Quenching treatment method for specific alloy multi-temperature-zone roller casting grinding section

Abstract

The invention discloses a specific alloy multi-temperature zone roller casting grinding section quenching treatment method, and relates to the technical field of metal material heat treatment, and the method comprises the following steps: smelting (greater than or equal to 1500 DEG C) alloy raw materials containing 200-330 parts by weight of C, less than or equal to 120 parts by weight of Si and the like, carrying out aluminum ingot deoxidation and slagging-off, and pouring at 1380-1480 DEG C; and the blank is subjected to heat preservation for 6-10 hours in a four-temperature zone (550-1020 DEG C), then is transferred into a roller with the diameter of 1.5-2 m, is quenched for 8-12 minutes by using 1: 8 oil type quenching liquid at the rotating speed of 15-30 r / min, and finally is spirally cleaned and dried. According to the method, the problems of uneven quenching and poor wear resistance of a traditional process are solved, the hardness difference value of the grinding section is smaller than or equal to 1.5 HRC, the wear loss is as low as 15.2 mg / h, the treatment capacity per unit time reaches 4.0-5.9 pieces per hour, the energy consumption is reduced by 10%-25%, and the method is suitable for large-scale high-performance grinding section production.

Description

Technical Field

[0001] This invention relates to the field of heat treatment technology for metallic materials, and in particular to a quenching treatment method for a multi-temperature zone roller casting mill section of a specific alloy. Background Technology

[0002] As a core component for grinding materials in industries such as mining and building materials, the uniformity of hardness and wear resistance of casting grinding segments directly determine grinding efficiency and service life. Heat treatment is a crucial factor affecting the performance of these segments. Currently, the industry faces two major technical challenges in batch processing of casting grinding segments: First, the use of single-temperature zone heating + static quenching leads to uneven heating due to segment accumulation, resulting in soft spots, hardness differences exceeding 4 HRC, and a decrease in wear resistance of over 30%. Furthermore, the high rate of residual oil on the surface after quenching makes subsequent cleaning difficult. Second, while some companies use mesh belt heat treatment furnaces to improve uniformity, the equipment manufacturing cost is high, energy consumption is 20% higher than traditional processes, and mesh belt conveying easily causes surface scratches, resulting in a surface defect rate of up to 10%. In addition, the existing smelting process lacks sufficient precision in alloy composition control; deviations in key elements such as Cr and C can lead to poor microstructure density in the grinding segments, further exacerbating wear problems during use and failing to meet the demands of large-scale, high-performance industrial-scale grinding segment production. Summary of the Invention

[0003] To address the technical problems existing in the background art, this invention proposes a quenching treatment method for the grinding section of a multi-temperature zone roller casting of a specific alloy.

[0004] This invention proposes a method for quenching a multi-temperature zone roller casting mill section of a specific alloy, comprising the following steps: by weight, alloy raw materials containing 200-330 parts C, ≤120 parts Si, 50-90 parts Mn, 1000-1900 parts Cr, ≤6 parts S, and ≤10 parts P are mixed and sequentially added to a medium-frequency melting furnace. The melting furnace is started and the temperature is increased to completely melt the alloy raw materials in the furnace, and the temperature of the molten alloy liquid is stably maintained at ≥1500℃. During this period, temperature data is collected in real time by a temperature sensor in the furnace to ensure that the melting temperature deviation does not exceed ±5℃.

[0005] Furthermore, the alloy raw materials are composed of scrap steel, high-carbon ferrochrome, medium-carbon ferromanganese, graphite recarburizer, and ferrosilicon. Based on a total weight of 1000 parts of alloy raw materials, the composition is as follows: 400-550 parts scrap steel, 250-350 parts high-carbon ferrochrome, 80-120 parts medium-carbon ferromanganese, 30-60 parts graphite recarburizer, and 10-30 parts ferrosilicon. The raw materials need to be pre-treated before input. The scrap steel is washed with a high-pressure water gun to remove surface rust and oil. The high-carbon ferrochrome and medium-carbon ferromanganese are crushed to a particle size of 50-100mm by a jaw crusher. The graphite recarburizer is placed in a drying oven and dried at 120℃-150℃ for 2-3 hours to achieve a moisture content of ≤0.5%.

[0006] Furthermore, two chemical composition tests are required during the smelting process: The first test is conducted 30 minutes after the alloy raw materials melt, using a sampling spoon to collect three alloy liquid samples from different locations within the furnace. After cooling, the C, Si, Mn, and Cr content is analyzed using a spectrometer. If the content of any element exceeds the preset ranges of C 200-330 parts, Si ≤ 120 parts, Mn 50-90 parts, and Cr 1000-1900 parts, the C content is adjusted by adding a carbon raiser, and the Si content is adjusted by adding ferrosilicon. Medium-carbon ferromanganese is added to adjust the Mn content, and high-carbon ferrochromium is added to adjust the Cr content. The amount added is calculated based on the deviation of element content in 1000 parts of alloy liquid. A second full-element retest is conducted 10 minutes before the furnace is tapped to ensure that the contents of C, Si, Mn, Cr, S, and P all meet the requirements of C 200-330 parts, Si ≤ 120 parts, Mn 50-90 parts, Cr 1000-1900 parts, S ≤ 6 parts, and P ≤ 10 parts. After passing the test, the next step is carried out.

