Powder forming process for an aluminum alloy automotive crash box

Abstract

The application relates to a powder forming process of an aluminum alloy automobile crash box and belongs to the technical field of automobile passive safety protection. The powder forming process of the aluminum alloy automobile crash box can solve the problems that the existing aluminum alloy automobile crash box manufacturing process is difficult to form a complex structure crash box, the manufacturing process flow is complicated, and the cycle is long. The powder forming process of the aluminum alloy automobile crash box comprises the following steps: a certain amount of pure metal ingot and / or alloy ingot is weighed according to the aluminum alloy component proportion; the pure metal ingot and the alloy ingot are vacuum melted to obtain pre-alloy ingots; the pre-alloy ingots are atomized to obtain pre-alloy powder; the pre-alloy powder is treated by a mesh screen to obtain pre-alloy powder meeting size and shape requirements; the pre-alloy powder obtained through screening is subjected to vacuum drying treatment; and the pre-alloy powder is formed into a target aluminum alloy automobile crash box through an additive manufacturing process. The application can realize forming of various complex structure aluminum alloy automobile crash boxes, does not need a heat treatment process, is simple in process, and is short in processing cycle.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of automobile passive safety protection technology, and particularly relates to a powder forming process of an aluminum alloy automobile crash box. BACKGROUND

[0002] The crash energy absorption device is an important backup safety protection system of a train, a bullet train, an automobile and the like, and mainly absorbs energy through self-collapse deformation, so as to reduce personnel casualties in a collision safety accident. According to the characteristics of the crash energy absorption device, the material used for the device needs to have moderate strength, good toughness, high energy absorption, light weight, good welding performance and good formability, so as to meet the needs of the crash energy absorption device of the transportation tool under different conditions.

[0003] Taking the automobile crash box as an example, aluminum alloy is the main application material of the crash box, and is generally formed by blank stamping. However, the stamping forming can only complete the forming of simple structures of the automobile crash box, such as quadrilateral, hexagonal or octagonal structures, and is difficult to form a complex structure automobile crash box. Moreover, in the process of forming the multi-edge structure aluminum alloy crash box by the stamping forming process, the edges and corners are prone to cracking, the stamping parameters are strictly required, and the process needs to go through processes such as mold making, stamping, annealing, pickling, hardening and heat treatment. The process is relatively complicated, the energy consumption is large, the factory occupies a large area, and the cycle is long.

[0004] The additive manufacturing technology uses powder and wire as raw materials, and realizes free forming through the establishment of a three-dimensional model and slicing, which is the best way to form a complex shape component. However, traditional aluminum alloys, such as 5083 (aluminum-magnesium alloy) and 6063 (aluminum-silicon alloy), are prone to printing cracks in the printing process, and cannot meet the use requirements of additive manufacturing. The existing aluminum alloy products obtained by adjusting the composition of the aluminum alloy for additive manufacturing have high strength and high density, but low toughness, and cannot meet the performance requirements of the automobile crash box. Therefore, there is an urgent need for a forming method of the aluminum alloy automobile crash box, which can form a complex structure automobile crash box and meet the performance requirements thereof. SUMMARY

[0005] In view of the above analysis, the embodiments of the present application aim to provide a powder forming process of an aluminum alloy automobile crash box, which can solve at least one of the following technical problems: 1. The existing aluminum alloy automobile crash box manufacturing process is difficult to form a complex structure automobile crash box; 2. The existing aluminum alloy automobile crash box manufacturing process is complicated and has a long cycle; and 3. The alloy product prepared by using the existing aluminum alloy for additive manufacturing process does not meet the use requirements of the automobile crash box, and cannot be used to prepare the automobile crash box.

[0006] The purpose of the present application is achieved by the following technical solutions:

[0007] The application provides a powder forming process of an aluminum alloy automobile crash box, comprising the following steps:

[0008] Step 1: a certain amount of pure metal ingot and / or alloy ingot is weighed according to the aluminum alloy component ratio;

[0009] Step 2: the pure metal ingot and the alloy ingot are vacuum melted to obtain a pre-alloy ingot;

[0010] Step 3: the pre-alloy ingot is atomized to obtain a pre-alloy powder;

[0011] Step 4: the pre-alloy powder is screened through a screen to obtain a pre-alloy powder meeting the size and shape requirements;

[0012] Step 5: the pre-alloy powder meeting the size and shape requirements obtained through screening is subjected to vacuum drying treatment;

[0013] Step 6: the pre-alloy powder is formed into a target aluminum alloy automobile crash box shape through an additive manufacturing process.

