A multi-metal bar, a screw and a method for manufacturing the same

Abstract

The application discloses a kind of multi-metal rod and its preparation method, multi-metal rod includes mandrel, wear-resistant corrosion-resistant outer layer and transmission shaft, wear-resistant corrosion-resistant outer layer is covered in the surface of mandrel along the axial direction, wear-resistant corrosion-resistant outer layer is metallurgical combination with mandrel, the end surface of mandrel and wear-resistant corrosion-resistant outer layer and the end surface of transmission shaft are metallurgical combination.Preparation method of multi-metal rod, in turn includes: step 1): mandrel is matched with transmission shaft;Step 2): the mandrel and transmission shaft of well-matched are loaded into sheath, then wear-resistant corrosion-resistant alloy powder is loaded into the gap of mandrel and sheath;Step 3): the sheath loaded with mandrel, transmission shaft, wear-resistant corrosion-resistant alloy powder is vacuumized and degassed;Step 4): the sheath after vacuumizing and degassing is carried out hot isostatic pressing processing.The hardness of the outer layer material of the working part of the application is high, wear-resistant corrosion-resistant, the toughness of the inner layer mandrel material is good, so that screw rod is wear-resistant corrosion-resistant, and not easy to break.

Description

Technical Field

[0001] This invention belongs to the technical field of plastic molding machinery parts, and specifically relates to a multi-metal rod, screw and its preparation method. Background Technology

[0002] Plastics, as a crucial polymer material, play a vital role in daily life and engineering. During plastic production, highly corrosive substances such as sulfuric acid, nitric acid, hydrochloric acid, and phosphoric acid are often generated. Simultaneously, to improve the strength, toughness, resistance to damage, and heat resistance of plastic products, large amounts of reinforcing additives, such as ceramic powder and glass fiber, are added. Therefore, with increasing performance requirements for plastic products, higher demands are placed on the heat resistance, wear resistance, and corrosion resistance of key components in plastic machinery. Previously widely used materials such as mold steel, stainless steel, and surface-nitrided steel are no longer sufficient. In corrosive media and environments containing glass fiber, components that directly contact the material, such as screws and barrels, quickly fail and become unusable, severely impacting injection molding production. This necessitates frequent component replacements, resulting in low production efficiency, high costs, and poor and inconsistent product quality. Wear-resistant and corrosion-resistant materials are therefore the inevitable choice for screws used in this type of plastic machinery.

[0003] Using integral wear-resistant and corrosion-resistant alloy bars to machine screws presents several challenges. Firstly, the high cost of this alloy material significantly increases costs. Secondly, its high hardness (HRC 60 and above) makes machining the external splines on the drive shaft extremely difficult, if not impossible. Furthermore, its high hardness and low toughness increase the risk of catastrophic breakage during use. Using ordinary bimetallic bars—where the inner mandrel and drive shaft are integral alloy steel with an outer wear-resistant and corrosion-resistant material—is problematic. If the mandrel and drive shaft are made of steel with low elastic modulus, low strength, and high plasticity, the drive shaft may deform under high torque conditions, failing to meet performance requirements. Conversely, if the mandrel and drive shaft are made of steel with high elastic modulus, high strength, and poor plasticity, the excessive stress between the mandrel and the wear-resistant layer during manufacturing can easily cause cracking in the wear-resistant layer.

[0004] Patent CN102773991 discloses a metal screw and its manufacturing method. The method involves placing a screw mandrel into a sheath and filling the gap between the mandrel and the sheath with a pre-mixed raw material powder; placing the entire sheath into a sealed container and evacuating it; sintering in the sealed container; and then precision machining the multi-component boride-based metal ceramic layer to obtain the metal screw. The metal screw prepared in this way exhibits high wear and corrosion resistance and high fracture toughness. However, a drawback of this invention is that it cannot simultaneously achieve good stiffness, strength, and toughness of the mandrel material. If a steel with low elastic modulus, low strength, and good plasticity is used, the transmission part will deform under high torque conditions, failing to meet usage requirements. If a steel with high elastic modulus, high strength, and poor plasticity is used, the stress between the mandrel and the wear-resistant layer during production is too high, easily causing cracking of the wear-resistant layer. Summary of the Invention

[0005] In view of the shortcomings and defects of the existing technology, the present invention aims to provide a multi-metal bar, a screw and a method for preparing the same.