[0007] Furthermore, after the pre-furnace chemical composition test is qualified, 2 minutes before tapping, aluminum ingots with a purity ≥99.5% are added at a rate of 40-70 parts per 1000 parts by weight of alloy raw materials. This is then evenly fed into the smelting furnace through a dedicated feeding funnel for deoxidation treatment. The feeding speed of the funnel is controlled at 10-15 parts / minute to avoid direct impact of the aluminum ingots with the furnace wall, which could damage the furnace lining. After the deoxidation reaction is completed, the alloy liquid is transferred to a transfer ladle through a guide channel. The inner wall of the transfer ladle is pre-coated with a high-temperature resistant coating made of alumina powder and water glass mixed in a weight ratio of 3:1. The transfer ladle is then placed in a preheating furnace and preheated to 300℃-400℃. After the alloy liquid is transferred in, it is allowed to stand for 5-8 minutes. A slag skimmer combined with a mechanical lifting device is used to remove oxide slag and impurities from the surface of the alloy liquid. During the slag skimming process, the lifting speed is controlled at 50-80mm / s to ensure a slag skimming rate ≥98%.

[0008] Further, after slag removal, the molten alloy is poured into a casting mill section blank: a resin sand casting mold is used, and the mold is placed in a heating furnace and preheated to 200℃-250℃. The inner wall of the mold cavity is coated with a release agent made of graphite powder and alcohol in a weight ratio of 1:5, and the coating thickness is controlled to be 0.1-0.2mm. The pouring flow rate is controlled by a pouring robot, and the molten alloy is poured into the mold at a pouring temperature of 1380℃-1480℃. The pouring speed is controlled to be 5-8L / min. During the pouring process, an infrared thermometer is used to monitor the temperature of the molten alloy at the mold gate in real time, with a sampling interval of 10 seconds. When the temperature is lower than 1350℃, the pouring is stopped immediately, and a new preheated mold is replaced to continue the operation. After the molten alloy cools naturally in the mold to 200℃-300℃, it is demolded by a mechanical ejection device to obtain the casting mill section blank.

[0009] Furthermore, the casting grinding section billets undergo multi-zone heating and heat preservation treatment: the billets are evenly stacked on high-temperature resistant corundum trays at 10-15mm intervals, with 5-8mm thick alumina ceramic pads laid at the bottom of the trays to prevent the billets from directly contacting and sticking to the trays; the trays are then conveyed into a continuous multi-zone heating furnace via a conveyor chain. The heating furnace is divided into four independent temperature zones, each independently controlled by a PID temperature control system. One temperature zone is set at 550℃-600℃ and held for 1.5-2.5 hours for further treatment. The process involves four temperature zones: Zone 1 - Zone 2 - Zone 3 - Zone 4 - Zone 5 - Zone 6 - Zone 6 - Zone 7 - Zone 6 - Zone 7 - Zone 8 - Zone 9 - Zone 1 - Zone 2 - Zone 3 - Zone 4 - Zone 5 - Zone 6 - Zone 7 - Zone 8 - Zone 9 - Zone 1 ...

[0010] Furthermore, after the multi-temperature zone heating and heat preservation is completed, the hydraulic pusher cylinder device at the outlet of the heating furnace is activated. The thrust of the pusher cylinder is adjusted to 50-80kN, and the pusher rod movement speed is controlled to 0.5m / s-0.8m / s, so that the austenitized casting mill section billet is pushed out of the heating furnace at a uniform speed. After the billet is pushed out, it is transferred to the quenching drum through a high-temperature resistant conveyor roller. The diameter of the quenching drum is 1.5m-2m, and the length is 3-4m. The inner wall of the drum is welded with a spiral guide plate with a height of 50mm-80mm and a spiral angle of 15°-20°. The outer wall of the drum is wrapped with aluminum silicate insulation cotton with a thickness of 100mm-150mm to avoid heat loss from the outer wall of the drum during the quenching process.

[0011] Furthermore, the quenching drum needs to be pre-treated before use: add an oil-like quenching fluid mixed at a weight ratio of 1:8 into the drum. The oil-like quenching fluid is made by mixing 850 parts base oil, 120 parts coolant, and 30 parts rust inhibitor. The amount of quenching fluid added is 1 / 3 to 1 / 2 of the drum volume, and the initial temperature of the quenching fluid is preheated to 40℃-50℃ through the electric heating tube in the drum jacket. After the billet enters the drum, adjust the drum speed according to the size and specifications of the billet in the casting grinding section. When the billet diameter is 50mm-80mm, the speed is adjusted to 25-30 revolutions per minute. When the billet diameter is 80mm-120mm, the speed is adjusted to 15-20 revolutions per minute, so that the billet can be fully turned 360° with the drum rotation, ensuring that each billet can be evenly contacted with the quenching fluid. The quenching time is controlled at 8-12 minutes.

[0012] Furthermore, during the quenching process, the temperature and concentration of the quenching fluid need to be monitored: platinum resistance temperature sensors are installed at the feed end, middle, and discharge end of the quenching drum to monitor the temperature of the quenching fluid in real time. When the temperature exceeds 50℃, the cooling jacket outside the drum is activated, and circulating cooling water at a temperature of 15℃-20℃ is introduced into the jacket. The flow rate of the cooling water is controlled at 10-15L / min. The temperature of the quenching fluid is reduced to 30℃-50℃ through heat exchange. At the same time, a quenching fluid sample is collected from the sampling port at the bottom of the drum every 30 minutes, and the concentration is detected using a refractometer. When the concentration is lower than 90% of the standard value, 100-120 parts of oil-type quenching fluid stock solution are added for every 1000 parts of quenching fluid to maintain a stable quenching fluid concentration.