[0014] Further, the component ratio of the target aluminum alloy automobile crash box is as follows in terms of mass percentage: Mg: 2.5-4.5%, Zr: 0.15-1.65%, Mn: 0.51-2.0%, Si: 0.1-1.5%, Sc≤0.5%, Zn≤0.5%, Ti≤0.5%, Fe≤0.4%, Er≤0.5%, Y≤0.5%, Sc+Er+Y: 0-0.5%, Mg+Mn: 3.0-5.5%, and the rest is Al and non-removable impurity elements.

[0015] Further, the component ratio of the target aluminum alloy automobile crash box is as follows in terms of mass percentage: Mg: 3.0-3.5%, Zr: 0.15-1.2%, Mn: 0.6-0.74%, Si: 0.5-0.8%, Sc≤0.5%, Zn≤0.5%, Ti≤0.5%, Fe≤0.4%, Er≤0.5%, Y≤0.5%, Sc+Er+Y: 0-0.5%, Mg+Mn: 4.10-4.24%, and the rest is Al and non-removable impurity elements.

[0016] Further, the powder forming process further comprises 2-3 times of sand blasting treatment on the target aluminum alloy automobile crash box obtained in step 6.

[0017] Further, in step 2, the vacuum melting comprises the following steps:

[0018] S21: the weighed Al ingot is placed into a crucible of a vacuum medium-frequency induction furnace, vacuum is drawn, and when the vacuum degree is less than 1*10 -2Pa, start heating and filling argon to make the furnace in a positive pressure environment;

[0019] S22: according to the melting point of the ingot, other pure metal ingots and / or alloy ingots are sequentially put in from high to low, after complete melting, degassing, stirring and pouring to obtain a pre-alloy ingot.

[0020] Further, in step 3, the atomization powder is completed by an argon atomization method, the atomization pressure is 1.5-4.5MPa, and the atomization temperature is 700-850℃.

[0021] Further, in step 4, the size of the pre-alloy powder is 15-105μm, and the powder shape is near-spherical or spherical.

[0022] Further, in step 5, the drying temperature of the vacuum drying is 100-140℃, and the drying time is 2-8h.

[0023] Further, the additive manufacturing process is selective laser melting, and the substrate of the selective laser melting equipment is preheated, and the preheating temperature is 25-350℃.

[0024] Further, the selective laser melting parameters are: the scanning power is 190-350W, the scanning speed is 200-800mm / s, the powder laying thickness is 0.01-0.05mm, and the scanning spacing is 0.05-0.1mm.

[0025] Compared with the prior art, the present application can at least achieve one of the following beneficial effects:

[0026] 1. The present application can realize the forming of various complex structure aluminum alloy automobile crash boxes by controlling the component proportion of the target aluminum alloy automobile crash box and forming the target structure by the additive manufacturing process, and can meet the structure requirements of different vehicle models for the crash box; the forming process does not need a heat treatment process, the process is simple, the weight of the automobile crash box is reduced, the processing cycle of the automobile crash box is greatly shortened, and the equipment demand is reduced; compared with the existing stamping technology for forming aluminum alloy automobile crash boxes, the processing cycle is shortened from more than one month to one week.

[0027] 2. The present application can obtain an automobile crash box with a tensile strength ≥220MPa, a yield strength ≥200MPa and an elongation ≥20%, and has good strength and toughness, by controlling the component proportion of the target aluminum alloy automobile crash box and forming the target structure by the additive manufacturing process.

[0028] 3. The present application can obtain a single automobile crash box with an absorption energy ≥4KJ, which is higher than that of the aluminum alloy crash box formed by stamping, by controlling the component proportion of the target aluminum alloy automobile crash box and forming the target structure by the additive manufacturing process.

