Bimetal casting and forging composite hammerhead and preparation method thereof

Abstract

The invention discloses a preparation method of a bimetal casting and forging composite hammerhead, which comprises the following steps: processing a hammer handle with a pull ring structure, manufacturing an evanescent mode for hammerhead processing, putting the hammer handle into the evanescent mode, pouring molten steel into the hammerhead evanescent mode through a pouring system, solidifying and fully cooling, and then taking out the hammerhead. And heating the cast composite hammerhead, cooling, annealing, machining, quenching, tempering at low temperature, and machining the annealed hammerhead to the final shape and size to finish the preparation. The impact resistance of the hammer head is guaranteed, and the wear resistance of the hammer head is improved. The invention further discloses the bimetal casting and forging composite hammer head which is prepared by adopting the preparation method of the bimetal casting and forging composite hammer head, and the problems that an existing hammer head is easy to wear and short in service life are solved.

Description

Technical Field

[0001] The invention belongs to the technical field of coal mining and processing equipment accessories, relates to a preparation method of a bimetallic casting and forging composite hammer head, and also relates to a bimetallic casting and forging composite hammer head. Background Art

[0002] my country is one of the resource-rich countries with a complete range of mineral types and abundant total mineral resources.

[0003] With the rapid development of my country's coal mining industry, the requirements for the efficiency and life of mining machinery and equipment are getting higher and higher. Crushing is a key link in coal mining operations. Coal, especially coal gangue, is hard and corrosive, which causes serious wear and tear on mining equipment.

[0004] The hammer is the main consumable part of coal crushing equipment. The hammer handle is constantly subjected to alternating bending stress and impact force during use, while the hammer head is mainly subjected to strong impact force and friction. At present, the more advanced hammer used in crushing equipment is based on alloy steel forgings, and the surface is welded with a layer of wear-resistant steel (3-10mm thick) by surfacing process. Since the high hardness and wear resistance of the surfacing material come from the surfacing material, and the thickness of the surfacing layer is limited, and due to the difference in material between the surfacing layer and the substrate, it is inevitable that the welding layer is easy to fall off, which will undoubtedly affect the service life of the hammer. Therefore, its main failure form is hammer wear. Summary of the invention

[0005] The purpose of the present invention is to provide a method for preparing a bimetallic cast-forged composite hammer head, thereby ensuring the impact resistance of the hammer head and improving the wear resistance of the hammer head.

[0006] Another object of the present invention is to provide a bimetallic cast-forged composite hammer head, which solves the problem of the existing hammer head being easy to wear and having a short service life.

[0007] The first technical solution adopted by the present invention is a method for preparing a bimetallic cast and forged composite hammer head, which includes processing a hammer handle with a pull ring structure, making a lost mold for hammer head processing, placing the hammer handle in the lost mold, pouring molten steel into the hammer head lost mold through a pouring system, taking out the part after solidification and sufficient cooling, heating the cast composite hammer head, cooling and annealing it, and then machining it, quenching and low-temperature tempering it after machining, and machining the annealed hammer head to the final shape and size to complete the preparation.

[0008] The first technical solution of the present invention is also characterized in that:

[0009] Follow the steps below to implement it:

[0010] Step 1: Processing the alloy quenched and tempered steel into a structural hammer handle with a pull ring through forging and machining;

[0011] Step 2: Make a lost foam mold that matches the hammer head, put the forged hammer handle into the lost foam mold and adjust the relative position;

[0012] Step 3: Dip and apply refractory coating on the lost foam mold and let it dry, then bury the hammer head lost foam into the sand box, seal the sand box, perform negative pressure suction, and prepare for pouring;

[0013] Step 4: Smelting alloy steel liquid metal for preparing hammer head;

[0014] Step 5: pouring the alloy steel molten metal into the hammer head lost foam mold through the pouring system for casting;

[0015] During the pouring process, the alloy steel molten metal flows from the surface of the hammer handle through the heated hammer handle, causing the surface of the hammer handle to be partially melted, so that the alloy steel is tightly wrapped around the periphery of the forged hammer handle and a local metallurgical bond is produced;