[0013] Furthermore, after quenching, the discharge port of the quenching drum is opened, and the casting grinding section is transferred to the spiral cleaning machine via an inclined chute. The spiral blades of the spiral cleaning machine are made of 304 stainless steel, with a blade diameter of 300-400mm, and the rotation speed is adjusted to 20-30 revolutions per minute. A weakly alkaline cleaning solution at 40℃-60℃ is introduced into the cleaning machine. The weakly alkaline cleaning solution is made of 50 parts sodium carbonate, 30 parts surfactant, and 920 parts water, with the pH value controlled at 8-9. During the cleaning process, the cleaning solution is sprayed through a high-pressure spray head at a pressure of 0.3MPa-0.5MPa, with a spray volume of 10L. Cleaning is performed at a rate of 15L / min for 10-15 minutes to remove residual quenching fluid oil from the surface of the grinding segment. After cleaning, the grinding segment enters the subsequent hot air drying section of the cleaning machine. The drying section uses electric heating tubes, with the drying temperature controlled at 80℃-100℃ and the hot air fan speed adjusted to 2m / s-3m / s. The drying time is 20-30 minutes. After drying, the grinding segments are sampled and tested using a Rockwell hardness tester. The sampling ratio is 5% of each batch of products. The hardness values ​​of each grinding segment are tested at three different locations to ensure that the hardness difference of the grinding segment is ≤2HRC. After passing the test, the grinding segments are vacuum-packed and stored.

[0014] The beneficial effects of this invention are: 1. Significantly improves hardness uniformity and product qualification rate: Through multi-temperature zone stepped temperature control (550-1020℃), alloying elements are fully diffused and the billet is completely austenitized. Combined with roller rolling quenching (speed 15-30r / min), the grinding section is uniformly heated in 360°. The maximum hardness difference is ≤1.5HRC, and the qualification rate reaches 100%. This is a significant improvement over traditional static quenching (difference 4.8HRC, qualification rate 24%), and completely solves the problem of soft spots during quenching. 2. Enhanced wear resistance and service life: Precise control of alloy composition (C200-330 parts, Cr1000-1900 parts) and smelting process (≥1500℃ melting + aluminum ingot deoxidation) improves the density of the structure, and the average wear of the grinding section is as low as 15.2mg / h. The relative wear resistance is improved by more than 65% compared with the traditional process, extending the grinding service life in mining, building materials and other scenarios. 3. Optimize surface quality and post-processing efficiency: When used in conjunction with an oil-based quenching fluid (1:8 ratio) and a spiral cleaning machine (40-60℃ weakly alkaline cleaning fluid), the surface oil residue rate is reduced to 0%, the roughness Ra≤1.3μm, and there are no surface scratches or defects. Compared with mesh belt quenching (residual rate 15%, defect rate 10%), it reduces subsequent processing steps and lowers labor costs. 4. Improved production efficiency and reduced energy consumption: Automated push-cylinder feeding + drum quenching design reduces single-batch processing time to 8.5-12.5 hours, with a throughput of 4.0-5.9 pieces / hour, representing an 11%-64% improvement over traditional static quenching; precise temperature control in multiple zones further reduces energy consumption. Compared with mesh belt furnaces, it reduces costs by 10%-25%, making it suitable for large-scale industrial production needs. Detailed Implementation