[0006] The technical solution adopted by this invention to solve the technical problem is as follows:

[0007] A multi-metal bar stock includes a mandrel, a wear-resistant and corrosion-resistant outer layer, and a drive shaft. The wear-resistant and corrosion-resistant outer layer covers the surface of the mandrel along the axial direction. The wear-resistant and corrosion-resistant outer layer is metallurgically bonded to the mandrel. The end faces of the mandrel and the wear-resistant and corrosion-resistant outer layer are metallurgically bonded to the end faces of the drive shaft.

[0008] In the above-mentioned multi-metal bar stock, as a preferred embodiment, the mandrel is made of alloy steel with high toughness and high strength; the drive shaft is made of alloy steel with high hardness, stiffness and high strength.

[0009] In the above-mentioned multi-metal bar stock, as a preferred embodiment, the material of the wear-resistant and corrosion-resistant outer layer is at least one of iron-based alloys, nickel-based alloys, cobalt-based alloys, and cermet materials;

[0010] In the above-mentioned multi-metal bar stock, as a preferred embodiment, the material of the mandrel is at least one of 45# steel, 40Cr, 35CrMo and 42CrMo steel.

[0011] In the above-mentioned multi-metal bar stock, as a preferred embodiment, the material of the drive shaft is at least one of M340, M390, CPM10V, Cr12MoV and 440C steel.

[0012] In the above-mentioned multi-metal bar stock, as a preferred embodiment, the end face of the drive shaft that is metallurgically joined with the mandrel is provided with a groove, and the end of the mandrel is disposed in the groove of the drive shaft; more preferably, the groove is located at the center of the end face of the drive shaft.

[0013] In the above-mentioned multi-metal bar stock, as a preferred embodiment, the depth of the groove is 5-10 mm.

[0014] A method for preparing a multi-metal rod, comprising the following steps:

[0015] Step 1): Connect the mandrel to the drive shaft;

[0016] Step 2): Install the fitted mandrel and drive shaft into the sleeve, and then fill the gap between the mandrel and the sleeve with wear-resistant and corrosion-resistant alloy powder;

[0017] Step 3): Vacuum degas the sleeve containing the mandrel, drive shaft, and wear-resistant and corrosion-resistant alloy powder;

[0018] Step 4): The cladding after vacuum degassing is subjected to hot isostatic pressing to obtain the multi-metal bar stock.

[0019] In the above-mentioned method for preparing multi-metal rods, as a preferred embodiment, in step 1), the mandrel material is processed into the required shape and size to obtain the mandrel; the drive shaft material is processed into the required shape and size to obtain the drive shaft.

[0020] In the above-mentioned method for preparing multi-metal rods, as a preferred embodiment, in step 1), the mandrel material is low alloy steel, preferably, the mandrel is at least one of 45# steel, 40Cr, 35CrMo and 42CrMo.

[0021] In the above-mentioned method for preparing multi-metal rods, as a preferred embodiment, in step 1), the material of the drive shaft is at least one of M340, M390, CPM10V, Cr12MoV and 440C alloy steel.

[0022] In the above-mentioned method for preparing multi-metal rods, as a preferred embodiment, step 1) specifically involves: providing a groove on the end face of one end of the drive shaft, inserting one end of the mandrel into the groove for mating, and then spot welding the mandrel and the drive shaft together to prevent separation of the mandrel from the drive shaft; preferably, the groove is located at the center of the end face of the drive shaft; preferably, the depth of the groove is 5-10 mm, which can effectively ensure the connection strength between the mandrel and the drive shaft; preferably, the spot welding is tungsten inert gas welding; preferably, the end side of the mandrel and the groove are in clearance fit, more preferably, when the groove and the mandrel are in clearance fit, the gap between the groove and the mandrel is 0.02-0.1 mm.

[0023] In the above-mentioned method for preparing multi-metal rods, as a preferred embodiment, in step 2), there is no gap between the drive shaft and the sleeve.

[0024] In the above-mentioned method for preparing multi-metal rods, as a preferred embodiment, in step 3), the wear-resistant and corrosion-resistant alloy powder is at least one of iron-based alloy powder, nickel-based alloy powder, Co-based alloy powder, and cermet powder; the iron-based alloy is preferably M390 or 10V; the nickel-based alloy is preferably Ni60 or Ni55; the cobalt-based alloy is preferably Stellite 12, Stellite 20, or Stellite 6; and the cermet material is preferably NiWC20 or NiWC30.

