A large arc surface guide rail additive and subtractive combined manufacturing method

Abstract

The application discloses a large-scale circular-arc guide rail additive and subtractive combined manufacturing method, which comprises the following steps: forging a material into a circular ring; completely annealing the circular ring; roughly turning the circular ring; stress relieving annealing the circular ring; dividing the circular ring into guide rail blanks; roughly turning the guide rail; stress relieving annealing the guide rail; semi-finish turning the guide rail; installing a guide rail shape-retaining tool; arc additive wear-resistant layer on the guide rail base material; stress relieving annealing; finish machining the guide rail and removing the guide rail shape-retaining tool. The application is an additive surfacing process which can prevent cracks, and a transition layer is surfaced on the base material, and a hard surface layer is surfaced on the transition layer; the transition layer is made of stainless steel material which has higher elongation than the base material and the hard surface layer material, and the transition layer is not easy to crack due to good ductility within a certain deformation range.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of additive manufacturing, and particularly relates to a large-scale circular-arc guide rail additive and subtractive combined manufacturing method. BACKGROUND

[0002] The circular-arc guide rail is a key transmission component of a radar antenna pedestal, and mainly serves as a support and guide. The circular-arc guide rail is connected with a back truss structure of a radar array surface, and multiple profiles thereof are rolled by a roller set to ensure the support strength and rigidity of the radar array surface, and to realize the pitching movement of the radar array surface around the center of the circular-arc guide rail. In order to meet the requirements of the rolling surface strength and wear resistance, the rolling surface of the circular-arc guide rail is usually provided with a high-hardness wear-resistant layer with a certain depth. The circular-arc guide rail has the characteristics of large structure size (the diameter can reach 10 m, and the weight is more than 10 T), multiple wear-resistant profiles (not less than 5 profiles), high hardness requirement of the wear-resistant layer (greater than HRC 48), and thick wear-resistant layer (greater than 6 mm).

[0003] At present, the material of the circular-arc guide rail mainly adopts medium-carbon quenched and tempered steel, a forged circular ring is used as a blank, the circular ring is first heat treated and roughly processed, then is divided into two semicircular rings, then the guide rail surface is quenched by medium frequency, and finally is precisely processed after being shaped and corrected. Practice shows that this manufacturing method has the following problems: 1) the quenched and tempered steel has a high carbon equivalent, has a large hardening tendency after welding, has low weld toughness, and is prone to delayed cracking after welding, which limits the connection mode of the guide rail and the support truss structure, welding cannot be used, and the structure weight is increased due to the design of the screw connection part mounting edge structure; 2) cracks are prone to occur during medium frequency quenching, in order to meet the required hardening layer depth in the final use state, and to ensure the size precision requirement after the precise processing after the medium frequency quenching, the medium frequency quenching depth of the blank is required to be more than 10 mm, when the medium frequency quenching depth is greater than 7 mm, the inner and outer temperature difference of the heating layer is too large, and the quenching surface is prone to cracking; 3) the guide rail is deformed greatly and uncontrollably after quenching, if the length of the part needs to be quenched by medium frequency, the power of the medium frequency induction equipment needs to reach 5000 KW, and there is no industrial equipment with such power requirement in China at present. Therefore, the medium frequency quenching can only be realized by two or more times of quenching, and the stress is superimposed, which will cause the part to be deformed too much. The internal stress distribution is complex due to the quenching of multiple profiles, the post-heat treatment cannot completely eliminate the internal stress due to the limitation of the tempering temperature, and the guide rail will continuously deform and be uncontrollable in the process of machining the quenched surface, which is not conducive to ensuring the part precision and the hard surface layer depth. SUMMARY

[0004] In order to solve the above problems, the present application provides a large-scale circular-arc guide rail additive and subtractive combined manufacturing method, which comprises the following steps:

[0005] Step 1: forging a material into a circular ring;

[0006] Step 2: complete annealing treatment of the ring;

[0007] Step 3: rough turning of the ring;