[0015] Example 1

[0016] The present invention proposes a method for quenching a multi-temperature zone roller casting grinding section for a specific alloy, the specific steps of which are as follows: S1. Raw Material Proportioning and Pretreatment: Prepare alloy raw materials by weight, including 200 parts C, 100 parts Si, 50 parts Mn, 1000 parts Cr, 4 parts S, and 8 parts P. This alloy raw material consists of 400 parts scrap steel, 250 parts high-carbon ferrochrome, 80 parts medium-carbon ferromanganese, 30 parts graphite recarburizer, and 10 parts ferrosilicon. The scrap steel is washed with a high-pressure water gun to remove surface rust and oil. The high-carbon ferrochrome and medium-carbon ferromanganese are crushed to a particle size of 50-60mm using a jaw crusher. The graphite recarburizer is placed in a drying oven and dried at 120℃ for 3 hours to reduce the moisture content to 0.4%. S2. Melting Treatment: The pretreated alloy raw materials are sequentially added to the medium-frequency melting furnace. The furnace is started and the temperature is increased to ensure complete melting of the alloy raw materials. The temperature of the molten alloy is maintained stably at 1500℃. During this period, temperature data is collected in real time by a temperature sensor inside the furnace to ensure that the melting temperature deviation does not exceed ±5℃. Thirty minutes after the alloy raw materials melt, three alloy liquid samples are collected from different locations in the furnace using a sampling spoon. After cooling, the samples are analyzed by a spectrometer. The C content is found to be 190 parts, which exceeds the preset range. Ten parts of graphite carburizing agent are added to adjust the C content to 200 parts. Ten minutes before tapping, three more samples are collected for retesting to confirm that the C, Si, Mn, Cr, S, and P contents meet the above-mentioned proportion requirements. S3. Deoxidation and Slag Removal: After the pre-furnace chemical composition test is qualified, 2 minutes before tapping, 40 parts of 99.5% pure aluminum ingots are added to the smelting furnace at a rate of 10 parts / minute using a dedicated feeding funnel for deoxidation. After deoxidation, the molten alloy is transferred through a guide channel to a transfer ladle with an inner wall coated with a high-temperature resistant coating of alumina powder and water glass (weight ratio 3:1) and preheated to 300°C. After standing for 5 minutes, a slag remover in conjunction with a mechanical lifting device (lifting speed 50mm / s) is used to remove oxide slag and impurities from the surface of the molten alloy, achieving a slag removal rate of 98%. S4. Casting and Molding: A resin sand casting mold preheated to 200℃ is used. A 0.1mm thick release agent made of graphite powder and alcohol (weight ratio 1:5) is applied to the inner wall of the mold cavity. The pouring flow rate is controlled by a pouring robot, injecting the molten alloy into the mold at a pouring temperature of 1380℃ and a pouring rate of 5L / min. During the pouring process, the temperature of the molten alloy at the mold gate is monitored every 10 seconds using an infrared thermometer to ensure that the temperature does not drop below 1350℃. After the molten alloy cools naturally to 200℃ inside the mold, it is demolded using a mechanical ejection device to obtain the cast grinding section blank. S5. Multi-zone heating and holding: The cast grinding section billet is evenly stacked on a high-temperature corundum tray with a spacing of 10mm. A 5mm thick alumina ceramic pad is laid at the bottom of the tray, and the billet is fed into a continuous multi-zone heating furnace via a conveyor chain. Zone 1 (550℃) is held for 2.5 hours to eliminate casting stress; Zone 2 (650℃) is held for 2.5 hours to achieve initial homogenization of the microstructure; Zone 3 (800℃) is held for 2.5 hours to promote full diffusion of alloying elements; and Zone 4 (950℃) is held for 2.5 hours to achieve complete austenitization of the billet. The heating rate of each zone is 5℃ / min, and the total holding time is 10 hours. S6. Drum Quenching: After multi-zone heating and heat preservation, a hydraulic pusher with a thrust of 50kN and a pusher movement speed of 0.5m / s is activated to push the austenitized billet out of the heating furnace. The billet is then transferred via a high-temperature resistant conveyor roller to a quenching drum with a diameter of 1.5 meters, a length of 3 meters, an inner wall weld height of 50mm (helix angle 15°), a spiral guide plate, and an outer wall wrapped with 100mm thick aluminum silicate insulation cotton. An oil-based quenching fluid, preheated to 40℃ and mixed at a 1:8 weight ratio (850 parts base oil, 120 parts coolant, 30 parts rust inhibitor), is added to the drum in a manner that fills 1 / 3 of the drum's volume. For a 50mm diameter billet, the drum speed is adjusted to 25 rpm, and quenching is performed for 8 minutes. During the quenching process, the temperature of the quenching fluid is monitored by platinum resistance temperature sensors at the feed end, middle, and discharge end of the drum. When the temperature exceeds 50℃, circulating cooling water at 15℃ and 10L / min is introduced into the external cooling jacket of the drum to reduce the temperature of the quenching fluid to 30-50℃. The concentration of the quenching fluid is sampled and tested every 30 minutes to ensure that the concentration is stable. S7. Cleaning and Drying: After quenching, the casting grinding section is transferred via an inclined chute to a spiral cleaning machine with spiral blades (304 stainless steel, 300mm diameter) rotating at 20 rpm. A weakly alkaline cleaning solution (pH 8) made of 50 parts sodium carbonate, 30 parts surfactant, and 920 parts water at 40℃ is introduced, and the section is cleaned for 15 minutes at a pressure of 0.3MPa and a spray rate of 10L / min to remove surface oil. After cleaning, the grinding section enters a drying section with electric heating elements at 80℃ and hot air velocity of 2m / s, and is dried for 30 minutes. S8. Testing and Packaging: After drying, 5% of each batch of products are sampled and tested for hardness at three different locations on each grinding section using a Rockwell hardness tester. The hardness difference is confirmed to be ≤2HRC. After passing the test, the products are vacuum-packed and put into storage.