[0029] 4、The shaped aluminum alloy automobile crash box of the present application does not need heat treatment in the shaping process, and can realize energy saving and emission reduction compared with the traditional stamping shaped crash box.

[0030] 5、The existing stamping shaped aluminum alloy automobile crash box is prone to corner cracking in the shaping process, and the yield rate is relatively low, the shaped aluminum alloy automobile crash box of the present application is shaped by controlling the component proportion of the target aluminum alloy automobile crash box and combining the additive manufacturing process, and the yield rate is basically 100%, which greatly improves the yield rate of the aluminum alloy automobile crash box.

[0031] In the present application, the above technical solutions can be combined with each other to realize more preferred combination solutions. Other features and advantages of the present application will be described in the subsequent specification, and some advantages will become apparent from the specification, or will be understood by implementing the present application. The purpose and other advantages of the present application can be realized and obtained from the contents specifically pointed out in the specification and the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0032] The accompanying drawings are included to provide a further understanding of the present application and are incorporated in and constitute a part of this specification, illustrate embodiments of the present application and serve to explain the principles of the present application, and are not intended to limit the scope of the present application.

[0033] Figure 1 Figure 1 is a schematic diagram of the shape of the target aluminum alloy automobile crash box of embodiment 1 of the present application;

[0034] Figure 2 Figure 2 is a microstructure diagram of the target aluminum alloy automobile crash box of embodiment 1 of the present application;

[0035] Figure 3 Figure 3 is a schematic diagram of the shape of the target aluminum alloy automobile crash box of embodiment 3 of the present application;

[0036] Figure 4 Figure 4 is a microstructure diagram of the target aluminum alloy automobile crash box of comparative example 2 of the present application. DETAILED DESCRIPTION

[0037] The preferred embodiments of the present application will be specifically described below in conjunction with the drawings, wherein the drawings constitute a part of this application, and are used to illustrate the principles of the embodiments of the present application, and are not intended to limit the scope of the present application.

[0038] The present application provides a powder forming process for an aluminum alloy automobile crash box, comprising the following steps:

[0039] Step 1: weigh a certain amount of pure metal ingot and / or alloy ingot according to the component proportion of the aluminum alloy;

[0040] Step 2: melt the pure metal ingot and / or alloy ingot by vacuum melting to obtain a pre-alloy ingot;

[0041] Step 3: The pre-alloy ingot is atomized to obtain a pre-alloy powder;

[0042] Step 4: The pre-alloy powder is sieved through a screen to obtain a pre-alloy powder meeting the size and shape requirements;

[0043] Step 5: The pre-alloy powder meeting the size and shape requirements obtained by sieving is subjected to vacuum drying treatment;

[0044] Step 6: The pre-alloy powder is formed into a target aluminum alloy automobile crash box shape through an additive manufacturing process.

[0045] The existing aluminum alloy automobile crash box mainly adopts a 6-series aluminum alloy and is manufactured through stamping forming. The shape is usually quadrilateral, hexagonal or octagonal, and it is difficult to form a complex structure automobile crash box. The energy absorption of the formed crash box is low, and the single absorption energy is about 3.2 KJ. In the stamping forming process, the processes of mold making, grinding, pickling, hardening and heat treatment need to be experienced, and the production cycle is long, usually more than one month. The powder forming process of the aluminum alloy automobile crash box of the present application does not need a heat treatment process, and the forming cycle is usually one week. The required equipment is only a 3D printer and a sandblasting equipment, which greatly shortens the process flow and cycle, and reduces the demand for factory and labor. The aluminum alloy automobile crash box formed by the method of the present application has a mass of less than 300 g, a tensile strength of ≥220 Mpa, a yield strength of ≥200 Mpa and an elongation of ≥20%. The aluminum alloy automobile crash box has good strength and toughness, and the single automobile crash box has an energy absorption of ≥4 KJ, which is higher than that of the stamping formed aluminum alloy crash box.

[0046] Specifically, in step 1, the component ratio of the target aluminum alloy automobile crash box is 2.5-4.5% of Mg, 0.15-1.65% of Zr, 0.51-2.0% of Mn, 0.1-1.5% of Si, ≤0.5% of Sc, ≤0.5% of Zn, ≤0.5% of Ti, ≤0.4% of Fe, ≤0.5% of Er, ≤0.5% of Y, 0-0.5% of Sc+Er+Y, 3.0-5.5% of Mg+Mn, and the rest is Al and non-removable impurity elements.

