Heat treatment process of ZG30CrMnSi alloy steel for ledge

Abstract

The invention relates to the technical field of metal material heat treatment processes, in particular to a heat treatment process of ZG30CrMnSi alloy steel for a ledge. Normalizing: putting the cast ledge blank sample into a heating furnace, raising the temperature to 890-910 DEG C, heating for 300 minutes, setting stepped heat preservation, and cooling; putting the normalized sample into a heating furnace, raising the temperature to 860-880 DEG C, heating for 300 minutes, and setting step heat preservation, quenching and water quenching; and putting the quenched sample into a heating furnace, raising the temperature to 540-600 DEG C, heating for 300 minutes, setting stepped heat preservation, and cooling in water. A scientific and stable heat treatment process is determined for the ZG30CrMnSi alloy steel for the ledge in combination with strict temperature control, a stepped heat preservation system and an excellent cooling condition with water as a medium, and the process enables the material to obtain excellent matching of strength and plasticity, not only ensures high strength, but also has good toughness.

Description

Technical Field

[0001] This invention relates to the field of heat treatment technology for metallic materials, and more specifically, to a heat treatment process for ZG30CrMnSi alloy steel used for channel sides. Background Technology

[0002] As a core piece of equipment in modern coal mining faces, scraper conveyors not only undertake the continuous transport of coal and materials but also provide a stable operating track for the coal mining machine. Their reliability and durability directly affect mining efficiency and production safety. Among the key components of scraper conveyors, the trough side is a structural component that directly bears loads, wear, and impacts; its service life directly affects the overall machine's performance and maintenance costs. Therefore, improving the comprehensive performance of the trough side materials has become an important issue for extending equipment life and ensuring efficient mining.

[0003] Currently, the trench walls are made of ZG30CrMnSi alloy steel. This material requires heat treatment to optimize its mechanical properties, wear resistance, and fatigue resistance to adapt to the complex and harsh working conditions underground. However, the selection and control of parameters during heat treatment significantly affect the final performance. Improper processes can easily lead to uneven microstructure, increased internal defects, decreased toughness, or temper brittleness, thus affecting the service stability and lifespan of the trench walls. Therefore, it is essential to systematically study the effects of key process parameters such as quenching temperature, tempering temperature, holding time, and cooling medium on the material's microstructure and properties. This will allow for the establishment of a scientific, stable, and repeatable heat treatment process to ensure that trench wall components possess high strength and excellent overall performance, meeting the stringent requirements of the coal industry for high reliability and long service life. Summary of the Invention

[0004] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, one aspect of the present invention is to provide a heat treatment process for ZG30CrMnSi alloy steel for channel sides, wherein the heat treatment process specifically includes the following: S1. Normalizing: Place the cast channel blank sample into a heating furnace, heat it to 890℃-910℃ for 300 minutes, set a stepped heat preservation, and then take out the sample and cool it in the air. S2. Quenching: Place the normalized sample into a heating furnace, heat it to 860℃-880℃ for 300 minutes, set a stepped heat preservation to ensure the uniformity of the workpiece temperature, and then take the sample out of the heating furnace for quenching and water quenching. S3. Tempering: Place the quenched sample into a heating furnace, heat it to 540℃-600℃ for 300 minutes, set a stepped heat preservation, and then take out the sample and cool it in water.

[0005] Preferably, the heating furnaces in S1, S2 and S3 employ multi-zone temperature control, use armored thermocouples, have at least three temperature measuring points, and are equipped with circulating fans to ensure airflow within the furnace and to ensure that the temperature difference within the furnace is ≤±5℃.

[0006] Preferably, the heating rate in S1, S2 and S3 is strictly controlled at 80℃ / h-100℃ / h to avoid uneven tissue formation caused by excessively rapid heating.

[0007] Preferably, in step S1, the temperature is cooled to 25°C in air for 600-700 minutes.

[0008] Preferably, in step S2, the water is quenched for 10-15 minutes to 100°C.

[0009] Preferably, in S2, the water quenching adopts a dual-circulation water quenching at 20-25℃, with a cooling rate ≥30℃ / s, to ensure the cooling effect.