[0017] Example 2

[0018] The present invention proposes a method for quenching a multi-temperature zone roller casting grinding section for a specific alloy, the specific steps of which are as follows: S1. Raw Material Proportioning and Pretreatment: By weight, the alloy raw material composition is C 265 parts, Si 110 parts, Mn 70 parts, Cr 1450 parts, S 5 parts, and P 9 parts, consisting of scrap steel 475 parts, high-carbon ferrochrome 300 parts, medium-carbon ferromanganese 100 parts, graphite recarburizer 45 parts, and ferrosilicon 20 parts. The scrap steel is cleaned with a high-pressure water gun to remove rust and oil; the high-carbon ferrochrome and medium-carbon ferromanganese are crushed to a particle size of 70-80mm; the graphite recarburizer is dried in a 135℃ drying oven for 2.5 hours, with the moisture content controlled at 0.3%. S2. Melting Treatment: Add the pretreated raw materials to the medium-frequency melting furnace, raise the temperature to completely melt the alloy liquid, and stabilize the temperature at 1550℃ with a temperature deviation of ±3℃. After melting for 30 minutes, take a sample for testing. The Mn content is 65 parts, and add 5 parts of medium-carbon ferromanganese to adjust it to 70 parts. Retest 10 minutes before tapping to ensure that the element content meets the ratio. S3. Deoxidation and Slag Removal: Two minutes before tapping, add 99.6% pure aluminum ingots (55 parts per 1000 parts by weight of alloy raw material) and deoxidize them by feeding them through a hopper at a rate of 12 parts / minute. Transfer the molten alloy to a preheated 350℃ transfer ladle (with a high-temperature resistant coating on the inner wall), let it stand for 6.5 minutes, and remove the slag using a mechanical lifting device (70mm / s), achieving a slag removal rate of 99%. S4. Casting and Molding: Preheat the mold to 225℃, and apply a 0.15mm thick release agent to the cavity. Inject the molten alloy into the mold at a pouring temperature of 1430℃ and a speed of 6.5L / min, monitoring the gate temperature in real time with an infrared thermometer. After cooling to 250℃, demold to obtain the blank. S5. Multi-zone heating and heat preservation: The billets are stacked with a 12mm spacing, and a 6mm ceramic gasket is placed on the tray before being sent into the heating furnace. Heat preservation in zone 1 (575℃) for 2 hours, zone 2 (700℃) for 2 hours, zone 3 (850℃) for 2 hours, and zone 4 (985℃) for 2 hours. The heating rate is 6.5℃ / min, and the total heat preservation time is 8 hours. S6. Drum quenching: A pusher with a thrust of 65kN and a speed of 0.65m / s feeds the billet into a quenching drum with a diameter of 1.75m and a length of 3.5m (guide plate height 65mm, helix angle 17°, outer wall wrapped with 125mm of insulation cotton). The quenching fluid (1:8 ratio) is preheated to 45℃ and added at 7 / 20 of the drum volume. For a 70mm diameter billet, the rotation speed is 27 rpm, and the quenching time is 10 minutes; the cooling water temperature is 17℃, the flow rate is 12L / min, and the quenching fluid temperature is maintained at 30-50℃. S7. Cleaning and Drying: The cleaning machine blades rotate at 25 rpm, and a weakly alkaline cleaning solution with a temperature of 50℃ and a pH of 8.5 is introduced. The spray pressure is 0.4 MPa and the flow rate is 12 L / min. The cleaning time is 12 minutes. The drying temperature is 90℃ and the air velocity is 2.5 m / s. The drying time is 25 minutes. S8. Testing and Packaging: Sampling tests are conducted on hardness, with a difference ≤2HRC. After passing the tests, the products are vacuum-packed.

[0019] Example 3

[0020] The present invention proposes a method for quenching a multi-temperature zone roller casting grinding section for a specific alloy, the specific steps of which are as follows: S1. Raw Material Proportioning and Pretreatment: By weight, the alloy raw material contains 330 parts C, 120 parts Si, 90 parts Mn, 1900 parts Cr, 6 parts S, and 10 parts P, and is composed of 550 parts scrap steel, 350 parts high-carbon ferrochrome, 120 parts medium-carbon ferromanganese, 60 parts graphite recarburizer, and 30 parts ferrosilicon. The scrap steel is cleaned with a high-pressure water gun; the high-carbon ferrochrome and medium-carbon ferromanganese are crushed to a particle size of 90-100mm; the graphite recarburizer is dried in a 150℃ drying oven for 2 hours, with a moisture content of 0.2%. S2. Melting Treatment: Raw materials are added to a medium-frequency induction melting furnace, and the temperature is raised to melt the alloy liquid, stabilizing at 1600℃ with a deviation of ±2℃. Samples are taken for testing 30 minutes after melting; the Cr content is 1850 parts per liter. 50 parts of high-carbon ferrochrome are added to adjust the content to 1900 parts per liter. A retest is conducted 10 minutes before tapping; the elemental content meets the standards. S3. Deoxidation and Slag Removal: Two minutes before tapping, add 99.6% purity aluminum ingots (70 parts per 1000 parts by weight of alloy raw material) at a feeding rate of 15 parts / minute. Transfer the molten alloy to a preheated ladle at 400℃, let it stand for 8 minutes, and then remove the slag using a mechanical lifting device (80mm / s), achieving a slag removal rate of 99.5%. S4. Casting and Molding: Preheat the mold to 250℃, and apply a 0.2mm thick release agent to the cavity. Inject the molten alloy into the mold at a pouring temperature of 1480℃ and a speed of 8L / min, monitoring the gate temperature in real time. Demold after cooling to 300℃. S5. Multi-zone heating and heat preservation: The billets are stacked with a spacing of 15mm, and an 8mm ceramic gasket is placed on the tray before being sent into the heating furnace. Heat preservation in zone 1 (600℃) for 1.5 hours, zone 2 (750℃) for 1.5 hours, zone 3 (900℃) for 1.5 hours, and zone 4 (1020℃) for 1.5 hours. The heating rate is 8℃ / min, and the total heat preservation time is 6 hours. S6. Drum quenching: A pusher with a thrust of 80kN and a speed of 0.8m / s feeds the billet into a quenching drum with a diameter of 2 meters and a length of 4 meters (guide plate height 80mm, helix angle 20°, outer wall wrapped with 150mm of insulation cotton). The quenching fluid is preheated to 50℃ and added at half the drum volume. For a 120mm diameter billet, the rotation speed is 20 rpm, and the quenching time is 12 minutes; the cooling water temperature is 20℃, and the flow rate is 15L / min to maintain the quenching fluid temperature. S7. Cleaning and Drying: The cleaning machine blades rotate at 30 rpm, and a weakly alkaline cleaning solution with a temperature of 60℃ and a pH of 9 is introduced. The spray pressure is 0.5 MPa and the flow rate is 15 L / min. Cleaning lasts for 10 minutes. Drying temperature is 100℃ and the air velocity is 3 m / s. Drying lasts for 20 minutes. S8. Testing and Packaging: Sampling tests are conducted on hardness, with a difference ≤2HRC. After passing the tests, the products are vacuum-packed.

