WE54 magnesium alloy CMT electric arc additive manufacturing process method

Abstract

The invention relates to a WE54 magnesium alloy CMT electric arc additive manufacturing process method, and belongs to the technical field of metal additive manufacturing. The method comprises the steps that 1, a CMT welding gun 1 is fixed to the front end of an automatic robot, printing parameters are set in 3DCAM software, a printing sample block is sliced through the 3DCAM software, and a printing path is planned; 2, surface oxides and impurities of a WE54 magnesium alloy substrate 12 are removed, the WE54 magnesium alloy substrate 12 is fixed to a working table top, the center and coordinate system of the WE54 magnesium alloy substrate 12 are determined through a welding wire 2 in a CMT welding gun 1, preheating treatment is conducted on the WE54 magnesium alloy substrate 12 through induction heating equipment, and the temperature is increased to 200 DEG C; and 3, a first cladding layer 10 is printed on the WE54 magnesium alloy substrate 12 through an electric arc 3 below the CMT welding gun 1, the surface is cleaned after printing is completed, and reciprocating printing of four-layer path planning is conducted in a reciprocating mode till a final printing sample block is formed. By means of the method, WE54 magnesium alloy CMT electric arc additive manufacturing is achieved, and the additive efficiency is effectively improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of metal additive manufacturing, and in particular relates to a WE54 magnesium alloy CMT arc additive manufacturing process method. Background Art

[0002] At present, most magnesium alloy parts are manufactured by traditional methods such as machining, casting or die casting. However, the traditional manufacturing methods of lightweight parts have great limitations in size and optimized design, and cannot meet the integrated manufacturing needs of large and complex structures.

[0003] The WAAM process uses an arc (MIG, TIG, plasma) as a heat source and metal welding wire as a filler material. Compared with traditional manufacturing methods, it can produce large and complex structures with less time and material. In addition, the equipment construction investment is relatively small.

[0004] At present, the research results on the microstructure and mechanical properties of WE54 magnesium alloy are mainly obtained under traditional manufacturing conditions, and there is no relevant report on the WE54 arc CMT additive manufacturing process. Therefore, it is necessary to clarify the microstructure and mechanical properties of WE54 arc CMT additive manufacturing and before and after heat treatment. Finally, it is proved that WAAM is a low-cost and rapid prototyping manufacturing method suitable for WE54, thereby improving the efficiency of magnesium alloy additive manufacturing. Summary of the invention

[0005] 1. Technical issues to be resolved

[0006] The technical problem to be solved by the present invention is how to provide a WE54 magnesium alloy CMT arc additive manufacturing process method to solve the problem that traditional manufacturing methods have great limitations in magnesium alloy size and optimized design and cannot meet the integrated manufacturing needs of large and complex structures.

[0007] (II) Technical solution

[0008] In order to solve the above technical problems, the present invention proposes a WE54 magnesium alloy CMT arc additive manufacturing process method, comprising the following steps:

[0009] Step 1: Fix the CMT welding gun 1 to the front end of the automated robot, set the printing parameters in the 3DCAM software, slice the printed sample through the 3DCAM software, and plan the printing path;

[0010] Step 2: remove surface oxides and impurities from the WE54 magnesium alloy substrate 12, fix it on the work surface, determine the center and coordinate system of the WE54 magnesium alloy substrate 12 through the welding wire 2 in the CMT welding gun 1, and preheat the WE54 magnesium alloy substrate 12 through the induction heating equipment to raise the temperature to 200° C.;

[0011] Step 3: Print the first cladding layer 10 on the WE54 magnesium alloy substrate 12 through the arc 3 under the CMT welding gun 1. After printing, clean the surface and perform reciprocating printing with 4-layer path planning until the final printed sample is formed.