[0025] In the above-mentioned method for preparing multi-metal rods, as a preferred embodiment, in step 3), the wear-resistant and corrosion-resistant alloy powder is a powder prepared by gas atomization; preferably, the wear-resistant and corrosion-resistant alloy powder is spherical or near-spherical; preferably, the particle size of the wear-resistant and corrosion-resistant alloy powder is less than 1000 micrometers.

[0026] In the above-mentioned method for preparing multi-metal rods, as a preferred embodiment, in step 3), the temperature for vacuum degassing is 300–600°C (e.g., 350°C, 400°C, 450°C, 500°C, 550°C, etc.), and the vacuum degree reaches 1×10⁻⁶. -2 The insulation time after Pa is 2 to 6 hours (e.g., 3 hours, 4 hours, 5 hours, etc.).

[0027] In the above-mentioned method for preparing polymetallic bars, as a preferred embodiment, in step 4), the hot isostatic pressing (HIP) temperature is 900–1200℃ (e.g., 950℃, 1000℃, 1050℃, 1100℃, 1150℃, etc.), the pressure is 100–150 MPa (e.g., 110 MPa, 120 MPa, 130 MPa, 140 MPa, etc.), and the holding time is 2–6 hours (e.g., 3 hours, 4 hours, 5 hours, etc.). If the HIP temperature is too low, a good bond cannot be achieved; if the HIP temperature is too high, it is detrimental to the performance of the obtained polymetallic bars.

[0028] A polymetallic rod, wherein the polymetallic rod is prepared by the above-described method for preparing polymetallic rods.

[0029] A screw, said screw being machined from said multi-metal bar stock.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] (1) This invention adopts a tri-metal gradient composite, in which the outer layer (hard layer), the mandrel, and the drive shaft are all perfectly metallurgically bonded to each other, resulting in high bonding strength. The outer layer material of the working part has high hardness, is wear-resistant and corrosion-resistant, and the inner mandrel material has good toughness, making the screw both wear-resistant and corrosion-resistant, and not easy to break.

[0032] (2) The mandrel material of the present invention has low hardness, good toughness and easy processing, so the internal thread of the screw is easy to process and the processing cost is low, which can solve the processing problem of the internal thread of the screw end of the whole wear-resistant and corrosion-resistant material.

[0033] (3) The transmission shaft of the present invention has moderate hardness and high strength. It has sufficient strength and is easy to process splines, which can solve the problem of difficult spline processing of the transmission part of the integral wear-resistant and corrosion-resistant screw and the traditional bimetallic wear-resistant and corrosion-resistant screw.

[0034] (4) The present invention uses relatively inexpensive alloy steel as the material for the transmission shaft, such as the screw transmission part, thereby reducing the material cost of the screw. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the structure of the multi-metal bar of the present invention;

[0036] Figure 2 This is a schematic diagram of the assembly structure of the mandrel and the drive shaft.

[0037] Figure 3 A schematic diagram of the package assembly structure;

[0038] Figure 4This is a micrograph of the interface between the outer cobalt-based alloy and the mandrel in an embodiment of the present invention. The left side is the mandrel, and the right side is the wear-resistant and corrosion-resistant outer layer.

[0039] Among them, 1 is the mandrel, 2 is the wear-resistant and corrosion-resistant outer layer, 3 is the drive shaft, 4 is the sheath, and 5 is the wear-resistant and corrosion-resistant alloy powder. Detailed Implementation

[0040] To highlight the objectives, technical solutions, and advantages of this invention, the following embodiments further illustrate the invention. These examples are provided to explain the invention and not to limit it. The technical solutions of this invention are not limited to the specific embodiments listed below, but also include any combination of the various specific embodiments.

[0041] like Figure 1 As shown, the multi-metal composite bar provided by this invention is composed of three materials: the intermediate mandrel 1 is an alloy steel with high toughness and high strength; the wear-resistant and corrosion-resistant outer layer 2 is a high-hardness iron-based alloy, nickel-based alloy, cobalt-based alloy, or cermet material with good wear resistance and corrosion resistance; and the drive shaft 3 is an alloy steel with high hardness, rigidity, and high strength. The hard layer, mandrel, and drive shaft are all perfectly metallurgically bonded to each other, resulting in high bonding strength. The high hardness of the outer layer material of the working part, its wear and corrosion resistance, and the good toughness of the inner mandrel material make the multi-metal bar both wear-resistant and corrosion-resistant, and not easily broken; the drive shaft part has moderate hardness and good toughness, possessing sufficient strength and rigidity, and is easy to machine with splines.