[0021] Experimental Section I. Experimental Objective The advantages of the "Quenching Treatment Method for Multi-Temperature Zone Roller Casting Grinding Segment of Specific Alloy" (corresponding to Examples 1-3) described in this invention in terms of grinding segment hardness uniformity, surface quality, wear resistance and production efficiency are verified. By comparing it with traditional heat treatment methods (Comparative Examples 1-2), the practical application value of the technical solution is quantitatively evaluated.

[0022] II. Experimental Materials and Equipment 1. Experimental materials 1.1 Alloy raw materials: scrap steel, high carbon ferrochrome, medium carbon ferromanganese, graphite carburizer, ferrosilicon, aluminum ingots (purity ≥99.5%), which are consistent with the raw material composition of Examples 1-3 and Comparative Examples 1-2; 1.2 Auxiliary materials: oil-based quenching fluid (base oil, coolant, and rust inhibitor are mixed in a weight ratio of 85:12:3), weakly alkaline cleaning fluid (sodium carbonate, surfactant, and water are mixed in a weight ratio of 5:3:92), and mold release agent (graphite powder and alcohol are mixed in a weight ratio of 1:5).

[0023] 2. Experimental equipment 2.1 Smelting equipment: medium-frequency smelting furnace (temperature control accuracy ±5℃), transfer ladle (with preheating function); 2.2 Heat treatment equipment: continuous multi-temperature zone heating furnace (4 independent temperature zones, PID temperature control), quenching drum with a diameter of 1.5-2m (with speed adjustment and cooling jacket), traditional mesh belt heat treatment furnace, traditional static quenching tank; 2.3 Testing equipment: Rockwell hardness tester (accuracy ±0.5HRC), abrasion tester (MLD-10 type), surface roughness tester (Ra accuracy ±0.02μm), electronic scale (accuracy ±0.1g), stopwatch.

[0024] III. Experimental Group Design

[0025] IV. Experimental Procedure 1. Sample preparation: Alloy raw materials are prepared according to the formula of each group. After melting, deoxidation, slag removal and casting, grinding section blanks of corresponding size are obtained to ensure that the initial state of each group of blanks is consistent (no cracks or surface defects). 2. Heat treatment operations: Heating, holding, and quenching are performed according to the methods for each group, including: 2.1 Examples 1-3: Strictly follow the requirements for multi-temperature zone heating rate (5-8℃ / min), holding time, and drum speed; 2.2 Comparative Example 1: The single-temperature zone heating furnace was heated to 850℃ at a uniform rate and held for 10 hours. The billet was then statically placed into the quenching tank (quenching liquid temperature 30-50℃). 2.3 Comparative Example 2: The mesh belt furnace was heated to 800℃ at 10℃ / min, held for 8 hours, and then conveyed to the quenching tank at a uniform speed (0.3m / s) by the mesh belt. 3. All samples were cleaned using the same spiral cleaning machine (40-60℃ weak alkaline cleaning solution, cleaning for 10-15 min) and hot air drying (80-100℃, 20-30 min) after quenching. 4. Performance Testing: 4.1 Hardness uniformity: Three test points (upper, middle and lower positions) are randomly selected for each sample, and the HRC value is measured with a Rockwell hardness tester. The average hardness and maximum difference of each group are calculated. 4.2 Surface quality: The Ra value of 10 samples in each group was measured using a surface roughness meter, and the surface oil residue rate was statistically analyzed (visual observation + alcohol wiping verification). 4.3 Wear resistance: Five samples were taken from each group and the wear amount after 1 hour was tested using an MLD-10 wear tester (load 200N, speed 200r / min, abrasive is quartz sand) (weighing method, accuracy ±0.1mg). 4.4 Production efficiency: Record the total time from heating to quenching completion for each group of 50 samples, and calculate the processing capacity per unit time (pieces / h).

[0026] V. Experimental Data and Results Analysis 1. Results of hardness uniformity test

[0027] 2. Surface quality test results

[0028] 3. Abrasion resistance test results

[0029] 4. Generation efficiency test results

[0030] VI. Experimental Conclusions 1. Hardness uniformity: The maximum hardness difference of groups 1-3 in Examples 1-3 is ≤1.5HRC, with a pass rate of 100%, which is significantly better than Comparative Example 1 (difference 4.8HRC, pass rate 24%) and Comparative Example 2 (difference 3.2HRC, pass rate 70%). This proves that multi-temperature zone heating + roller rolling quenching can achieve uniform heat exchange and avoid the generation of soft spots. 2. Surface quality: The surface roughness Ra of the example group was ≤1.3μm and the oil residue rate was 0%, which was better than that of Comparative Example 1 (Ra=2.8μm, residue rate 35%) and Comparative Example 2 (Ra=1.8μm, residue rate 15%), indicating that the combination of the cleaning process and quenching method of the present invention can improve the surface cleanliness. 3. Wear resistance: The average wear rate of the group in Example 3 was only 15.2 mg / h, and the relative wear resistance was improved by 65% ​​compared with Comparative Example 1. This was due to the reasonable alloy ratio and the austenitization effect, which enhanced the density of the microstructure. 4. Production efficiency: The processing capacity of Example 3 group was 5.9 pieces / h, which is 64% higher than that of Comparative Example 1, and the energy consumption was reduced by 32%, demonstrating the high efficiency advantages of multi-temperature zone temperature control and automated drum quenching.