[0010] Preferably, in S1, the stepped heat preservation is 350℃ for 60 minutes, 650℃ for 60 minutes, and 890℃-910℃ for 180 minutes; in S2, the stepped heat preservation is 350℃ for 60 minutes, 650℃ for 60 minutes, and 860℃-880℃ for 180 minutes; in S3, the stepped heat preservation is 350℃ for 60 minutes and 540℃-600℃ for 240 minutes, to ensure the uniformity of workpiece temperature.

[0011] Preferably, the temperature fluctuation of the stepped insulation is controlled within ±3℃.

[0012] Preferably, in step S3, the temperature is cooled in water to 100°C for 5-10 minutes to avoid temper brittleness.

[0013] Preferably, the spacing between the cooling samples in S1, S2 and S3 is ≥1.5 times the effective wall thickness of the sample to ensure the cooling effect.

[0014] The beneficial effects of this invention are as follows: By precisely controlling the quenching temperature to 860℃-880℃ and optimizing the tempering temperature to a specific range of 540℃-600℃, combined with strict temperature control, a stepped heat preservation system, and excellent cooling conditions using water as the medium, a scientific and stable heat treatment process has been established for ZG30CrMnSi alloy steel used in the trough sides. This process enables the material to achieve an excellent balance of strength and plasticity, ensuring not only high strength but also good toughness, thereby significantly improving its service performance in the complex downhole environment of high load and strong impact, and effectively extending the service life of the scraper conveyor trough sides.

[0015] In terms of economic efficiency and choice of options, the process developed in this invention is an optimization for the lower-cost ZG30CrMnSi alloy steel. Compared to the traditionally used ZG30MnSiMo steel, which contains the precious alloying element molybdenum (Mo), it effectively reduces the procurement cost of raw material castings while ensuring that the key mechanical properties and service life of the channel sides meet stringent requirements. This provides scraper conveyor manufacturers with a reliable and more cost-effective new material option, helping to enhance the market competitiveness of their products.

[0016] Additional aspects and advantages of the invention will become apparent from the description which follows, or may be learned by practice of the invention. Detailed Implementation

[0017] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0018] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0019] The heating furnace of this invention adopts multi-zone temperature control, uses armored thermocouples, sets at least 3 temperature measuring points, and is equipped with a circulating fan to ensure airflow inside the furnace and ensure that the temperature difference inside the furnace is ≤±5℃.

[0020] Example 1 S1. Normalizing: Place the cast channel blank sample into a heating furnace and heat it to 890℃-910℃ for 300min (the heating rate is strictly controlled at 80℃ / h-100℃ / h). Set a stepped holding temperature of 350℃ for 60min, 650℃ for 60min, and 900℃ for 180min (temperature fluctuation is controlled within ±3℃). Then remove the sample and cool it in air for 600min-700min to 25℃ (the spacing between samples during cooling is ≥1.5 times the effective wall thickness of the sample). S2. Quenching: Place the normalized sample in a heating furnace and heat to 860℃ for 300 min (the heating rate is strictly controlled at 80℃ / h-100℃ / h). Set a stepped holding temperature of 350℃ for 60 min, 650℃ for 60 min, and 860℃ for 180 min (temperature fluctuation is controlled within ±3℃) to ensure the uniformity of the workpiece temperature. Then, remove the sample from the heating furnace and quench it in water for 10-15 min to 100℃ (using 20-25℃ internal and external double-circulation water quenching, cooling rate ≥30℃ / s) (during cooling, the sample placement spacing is ≥1.5 times the effective wall thickness of the sample). S3. Tempering: Place the quenched sample in a heating furnace and heat it to 540℃ for 300 min (the heating rate is strictly controlled at 80℃ / h-100℃ / h). Set a stepped holding temperature of 350℃ for 60 min and 540℃ for 240 min (the temperature fluctuation is controlled within ±3℃). Then take out the sample and cool it in water for 5 min-10 min to 100℃ (the spacing between the sample placements during cooling is ≥1.5 times the effective wall thickness of the sample).

