A manufacturing process of double hardness hammer head

Abstract

The present invention relates to the technical field of double hardness hammer heads, specifically to a manufacturing process of double hardness hammer heads, comprising: pouring molten steel into a sand mold after refining treatment, taking out the casting after cooling, and obtaining a rough hammer head; hanging the rough hammer head on a hanger and moving it into an insulation shell for normalizing heat treatment, and air cooling to room temperature; adjusting the working part of the rough hammer head to be located at the position of the electromagnetic heater of group A, heating the working part, then moving the working part down to the quenching oil, cooling the oil to room temperature, repeating the above operation, and performing cyclic quenching; removing the rough hammer head from the hanger, and performing surface treatment on the working part; hanging the rough hammer head after surface treatment on the hanger again, moving the working part to the position of the electromagnetic heater of group A, performing tempering heat treatment, and then moving it out of the insulation shell, air cooling to room temperature, and obtaining a double hardness hammer head. The present invention improves the overall quality of the working part of the hammer head through the cooperation of cyclic quenching / rare earth nitriding / tempering stress relief process.

Description

Technical Field

[0001] The invention relates to the technical field of double-hardness hammer heads, in particular to a manufacturing process of double-hardness hammer heads. Background Art

[0002] Hammer crusher is a machine that uses high-speed rotating hammers to impact materials, causing them to break along their natural cracks, bedding planes, joint planes and other fragile parts. According to its working characteristics, the head of the crusher hammer must have high wear resistance, and the hammer handle must have good impact resistance.

[0003] At present, for the manufacture of an integrated double-hardness hammer head, molten steel is poured into a sand mold to form a hammer head casting, the hammer head is first heated as a whole, and then the head of the hammer head is quenched and tempered separately, so that the head of the hammer head has good hardness and the handle has good toughness. In this way, the hardness and toughness of the handle and head of the hammer head are different to meet the working requirements of the hammer head. However, using the above-mentioned manufacturing method, although the head of the obtained hammer head has good hardness, its toughness deviation will cause cracks during long-term use, eventually leading to damage to the hammer head, which seriously shortens the service life of the hammer head. Based on this, a manufacturing process for a double-hardness hammer head is proposed. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention provides a manufacturing process for a double-hardness hammer head, which improves the overall quality of the working part of the hammer head through the cooperation of cyclic quenching / rare earth nitriding / tempering stress relief processes.

[0005] To achieve the above object, the present invention provides the following technical solution: a manufacturing process of a double-hardness hammer head, comprising the following steps:

[0006] (1) After refining, the molten steel is poured into a sand mold, the casting is taken out after cooling, and the pouring head is removed to obtain a rough hammer head;

[0007] (2) The rough blank hammer head is hung on a hanger and moved into an insulation shell for normalizing heat treatment, then removed from the insulation shell and air-cooled to room temperature;

[0008] (3) The working part of the rough billet hammer is adjusted to be located at the position of the electromagnetic heater of group A, and its mounting part is exposed to the external environment, the working part is heated, and then the working part is moved down to penetrate into the quenching oil, and the oil is cooled to room temperature, and the above operation is repeated to perform cyclic quenching;

[0009] (4) Remove the rough hammer head from the hanger and perform surface treatment on its working part;

[0010] (5) The rough hammer head after surface treatment is hung on the hanger again, and its working part is moved to the position of the electromagnetic heater of group A for tempering heat treatment, and then removed from the insulation shell and air-cooled to room temperature to obtain a double hardness hammer head.

[0011] Preferably, in step (1), the molten steel comprises the following composition, by mass percentage: C 0.3-0.6%, Si 0.5-1.5%, Mn 0.6-0.8%, Cr 1.2-3.5%, Ni 0.5-1.5%, Mo 0.2-0.8%, V 0.1-0.2%, Al0.02-0.04%, Zr 0.02-0.04%, P<0.01%, S<0.01%, and the balance is Fe and unavoidable impurities.