[0008] Step 4: stress relief annealing treatment of the ring;

[0009] Step 5: dividing the ring into guide rail blanks;

[0010] Step 6: rough turning of the guide rail;

[0011] Step 7: stress relief annealing treatment of the guide rail;

[0012] Step 8: semi-finish turning of the guide rail;

[0013] Step 9: installing a guide rail shape-retaining tool;

[0014] Step 10: arc additive wear-resistant layer on the guide rail base material, wrapping and heating the printing area with an induction heating blanket before starting printing, then cladding with austenitic stainless steel material as the base layer, then building up multiple layers of wear-resistant material until the preset thickness is reached, cleaning and polishing the surface oxide skin after each layer of printing is completed, and controlling the interlayer temperature;

[0015] Step 11: stress relief annealing treatment;

[0016] Step 12: finish machining of the guide rail, and removing the guide rail shape-retaining tool.

[0017] Preferably, in the step 1, the raw material is an alloy structural steel.

[0018] Preferably, in the step 9, the shape-retaining tool is a truss structure, and the frame is formed by screwing.

[0019] Preferably, in the step 10, the welding power source uses a CMT welder, the wire feeding speed is 4-7 m / min, the welding speed is 6-9 mm / s, and the build-up layer thickness is 2.0-2.5 mm.

[0020] Preferably, in the step 10, the preheating temperature before printing is in the range of 150-200℃.

[0021] Preferably, in the step 10, a Φ1.2 316L stainless steel welding wire is used as the base transition layer.

[0022] Preferably, in the step 10, a Φ1.2 wear-resistant welding wire is used to build up the surface wear-resistant layer, and the chemical composition of the welding wire is: C≤0.4%, Mn 1.4-1.8%, Si 0.6-1.0%, Cr 5.5-8.5%, Mo 0.8-1.4%, W 0.9-1.3%, V 0.2-0.8%, other <0.5%, and the balance is Fe; wherein the chemical composition of the welding wire is in mass percent.

[0023] Preferably, in the step 10, the interlayer temperature is controlled to 100-150℃.

[0024] Preferably, in the step 11, the annealing temperature is 250-300℃, the holding time is 2-3 hours, and the furnace is cooled to 100℃ before the furnace is discharged and air-cooled.

[0025] Compared with the prior art, the present application has the advantages of:

[0026] 1) By selecting an alloy structural steel with better welding performance as the guide rail base material, the shortcomings of medium-carbon quenched and tempered steel guide rails that cannot be welded are overcome to adapt to different application installation conditions.

[0027] 2) The electric arc additive wear-resistant layer can obtain a more precise and deeper hard-facing layer thickness than medium-frequency quenching by controlling the layer thickness and number of layers to adapt to the hard-facing layer depth requirements of the guide rail under different load conditions.

[0028] 3) It is an additive welding process that can prevent cracks, which welds a transition layer on the base material, and then welds a hard-facing layer on the transition layer. The transition layer material is a stainless steel material with higher elongation than the base material and hard-facing layer material, which is not easy to crack due to its good ductility within a certain deformation range.

[0029] 4) By using a shape-retaining tooling and stress relief annealing, the stress generated during the additive process of the wear-resistant layer is eliminated, the deformation of the guide rail is avoided, and the consistency of the wear-resistant layer depth after machining is ensured. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 is a large circular arc surface guide rail structure schematic diagram of the embodiment of the present application.

[0031] Figure 2 is a guide rail cross-sectional schematic diagram of the embodiment of the present application.

[0032] REFERENCE NUMERALS:

[0033] First profile 1, second profile 2, third profile 3, fourth profile 4, fifth profile 5. DETAILED DESCRIPTION

[0034] The technical solution of the present application is to manufacture a guide rail by using additive and subtractive material combination method, forge the material into a guide rail blank, roughen the guide rail by subtractive method, then form the wear-resistant layer of the guide rail surface by additive method, and finally finish the guide rail by subtractive method.