[0042] The method for preparing the multi-metal composite rod provided by the present invention includes the following steps:

[0043] Step 1: Process the mandrel material into the required shape and size according to product requirements. The mandrel material can be low alloy steel such as 45# steel, 40Cr, 35CrMo, and 42CrMo. Process the drive shaft material into the required shape and size according to product requirements. The drive shaft material can be alloy steel such as Cr12MoV and 440C. There is a groove in the center of the end face of one end of the drive shaft. This groove is clearance-fitted with one end of the mandrel. The depth of the groove on the end face of the drive shaft is 5-10mm, and the clearance between the groove and the mandrel is 0.02-0.1mm.

[0044] Step 2: Insert one end of the mandrel 1 into the groove on the end face of the drive shaft 3 for mating, and then spot weld the mandrel and the drive shaft together using tungsten inert gas welding to prevent the mandrel from separating from the drive shaft;

[0045] Step 3: Place the assembled and spot-welded mandrel 1 and drive shaft 3 together into a cylindrical hot isostatic pressing sleeve 4 with one end open, and fix it at the center of the sleeve 4.

[0046] Step 4: Fill the gap between the sleeve and the mandrel with wear-resistant and corrosion-resistant alloy powder 5, and compact it completely; the wear-resistant and corrosion-resistant alloy powder 5 can be one of iron-based alloy powder, nickel-based alloy powder, Co-based alloy powder, and cermet powder; the compaction method can be by tapping the outer wall of the sleeve or by using a vibration table.

[0047] Step 5: Place the compacted package into a degassing furnace for vacuum degassing. The furnace temperature should be maintained at 300–600℃, and the vacuum level should reach 1×10⁻⁶. -2 After Pa, the heat preservation time is 2 to 6 hours;

[0048] Step 6: Place the degassed and sealed sheath into a hot isostatic pressing furnace for hot isostatic pressing treatment. The hot isostatic pressing treatment temperature is 900-1200℃, the pressure is 100-150MPa, and the holding time is 2-6 hours. After cooling and removing from the furnace, multi-metal rods are obtained.

[0049] Example 1

[0050] A multi-metal bar stock includes a mandrel 1, a wear-resistant and corrosion-resistant outer layer 2, and a drive shaft 3. The mandrel 1 and the wear-resistant and corrosion-resistant outer layer 2 are located at the front section of the multi-metal bar stock, and the drive shaft 3 is located at the rear section of the multi-metal bar stock. The wear-resistant and corrosion-resistant outer layer 2 is axially wrapped around the surface of the mandrel 1. One end of the mandrel 1 is located in a groove (the groove depth is 5mm) at the center of one end face of the drive shaft 3. The mandrel 1, the wear-resistant and corrosion-resistant outer layer 2, and the drive shaft 3 are all metallurgically bonded together.

[0051] The material of the mandrel 1 is 42CrMo, the material of the drive shaft 3 is Cr12MoV, and the material of the wear-resistant and corrosion-resistant outer layer 2 is iron-based alloy powder. The specific chemical composition by mass percentage is C: 2.5%; V: 10%; Cr: 25%; Mo: 1.5%; W: 0.5%; Ta: 2%; Si: 0.7%; Mn: 0.4%; with the balance being Fe and a small amount of impurities.

[0052] The steps for preparing multi-metal rods using 42CrMo material as a mandrel are as follows:

[0053] a) Process 42CrMo bar stock into round bars with a diameter of 15mm and a length of 600mm to serve as mandrels.

[0054] b) The Cr12MoV bar is machined into a round bar with a diameter of 50mm and a length of 380mm to serve as the drive shaft. A groove with a diameter of 15mm and a depth of 5mm is machined on the center of one end face. The diameter tolerance of the groove is such that it can be clearance-fitted with the mandrel, with a clearance of 0.02 to 0.1mm.

[0055] c) Insert one end of the mandrel into the groove on the end face of the drive shaft for fitting, and then spot weld the mandrel and the drive shaft together using tungsten inert gas welding.

