Heat treatment method suitable for hot-rolled round steel for 35MnBM track connecting piece

Abstract

The invention discloses a heat treatment method suitable for hot-rolled round steel for a 35MnBM track connecting piece, which comprises the following steps: (1) normalizing: putting a rough-machined hot-rolled round steel blank sample for the 35MnBM track connecting piece into a heating furnace, heating to 860-880 DEG C, preserving heat for 110 minutes, and then cooling in air; and (2) end quenching: putting the normalized sample into a heating furnace, heating to 820-830 DEG C, preserving heat for 70 minutes, then taking out the sample, and quenching in water. The method provided by the invention is more suitable for heat treatment of the hot-rolled round steel for the 35MnBM track connecting piece, and can provide the hot-rolled round steel for the 35MnBM track connecting piece with more excellent comprehensive mechanical properties, so that the service life of the hot-rolled round steel is remarkably prolonged, and the use safety of the hot-rolled round steel is remarkably improved.

Description

Technical Field

[0001] The invention belongs to the technical field of hot-rolled round steel manufacturing for crawler track connectors, and in particular relates to a heat treatment method suitable for hot-rolled round steel for 35MnBM crawler track connectors. Background Art

[0002] 35MnBM track connectors are one of the key components in construction machinery that withstands heavy loads and complex working conditions, so their steel must have excellent mechanical properties, including high strength, good toughness and durability. With the continuous development of global infrastructure construction and construction machinery markets, the demand for higher performance and higher quality 35MnBM track connectors continues to increase. For heat-treated steel, the product performance is stronger than hot-rolled steel, so developing a heat treatment method for hot-rolled round steel for 35MnBM track connectors is crucial to improving its mechanical properties.

[0003] At present, a heat treatment process suitable for hot-rolled round steel (40Mn2M alloy steel) for track links has been developed (see document CN118703759A, hereinafter referred to as document 1), which includes (1) normalizing: placing the rough-machined hot-rolled round steel blank sample for track links in a heating furnace, heating it to 865°C-885°C, keeping it warm for 120 minutes, and then cooling it in air; and (2) end quenching: placing the normalized sample in a heating furnace, heating it to 845-855°C, keeping it warm for 50 minutes, then taking the sample out and quenching it in water. The performance indicators of the hot-rolled round steel for track links treated by the heat treatment process disclosed in document 1 are all higher than the index requirements. A heat treatment process suitable for 45BM hot-rolled round steel for engineering machinery track connectors has also been developed (see document CN118480647A, hereinafter referred to as document 2), which includes (1) normalizing: placing the rough-processed 45BM hot-rolled round steel blank for engineering machinery track connectors in a heating furnace, heating it to 860°C-880°C, keeping it warm for 120 minutes, and then cooling it in air; and (2) end quenching: placing the normalized sample in a heating furnace, heating it to 840-850°C, keeping it warm for 50 minutes, then taking the sample out and quenching it in water. The performance indicators of the 45BM hot-rolled round steel for engineering machinery track connectors treated by the heat treatment process disclosed in document 2 are all higher than the index requirements. However, the inventors found that when the heat treatment processes disclosed in the above-mentioned documents 1 and 2 were applied to hot-rolled round steel for 35MnBM track connectors, the improvement in its mechanical properties (relative to the heat treatment system disclosed in the embodiment of patent document CN118480725A (hereinafter referred to as document 3)) was limited. Summary of the invention

[0004] The object of the present invention is to provide a heat treatment method suitable for hot-rolled round steel for 35MnBM track connectors, so that it has better comprehensive mechanical properties, impact toughness and / or hardenability, thereby further significantly improving the overall life and safety of the hot-rolled round steel for 35MnBM track connectors.

[0005] The specific technical solutions of the present invention are as follows:

[0006] The present invention provides a heat treatment method for hot-rolled round steel for 35MnBM crawler connectors, wherein the hot-rolled round steel for 35MnBM crawler connectors is produced by the production method disclosed in patent document CN118480725A, wherein the heat treatment method comprises:

[0007] (1) Normalizing: Place the rough-machined 35MnBM track connector hot-rolled round steel blank into a heating furnace, heat it to 860°C to 880°C, keep it at that temperature for 110 minutes, and then cool it in air; and

[0008] (2) End quenching: Place the normalized sample into a heating furnace, heat it to 820-830°C, keep it warm for 70 minutes, then take out the sample and quench it in water.

[0009] In some embodiments, the heat treatment method comprises:

[0010] (1) Normalizing: Place the rough-machined 35MnBM track connector hot-rolled round steel blank into a heating furnace, heat it to 860°C, keep it at this temperature for 110 minutes, and then cool it in air; and

[0011] (2) End quenching: Place the normalized sample into a heating furnace, heat it to 820°C, keep it warm for 70 minutes, then take out the sample and quench it in water.