[0016] Step 6: After the alloy steel molten metal solidifies and cools sufficiently, unpack the parts and cut off the pouring system and riser;

[0017] Step 7: Place the cast composite hammer head parts into a heating furnace for heating and then heat preservation, and complete annealing before processing with furnace cooling to eliminate casting stress and reduce hardness;

[0018] Step 8: Rough machining of the hammer head shape through preliminary machining;

[0019] Step 9: Place the rough-machined composite hammer head parts into a heating furnace for heating and then heat preservation, air cooling, and complete the quenching of the hammer head alloy steel and the normalizing of the hammer handle; then put them back into the heating furnace for heating and heat preservation, and complete low-temperature tempering with furnace cooling to eliminate quenching stress and stabilize the size of the hammer head;

[0020] Step 10: Process the annealed hammer head to the final size according to the part size requirements, complete the processing of the hammer head thread part, and complete the preparation.

[0021] The pull ring of the prepared hammer handle is cast inside the hammer head and is used for fixing and connecting the hammer head and the hammer handle.

[0022] The lost foam mold is a polystyrene foam mold.

[0023] The elements contained in the alloy steel liquid include: C, Cr, Si, Mo, Mn, S, P, and Re. The mass percentages of the above elements in the alloy steel liquid are as follows: C content is 0.45-0.6%, Cr content is 1.0-1.3%, Si content is 1.8-2.2%, Mo content is 0.3-0.5%, Mn content is 2.5-3.0%, S content is less than 0.06%, and P content is less than 0.06%.

[0024] The melting temperature of step 4 is 1620±50°C.

[0025] The pouring temperature in step 5 is 1600±50°C, and the cooling time of the alloy steel molten metal in step 6 is greater than or equal to 24h.

[0026] The heating temperature of step 7 is 920° C. to 940° C., and the insulation time is 3 to 4 hours.

[0027] The heating temperature of the rough-machined composite hammer head part in step 9 is 950° C. to 970° C., and the holding time is 2 to 3 hours;

[0028] After completing the quenching of the hammer head alloy steel and the normalizing of the hammer handle, the reheating temperature is 240℃~260℃, and the insulation time is ≥12 hours.

[0029] The second technical solution adopted by the present invention is that the bimetallic cast-forged composite hammer head is prepared by the preparation method of the bimetallic cast-forged composite hammer head of the present invention.

[0030] The beneficial effects of the present invention are:

[0031] The preparation method of the bimetallic cast-forged composite hammer head of the present invention ensures or even improves the strength and toughness of the forged hammer handle after the subsequent casting process and subsequent normalizing and low-temperature tempering; the cast hammer head is quenched and low-temperature tempered, and the hardness and wear resistance are just right, which fundamentally ensures the impact resistance of the hammer head and greatly improves the wear resistance of the hammer head, thereby extending the service life of equipment components, reducing component replacement and maintenance costs, and improving equipment productivity.

[0032] The bimetallic cast-forged composite hammer head of the present invention is a forged hammer handle of special material and structure tightly combined with a wear-resistant alloy steel hammer head. The hammer handle and the hammer head not only have good mechanical combination, but also have local metallurgical combination. The combination of the two metals is tight and not easy to break or fall off. The new composite hammer head not only improves the wear resistance of the hammer head, but also improves the impact resistance of the hammer head. The service life can reach more than 2.5 times that of an ordinary surfacing hammer head. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic diagram of the structure of the bimetallic casting and forging composite hammer head of the present invention;

[0034] FIG2 is a schematic structural diagram of the hammer handle portion of the bimetallic cast-forged composite hammer head of the present invention, wherein FIG2(a) is a front view and FIG2(b) is a side view;

[0035] FIG3 is a schematic structural diagram of the hammer head portion of the bimetallic cast-forged composite hammer head of the present invention, wherein FIG3(a) is a front view and FIG3(b) is a side view. DETAILED DESCRIPTION

[0036] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0037] Example 1

[0038] The present embodiment provides a preparation method of a bimetallic cast and forged composite hammer head, comprising processing a hammer handle with a pull ring structure, making a lost foam for hammer head processing, placing the hammer handle in the lost foam, pouring molten steel into the hammer head lost foam through a pouring system, taking out the part after solidification and sufficient cooling, heating the cast composite hammer head, cooling and annealing, and then machining, quenching and low-temperature tempering after machining, machining the annealed hammer head to the final shape and size, and completing the preparation.