[0012] Among them, in the step 1, the 3DCAM software plans the printing path for the print sample block by setting the CMT welding gun 1 processing path, and the specific setting is: the first layer path planning 11, the second layer path planning 9, the third layer path planning 7 and the fourth layer path planning 5 all adopt serpentine reciprocating path planning, and the serpentine reciprocating path spacing is set to 2.2mm. The arc starting and arc ending point positions of the four-layer path planning are staggered, and the starting point of the next layer is placed on the side of the arc ending.

[0013] The thickness of the first cladding layer 10 is set to 3.2 mm, and the thickness of the second cladding layer 8, the third cladding layer 6 and the fourth cladding layer 4 are all set to 2.8 mm.

[0014] The parameters set in the DCAM software in step 1 include: the scanning speed is set to 0.02 m / s, and the inter-layer waiting time is set to 30 s.

[0015] Wherein, before processing the first cladding layer 10 in step 3, the external parameters of the CMT welding gun 1 are adjusted, the wire feeding speed is set to 6.5 m / min, the current is 132 A, the shielding gas is argon, and the gas flow rate is 22 L / min.

[0016] Among them, after the first layer of cladding layer 10 in step 3 is processed, the wire feeding speed of the CMT welding gun 1 is adjusted to 5.5m / min, the current is changed to 102A, and the other parameters remain unchanged. The temperature of the current first layer of cladding layer 10 is measured by a temperature measuring gun. When the temperature is lower than 100°C, the second layer of cladding layer 8 is printed.

[0017] Among them, in the step 3, the formed printed sample piece together with the WE54 magnesium alloy substrate 12 is subjected to a heat treatment process of keeping at 525° C. for 8 hours and then water quenching at 80° C. to complete the printing work.

[0018] Among them, by placing the starting point of the next layer of processing of the printed sample block on the side of the arc closure, the heat accumulation at the arc starting point is ensured, so that the starting point WE54 welding wire 2 melts more fully.

[0019] The WE54 magnesium alloy substrate 12 has a size of 200mmx200mmx20mm.

[0020] (III) Beneficial effects

[0021] The present invention proposes a WE54 magnesium alloy CMT arc additive manufacturing process method, which realizes WE54 magnesium alloy CMT arc additive manufacturing, effectively improves additive efficiency, and controls the forming stability and consistency of WE54 magnesium alloy CMT arc printing, achieving higher mechanical properties of formed parts than castings, and verifies the feasibility of WE54 magnesium alloy arc additive manufacturing. It lays a solid foundation for new magnesium alloy manufacturing methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the additive manufacturing surfacing method of the present invention. DETAILED DESCRIPTION

[0023] In order to make the purpose, content and advantages of the present invention more clear, the specific implementation methods of the present invention are further described in detail below in conjunction with the drawings and examples.

[0024] This embodiment provides a WE54 magnesium alloy CMT arc additive manufacturing process method, comprising the following steps:

[0025] Step 1: Fix the CMT welding gun 1 to the front end of the automated robot, set the printing parameters in the 3DCAM software, slice the printed sample through the 3DCAM software, and plan the printing path;

[0026] Step 2: remove surface oxides and impurities from the WE54 magnesium alloy substrate 12, fix it on the work surface, determine the center and coordinate system of the WE54 magnesium alloy substrate 12 through the welding wire 2 in the CMT welding gun 1, and preheat the WE54 magnesium alloy substrate 12 through the induction heating equipment to raise the temperature to 200° C.;

[0027] Step 3: Print the first cladding layer 10 on the WE54 magnesium alloy substrate 12 through the arc 3 under the CMT welding gun 1. After printing, clean the surface and perform reciprocating printing with 4-layer path planning until the final printed sample is formed.

[0028] Among them, in the step 1, the 3DCAM software plans the printing path for the print sample block by setting the CMT welding gun 1 processing path, and the specific setting is: the first layer path planning 11, the second layer path planning 9, the third layer path planning 7 and the fourth layer path planning 5 all adopt serpentine reciprocating path planning, and the serpentine reciprocating path spacing is set to 2.2mm. The arc starting and arc ending point positions of the four-layer path planning are staggered, and the starting point of the next layer is placed on the side of the arc ending.