[0031] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for quenching a multi-temperature zone roller casting grinding section of a specific alloy, characterized in that, The process includes raw material proportioning and smelting steps: By weight, alloy raw materials containing 200-330 parts C, ≤120 parts Si, 50-90 parts Mn, 1000-1900 parts Cr, ≤6 parts S, and ≤10 parts P are mixed and added sequentially into a medium-frequency melting furnace. The melting furnace is started and the temperature is raised to ensure that the alloy raw materials in the furnace are completely melted, and the temperature of the molten alloy is stably maintained at ≥1500℃. During this period, temperature data is collected in real time by a temperature sensor in the furnace to ensure that the smelting temperature deviation does not exceed ±5℃.

2. The method for quenching treatment of a multi-temperature zone roller casting mill section for a specific alloy according to claim 1, characterized in that, The alloy raw materials consist of scrap steel, high-carbon ferrochrome, medium-carbon ferromanganese, graphite recarburizer, and ferrosilicon. Based on a total weight of 1000 parts, the raw materials comprise 400-550 parts scrap steel, 250-350 parts high-carbon ferrochrome, 80-120 parts medium-carbon ferromanganese, 30-60 parts graphite recarburizer, and 10-30 parts ferrosilicon. Before input, the raw materials undergo pretreatment. Scrap steel is washed with a high-pressure water gun to remove surface rust and oil. High-carbon ferrochrome and medium-carbon ferromanganese are crushed to a particle size of 50-100mm using a jaw crusher. The graphite recarburizer is placed in a drying oven and dried at 120℃-150℃ for 2-3 hours until the moisture content is ≤0.5%.

3. The method for quenching treatment of a multi-temperature zone roller casting mill section for a specific alloy according to claim 1, characterized in that, Two chemical composition tests are required during the smelting process: The first test is conducted 30 minutes after the alloy raw materials melt. Three samples of the molten alloy are collected from different locations in the furnace using a sampling spoon. After cooling, the C, Si, Mn, and Cr content is analyzed using a spectrometer. If the content of any element exceeds the preset ranges (C 200-330 parts, Si ≤ 120 parts, Mn 50-90 parts, Cr 1000-1900 parts), the C content is adjusted by adding a carburizing agent, the Si content is adjusted by adding ferrosilicon, and so on. The Mn content is adjusted by adding carbon-manganese ferroalloy, and the Cr content is adjusted by adding high-carbon ferrochrome. The amount of addition is calculated based on the deviation of element content in 1000 parts of alloy liquid. A second time, 10 minutes before unloading, three samples are collected again for full element retesting to ensure that the contents of C, Si, Mn, Cr, S, and P all meet the requirements of C 200-330 parts, Si ≤ 120 parts, Mn 50-90 parts, Cr 1000-1900 parts, S ≤ 6 parts, and P ≤ 10 parts. After passing the test, the next step is carried out.

4. The method for quenching treatment of a multi-temperature zone roller casting mill section for a specific alloy according to claim 1, characterized in that, After the pre-furnace chemical composition test is qualified, 2 minutes before tapping, aluminum ingots with a purity ≥99.5% are added at a rate of 40-70 parts per 1000 parts by weight of alloy raw materials. The ingots are then evenly fed into the smelting furnace through a special feeding funnel for deoxidation treatment. The feeding speed of the feeding funnel is controlled at 10-15 parts / minute to avoid direct impact of the aluminum ingots on the furnace wall, which could damage the furnace lining. After the deoxidation reaction is completed, the alloy liquid is transferred to a transfer ladle through a guide channel. The inner wall of the transfer ladle is pre-coated with a high-temperature resistant coating made of alumina powder and water glass in a weight ratio of 3:

1. The transfer ladle is then placed in a preheating furnace and preheated to 300℃-400℃. After the alloy liquid is transferred in, it is allowed to stand for 5-8 minutes. A slag skimmer is used in conjunction with a mechanical lifting device to remove oxide slag and impurities from the surface of the alloy liquid. During the slag skimming process, the lifting speed is controlled at 50-80mm / s to ensure a slag skimming rate ≥98%.

5. The method for quenching treatment of a multi-temperature zone roller casting mill section for a specific alloy according to claim 4, characterized in that, After slag removal, the molten alloy is poured into a casting mill section blank: a resin sand casting mold is used, and the mold is placed in a heating furnace and preheated to 200℃-250℃. The inner wall of the mold cavity is coated with a release agent made of graphite powder and alcohol in a weight ratio of 1:5, and the coating thickness is controlled to be 0.1-0.2mm. The pouring flow rate is controlled by a pouring robot, and the molten alloy is poured into the mold at a pouring temperature of 1380℃-1480℃. The pouring speed is controlled to be 5-8L / min. During the pouring process, an infrared thermometer is used to monitor the temperature of the molten alloy at the mold gate in real time, with a sampling interval of 10 seconds. When the temperature is lower than 1350℃, the pouring is stopped immediately, and a new preheated mold is replaced to continue the operation. After the molten alloy cools naturally in the mold to 200℃-300℃, it is demolded by a mechanical ejection device to obtain the casting mill section blank.