[0012] In some embodiments, the heat treatment method comprises:

[0013] (1) Normalizing: Place the rough-machined 35MnBM track connector hot-rolled round steel blank into a heating furnace, heat it to 880°C, keep it at this temperature for 110 minutes, and then cool it in air; and

[0014] (2) End quenching: Place the normalized sample into a heating furnace, heat it to 830°C, keep it warm for 70 minutes, then take out the sample and quench it in water.

[0015] In some embodiments, the heat treatment method comprises:

[0016] (1) Normalizing: Place the rough-machined 35MnBM track connector hot-rolled round steel blank into a heating furnace, heat it to 870°C, keep it at this temperature for 110 minutes, and then cool it in air; and

[0017] (2) End quenching: Place the normalized sample into a heating furnace, heat it to 825°C, keep it warm for 70 minutes, then take out the sample and quench it in water.

[0018] In some embodiments, the mechanical properties of the heat-treated 35MnBM track connector hot-rolled round steel meet the following requirements: P0.2 ≥794MPa, R m ≥976MPa, A≥12.0%, Z≥55%.

[0019] In some embodiments, the end hardenability (HRC) of the heat-treated 35MnBM hot-rolled round steel for track connectors meets the following requirements: J1.5 is between 51 and 57 HRC, J13 is between 42 and 50 HRC, and J19 is between 28 and 40.

[0020] The beneficial effect of the present invention is as follows: the present invention provides a heat treatment method suitable for hot-rolled round steel for 35MnBM track connectors by studying the influence of heat treatment heating system, including normalizing temperature, quenching temperature and holding time, on the structure and performance of hot-rolled round steel for 35MnBM track connectors, which can further improve the comprehensive mechanical properties, impact toughness and / or hardenability of hot-rolled round steel for 35MnBM track connectors, thereby further significantly improving the overall life and safety of hot-rolled round steel for 35MnBM track connectors. DETAILED DESCRIPTION

[0021] The following specific examples are used to explain the present invention in detail. The examples are intended to help understand the present invention, but are not intended to limit the present invention. The production method of the 35MnBM hot-rolled round steel for track connectors involved in the following examples is carried out according to the above document 3.

[0022] The heat treatment method for hot-rolled round steel for 35MnBM crawler connector provided by the present invention comprises:

[0023] (1) Normalizing: Place the rough-machined 35MnBM track connector hot-rolled round steel blank into a heating furnace, heat it to 860°C to 880°C, keep it at that temperature for 110 minutes, and then cool it in air; and

[0024] (2) End quenching: Place the normalized sample into a heating furnace, heat it to 820-830°C, keep it warm for 70 minutes, then take out the sample and quench it in water.

[0025] After heat treatment, the rough-machined blank samples are fine-machined and various performance tests are carried out.

[0026] Embodiment 1:

[0027] This embodiment is directed to the heat treatment of the 35MnBM hot-rolled round steel for track connectors produced in Example 1 of the above document 3, specifically comprising:

[0028] (1) Normalizing: Place the rough-processed 35MnBM track connector hot-rolled round steel blank into a heating furnace, heat it to 860°C, keep it warm for 110 minutes, and then cool it in air;

[0029] (2) End quenching: Place the normalized sample into a heating furnace, heat it to 820°C, keep it warm for 70 minutes, then take out the sample and quench it in water.

[0030] Embodiment 2:

[0031] This embodiment is directed to the heat treatment of the 35MnBM hot-rolled round steel for track connectors produced in Example 2 of the above document 3, specifically comprising:

[0032] (1) Normalizing: Place the rough-processed 35MnBM track connector hot-rolled round steel blank into a heating furnace, heat it to 880°C, keep it warm for 110 minutes, and then cool it in air;

[0033] (2) End quenching: Place the normalized sample into a heating furnace, heat it to 830°C, keep it warm for 70 minutes, then take out the sample and quench it in water.

[0034] Embodiment 3:

[0035] This embodiment is directed to the heat treatment of the 35MnBM hot-rolled round steel for track connectors produced in Example 3 of the above document 3, specifically comprising:

[0036] (1) Normalizing: Place the rough-processed 35MnBM track connector hot-rolled round steel blank into a heating furnace, heat it to 870°C, keep it warm for 110 minutes, and then cool it in air;

[0037] (2) End quenching: Place the normalized sample into a heating furnace, heat it to 825°C, keep it warm for 70 minutes, then take out the sample and quench it in water.