[0029] The thickness of the first cladding layer 10 is set to 3.2 mm, and the thickness of the second cladding layer 8, the third cladding layer 6 and the fourth cladding layer 4 are all set to 2.8 mm.

[0030] The parameters set in the DCAM software in step 1 include: the scanning speed is set to 0.02 m / s, and the inter-layer waiting time is set to 30 s.

[0031] Wherein, before processing the first cladding layer 10 in step 3, the external parameters of the CMT welding gun 1 are adjusted, the wire feeding speed is set to 6.5 m / min, the current is 132 A, the shielding gas is argon, and the gas flow rate is 22 L / min.

[0032] Among them, after the first layer of cladding layer 10 in step 3 is processed, the wire feeding speed of the CMT welding gun 1 is adjusted to 5.5m / min, the current is changed to 102A, and the other parameters remain unchanged. The temperature of the current first layer of cladding layer 10 is measured by a temperature measuring gun. When the temperature is lower than 100°C, the second layer of cladding layer 8 is printed.

[0033] Among them, in the step 3, the formed printed sample piece together with the WE54 magnesium alloy substrate 12 is subjected to a heat treatment process of keeping at 525° C. for 8 hours and then water quenching at 80° C. to complete the printing work.

[0034] Among them, by placing the starting point of the next layer of processing of the printed sample block on the side of the arc closure, the heat accumulation at the arc starting point is ensured, so that the starting point WE54 welding wire 2 melts more fully.

[0035] The WE54 magnesium alloy substrate 12 has a size of 200mmx200mmx20mm.

[0036] Example 1

[0037] A CMT arc additive manufacturing process for WE54 magnesium alloy. The material used in the experiment is a WE54 magnesium alloy substrate of 200mmx200mmx20mm, and a customized WE54 magnesium alloy welding wire with a diameter of φ1.2mm is used. The substrate is subjected to a 200℃ prediction treatment before printing. The actuator used in the experiment is a KUKA-KR70HA robot system, the cladding power source is a Fronius-CMT Advanced-4000R welding system, and the welding gun has a push-pull mechanism. The CMT+pulsed+Advanced unified expert library process is adopted. The first layer printing parameters ensure full bonding with the substrate, and a large wire feeding speed and current are selected, which are a wire feeding speed of 6.5m / min, a current of 132A, a welding speed of 0.02m / s, a layer height of 3.2mm, an interlayer cooling time of 30s, an argon gas as the shielding gas, and a gas flow of 22L / min. The parameters for the second layer and beyond are fixed as follows: wire feeding speed of 5.5m / min, current of 102A, welding speed of 0.02m / s, layer height of 2.8mm, interlayer cooling time of 30s (to ensure that the temperature of the layer before printing is lower than 100℃ to prevent metal shrinkage defects caused by interlayer overheating), shielding gas of argon, and gas flow of 22L / min. Figure 1 As shown in the figure, the additive manufacturing cladding method adopted is a layer-by-layer serpentine reciprocating scanning trajectory, the purpose of which is to gather the heat of the arc cladding layer, fully melt the magnesium alloy welding wire metal, and ensure that the cladding metal is fully connected with the previous cladding layer and there is no unfused defect. The starting and closing points of the four layers are alternated and reciprocated in turn to prevent the edge collapse of the arc closing position due to the large heat input, and to make the heat distribution uniform, and to prevent stress deformation caused by the accumulation of thermal stress due to excessive heat concentration. After each layer is printed, the cladding layer is cleaned to prevent the smoke and dust remaining in the current printing layer from affecting the printing of the next layer, which can effectively reduce printing defects such as slag inclusions and pores. Therefore, the printing quality and forming stability of WE54 magnesium alloy parts can be effectively improved. After the performance sample is printed, it is heat treated in the T4 state (525℃ insulation for 8h and then 80℃ water quenching). The microstructure of the sample is evenly distributed with equiaxed crystals, without metallurgical defects such as pores, cracks and unfused, and some white granular second phases are evenly distributed on the matrix. The average transverse tensile strength, yield strength, elongation and cross-sectional shrinkage of the T4 state sample were 217MPa, 139MPa, 4.2% and 8% respectively. The average longitudinal tensile strength, yield strength, elongation and cross-sectional shrinkage of the T4 state sample were 215MPa, 140MPa, 4% and 6% respectively.