[0035] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application.

[0037] like Figure 1 As shown, this embodiment provides a method for manufacturing a large arc-shaped guide rail using additive and subtractive materials, producing an arc-shaped guide rail with a diameter of 10m and a weight of 10t. The structure is shown in [see diagram]. Figure 1 The guide rail has a 175° arc surface and an "I" shaped cross-section. See details for the specific structure. Figure 2 Among them, surfaces 1, 2, 3, 4, and 5 are wear-resistant surfaces with a surface hardness of not less than HRC48 and a hardened layer depth of 6-10mm. The specific steps include:

[0038] Step 1: The material is forged into a ring. In this embodiment, Q345 material is used to forge the ring.

[0039] Step 2: The ring is fully annealed to eliminate forging stress.

[0040] Step 3: Rough turn the ring, leaving a machining allowance of 6-10mm.

[0041] Step 4: Stress-relieving annealing of the ring to eliminate cutting stress.

[0042] Step 5: Divide the ring into two guide rail blanks.

[0043] Step 6: Rough-machine the guide rail, leaving a machining allowance of 4-8mm.

[0044] Step 7: Stress-relieving annealing treatment of the guide rail to eliminate cutting stress.

[0045] Step 8: Semi-finish machine the guide rail, leaving a machining allowance of 3-5mm.

[0046] Step 9: Install the guide rail conformal fixture. The conformal fixture is a truss structure that forms a frame through bolting, increasing the rigidity of the guide rail and controlling its deformation.

[0047] Step 10: On the guide rail Figure 2As shown, the arc additive wear-resistant layer is sequentially added on the first profile 1, the second profile 2, the third profile 3, the fourth profile 4 and the fifth profile 5. The welding power source adopts a CMT welding machine, the wire feeding speed is 4-7 m / min, the welding speed is 6-9 mm / s, and the thickness of the surfacing layer is 2.0-2.5 mm. First, the printing area is wrapped and heated to 150-200°C by using an induction heating blanket before starting printing; then, Φ1.2 3l6L stainless steel wire is used as the backing transition layer, which has good combination with the guide rail base material and the wear-resistant layer material, avoiding cracking of the high-strength wear-resistant layer material when directly welded with the base material, the wire feeding speed is 7 m / min, the welding speed is 8 mm / s, and the thickness of the surfacing layer is 2 mm; finally, Φ1.2 wear-resistant wire is used to surfacing multiple wear-resistant layers, the chemical composition (wt.%) of the wire is: C 0.29%, Mn 1.6%, Si 0.9%, Cr 6.9%, Mo 1.2%, W 1.1%, V 0.22%, other <0.5%, and the balance is Fe, the wire feeding speed is 5 m / min, the welding speed is 6 mm / s, the thickness of the surfacing layer is 2.5 mm, and the number of surfacing layers is 4; after printing each layer, the surface oxide scale is cleaned and polished, and the interlayer temperature is controlled at 100-150°C.

[0048] Step 11: stress relief annealing treatment, annealing temperature 250-300°C, holding time 2-3 hours, furnace cooling to 100°C, and then air cooling.

[0049] Step 12: using turning and grinding combined machining method, finishing the guide rail, ensuring the guide rail precision requirements, removing the guide rail shape tooling, detecting the wear-resistant surface hard layer depth of 6-8 mm, and the surface hardness of HRC49-HRC54.