[0012] Preferably, in step (2), the normalizing heat treatment is performed by using electromagnetic heaters of group A and group B to heat the rough blank hammer head to 830-850°C at a rate of 40-50°C / min, and keeping the temperature for 4-5.5h.

[0013] Preferably, in step (3), the cyclic quenching includes three stages, specifically: the first stage is to heat the working part of the rough billet hammer to 825°C and keep it warm for 30 minutes for oil quenching; the second stage is to heat the working part of the rough billet hammer to 825°C and keep it warm for 5 minutes for oil quenching; the third stage is to heat the working part of the rough billet hammer to 835°C and keep it warm for 3 minutes for oil quenching.

[0014] Preferably, in step (4), the surface treatment is specifically as follows: the mounting portion of the rough hammer head is wrapped and covered to expose the working portion, and then it is sent into a plasma nitriding furnace, and rare earth is placed in the furnace for nitriding treatment.

[0015] Preferably, the nitriding treatment temperature is controlled to be 450° C., the nitriding treatment time is 4 hours, the nitrogen flow rate is 0.1 L / min, and the hydrogen flow rate is 0.4 L / min.

[0016] Preferably, the rare earth is lanthanum-cerium rare earth chloride, wherein the lanthanum content is 33% and the cerium content is 66%.

[0017] Preferably, in step (5), the tempering heat treatment is to heat the working part of the rough hammer head to 220-230° C. and keep it warm for 2-3 hours.

[0018] Preferably, in steps (2), (3) and (5), during the normalizing heat treatment, the heating stage of the cyclic quenching and the tempering heat treatment, the insulation shell is sealed with a seal.

[0019] Preferably, the sealing member is composed of an upper sealing plate with a notch, a lower sealing plate, and a connecting rod bridging the upper sealing plate and the lower sealing plate.

[0020] The present invention provides a manufacturing process for a double-hardness hammer head, which has the following beneficial effects compared with the prior art:

[0021] The present invention performs cyclic quenching treatment on the working part of the hammer head, so that the martensitic needles in the alloy structure are finer, the grains are further refined and uniform, and the hardness and strength of the hammer head are improved; after the cyclic quenching, the working part is subjected to surface rare earth nitriding treatment. Since the martensitic structure is formed after quenching, nitrogen atoms are not easy to penetrate into the interior of the alloy structure. Through the catalytic penetration of the rare earth, nitrides can be embedded on the surface of the structure, and the hardness can be further improved without affecting the toughness of the working part of the hammer head; after the quenching and nitriding treatment, a high-hardness martensitic structure is obtained, but the internal stress is high, and the internal stress of the martensitic structure can be eliminated through tempering treatment; that is, the present invention improves the overall quality of the working part of the hammer head through the cooperation of cyclic quenching / rare earth nitriding / tempering stress relief process.

[0022] The present invention uses a heat treatment device for a double-hardness hammer head in conjunction with the cyclic quenching process of the hammer head, so that the heating and oil cooling of the working part of the hammer head are located in the same process, thereby improving the efficiency of the cyclic quenching; at the same time, the coordinated use of the insulation shell and the seal can effectively reduce the loss of heat, thereby achieving the effect of saving energy consumption and reducing production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0024] Figure 1 This is a diagram of the organizational morphology of the hammer working part in Example 4 of the present invention;

[0025] Figure 2 It is a schematic diagram of the structure of the heat treatment equipment of the present invention;

[0026] Figure 3 This is a schematic diagram of the positions of the hammer head and the insulation shell during normalizing of the present invention;

[0027] Figure 4 This is a schematic diagram of the positions of the hammer head and the insulation shell during cyclic quenching of the present invention;

[0028] Figure 5 It is a schematic diagram of the sealing structure of the present invention. DETAILED DESCRIPTION

[0029] The following examples are used to explain the implementation methods of the present application in detail, so that the implementation process of how the present application uses technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly.