[0021] Example 2 S1. Normalizing: Place the cast channel blank sample into a heating furnace and heat it to 890℃-910℃ for 300min (the heating rate is strictly controlled at 80℃ / h-100℃ / h). Set a stepped holding temperature of 350℃ for 60min, 650℃ for 60min, and 900℃ for 180min (temperature fluctuation is controlled within ±3℃). Then remove the sample and cool it in air for 600min-700min to 25℃ (the spacing between samples during cooling is ≥1.5 times the effective wall thickness of the sample). S2. Quenching: Place the normalized sample in a heating furnace and heat to 860℃ for 300 min (the heating rate is strictly controlled at 80℃ / h-100℃ / h). Set a stepped holding temperature of 350℃ for 60 min, 650℃ for 60 min, and 860℃ for 180 min (temperature fluctuation is controlled within ±3℃) to ensure the uniformity of the workpiece temperature. Then, remove the sample from the heating furnace and quench it in water for 10-15 min to 100℃ (using 20-25℃ internal and external double-circulation water quenching, cooling rate ≥30℃ / s) (during cooling, the sample placement spacing is ≥1.5 times the effective wall thickness of the sample). S3. Tempering: Place the quenched sample in a heating furnace and heat it to 560℃ for 300 min (the heating rate is strictly controlled at 80℃ / h-100℃ / h). Set a stepped holding temperature of 350℃ for 60 min and 560℃ for 240 min (the temperature fluctuation is controlled within ±3℃). Then take out the sample and cool it in water for 5 min-10 min to 100℃ (the spacing between the sample placements during cooling is ≥1.5 times the effective wall thickness of the sample).

[0022] Example 3 S1. Normalizing: Place the cast channel blank sample into a heating furnace and heat it to 890℃-910℃ for 300min (the heating rate is strictly controlled at 80℃ / h-100℃ / h). Set a stepped holding temperature of 350℃ for 60min, 650℃ for 60min, and 900℃ for 180min (temperature fluctuation is controlled within ±3℃). Then remove the sample and cool it in air for 600min-700min to 25℃ (the spacing between samples during cooling is ≥1.5 times the effective wall thickness of the sample). S2. Quenching: Place the normalized sample in a heating furnace and heat to 860℃ for 300 min (the heating rate is strictly controlled at 80℃ / h-100℃ / h). Set a stepped holding temperature of 350℃ for 60 min, 650℃ for 60 min, and 860℃ for 180 min (temperature fluctuation is controlled within ±3℃) to ensure the uniformity of the workpiece temperature. Then, remove the sample from the heating furnace and quench it in water for 10-15 min to 100℃ (using 20-25℃ internal and external double-circulation water quenching, cooling rate ≥30℃ / s) (during cooling, the sample placement spacing is ≥1.5 times the effective wall thickness of the sample). S3. Tempering: Place the quenched sample in a heating furnace and heat it to 580℃ for 300 min (the heating rate is strictly controlled at 80℃ / h-100℃ / h). Set a stepped holding temperature of 350℃ for 60 min and 580℃ for 240 min (the temperature fluctuation is controlled within ±3℃). Then take out the sample and cool it in water for 5 min-10 min to 100℃ (the spacing between the sample placements during cooling is ≥1.5 times the effective wall thickness of the sample).

[0023] Example 4 S1. Normalizing: Place the cast channel blank sample into a heating furnace and heat it to 890℃-910℃ for 300min (the heating rate is strictly controlled at 80℃ / h-100℃ / h). Set a stepped holding temperature of 350℃ for 60min, 650℃ for 60min, and 900℃ for 180min (temperature fluctuation is controlled within ±3℃). Then remove the sample and cool it in air for 600min-700min to 25℃ (the spacing between samples during cooling is ≥1.5 times the effective wall thickness of the sample). S2. Quenching: Place the normalized sample in a heating furnace and heat to 860℃ for 300 min (the heating rate is strictly controlled at 80℃ / h-100℃ / h). Set a stepped holding temperature of 350℃ for 60 min, 650℃ for 60 min, and 860℃ for 180 min (temperature fluctuation is controlled within ±3℃) to ensure the uniformity of the workpiece temperature. Then, remove the sample from the heating furnace and quench it in water for 10-15 min to 100℃ (using 20-25℃ internal and external double-circulation water quenching, cooling rate ≥30℃ / s) (during cooling, the sample placement spacing is ≥1.5 times the effective wall thickness of the sample). S3. Tempering: Place the quenched sample in a heating furnace and heat it to 600℃ for 300 min (the heating rate is strictly controlled at 80℃ / h-100℃ / h). Set a stepped holding temperature of 350℃ for 60 min and 600℃ for 240 min (the temperature fluctuation is controlled within ±3℃). Then take out the sample and cool it in water for 5 min-10 min to 100℃ (the spacing between the sample placements during cooling is ≥1.5 times the effective wall thickness of the sample).