[0050] The large circular guide rail additive and subtractive combined manufacturing method comprises the following steps: 1) the alloy structural steel with good welding performance is selected as the guide rail base material, so that the shortcomings of the medium carbon quenched steel guide rail cannot be welded are overcome, and different application and installation conditions are adapted; 2) the electric arc additive wear-resistant layer can obtain more accurate and deeper hard surface layer thickness than the medium frequency quenching by controlling the layer thickness and the number of layers, so that the hard surface layer depth requirements of the guide rail under different bearing conditions are adapted; 3) the material welded by the electric arc additive wear-resistant layer belongs to the hard alloy, the hard alloy has high hardness but poor toughness and plasticity, cracks will appear on the surface after direct welding, the cracks affect the wear resistance on the one hand, and the cracks may expand in the later operation, once the cracks expand to the base material, an accident may be caused. The additive welding process can prevent the cracks, a transition layer is welded on the base material, and then a hard surface layer is welded on the transition layer, the transition layer material is a stainless steel material with higher elongation than the base material and the hard surface layer material, the transition layer material is not easy to crack in a certain deformation range due to the good ductility; 4) the stress generated in the additive process of the wear-resistant layer is eliminated by adopting the shape-retaining tooling and stress relief annealing, the guide rail deformation is avoided, and the consistency of the wear-resistant layer depth after machining is ensured.

[0051] The above only describes the preferred embodiments of the present application, and is not intended to limit the present application, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A method for manufacturing a large arc-shaped guide rail using additive and subtractive materials, characterized in that, Includes the following steps: Step 1: Forging the material into a ring; Step 2: Complete annealing of the ring; Step 3: Rough turn the ring; Step 4: Stress-relieving annealing treatment of the ring; Step 5: Divide the ring into guide rail blanks; Step 6: Rough machining of the guide rails; Step 7: Stress-relieving annealing treatment of the guide rail; Step 8: Semi-finish machining of the guide rails; Step 9: Install the guide rail conformal fixture; Step 10: Apply an arc additive wear-resistant layer to the guide rail substrate. Before printing, use an induction heating blanket to wrap and heat the printing area. Then, use austenitic stainless steel as the base layer for cladding. Then, weld multiple layers of wear-resistant material until the preset thickness is reached. After each layer is printed, clean and polish the oxide scale on the surface and control the interlayer temperature. Step 11: Stress-relieving annealing treatment; Step 12: Perform precision machining on the guide rail and remove the guide rail conformal fixture.

2. The method for manufacturing large arc-shaped guide rails using additive and subtractive materials according to claim 1, characterized in that, In step 1, the raw material is alloy structural steel.

3. The method for manufacturing a large arc-shaped guide rail using additive and subtractive materials according to claim 1, characterized in that, In step 9, the conformal fixture is a truss structure, which is formed by bolting to form a frame.

4. The method for manufacturing a large arc-shaped guide rail using additive and subtractive materials according to claim 1, characterized in that, In step 10, the welding power source is a CMT welding machine with a wire feed speed of 4-7 m / min, a welding speed of 6-9 mm / s, and a weld overlay thickness of 2.0-2.5 mm.

5. The method for manufacturing a large arc-shaped guide rail using additive and subtractive materials according to claim 1, characterized in that, In step 10, the preheating temperature range before printing is 150-200℃.

6. The method for manufacturing a large arc-shaped guide rail using additive and subtractive materials according to claim 1, characterized in that, In step 10, Φ1.2 3l6L stainless steel welding wire is used as the root pass.

7. The method for manufacturing a large arc-shaped guide rail using additive and subtractive materials according to claim 1, characterized in that, In step 10, a wear-resistant layer is deposited on the surface using Φ1.2 wear-resistant welding wire. The chemical composition of the welding wire is: C≤0.4%, Mn1.4~1.8%, Si0.6-1.0%, Cr5.5~8.5%, Mo0.8~1.4%, W0.9~1.3%, V0.2~0.8%, others <0.5%, and the balance is Fe; where the chemical composition of the welding wire is expressed as a mass percentage.

8. The method for manufacturing a large arc-shaped guide rail using additive and subtractive materials according to claim 1, characterized in that, In step 10, the interlayer temperature is controlled to 100-150℃.

9. The method for manufacturing a large arc-shaped guide rail using additive and subtractive materials according to claim 1, characterized in that, In step 11, the annealing temperature is 250-300℃, the holding temperature is 2-3 hours, and the furnace temperature is reduced to 100℃ before being removed from the furnace and air-cooled.

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