[0030] Example 1

[0031] A heat treatment device for a double-hardness hammer head, including a quenching pool and a mounting frame arranged beside the quenching pool, wherein quenching oil is poured into the quenching pool, and a circulation pipe is connected to the quenching pool. The quenching oil in the pool can be circulated by the drive of an external force pump to prevent the local temperature of the quenching oil from being too high and affecting the quenching effect. Several groups of insulation shells are fixedly installed on the mounting frame, and the upper and lower parts of the inner walls of the insulation shells are respectively installed with group A electromagnetic heaters and group B electromagnetic heaters. A seal can also be movably arranged on the mounting frame, and the seal consists of an upper sealing plate with a notch, a lower sealing plate, and a connecting rod bridging the upper sealing plate and the lower sealing plate. The notch is provided for the installation part of the hanger and the hammer head to pass through.

[0032] During the normalizing heat treatment, the rough billet hammer head is hung on the hanger and moved into the insulation shell, and then the top and bottom of the insulation shell are sealed with seals. Then the electromagnetic heaters group A and group B are started to heat the working part and the installation part of the rough billet hammer head together, which can reduce heat loss and thus reduce energy consumption.

[0033] During the cyclic quenching treatment, since the working part only needs to be heated and oil-cooled multiple times, only the electromagnetic heater group A needs to be started, and the installation part of the rough hammer head can be controlled to extend out of the insulation shell, so that the working part is located in the electromagnetic heater group A in the insulation shell, and then sealed with a seal. This structural setting can not only avoid the temperature rise of the installation part, but also use only a single electromagnetic heater group to heat the working part, reduce energy consumption, and save costs.

[0034] During the tempering treatment, the working part of the rough hammer head is heated and kept warm by using a group A electromagnetic heater, and is sealed by a seal during the treatment.

[0035] Example 2

[0036] A manufacturing process of a double-hardness hammer head comprises the following steps:

[0037] (1) After refining, the molten steel is poured into a sand mold, the casting is taken out after cooling, and the pouring head is removed to obtain a rough hammer head;

[0038] The molten steel includes the following composition, in percentage by mass: C 0.6%, Si 0.5%, Mn 0.8%, Cr 1.2%, Ni 1.5%, Mo 0.2%, V 0.2%, Al 0.02%, Zr 0.04%, P < 0.01%, S < 0.01%, and the balance is Fe and unavoidable impurities.

[0039] (2) The rough-blank hammer head is hung on a hanger and moved into an insulation shell for normalizing heat treatment (during which the insulation shell is sealed with a sealant), that is, the rough-blank hammer head is heated to 850°C at a rate of 40°C / min using the electromagnetic heaters of group A and group B, and kept warm for 4 hours, then removed from the insulation shell and air-cooled to room temperature.

[0040] (3) The working part of the rough blank hammer is adjusted to be located at the position of the electromagnetic heater of group A, and its mounting part is exposed to the external environment, and the working part is heated (during which the insulation shell is sealed with a seal), and then the working part is moved down to penetrate into the quenching oil, and the oil is cooled to room temperature, and the above operation is repeated to perform cyclic quenching;

[0041] The cyclic quenching includes three stages, specifically: the first stage is that the working part of the rough billet hammer is heated to 825°C and kept warm for 30 minutes for oil quenching; the second stage is that the working part of the rough billet hammer is heated to 825°C and kept warm for 5 minutes for oil quenching; the third stage is that the working part of the rough billet hammer is heated to 835°C and kept warm for 3 minutes for oil quenching.

[0042] (4) Remove the rough hammer head from the hanger and perform surface treatment on its working part, that is, wrap and cover the mounting part of the rough hammer head (it can be covered with aluminum foil) to expose the working part, and then send it into a plasma nitriding furnace, and place lanthanum cerium rare earth chloride (lanthanum content is 33%, cerium content is 66%) in the furnace for nitriding treatment.

[0043] The nitriding treatment temperature was controlled to be 450°C, the nitriding treatment time was 4h, the nitrogen flow rate was 0.1L / min, and the hydrogen flow rate was 0.4L / min.