[0047] The component ratio of the target aluminum alloy automobile crash box in the present application is limited as follows, and only % is used to represent the mass percentage in the composition:

[0048] Mg: forms a strengthening phase with silicon elements, which can improve the strength and yield limit and improve the cutting machinability of the aluminum alloy, but is easy to oxidize and burn in the smelting process; if the Mg content is too high, undissolved phases will be formed, and if the Mg content is too low, the strengthening effect will be insufficient and the alloy performance will not be high; the Mg content is controlled in the range of 2.5-4.5%.

[0049] Zr: modification element, promotes the formation of equiaxed crystals, reduces the printing cracking tendency of aluminum alloy, when the content is lower than 0.15%, the printing formability of aluminum alloy cannot be modified, when the content exceeds 1.65%, the improvement of the printing formability of aluminum alloy is limited, and the density of the aluminum alloy is significantly improved; therefore, the content of Zr is controlled to be 0.15-1.65%.

[0050] Mn: improves the yield strength and collapse energy absorption effect of the aluminum alloy, when the content of Mn increases by 0.1%, the strength of the alloy increases by 5-7 MPa, when the content of manganese is too much, coarse and brittle Al6Mn phases are formed, which damages the toughness of the aluminum alloy; considering the strength and toughness of the automobile crash box, the content of Mn is controlled to be 0.51-2.0%, the content of Mn element in the application is relatively low, and the forming method does not have a heat treatment process, so that the Al6Mn phase which damages the toughness of the aluminum alloy basically does not exist.

[0051] Si: modification element, reduces the printing cracking tendency of the aluminum alloy, thereby reducing the addition of Zr and Sc, and improving the welding performance and strength of the aluminum alloy, when the content is too low, the printing performance cannot be improved, and when the content is too high, Si is precipitated along the grain boundary network, which affects the toughness of the material and needs to be eliminated by heat treatment, thereby increasing the process flow; therefore, the content of Si is controlled to be 0.1-1.5%.

[0052] Sc: modification element, reduces the printing cracking tendency of the aluminum alloy, so that the aluminum alloy has good formability, when the content exceeds 0.5%, the strength of the aluminum alloy is too high, which cannot match the strength of the bumper beam, and the material cost is increased; therefore, the content of Sc is controlled to be ≤0.5%.

[0053] Zn: improves the corrosion resistance of the aluminum alloy, and the content of Zn is usually controlled to be below 0.5%.

[0054] Ti: deoxidizing element, controls the oxygen content of the aluminum alloy, and when the content is too high, brittle phases are easily precipitated, and the content of Ti is usually controlled to be below 0.5%.

[0055] Fe: improves the recrystallization temperature of the aluminum alloy and the strength of the alloy, but when the content is too high, the corrosion resistance and mechanical properties of the alloy are damaged, and the content of Fe is usually controlled to be below 0.4%.

[0056] Er+Y: modification element, reduces the printing cracking tendency of the aluminum alloy, so that the aluminum alloy has good formability, when the content exceeds 0.5%, the formability of the aluminum alloy is not obviously improved; therefore, the content of Er+Y is controlled to be ≤0.5%.

[0057] Mg+Mn: the synergistic effect of Mg element and Mn element can improve the strength and plasticity matching performance of the aluminum alloy, and improve the yield strength of the aluminum alloy, so that the yield strength requirement of the aluminum alloy can be met without heat treatment in the forming process. When the content is less than 3.00%, the improvement of the strength and plasticity matching performance and the yield strength of the aluminum alloy is not obvious, and the requirement cannot be met. When the content is higher than 5.5%, the toughness of the aluminum alloy is damaged. In combination, the content of Mg+Mn is controlled to be 3.0-5.5%.

[0058] Preferably, the component ratio of the target aluminum alloy automobile crash box is as follows in terms of mass percentage: Mg: 2.5-4.5%, Zr: 0.15-1.65%, Mn: 0.51-2.0%, Si: 0.1-1.5%, Zn≤0.5%, Ti≤0.5%, Fe≤0.4%, Mg+Mn: 3.0-5.5%, and the rest is Al and non-removable impurity elements.

