[0093] The calculation method of holding time is based on the equivalent wall thickness of the workpiece, which is 1 to 1.5 times the actual wall thickness. In this example, the equivalent wall thickness of the stud roller sleeve is 550 mm (1.42 times the actual wall thickness).

[0094] Refer to the attached Figure 1 In this embodiment, the column nail roller sleeve is horizontally loaded into a low-temperature resistance furnace, and the furnace is started to heat up to 290℃ and kept warm for 5.5h (heat preservation is calculated as 1h / 100mm), and then the temperature is raised to 570℃ at ≤30℃ / h and kept warm for 8.5h.

[0095] Refer to the attached Figure 1 2 hours before the column nail roller is put into the furnace, start the high-temperature resistance furnace and heat it up to 990℃ to wait for the material to ensure that the pad iron is burned through.

[0096] Refer to the attached Figure 1 The stud roller sleeve (workpiece) is transferred from the low-temperature resistance furnace to the high-temperature resistance furnace for rapid heating. After the workpiece is transferred in, two thermocouples are applied to measure the workpiece temperature. When the thermocouple temperature (workpiece temperature) rises to 900°C, the furnace temperature is lowered and the holding time begins. Finally, the furnace temperature and the thermocouple temperature (workpiece temperature) reach 930±10°C. After holding for 1.0 hour, the workpiece is removed from the furnace and spray quenched.

[0097] The outer circle of the column roller sleeve is spray quenched by a horizontal spray quenching machine. The specific parameters are 0.40MPa water pressure spray quenching for 9min, 0.25Mpa water pressure spray quenching for 12min, and 0.15Mpa water pressure spray quenching for 13min. When the spraying is stopped, the outer circle temperature can be measured to be ≤400℃. Then, 0.11Mpa water pressure and 0.11Mpa air pressure are used for spray quenching for 38 minutes. After stopping the spraying, the outer circle temperature can be measured to be ≤100℃.

[0098] While quenching the outer circle, use the inner hole nozzle auxiliary tool to quench the inner hole of the stud roller sleeve. Quench for 13 minutes at a water pressure of 0.35MPa. After stopping the spraying, the inner hole will return to the temperature and temper by itself. The returning temperature is 640-650℃. If the temperature is higher than this range, continue to spray for 1-2 minutes.

[0099] After the spray quenching is completed, the column nail roller sleeve is placed horizontally on the iron pad of the 150-300℃ low-temperature resistance furnace for air cooling and returning to temperature. No through draft is allowed in the factory. When the outer circle temperature is finally measured to drop to 300-350℃, it is put into the furnace for tempering.

[0100] Refer to the attached Figure 1 After returning to temperature, start the furnace and heat it to 250℃ and keep it for 6h, then heat it to 530±5℃ and keep it for 22h at ≤30℃ / h, then cool it to 400℃ at ≤20℃ / h, and then cool it to ≤150℃ at ≤15℃ / h before taking it out of the furnace.

[0101] The performance indicators of the spike roller sleeve after heat treatment in this embodiment are shown in Table 1.

[0102] Table 1: Performance indicators of the spike roller sleeves after heat treatment in various embodiments

[0103]

[0104] It can be seen from Table 1 that the outer circle hardness of the column nail roller sleeve of each embodiment can be controlled at 42~54HRC, the uniformity of the outer circle hardness is ≤3HRC, the depth of the hardened layer is ≥40mm (single side), the inner hole hardness is 260~320HB, the inner hole hardness uniformity is ≤30HB, the core performance σb>780MPa, σs>510MPa, δ5>16%, ψ>40%, AkU>40J.

[0105] According to statistics, 200 batches of roller sleeves of different specifications have been produced according to the process of the present invention, all performance indicators are qualified, and no peeling or accidents have occurred during continuous use for more than 20,000 hours.

Claims

1. A heat treatment method for a spike roller sleeve, characterized in that: Including low-temperature resistance furnace heating, high-temperature resistance furnace heating, water cooling, air cooling, and tempering processes; (1) Low temperature resistance furnace heating process: put the pin roller into the low temperature resistance furnace and keep it at 250-300℃ for 0.5-1.0h / 100mm, then heat it to 550-570℃ and keep it for ≥1.5h / 100mm; (2) High temperature resistance furnace heating process: put the column nail roller sleeve into the high temperature resistance furnace and quickly heat it to 900-960℃ and keep it at this temperature for 0.5-1.0h before taking it out of the furnace and cooling it with water; (3) Water cooling process: Spray water on the outer circle and inner hole simultaneously. After spraying water on the outer circle until its surface temperature is ≤400℃, switch to spraying. Stop spraying when the spraying reaches its surface temperature ≤100℃. Stop spraying when the inner hole surface temperature is maintained at 600~650℃ and no longer rises. (4) Air cooling process: After water cooling, air cool on the preheated pad iron to return to the outer circle temperature of 300-350℃ and then put into the furnace for tempering; the temperature of the preheated pad iron is 150-300℃; (5) Tempering process: tempering temperature 500-540℃, holding time ≥4h / 100mm; The outer diameter of the column roller sleeve ranges from 1000 to 2200 mm, and the inner hole diameter ranges from 500 to 1500 mm.

2. The heat treatment method of the stud roller sleeve according to claim 1, characterized in that: The low-temperature resistance furnace heating process is to keep the temperature at 250-300°C and then increase the temperature to 550-570°C at a speed of ≤30°C / h.

3. The heat treatment method of the stud roller sleeve according to claim 2, characterized in that: The high-temperature resistance furnace heating process is carried out at least 2 hours before the column nail roller sleeve is turned in, and the temperature of the high-temperature resistance furnace is set to ≥980℃ and the empty furnace is heated to wait for the material.

4. The heat treatment method of the stud roller sleeve according to claim 3, characterized in that: In the water cooling process, the outer circle water spraying time is 25 to 35 minutes, and the water pressure drops from 0.40 MPa to 0.15 MPa during the water spraying process; the spraying is 0.10±0.02 MPa water pressure + wind pressure of the same pressure, and the spraying time is 30 to 40 minutes.

5. The heat treatment method of the stud roller sleeve according to claim 4, characterized in that: The specific operation of the water cooling process in which the water pressure is reduced from 0.40 MPa to 0.15 MPa during the outer circle water spraying process is: spraying water at a water pressure of 0.40 MPa for ≥5 minutes; Water pressure spraying of 0.25Mpa ≥ 10min, water pressure spraying of 0.15Mpa ≥ 10min.

6. The heat treatment method of the stud roller sleeve according to claim 5, characterized in that: In the water cooling process, the water pressure of the inner hole water spraying is 0.35-0.40 MPa, and the water spraying time is 5-15 minutes.

7. The heat treatment method of the stud roller sleeve according to claim 6, characterized in that: The tempering process is specifically as follows: after the spike roller is put into the furnace, it is first kept at 250-300°C for ≥1h / 100mm, then heated to the tempering temperature and kept warm, and then cooled to ≤150°C before being taken out of the furnace.

8. The heat treatment method of the stud roller sleeve according to claim 7, characterized in that: The tempering process comprises the following steps: keeping the temperature at 250-300°C, then heating the temperature to the tempering temperature at a rate of ≤30°C / h, and then cooling the temperature to ≤150°C at a rate of ≤20°C / h.

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