[0039] Follow the steps below to implement it:

[0040] Step 1: Processing 42CrMo forged steel into a structural hammer handle with a pull ring through forging and machining;

[0041] Step 2: Make a lost foam mold that matches the hammer head. The lost foam mold is a polystyrene foam mold. Put the forged hammer handle into the lost foam mold and adjust the relative position.

[0042] Step 3: Dip and apply refractory coating on the lost foam mold and let it dry, then bury the hammer head lost foam into the sand box, seal the sand box, perform negative pressure suction, and prepare for pouring;

[0043] Step 4: Melting the alloy steel liquid metal for preparing the hammer head, the melting temperature is 1570°C;

[0044] Step 5: pouring the alloy steel molten metal into the hammer head lost foam mold through the pouring system, casting and molding, the pouring temperature is 1550℃;

[0045] The elements contained in the alloy steel molten metal include: C, Cr, Si, Mo, Mn, S, P, Re, and the mass percentages of the above elements in the alloy steel molten metal are as follows: C content is 0.45%, Cr content is 1.0%, Si content is 1.8%, Mo content is 0.3%, Mn content is 2.5%, S content is 0.05%, and P content is 0.05%;

[0046] During the pouring process, the alloy steel molten metal flows from the surface of the hammer handle through the heated hammer handle, causing the surface of the hammer handle to be partially melted, so that the alloy steel is tightly wrapped around the periphery of the forged hammer handle and a local metallurgical bond is produced;

[0047] Step 6: After the alloy steel molten metal solidifies and fully cools (cooling time is equal to 24 hours), unpack and remove the parts, and cut off the pouring system and riser;

[0048] Step 7: Place the cast composite hammer head parts into a heating furnace and heat them at 920°C for 3 hours, and then cool them in the furnace to complete the annealing before processing, eliminate casting stress and reduce hardness;

[0049] Step 8: Rough machining of the hammer head shape through preliminary machining;

[0050] Step 9: Place the rough-machined composite hammer head parts in a heating furnace and heat them at 950°C for 2 hours, then air-cool them to complete the quenching of the hammer head alloy steel and the normalizing of the hammer handle; then place them in a heating furnace again and heat them at 240°C for 12 hours, and complete low-temperature tempering with furnace cooling to eliminate quenching stress and stabilize the size of the hammer head;

[0051] Step 10: Process the annealed hammer head to the final size according to the part size requirements, complete the processing of the hammer head thread part, and complete the preparation. The pull ring of the prepared hammer handle is cast inside the hammer head to fix the connection between the hammer head and the hammer handle.

[0052] This embodiment also provides a bimetallic cast and forged composite hammer head, such as Figure 1 As shown, it is prepared by the preparation method of the bimetallic casting and forging composite hammer head of this embodiment.

[0053] Example 2

[0054] The present embodiment provides a preparation method of a bimetallic cast and forged composite hammer head, comprising processing a hammer handle with a pull ring structure, making a lost foam for hammer head processing, placing the hammer handle in the lost foam, pouring molten steel into the hammer head lost foam through a pouring system, taking out the part after solidification and sufficient cooling, heating the cast composite hammer head, cooling and annealing, and then machining, quenching and low-temperature tempering after machining, machining the annealed hammer head to the final shape and size, and completing the preparation.

[0055] Follow the steps below to implement it:

[0056] Step 1: Process the 35CrMo alloy quenched and tempered steel into Figure 2(a)-2(b) The structural hammer handle with pull ring shown;

[0057] Step 2: Make a lost foam mold that matches the hammer head. The lost foam mold is a polystyrene foam mold. Put the forged hammer handle into the lost foam mold and adjust the relative position.

