Induction quenching method for deep-hardness layer
By using 50HZ/250HZ quenching equipment and 3 induction ring heating methods on Cr5 material rolls, the quenching process is optimized, and the problem that traditional technology cannot meet the depth requirements of the roll hardening layer is solved, and the roll body hardness and hardening layer are realized Accurate depth control improves the performance of the roll.
Patent Information
- Application Number
- CN202411706279.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-26
- Publication Date
- 2025-02-21
AI Technical Summary
Traditional surface heat treatment methods cannot meet the requirements of the hardening layer depth of the Cr5 material roll, and the prior art is difficult to meet the hardness range of the roll body HSD93-97 and the hardening layer depth of 35-40mm.
The 50HZ/250HZ quenching equipment is adopted, and the quenching process parameters are optimized through 3 induction rings to achieve reasonable distribution of the surface temperature of the roll body, complete the quenching process, and meet the technical requirements of the hardness range HSD93-97 and the quenching layer depth of 35-40mm.
The roll body hardness range HSD93-97 and the hardened layer depth of 35-40mm are achieved, which meets the technical quality indicators and improves the wear resistance and thermal shock resistance of the roll.
Smart Images
Figure CN119491090A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the field of heat treatment technology, and relates to a method for heat treatment quenching of a roller surface made of Cr5, and specifically to a method for induction quenching a deep hardness layer using 50HZ / 250HZ quenching equipment to meet the roller hardness requirement of 93-97HSD and accurately control the depth to reach the quality requirement of 35-40mm. Background Art
[0002] The material composition requirements of Cr5 rolls are: C: 0.75-0.95, Si: 0.40-0.8, Mn: 0.50-0.80, Cr: 0.48-0.55, P: ≤0.020, S: ≤0.015, Ni: 0.20-0.4, V: 0.10-0.2. This type of roll is mostly used for the finishing stand of rolling mills at home and abroad, and is required to have high resistance to fracture, peeling, thermal shock, accidents and wear. Generally, alloy forged steel is selected, and it is made through electric furnace smelting, ladle refining, electroslag remelting, forging, quenching and tempering heat treatment, rough machining, roll surface quenching, finishing, and cylindrical grinding. The hardness of the finished work roll is generally required to be HSD93-97, and the hardened layer is 25-30mm, which is obtained through surface heat treatment. At present, some steel enterprises have improved equipment, increased efficiency and reduced roll consumption, requiring the roll body hardness to be HSD93-97 and the hardened layer to be 35-40mm. Traditional surface heat treatment methods can no longer meet the requirements for the depth of the hardened layer.
[0003] The traditional process is achieved like this: 1) Through quenching and tempering heat treatment, the overall hardness of the roll is controlled at HSD35-50. Use two induction coil surface induction equipment to quench the roll body with hardness requirement of HSD93-97, spray water on the surface for rapid cooling, and adjust the surface hardness to a hardness higher than HSD97. Use tempering furnace to adjust the hardness to the required range.
[0004] 2) Although the hardness of the traditional surface quenching method can reach the required hardness, the depth of the hardened layer of the Cr5 material roller can only reach 25-30mm. Summary of the invention
[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a deep hardness layer induction quenching method that uses 50HZ / 250HZ quenching equipment and a configuration method of heating with three induction coils, each with a width of 165±5mm, to increase the hardness range of the roller body to HSD93-97, and accurately control the depth of the hardened layer to meet the quality requirement of 35-40mm. By optimizing the temperature distribution during the quenching process, the roller body part with a hardness requirement of HSD93-97 is quenched, and the surface is rapidly cooled by spraying water to reach a surface hardness higher than HSD97. The hardness is adjusted to the required range by tempering in a tempering furnace, and the depth of the hardened layer meets the quality requirement of 35-40mm.