6. The method for quenching treatment of a multi-temperature zone roller casting mill section for a specific alloy according to claim 5, characterized in that, Multi-zone heating and heat preservation treatment is applied to the casting grinding section billets: The billets are evenly stacked on high-temperature resistant corundum trays at 10-15mm intervals. A 5-8mm thick alumina ceramic gasket is placed at the bottom of the tray to prevent direct contact and adhesion between the billets and the tray. The trays are then conveyed into a continuous multi-zone heating furnace. The furnace is divided into four independent temperature zones, each controlled independently by a PID temperature control system. One zone is set to 550℃-600℃ and held for 1.5-2.5 hours to eliminate heat. The billet is subjected to casting stress; the second temperature zone is set at 650℃-750℃ and held for 1.5-2.5 hours to achieve initial homogenization of the billet microstructure; the third temperature zone is set at 800℃-900℃ and held for 1.5-2.5 hours to allow for full diffusion of alloying elements in the billet; the fourth temperature zone is set at 950℃-1020℃ and held for 1.5-2.5 hours to achieve complete austenitization of the billet; the heating rate of all four temperature zones is controlled at 5℃ / min-8℃ / min, and the total holding time is 6-10 hours.

7. The method for quenching treatment of a multi-temperature zone roller casting mill section for a specific alloy according to claim 6, characterized in that, After the multi-temperature zone heating and heat preservation is completed, the hydraulic pusher cylinder device at the outlet of the heating furnace is activated. The thrust of the pusher cylinder is adjusted to 50-80kN, and the pusher rod movement speed is controlled to 0.5m / s-0.8m / s, so that the austenitized casting mill section billet is pushed out of the heating furnace at a uniform speed. After the billet is pushed out, it is transferred to the quenching drum through a high-temperature resistant conveyor roller. The diameter of the quenching drum is 1.5m-2m, and the length is 3-4m. The inner wall of the drum is welded with a spiral guide plate with a height of 50mm-80mm and a spiral angle of 15°-20°. The outer wall of the drum is wrapped with aluminum silicate insulation cotton with a thickness of 100mm-150mm to avoid heat loss from the outer wall of the drum during the quenching process.

8. The method for quenching treatment of a multi-temperature zone roller casting mill section for a specific alloy according to claim 7, characterized in that, Before using the quenching drum, pretreatment is required: Add an oil-like quenching fluid mixed at a weight ratio of 1:8 into the drum. The oil-like quenching fluid is made by mixing 850 parts base oil, 120 parts coolant, and 30 parts rust inhibitor. The amount of quenching fluid added should be 1 / 3 to 1 / 2 of the drum volume, and the initial temperature of the quenching fluid should be preheated to 40℃-50℃ through the electric heating tube in the drum jacket. After the billet enters the drum, adjust the drum speed according to the size and specifications of the billet in the casting grinding section. When the billet diameter is 50mm-80mm, the speed should be adjusted to 25-30 revolutions per minute. When the billet diameter is 80mm-120mm, the speed should be adjusted to 15-20 revolutions per minute, so that the billet can be fully turned 360° with the drum rotation, ensuring that each billet can be evenly contacted with the quenching fluid. The quenching time should be controlled at 8-12 minutes.

9. The method for quenching treatment of a multi-temperature zone roller casting mill section for a specific alloy according to claim 8, characterized in that, During the quenching process, the temperature and concentration of the quenching fluid need to be monitored: Platinum resistance temperature sensors are installed at the feed end, middle, and discharge end of the quenching drum to monitor the temperature of the quenching fluid in real time. When the temperature exceeds 50℃, the cooling jacket outside the drum is activated, and circulating cooling water at a temperature of 15℃-20℃ is introduced into the jacket. The flow rate of the cooling water is controlled at 10-15L / min. The temperature of the quenching fluid is reduced to 30℃-50℃ through heat exchange. At the same time, a quenching fluid sample is collected from the sampling port at the bottom of the drum every 30 minutes, and the concentration is detected by a refractometer. When the concentration is lower than 90% of the standard value, 100-120 parts of oil-like quenching fluid stock solution are added for every 1000 parts of quenching fluid to maintain a stable quenching fluid concentration.

10. The method for quenching treatment of a multi-temperature zone roller casting mill section for a specific alloy according to claim 8, characterized in that, After quenching, open the discharge port of the quenching drum and transfer the casting grinding section to the spiral cleaning machine through the inclined chute. The spiral blades of the spiral cleaning machine are made of 304 stainless steel with a blade diameter of 300-400mm and the speed is adjusted to 20-30 revolutions per minute. A weakly alkaline cleaning solution at 40℃-60℃ is introduced into the cleaning machine. This solution is made by mixing 50 parts sodium carbonate, 30 parts surfactant, and 920 parts water, with a pH value controlled at 8-9. During the cleaning process, the cleaning solution is sprayed through a high-pressure spray head at a pressure of 0.3MPa-0.5MPa, with a spray rate of 10L / min-15L / min, for 10-15 minutes to remove residual quenching fluid oil stains from the surface of the grinding segment. After cleaning, the grinding segment enters the subsequent hot air drying section of the cleaning machine. The drying section uses electric heating tubes, with the drying temperature controlled at 80℃-100℃ and the hot air fan speed adjusted to 2m / s-3m / s. The drying time is 20-30 minutes. After drying, the grinding segments are sampled and tested using a Rockwell hardness tester. The sampling ratio is 5% of each batch of products. The hardness value of each grinding segment is tested at three different locations to ensure that the hardness difference of the grinding segment is ≤2HRC. After passing the test, the grinding segments are vacuum-packed and stored.

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