[0038] Comparative Example 1

[0039] Comparative Example 1 is directed to the heat treatment of the 35MnBM track connector hot-rolled round steel produced in Example 1 of the above document 3, specifically comprising:

[0040] (1) Normalizing: Place the rough-processed 35MnBM track connector hot-rolled round steel blank into a heating furnace, heat it to 860°C, keep it warm for 120 minutes, and then cool it in air;

[0041] (2) End quenching: Place the normalized sample into a heating furnace, heat it to 840°C, keep it warm for 50 minutes, then take out the sample and quench it in water.

[0042] Comparative Example 2

[0043] Comparative Example 2 is directed to the heat treatment of the 35MnBM track connector hot-rolled round steel produced in Example 2 of the above document 3, specifically comprising:

[0044] (1) Normalizing: Place the rough-processed 35MnBM track connector hot-rolled round steel blank into a heating furnace, heat it to 880°C, keep it warm for 120 minutes, and then cool it in air;

[0045] (2) End quenching: Place the normalized sample into a heating furnace, heat it to 850°C, keep it warm for 50 minutes, then take out the sample and quench it in water.

[0046] After the heat treatment is completed, the rough-machined blank samples of Examples 1-3 and Comparative Examples 1-2 are finely machined and various performance tests are carried out. The test results are shown in Tables 1 and 2 below. It can be seen from Tables 1 and 2 that the various performance indicators of the 35MnBM track connector hot-rolled round steel of each embodiment and comparative example are higher than the index requirements, and the performance of the samples after heat treatment is qualified. However, compared with Comparative Examples 1-2, the various performance indicators of the 35MnBM track connector hot-rolled round steel after heat treatment in Examples 1-3 are significantly higher. These results show that the heat treatment method provided by the present invention is more suitable for the heat treatment of 35MnBM track connector hot-rolled round steel, which can provide 35MnBM track connector hot-rolled round steel with better comprehensive mechanical properties, thereby significantly improving its service life and safety of use.

[0047] Table 1: Mechanical properties at room temperature after heat treatment

[0048]

[0049] Table 2: End hardenability after heat treatment

[0050]

[0051] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A heat treatment method for 35MnBM hot-rolled round steel for crawler connectors, wherein the 35MnBM hot-rolled round steel for crawler connectors is produced by the production method disclosed in patent document CN118480725A, characterized in that: The heat treatment method comprises: (1) Normalizing: Place the rough-machined 35MnBM track connector hot-rolled round steel blank into a heating furnace, heat it to 860°C to 880°C, keep it at that temperature for 110 minutes, and then cool it in air; and (2) End quenching: Place the normalized sample into a heating furnace, heat it to 820-830°C, keep it warm for 70 minutes, then take out the sample and quench it in water.

2. The heat treatment method according to claim 1, characterized in that The heat treatment method comprises: (1) Normalizing: Place the rough-machined 35MnBM track connector hot-rolled round steel blank into a heating furnace, heat it to 860°C, keep it at this temperature for 110 minutes, and then cool it in air; and (2) End quenching: Place the normalized sample into a heating furnace, heat it to 820°C, keep it warm for 70 minutes, then take out the sample and quench it in water.

3. The heat treatment method according to claim 1, characterized in that: The heat treatment method comprises: (1) Normalizing: Place the rough-machined 35MnBM track connector hot-rolled round steel blank into a heating furnace, heat it to 880°C, keep it at this temperature for 110 minutes, and then cool it in air; and (2) End quenching: Place the normalized sample into a heating furnace, heat it to 830°C, keep it warm for 70 minutes, then take out the sample and quench it in water.

4. The heat treatment method according to claim 1, characterized in that: The heat treatment method comprises: (1) Normalizing: Place the rough-machined 35MnBM track connector hot-rolled round steel blank into a heating furnace, heat it to 870°C, keep it at this temperature for 110 minutes, and then cool it in air; and (2) End quenching: Place the normalized sample into a heating furnace, heat it to 825°C, keep it warm for 70 minutes, then take out the sample and quench it in water.

5. The heat treatment method according to any one of claims 1 to 4, characterized in that: The mechanical properties of the heat-treated 35MnBM hot-rolled round steel for track connectors meet the following requirements: P0.2 ≥794MPa, R m ≥976MPa, A≥12.0%, Z≥55%.

6. The heat treatment method according to any one of claims 1 to 5, characterized in that: The end hardenability (HRC) of the hot-rolled round steel for 35MnBM track connectors after heat treatment meets the following requirements: J1.5 is between 51 and 57 HRC, J13 is between 42 and 50 HRC, and J19 is between 28 and 40.

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