[0044] (5) The rough hammer head that has undergone surface treatment is re-suspended on the hanger so that its working part is moved to the position of the electromagnetic heater of group A for tempering heat treatment (during which the insulation shell is sealed with a sealant), that is, the working part of the rough hammer head is heated to 230°C and kept warm for 2 hours, then removed from the insulation shell and air-cooled to room temperature to obtain a double hardness hammer head.

[0045] Example 3

[0046] A manufacturing process of a double-hardness hammer head comprises the following steps:

[0047] (1) After refining, the molten steel is poured into a sand mold, the casting is taken out after cooling, and the pouring head is removed to obtain a rough hammer head;

[0048] The molten steel includes the following composition, in percentage by mass: C 0.3%, Si 1.5%, Mn 0.6%, Cr 3.5%, Ni0.5%, Mo 0.8%, V 0.1%, Al 0.04%, Zr 0.02%, P<0.01%, S<0.01%, and the balance is Fe and inevitable impurities.

[0049] (2) The rough-blank hammer head is hung on a hanger and moved into an insulation shell for normalizing heat treatment (during which the insulation shell is sealed with a sealant), that is, the rough-blank hammer head is heated to 830°C at a rate of 50°C / min using the electromagnetic heaters of group A and group B, and kept warm for 5.5 hours, then removed from the insulation shell and air-cooled to room temperature.

[0050] (3) The working part of the rough blank hammer is adjusted to be located at the position of the electromagnetic heater of group A, and its mounting part is exposed to the external environment, and the working part is heated (during which the insulation shell is sealed with a seal), and then the working part is moved down to penetrate into the quenching oil, and the oil is cooled to room temperature, and the above operation is repeated to perform cyclic quenching;

[0051] The cyclic quenching includes three stages, specifically: the first stage is that the working part of the rough billet hammer is heated to 825°C and kept warm for 30 minutes for oil quenching; the second stage is that the working part of the rough billet hammer is heated to 825°C and kept warm for 5 minutes for oil quenching; the third stage is that the working part of the rough billet hammer is heated to 835°C and kept warm for 3 minutes for oil quenching.

[0052] (4) Remove the rough hammer head from the hanger and perform surface treatment on its working part, that is, wrap and cover the mounting part of the rough hammer head (it can be covered with aluminum foil) to expose the working part, and then send it into a plasma nitriding furnace, and place lanthanum cerium rare earth chloride (lanthanum content is 33%, cerium content is 66%) in the furnace for nitriding treatment.

[0053] The nitriding treatment temperature was controlled to be 450°C, the nitriding treatment time was 4h, the nitrogen flow rate was 0.1L / min, and the hydrogen flow rate was 0.4L / min.

[0054] (5) The rough hammer head that has undergone surface treatment is re-suspended on the hanger so that its working part is moved to the position of the electromagnetic heater of group A for tempering heat treatment (during which the insulation shell is sealed with a sealant), that is, the working part of the rough hammer head is heated to 220°C and kept warm for 3 hours, then removed from the insulation shell and air-cooled to room temperature to obtain a double hardness hammer head.

[0055] Example 4

[0056] A manufacturing process of a double-hardness hammer head comprises the following steps:

[0057] (1) After refining, the molten steel is poured into a sand mold, the casting is taken out after cooling, and the pouring head is removed to obtain a rough hammer head;

[0058] In terms of mass percentage, the molten steel includes the following composition: C 05%, Si 1.2%, Mn 0.7%, Cr 2.5%, Ni1.2%, Mo 0.5%, V 0.15%, Al 0.03%, Zr 0.03%, P<0.01%, S<0.01%, and the balance is Fe and inevitable impurities.

[0059] (2) The rough-blank hammer head is hung on a hanger and moved into an insulation shell for normalizing heat treatment (during which the insulation shell is sealed with a sealant), that is, the rough-blank hammer head is heated to 840°C at a rate of 45°C / min using the electromagnetic heaters of group A and group B, and kept warm for 5 hours, then removed from the insulation shell and air-cooled to room temperature.

[0060] (3) The working part of the rough blank hammer is adjusted to be located at the position of the electromagnetic heater of group A, and its mounting part is exposed to the external environment, and the working part is heated (during which the insulation shell is sealed with a seal), and then the working part is moved down to penetrate into the quenching oil, and the oil is cooled to room temperature, and the above operation is repeated to perform cyclic quenching;

[0061] The cyclic quenching includes three stages, specifically: the first stage is that the working part of the rough billet hammer is heated to 825°C and kept warm for 30 minutes for oil quenching; the second stage is that the working part of the rough billet hammer is heated to 825°C and kept warm for 5 minutes for oil quenching; the third stage is that the working part of the rough billet hammer is heated to 835°C and kept warm for 3 minutes for oil quenching.

[0062] (4) Remove the rough hammer head from the hanger and perform surface treatment on its working part, that is, wrap and cover the mounting part of the rough hammer head (it can be covered with aluminum foil) to expose the working part, and then send it into a plasma nitriding furnace, and place lanthanum cerium rare earth chloride (lanthanum content is 33%, cerium content is 66%) in the furnace for nitriding treatment.

[0063] The nitriding treatment temperature was controlled to be 450°C, the nitriding treatment time was 4h, the nitrogen flow rate was 0.1L / min, and the hydrogen flow rate was 0.4L / min.

[0064] (5) The rough hammer head that has undergone surface treatment is re-suspended on the hanger so that its working part is moved to the position of the electromagnetic heater of group A for tempering heat treatment (during which the insulation shell is sealed with a sealant), that is, the working part of the rough hammer head is heated to 225°C and kept warm for 2.5 hours, then removed from the insulation shell and air-cooled to room temperature to obtain a double hardness hammer head.

[0065] Comparative Example 1

[0066] A manufacturing process for a dual-hardness hammer head, steps (1)-(2) and steps (4)-(5) are the same as those in Example 4, except for step (3).

[0067] Specifically: adjust the working part of the rough billet hammer to the position of the electromagnetic heater in group A, expose its installation part to the external environment, heat the working part (use seals to seal the insulation shell during this period), then move the working part down to the quenching oil, and cool the oil to room temperature.

[0068] Comparative Example 2

[0069] A manufacturing process for a dual-hardness hammer head, steps (1)-(3) and step (5) are the same as those in Example 4, except for step (4).

[0070] Specifically, the rough hammer head is removed from the hanger, and the working part thereof is subjected to surface treatment, which is a simple cleaning and drying treatment.

[0071] Comparative Example 3

[0072] A manufacturing process for a dual-hardness hammer head, steps (1)-(3) and step (5) are the same as those in Example 4, except for step (4).

[0073] Remove the rough hammer from the hanger and perform surface treatment on its working part, that is, wrap and cover the installation part of the rough hammer (can be covered with aluminum foil) to expose the working part, and then send it into the plasma nitriding furnace for nitriding treatment. The nitriding treatment temperature is controlled to be 450℃, the nitriding treatment time is 4h, the nitrogen flow rate is 0.1L / min, and the hydrogen flow rate is 0.4L / min.

[0074] Quality Inspection

[0075] 1. The dual hardness hammers prepared in Examples 2-4 and Comparative Examples 1-3 were tested. The hardness was tested according to the standard of GB / T230.1-2004; the impact toughness was tested according to the standard of GB / T 229-1994; the tensile strength, yield strength and elongation were tested according to the standard of GB / T 228-2002. The specific test results are shown in the following table.

[0076] Table 1 Hardness and impact toughness

[0077]

[0078] Table 2 Strength and elongation

[0079]

[0080]

[0081] It can be seen from the above table that: the double-hardness hammer manufactured in the embodiment has excellent impact toughness and good hardness at its mounting end, and its working end has high hardness and good performance in impact toughness; compared with Example 4, the overall performance of Example 1 is reduced, indicating that the cyclic quenching treatment can indeed improve the quality of the working part of the hammer; compared with Example 4, the hammer of Example 2 is not subjected to rare earth nitriding treatment, and the hardness of the working part is significantly reduced; compared with Example 4, the hammer of Example 3 does not use rare earth during nitriding treatment, resulting in limited penetration, which ultimately affects the quality of the working part of the hammer.