[0058] Step 3: Dip and apply refractory coating on the lost foam mold and let it dry, then bury the hammer head lost foam into the sand box, seal the sand box, perform negative pressure suction, and prepare for pouring;

[0059] Step 4: Melting the alloy steel liquid metal for preparing the hammer head, the melting temperature is 1620°C;

[0060] Step 5: pouring the alloy steel molten metal into the hammer head lost foam mold through the pouring system, casting and molding, the pouring temperature is 1600℃;

[0061] The elements contained in the alloy steel molten metal include: C, Cr, Si, Mo, Mn, S, P, Re, and the mass percentages of the above elements in the alloy steel molten metal are as follows: C content is 0.5%, Cr content is 1.2%, Si content is 2.0%, Mo content is 0.4%, Mn content is 2.8%, S content is 0.04%, and P content is 0.03%;

[0062] During the pouring process, the alloy steel molten metal flows from the surface of the hammer handle through the heated hammer handle, causing the surface of the hammer handle to be partially melted, so that the alloy steel is tightly wrapped around the periphery of the forged hammer handle and a local metallurgical bond is produced;

[0063] Step 6: After the alloy steel molten metal solidifies and fully cools (cooling time is 26 hours), unpack and remove the parts, and cut off the pouring system and riser;

[0064] Step 7: Place the cast composite hammer head parts into a heating furnace and heat them at 930°C for 4 hours, and then cool them in the furnace to complete the annealing before processing, eliminate casting stress and reduce hardness;

[0065] Step 8: Rough machining of the hammer head shape through preliminary machining;

[0066] Step 9: Place the rough-machined composite hammer head parts in a heating furnace and heat them at 960°C for 3 hours, then air-cool them to complete the quenching of the hammer head alloy steel and the normalizing of the hammer handle; then place them in a heating furnace again and heat them at 250°C for 14 hours, and complete low-temperature tempering with furnace cooling to eliminate quenching stress and stabilize the size of the hammer head;

[0067] Step 10: Figure 3(a)-3(b) As shown, the annealed hammer head is processed to the final size according to the part size requirements, and the threaded part of the hammer head is processed to complete the preparation. The pull ring of the prepared hammer handle is cast inside the hammer head for fixing the connection between the hammer head and the hammer handle.

[0068] This embodiment also provides a bimetallic cast-forged composite hammer head, which is prepared by the preparation method of the bimetallic cast-forged composite hammer head of this embodiment.

[0069] Example 3

[0070] The present embodiment provides a preparation method of a bimetallic cast and forged composite hammer head, comprising processing a hammer handle with a pull ring structure, making a lost foam for hammer head processing, placing the hammer handle in the lost foam, pouring molten steel into the hammer head lost foam through a pouring system, taking out the part after solidification and sufficient cooling, heating the cast composite hammer head, cooling and annealing, and then machining, quenching and low-temperature tempering after machining, machining the annealed hammer head to the final shape and size, and completing the preparation.

[0071] Follow the steps below to implement it:

[0072] Step 1: Processing 35CrMo alloy quenched and tempered steel into a structural hammer handle with a pull ring through forging and machining;

[0073] Step 2: Make a lost foam mold that matches the hammer head. The lost foam mold is a polystyrene foam mold. Put the forged hammer handle into the lost foam mold and adjust the relative position.

[0074] Step 3: Dip and apply refractory coating on the lost foam mold and let it dry, then bury the hammer head lost foam into the sand box, seal the sand box, perform negative pressure suction, and prepare for pouring;

[0075] Step 4: Melting the alloy steel liquid metal for preparing the hammer head, the melting temperature is 1670°C;

[0076] Step 5: pouring the alloy steel molten metal into the hammer head lost foam mold through the pouring system, casting and molding, the pouring temperature is 1650℃;

[0077] The elements contained in the alloy steel molten metal include: C, Cr, Si, Mo, Mn, S, P, Re, and the mass percentages of the above elements in the alloy steel molten metal are as follows: C content is 0.6%, Cr content is 1.3%, Si content is 2.2%, Mo content is 0.5%, Mn content is 3.0%, S content is 0.05%, and P content is 0.04%;