[0056] d) Place the assembled and spot-welded mandrel and drive shaft together into a cylindrical hot isostatic pressing sleeve with one end open, and fix it at the center of the sleeve.

[0057] e) The iron-based alloy powder prepared by gas atomization is filled into the gap between the sleeve and the mandrel, and then compacted using a vibrating table (with no gap between the drive shaft and the sleeve). The chemical composition of the iron-based alloy powder is as follows (mass percentage): C: 2.5%; V: 10%; Cr: 25%; Mo: 1.5%; W: 0.5%; Ta: 2%; Si: 0.7%; Mn: 0.4%; with the balance being Fe and a small amount of impurities.

[0058] f) After the packing and compaction are completed, the package is placed in a degassing furnace for vacuum degassing. The degassing furnace is kept at a temperature of 300℃, and the vacuum level reaches 1×10⁻⁶. -2 The heat preservation time after Pa is 2 hours;

[0059] g) After degassing and sealing, the sheath is placed in a hot isostatic pressing furnace for hot isostatic pressing treatment. The hot isostatic pressing treatment temperature is 1200℃, the pressure is 100MPa, and the holding time is 2 hours. After cooling and exiting the furnace, multi-metal rods are obtained.

[0060] The hardness of the wear-resistant and corrosion-resistant outer layer of the multi-metal bar is HRC 41. The tensile strength of the interface between the wear-resistant and corrosion-resistant outer layer and the drive shaft is 610 MPa.

[0061] Example 2

[0062] The steps for preparing multi-metal rods using 42CrMo material as a mandrel are as follows:

[0063] a) Process 42CrMo bar stock into round bars with a diameter of 20mm and a length of 690mm to serve as mandrels.

[0064] b) The 440C bar stock is machined into a round bar with a diameter of 55mm and a length of 420mm to serve as the drive shaft. A groove with a diameter of 20mm and a depth of 10mm is machined on the center of one end face. The diameter tolerance of the groove is such that it can be clearance-fitted with the mandrel, with a clearance of 0.02 to 0.1mm.

[0065] c) Insert one end of the mandrel into the groove on the end face of the drive shaft for fitting, and then spot weld the mandrel and the drive shaft together using tungsten inert gas welding.

[0066] d) Place the assembled and spot-welded mandrel and drive shaft together into a cylindrical hot isostatic pressing sleeve with one end open, and fix it at the center of the sleeve.

[0067] e) The Ni-based alloy powder prepared by gas atomization is filled into the gaps between the sleeve and the mandrel and the drive shaft, and then compacted using a vibrating table. The mass percentage of the chemical composition of the nickel-based alloy powder is: C: 1.1%; Cr: 10%; Si: 2.5%; B: 1.5%; W: 15%; with the balance being Ni and a small amount of impurities.

[0068] f) After the packing and compaction are completed, the package is placed in a degassing furnace for vacuum degassing. The degassing furnace is kept at a temperature of 600℃, and the vacuum level reaches 1×10⁻⁶. -2 The insulation time after Pa is 6 hours;

[0069] g) After degassing and sealing, the sheath is placed in a hot isostatic pressing furnace for hot isostatic pressing treatment. The hot isostatic pressing treatment temperature is 900℃, the pressure is 150MPa, and the holding time is 6 hours. After cooling and exiting the furnace, multi-metal rods are obtained.

[0070] The hardness of the wear-resistant and corrosion-resistant outer layer of the multi-metal bar is HRC 63. The tensile strength of the interface between the wear-resistant and corrosion-resistant outer layer and the drive shaft is 450 MPa.

[0071] Example 3

[0072] The steps for preparing multi-metal rods using 42CrMo material as a mandrel are as follows:

[0073] a) The 42CrMo bar stock is machined into a round bar with a diameter of 30mm and a length of 750mm to serve as a mandrel.

[0074] b) The Cr18MoV bar is machined into a round bar with a diameter of 65mm and a length of 450mm to serve as the drive shaft. A groove with a diameter of 30mm and a depth of 8mm is machined on the center of one end face. The diameter tolerance of the groove is such that it can be clearance-fitted with the mandrel, with a clearance of 0.02 to 0.1mm.

[0075] c) Insert one end of the mandrel into the groove on the end face of the drive shaft for fitting, and then spot weld the mandrel and the drive shaft together using tungsten inert gas welding.