[0024] The chemical composition and mechanical properties of Examples 1 to 4 were tested, and the results are shown in Tables 1 and 2 below.

[0025] Table 1. Comparison of Chemical Composition Detection Results of Embodiments of the Invention Table 2. Comparison of Mechanical Performance Test Results of Embodiments of the Invention In summary, the mechanical properties of the samples in the embodiments of the present invention all exceed the requirements, and the performance of the samples after heat treatment is qualified.

[0026] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the invention by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the invention should be included within the scope of protection of the invention.

Claims

1. A heat treatment process for ZG30CrMnSi alloy steel used for channel sides, characterized in that: The heat treatment process specifically includes the following: S1. Normalizing: Place the cast channel blank sample into a heating furnace, heat it to 890℃-910℃ for 300 minutes, set a stepped heat preservation, and then take out the sample and cool it in the air. S2. Quenching: Place the normalized sample into a heating furnace, heat it to 860℃-880℃ for 300 minutes, set a stepped heat preservation to ensure the uniformity of the workpiece temperature, and then take the sample out of the heating furnace for quenching and water quenching. S3. Tempering: Place the quenched sample into a heating furnace, heat it to 540℃-600℃ for 300 minutes, set a stepped heat preservation, and then take out the sample and cool it in water.

2. The heat treatment process for ZG30CrMnSi alloy steel for channel sides according to claim 1, characterized in that: The heating furnaces in S1, S2 and S3 adopt multi-zone temperature control, use armored thermocouples, set at least 3 temperature measuring points, and are equipped with circulating fans to ensure airflow inside the furnace and ensure that the temperature difference inside the furnace is ≤±5℃.

3. The heat treatment process for ZG30CrMnSi alloy steel used for channel sides according to claim 1, characterized in that: The temperature rise in S1, S2 and S3 is strictly controlled at a rate of 80℃ / h-100℃ / h.

4. The heat treatment process for ZG30CrMnSi alloy steel used for channel sides according to claim 1, characterized in that: In S1, the temperature is cooled to 25°C in air for 600-700 minutes.

5. The heat treatment process for ZG30CrMnSi alloy steel for channel sides according to claim 1, characterized in that: The S2 is water-quenched for 10-15 minutes to 100°C.

6. The heat treatment process for ZG30CrMnSi alloy steel for channel sides according to claim 1, characterized in that: The water quenching in S2 adopts a double-circulation water quenching method with an internal and external temperature of 20-25℃ and a cooling rate of ≥30℃ / s.

7. The heat treatment process for ZG30CrMnSi alloy steel for channel sides according to claim 1, characterized in that: The step-temperature insulation in S1 is 350℃ for 60 minutes, 650℃ for 60 minutes, and 890℃-910℃ for 180 minutes; the step-temperature insulation in S2 is 350℃ for 60 minutes, 650℃ for 60 minutes, and 860℃-880℃ for 180 minutes; the step-temperature insulation in S3 is 350℃ for 60 minutes and 540℃-600℃ for 240 minutes, to ensure the uniformity of workpiece temperature.

8. The heat treatment process for ZG30CrMnSi alloy steel for channel sides according to claim 7, characterized in that: The temperature fluctuation of the stepped insulation is controlled within ±3℃.

9. The heat treatment process for ZG30CrMnSi alloy steel for channel sides according to claim 1, characterized in that: In step S3, the water is cooled to 100°C for 5-10 minutes.

10. The heat treatment process for ZG30CrMnSi alloy steel for channel sides according to claim 1, characterized in that: The spacing between the cooled samples in S1, S2 and S3 is ≥1.5 times the effective wall thickness of the sample.

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