[0078] During the pouring process, the alloy steel molten metal flows from the surface of the hammer handle through the heated hammer handle, causing the surface of the hammer handle to be partially melted, so that the alloy steel is tightly wrapped around the periphery of the forged hammer handle and a local metallurgical bond is produced;

[0079] Step 6: After the alloy steel molten metal solidifies and fully cools (cooling time is 27 hours), unpack and remove the parts, and cut off the pouring system and riser;

[0080] Step 7: Place the cast composite hammer head parts into a heating furnace and heat them at 940°C for 3 hours, and then cool them in the furnace to complete the annealing before processing, eliminate casting stress, and reduce hardness;

[0081] Step 8: Rough machining of the hammer head shape through preliminary machining;

[0082] Step 9: Place the rough-machined composite hammer head parts in a heating furnace and heat them at 970°C for 2 hours, then air-cool them to complete the quenching of the hammer head alloy steel and the normalizing of the hammer handle; then place them in a heating furnace again and heat them at 260°C for 12 hours, and complete low-temperature tempering with furnace cooling to eliminate quenching stress and stabilize the size of the hammer head;

[0083] Step 10: Process the annealed hammer head to the final size according to the part size requirements, complete the processing of the hammer head thread part, and complete the preparation. The pull ring of the prepared hammer handle is cast inside the hammer head to fix the connection between the hammer head and the hammer handle.

[0084] This embodiment also provides a bimetallic cast-forged composite hammer head, which is prepared by the preparation method of the bimetallic cast-forged composite hammer head of this embodiment.

[0085] The above-mentioned embodiment is compared with the following comparative example to verify the performance of the bimetallic casting and forging composite hammer head of the present invention.

[0086] Comparative Example 1

[0087] The base material of the hammer head is 42CrMo forged steel, which is forged and machined into a hammer head shape. A 3-10 mm wear-resistant layer is built-up on the surface of the hammer head through a surfacing welding process using a D322 wear-resistant welding rod.

[0088] Comparative Example 2

[0089] The universal hammer head for mining crushing equipment is made of ZGMn13 base material. It is cast and machined into the shape of a hammer head. The wear resistance of the hammer head is improved through the principle of work hardening.

[0090] Comparative Example 3

[0091] The bimetallic composite hammer head has a hammer handle made of cast steel, which is machined into a specific shape. The hammer head is made of high-chromium wear-resistant cast iron 25CrMo, and the hammer head is prepared through a composite casting process.

[0092] The performance data of each hammer are shown in Table 1.

[0093] Table 1 Hammer performance comparison table

[0094]

[0095] It can be seen from Table 1 that the toughness of Examples 1 to 3 is not as good as that of the cast steel ZGMn13 of Comparative Example 2, but much higher than that of the high chromium cast iron of Comparative Example 3; while the hardness is similar to that of the high chromium cast iron of Comparative Example 3, and much higher than that of the cast steel ZGMn13 of Comparative Example 2. That is to say, the composite hammer heads of Examples 1 to 3 have excellent comprehensive properties, so their wear rate is the lowest, and their service life is about 4 times that of the cladding hammer head of Comparative Example 1 and the cast steel ZGMn13 of Comparative Example 2, and 2 times that of Comparative Example 3.

[0096] Examples 1 to 3 have a longer service life because, compared with the surfacing process of comparative example 1, under the premise of similar wear resistance and toughness, the thickness of the wear-resistant layer is much greater than that of comparative example 1; the hardness and wear resistance are far superior to the cast steel ZGMn13 of comparative example 2; and the toughness is far superior to the high chromium cast iron of comparative example 3, thus proving that high hardness does not mean good wear resistance. Under the premise of similar hardness, higher strength and toughness are also conducive to ensuring the wear resistance of the material. Therefore, the bimetallic cast-forged composite hammer head of the present invention solves the problem of the existing hammer head being easy to wear and having a short service life.

Claims

1. A method for preparing a bimetallic casting and forging composite hammer head, characterized in that: The method includes processing a hammer handle with a pull ring structure, making a lost foam for hammer head processing, placing the hammer handle in the lost foam, pouring molten steel into the hammer head lost foam through a pouring system, taking out the part after solidification and sufficient cooling, heating the cast composite hammer head, cooling and annealing, and then machining, quenching and low-temperature tempering after machining, and machining the annealed hammer head to the final shape and size to complete the preparation.