[0076] d) Place the assembled and spot-welded mandrel and drive shaft together into a cylindrical hot isostatic pressing sleeve with one end open, and fix it at the center of the sleeve.

[0077] e) The Co-based alloy powder prepared by gas atomization is filled into the gaps between the sleeve and the mandrel and the drive shaft, and then compacted using a vibrating table. The chemical composition of the cobalt-based alloy powder is as follows (mass percentage): C: 1.8%; Cr: 30%; Si: 1.5%; W: 10%; with the balance being Co and a small amount of impurities.

[0078] f) After the packing and compaction are completed, the package is placed in a degassing furnace for vacuum degassing. The degassing furnace is kept at a temperature of 500℃, and the vacuum level reaches 1×10⁻⁶. -2 The insulation time after Pa is 3 hours;

[0079] g) After degassing and sealing, the sheath is placed in a hot isostatic pressing furnace for hot isostatic pressing treatment. The hot isostatic pressing treatment temperature is 1100℃, the pressure is 120MPa, the holding time is 3 hours, and after cooling and exiting the furnace, multi-metal rods are obtained.

[0080] The hardness of the wear-resistant and corrosion-resistant outer layer of the multi-metal bar is HRC 60. The interfacial tensile strength between the wear-resistant and corrosion-resistant outer layer and the drive shaft is 760 MPa.

[0081] The screw of the present invention can be manufactured from the multi-metal bar material obtained in Examples 1-3, according to actual needs (structure).

[0082] The above embodiments describe the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are only illustrative of the principles of the present invention. Various changes and modifications can be made to the present invention without departing from the scope of the principles of the present invention, and all such changes and modifications fall within the protection scope of the present invention.

Claims

1. A method of producing a multi-metal bar, characterized by, The preparation method comprises the following steps in sequence: Step 1): matching the mandrel with the transmission shaft; Step 2): loading the matched mandrel and transmission shaft into a sheath, and then loading wear-resistant and corrosion-resistant alloy powder into the gap between the mandrel and the sheath; Step 3): vacuumizing and degassing the sheath loaded with the mandrel, transmission shaft and wear-resistant and corrosion-resistant alloy powder; Step 4): performing hot isostatic pressing treatment on the sheath after vacuumizing and degassing, to obtain the multi-metal rod; The mandrel is 42CrMo; In the step 1), the transmission shaft is made of Cr18MoV; The step 1) specifically comprises the following steps: a groove is arranged on the end face of one end of the transmission shaft, one end of the mandrel is inserted into the groove for matching, and then the mandrel and the transmission shaft are spot-welded to prevent the mandrel and the transmission shaft from being separated; In the step 3), the wear-resistant and corrosion-resistant alloy powder is Co-based alloy powder; The temperature of the vacuum degassing is 500℃, and the vacuum degree reaches 1x10 -2 The holding time is 3 hours after 500℃. In the step 4), the temperature of the hot isostatic pressing treatment is 1100 DEG C, the pressure is 120 MPa, and the holding time is 3 hours.

2. The method of producing a multi-metal bar according to claim 1, wherein In the step 1), the mandrel material is processed into a required shape and size to obtain the mandrel, and the transmission shaft material is processed into a required shape and size to obtain the transmission shaft.

3. The method of producing a multi-metallic bar according to claim 1, wherein The groove is located at the center of the end face of the transmission shaft, the depth of the groove is 5-10 mm, the spot welding is tungsten electrode argon arc welding, the end side surface of the mandrel is in clearance fit with the groove, and when the groove is in clearance fit with the mandrel, the clearance between the groove and the mandrel is 0.02-0.1 mm.

4. The method of producing a multi-metallic bar according to claim 1, wherein In the step 2), there is no gap between the transmission shaft and the sheath.

5. The preparation method of the multi-metal rod according to claim 1, wherein the wear-resistant and corrosion-resistant alloy powder is a powder prepared by a gas atomization method, the wear-resistant and corrosion-resistant alloy powder is spherical or near-spherical, and the particle size of the wear-resistant and corrosion-resistant alloy powder is less than 1000 microns. The multi-metal rod is prepared by the preparation method of the multi-metal rod according to any one of claims 1-5.

6. A multi-metallic bar characterized in that, The screw rod is processed from the multi-metal rod according to claim 6.

7. A screw characterized in that, The screw rod is processed from the multi-metal rod according to claim 6.

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