[0006] The technical solution of the present invention is implemented as follows: a method for heat treatment and quenching of the surface of a roller made of Cr5, specifically a method for induction quenching of a deep hardness layer using 50HZ / 250HZ quenching equipment to meet the roller hardness requirement of 93-97HSD and accurately control the depth to reach 35-40mm quality requirements. The roller body of the Cr5 material roller uses 50HZ / 250HZ quenching equipment and uses 3 induction coils for induction heating to optimize the quenching process parameters to achieve a reasonable distribution of the roller body surface temperature during the quenching process, complete the quenching process, achieve the roller body hardness range, and accurately control the technical requirements of the hardened layer depth. The specific steps are as follows: Step 1), the roller body is surface quenched using 50HZ / 250HZ equipment and 3 induction coils, of which 2 induction coils are installed on the 50HZ transformer busbar, and 1 induction coil is installed on the 250HZ transformer busbar, and the induction coils are fixed on the water spray ring using columns; Step 2), the first 50HZ induction coil and the second 50HZ induction coil installed on the 50HZ transformer busbar, the inner diameter of the first 50HZ induction coil ≧ the inner diameter of the second 50HZ induction coil, the gap between the inner diameter of the first 50HZ induction coil and the workpiece diameter is controlled at 30±5mm, the gap between the inner diameter of the second 50HZ induction coil and the workpiece diameter is controlled at 25±5mm, and the installation distance between the first 50HZ induction coil and the second 50HZ induction coil is controlled at 10±2mm; 250 The HZ induction coil is installed on the 250HZ transformer busbar, and the clearance between the 250HZ induction coil and the workpiece is controlled at 25±5mm. The distance between the second 50HZ induction coil installed on the 50HZ transformer busbar and the 250HZ induction coil installed on the 250HZ transformer busbar is controlled at 30±2mm. The roller body is quickly heated to a temperature of 950-970℃ using 50HZ / 250HZ dual-frequency induction equipment, and then the workpiece enters the water spray ring for rapid cooling. Step 3), after quenching, slowly cool for 90±10min; Step 4) Tempering in the tempering furnace to adjust the hardness range to meet the HSD93-97 technical requirements.
[0007] The present invention has the following advantages: 1) utilizing the characteristics of 50HZ / 250HZ dual-frequency machine tools, installing three induction coils to realize the roller surface quenching process; 2) the surface hardness of the Cr5 roller reaches HSD93-97, and the depth of the hardened layer is accurately controlled at 35-40mm, meeting the technical quality indicators. BRIEF DESCRIPTION OF THE DRAWINGS
[0008] Figure 1 It is a schematic diagram of quenching the roller body of the Cr5 material roller of the present invention.
[0009] Figure 2 Schematic diagram of 50HZ / 250HZ quenching induction coil.
[0010] The markings in the figure are: 1-roller body; 2-first 50HZ induction coil; 3-second 50HZ induction coil; 4-250HZ induction coil; 5-water spray ring. DETAILED DESCRIPTION
[0011] Example 1: As shown in the figure, the quenching process of the Cr5 roller with a diameter of Φ500*14500 is used for process verification. The roller body 1 made of Cr5 material is induction heated by 50HZ / 250HZ quenching equipment and three induction coils, each with a width of 165±5mm. The quenching process parameters are optimized to achieve a reasonable distribution of the roller body surface temperature during the quenching process, complete the quenching process, and achieve the technical requirements of the roller body hardness range and the depth of the hardened layer. The specific steps are as follows: Step 1), before quenching the roll, the roll is subjected to tempering heat treatment to make the overall hardness of the roll reach 35-50HSD, meeting certain heat treatment performance indicators; Step 2), use 50HZ / 250HZ dual-frequency induction equipment for surface heating and quenching, each induction coil width is 165±5mm, the first 50HZ induction coil 2 and the second 50HZ induction coil 3 are installed on the 50HZ transformer bus at the same time, the inner diameter of the first 50HZ induction coil 2 and the workpiece diameter gap are controlled at 30±5mm, the inner diameter of the second 50HZ induction coil 3 and the workpiece diameter gap are controlled at 25±5mm, and the installation distance between the first 50HZ induction coil 2 and the second 50HZ induction coil 3 is controlled at 10±2mm. The 250HZ induction coil 4 is installed on the 250HZ transformer bus, the gap between the 250HZ induction coil 4 and the workpiece diameter is controlled at 25±5mm, and the distance between the second 50HZ induction coil 3 and the 250HZ induction coil 4 is controlled at 30±2mm. When quenching with 50HZ / 250HZ dual-frequency induction equipment, the workpiece moving speed is 0.55±0.1mm / s, and the 50HZ transformer power is adjusted to quickly heat the workpiece roller body to ensure that the workpiece temperature at the outlet of the induction ring 2 is 950-960℃. The 250HZ transformer power is adjusted to stably control the workpiece roller body temperature at 960-970℃, and then the workpiece enters the water spray ring 5 for rapid cooling; Step 3), after quenching, slowly cool for 90±10min; Step 4), after quenching, the hardness reaches 99-100HSD, and a -80° deep cooling process is performed; Step 5) Tempering in the tempering furnace to adjust the hardness range to meet the HSD93-97 technical requirements.
Claims
1. A deep hardness layer induction quenching method, characterized in that: The roller body (1) made of Cr5 material is induction heated by 50HZ / 250HZ quenching equipment with three induction coils, each with a width of 165±5mm. The quenching process parameters are optimized to achieve a reasonable distribution of the roller body surface temperature during the quenching process, complete the quenching process, and achieve the technical requirements of the roller body hardness range and hardened layer depth. The specific steps are as follows: Step 1), the roller body (1) is surface hardened by using 50HZ / 250HZ equipment and three induction coils, wherein two induction coils are installed on the 50HZ transformer busbar, and one induction coil is installed on the 250HZ transformer busbar, and the induction coils are fixed on the water spray ring by using columns; Step 2), install the first 50HZ induction coil (2) and the second 50HZ induction coil (3) on the 50HZ transformer busbar, the inner diameter of the first 50HZ induction coil (2) ≧ the inner diameter of the induction coil of the second 50HZ induction coil (3), the gap between the inner diameter of the first 50HZ induction coil (2) and the diameter of the workpiece is controlled at 30±5mm, the gap between the inner diameter of the second 50HZ induction coil (3) and the diameter of the workpiece is controlled at 25±5mm, and the installation distance between the first 50HZ induction coil (2) and the second 50HZ induction coil (3) is controlled at 10±2m m; the 250HZ induction coil (4) is installed on the 250HZ transformer bus, the clearance between the 250HZ induction coil (4) and the workpiece diameter is controlled at 25±5mm, and the distance between the second 50HZ induction coil (3) installed on the 50HZ transformer bus and the 250HZ induction coil (4) installed on the 250HZ transformer bus is controlled at 30±2mm; using the 50HZ / 250HZ dual-frequency induction equipment, the roller body is quickly heated to a temperature of 950-970°C, and then the workpiece enters the water spray ring (5) for rapid cooling; Step 3), after quenching, slowly cool for 90±10min; Step 4) Tempering in the tempering furnace to adjust the hardness range to meet the HSD93-97 technical requirements.
2. A deep hardness layer induction hardening method according to claim 1, characterized in that: When quenching with 50HZ / 250HZ dual-frequency induction equipment, the width of each induction coil is 165±5mm, the workpiece moving speed is 0.55±0.1mm / s, and the power of the 50HZ transformer is adjusted to quickly heat the workpiece roller body to ensure that the workpiece temperature at the exit position of the second 50HZ induction coil (3) is 950-960℃. The power of the 250HZ transformer is adjusted to stably control the workpiece roller body temperature at 960-970℃, and then the workpiece enters the water spray ring (5) for rapid cooling.