2. The method for preparing a bimetallic casting and forging composite hammer according to claim 1, characterized in that: Follow the steps below to implement it: Step 1: Processing the alloy quenched and tempered steel into a structural hammer handle with a pull ring through forging and machining; Step 2: Make a lost foam mold that matches the hammer head, put the forged hammer handle into the lost foam mold and adjust the relative position; Step 3: Dip and apply refractory coating on the lost foam mold and let it dry, then bury the hammer head lost foam into the sand box, seal the sand box, perform negative pressure suction, and prepare for pouring; Step 4: Smelting alloy steel liquid metal for preparing hammer head; Step 5: pouring the alloy steel molten metal into the hammer head lost foam mold through the pouring system for casting; During the pouring process, the alloy steel molten metal flows from the surface of the hammer handle through the heated hammer handle, causing the surface of the hammer handle to be partially melted, so that the alloy steel is tightly wrapped around the periphery of the forged hammer handle and a local metallurgical bond is produced; Step 6: After the alloy steel molten metal solidifies and cools sufficiently, unpack the parts and cut off the pouring system and riser; Step 7: Place the cast composite hammer head parts into a heating furnace for heating and then heat preservation, and complete annealing before processing with furnace cooling to eliminate casting stress and reduce hardness; Step 8: Rough machining of the hammer head shape through preliminary machining; Step 9: Place the rough-machined composite hammer head parts into a heating furnace for heating and then heat preservation, air cooling, and complete the quenching of the hammer head alloy steel and the normalizing of the hammer handle; then put them back into the heating furnace for heating and heat preservation, and complete low-temperature tempering with furnace cooling to eliminate quenching stress and stabilize the size of the hammer head; Step 10: Process the annealed hammer head to the final size according to the part size requirements, complete the processing of the hammer head thread part, and complete the preparation.

3. The method for preparing a bimetallic casting and forging composite hammer according to claim 2, characterized in that: The prepared pull ring of the hammer handle is cast inside the hammer head and is used for fixedly connecting the hammer head and the hammer handle.

4. The method for preparing a bimetallic casting and forging composite hammer according to claim 1, characterized in that: The lost foam mold is a polystyrene foam mold.

5. The method for preparing a bimetallic casting and forging composite hammer according to claim 1, characterized in that: The elements contained in the alloy steel molten metal include: C, Cr, Si, Mo, Mn, S, P, and Re. The mass percentages of the above elements in the alloy steel molten metal are as follows: the C content is 0.45-0.6%, the Cr content is 1.0-1.3%, the Si content is 1.8-2.2%, the Mo content is 0.3-0.5%, the Mn content is 2.5-3.0%, the S content is less than 0.06%, and the P content is less than 0.06%.

6. The method for preparing a bimetallic casting and forging composite hammer according to claim 5, characterized in that: The melting temperature of step 4 is 1620±50°C.

7. The method for preparing a bimetallic casting and forging composite hammer according to claim 1, characterized in that: The pouring temperature of step 5 is 1600±50°C, and the cooling time of the alloy steel molten metal in step 6 is greater than or equal to 24 hours.

8. The method for preparing a bimetallic casting and forging composite hammer according to claim 1, characterized in that: The heating temperature of step 7 is 920° C. to 940° C., and the insulation time is 3 to 4 hours.

9. The method for preparing a bimetallic casting and forging composite hammer according to claim 1, characterized in that: The heating temperature of the rough-machined composite hammer head part in step 9 is 950° C. to 970° C., and the holding time is 2 to 3 hours; After completing the quenching of the hammer head alloy steel and the normalizing of the hammer handle, the reheating temperature is 240℃~260℃, and the insulation time is ≥12 hours.

10. Bimetallic casting and forging composite hammer head, characterized in that: The hammer head is prepared by the method for preparing the bimetallic casting and forging composite hammer head as claimed in claim 1.

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