[0082] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A manufacturing process for a double hardness hammer head, characterized in that: The following steps are involved: (1) After refining, the molten steel is poured into a sand mold, the casting is taken out after cooling, and the pouring head is removed to obtain a rough hammer head; (2) The rough blank hammer head is hung on a hanger and moved into an insulation shell for normalizing heat treatment, then removed from the insulation shell and air-cooled to room temperature; (3) The working part of the rough billet hammer is adjusted to be located at the position of the electromagnetic heater of group A, and its mounting part is exposed to the external environment, the working part is heated, and then the working part is moved down to penetrate into the quenching oil, and the oil is cooled to room temperature, and the above operation is repeated to perform cyclic quenching; (4) Remove the rough hammer head from the hanger and perform surface treatment on its working part; (5) The rough hammer head after surface treatment is hung on the hanger again, and its working part is moved to the position of the electromagnetic heater of group A for tempering heat treatment, and then removed from the insulation shell and air-cooled to room temperature to obtain a double hardness hammer head.

2. The manufacturing process of the double hardness hammer according to claim 1, characterized in that: In step (1), the molten steel comprises the following composition, in percentage by mass: C 0.3-0.6%, Si 0.5-1.5%, Mn 0.6-0.8%, Cr 1.2-3.5%, Ni0.5-1.5%, Mo 0.2-0.8%, V 0.1-0.2%, Al 0.02-0.04%, Zr0.02-0.04%, P<0.01%, S<0.01%, and the balance is Fe and unavoidable impurities.

3. The manufacturing process of the double hardness hammer according to claim 1, characterized in that: In step (2), the normalizing heat treatment is to use the electromagnetic heaters of group A and group B to heat the rough blank hammer head to 830-850°C at a rate of 40-50°C / min and keep it at this temperature for 4-5.5h.

4. The manufacturing process of the double hardness hammer head according to claim 1, characterized in that: In step (3), the cyclic quenching includes three stages, specifically: The first stage is to heat the working part of the rough hammer to 825℃ and keep it for 30 minutes for oil quenching; The second stage is to heat the working part of the rough hammer to 825℃ and keep it for 5 minutes for oil quenching; The third stage is to heat the working part of the rough hammer to 835℃ and keep it at that temperature for 3 minutes and then oil quench.

5. The manufacturing process of the double hardness hammer according to claim 1, characterized in that: In step (4), the surface treatment is specifically as follows: the mounting part of the rough hammer head is wrapped and covered to expose the working part, and then it is sent into a plasma nitriding furnace, and rare earth is placed in the furnace for nitriding treatment.

6. The manufacturing process of the double hardness hammer according to claim 5, characterized in that: The nitriding treatment temperature was controlled to be 450°C, the nitriding treatment time was 4h, the nitrogen flow rate was 0.1L / min, and the hydrogen flow rate was 0.4L / min.

7. The manufacturing process of the double hardness hammer according to claim 5, characterized in that: The rare earth is lanthanum-cerium rare earth chloride, wherein the lanthanum content is 33% and the cerium content is 66%.

8. The manufacturing process of the double hardness hammer according to claim 1, characterized in that: In step (5), the tempering heat treatment is to heat the working part of the rough hammer head to 220-230° C. and keep it warm for 2-3 hours.

9. The manufacturing process of the double hardness hammer head according to claim 1, characterized in that: In steps (2), (3) and (5), during the normalizing heat treatment, the heating stage of the cyclic quenching and the tempering heat treatment, the insulation shell is sealed with a seal.

10. The manufacturing process of the double hardness hammer according to claim 9, characterized in that: The sealing element is composed of an upper sealing plate with a notch, a lower sealing plate and a connecting rod bridging the upper sealing plate and the lower sealing plate.

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