[0038] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A WE54 magnesium alloy CMT arc additive manufacturing process, characterized in that: The following steps are involved: Step 1: Fix the CMT welding gun (1) to the front end of the automated robot, set the printing parameters in the 3DCAM software, slice the printed sample block through the 3DCAM software, and plan the printing path; Step 2: removing surface oxides and impurities from the WE54 magnesium alloy substrate (12), fixing the substrate on a work surface, determining the center and coordinate system of the WE54 magnesium alloy substrate (12) by means of a welding wire (2) in a CMT welding gun (1), and preheating the WE54 magnesium alloy substrate (12) by means of an induction heating device, raising the temperature to 200° C.; Step 3: Print the first cladding layer (10) on the WE54 magnesium alloy substrate (12) through the arc (3) below the CMT welding gun (1). After printing, clean the surface and perform reciprocating printing with 4-layer path planning until the final printed sample is formed.

2. The WE54 magnesium alloy CMT arc additive manufacturing process according to claim 1, characterized in that: In the step 1, the 3DCAM software plans the printing path for the printing sample block by setting the CMT welding gun (1) processing path, and the specific setting is: the first layer path planning (11), the second layer path planning (9), the third layer path planning (7) and the fourth layer path planning (5) all adopt serpentine reciprocating path planning, the serpentine reciprocating path spacing is set to 2.2mm, the arc starting and arc ending point positions of the four-layer path planning are staggered, and the starting point of the next layer is placed on the side of the arc ending.

3. The WE54 magnesium alloy CMT arc additive manufacturing process according to claim 1, characterized in that: The thickness of the first cladding layer (10) is set to 3.2 mm, and the thickness of the second cladding layer (8), the third cladding layer (6) and the fourth cladding layer (4) are all set to 2.8 mm.

4. The WE54 magnesium alloy CMT arc additive manufacturing process according to claim 1, characterized in that: The parameters set in the DCAM software in step 1 include: the scanning speed is set to 0.02 m / s, and the inter-layer waiting time is set to 30 s.

5. The WE54 magnesium alloy CMT arc additive manufacturing process according to claim 1, characterized in that: Before processing the first cladding layer (10) in step 3, the external parameters of the CMT welding gun (1) are adjusted, the wire feeding speed is set to 6.5 m / min, the current is 132 A, the shielding gas is argon, and the gas flow rate is 22 L / min.

6. The WE54 magnesium alloy CMT arc additive manufacturing process according to claim 1, characterized in that: After the first cladding layer (10) is processed in step 3, the wire feeding speed of the CMT welding gun (1) is adjusted to 5.5 m / min, the current is changed to 102 A, and the other parameters remain unchanged. The temperature of the current first cladding layer (10) is measured by a temperature measuring gun. When the temperature is lower than 100° C., the second cladding layer (8) is printed.

7. The WE54 magnesium alloy CMT arc additive manufacturing process according to claim 1, characterized in that: In step 3, the formed printed sample piece together with the WE54 magnesium alloy substrate (12) is subjected to a heat treatment process of being kept at 525° C. for 8 hours and then water quenched at 80° C. to complete the printing work.

8. The WE54 magnesium alloy CMT arc additive manufacturing process according to claim 2, characterized in that: By placing the next processing starting point of the printed sample block on the side of the arc extinguishing, the heat accumulation at the arc starting point is ensured, so that the WE54 welding wire (2) at the starting point can be melted more fully.

9. The WE54 magnesium alloy CMT arc additive manufacturing process according to claim 1, characterized in that: The WE54 magnesium alloy substrate (12) has a size of 200mmx200mmx20mm.

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