[0059] Preferably, the component ratio of the target aluminum alloy automobile crash box is as follows in terms of mass percentage: Mg: 3.0-3.5%, Zr: 0.15-1.2%, Mn: 0.6-0.74%, Si: 0.5-0.8%, Sc≤0.5%, Zn≤0.5%, Ti≤0.5%, Fe≤0.4%, Er≤0.5%, Y≤0.5%, Sc+Er+Y: 0-0.5%, Mg+Mn: 4.10-4.24%, and the rest is Al and non-removable impurity elements.

[0060] Specifically, in step 1, a certain amount of pure metal ingot and / or alloy ingot is weighed according to the component ratio, the pure metal ingot includes Al ingot, Mg ingot, Zr ingot, Mn ingot, Zn ingot, Ti ingot, Er ingot, Sc ingot and Y ingot; the alloy ingot includes Al-Mg intermediate alloy, Al-Si intermediate alloy, Al-Mg-Si intermediate alloy, Al-Sc intermediate alloy, Al-Zn intermediate alloy and Al-Ti intermediate alloy, and is ready for use.

[0061] Specifically, in step 2, the vacuum melting includes the following steps:

[0062] S21: Put the weighed Al ingot into the crucible of the vacuum medium-frequency induction furnace, and vacuumize. When the vacuum degree is less than 1*10 -2 Pa, start heating and fill argon to make the furnace in a positive pressure environment;

[0063] S22: Put other pure metal ingots and / or alloy ingots into the furnace in turn according to the melting point of the ingot from high to low. After complete melting, degassing, stirring and pouring to obtain a pre-alloy ingot.

[0064] Specifically, in step S21, the Al ingot is heated at a heating rate of 5-20℃ / s, and the heating is stopped when the temperature in the furnace reaches 700-850℃, and the holding time is 0.5-2h. In this temperature range, the Al ingot is completely melted and in a liquid state.

[0065] Specifically, in step S22, the other pure metal ingots and alloy ingots are sequentially placed in the order of the melting point of the ingots from high to low, and after the alloy ingot is completely melted, hexachloroethane is added for degassing, and then electromagnetic stirring is performed at a speed of 200-500r / min to mix the elements uniformly, and after holding and calming for 30-40min, pouring is started, the pouring temperature is 700-850℃, and the pouring alloy flow rate is 5-10Kg / min.

[0066] Specifically, in step 3, atomization and powdering can be achieved by nitrogen gas atomization method, argon gas atomization method, plasma rotary atomization method, etc.; preferably, atomization and powdering are completed by argon gas atomization method, the atomization pressure is 1.5-4.5MPa, and the atomization temperature is 700-850℃.

[0067] Specifically, in step 4, the pre-alloy powder is sieved through a 100-1000 mesh screen to obtain a pre-alloy powder that meets the size and shape requirements, the size of the pre-alloy powder is 15-105μm, and the powder shape is near-spherical or spherical, so that the flowability of the powder can be ensured; preferably, the size of the pre-alloy powder is 15-53μm.

[0068] Specifically, in step 5, the pre-alloy powder that meets the size and shape requirements obtained by sieving is subjected to vacuum drying treatment in a vacuum oven, the drying temperature is 100-140℃, and the drying time is 2-8h; if the drying temperature is too high and the drying time is too long, the powder surface will be severely oxidized, and if the drying temperature is too low and the time is too short, the moisture in the powder cannot be completely removed, affecting the sintering activity of the powder.

[0069] Specifically, in step 6, the additive manufacturing process, preferably, the pre-alloy powder is formed into a target aluminum alloy automobile crash box shape by selective laser melting (SLM). The additive manufacturing parameters are: scanning power is 190-350W, scanning speed is 200-800mm / s, powder laying thickness is 0.01-0.05mm, and scanning spacing is 0.05-0.1mm. The substrate of the selective laser melting equipment is preheated, and the preheating temperature is 25-350℃, the main purpose is to promote the nucleation of aluminum alloy equiaxed crystals and reduce the cracking tendency of aluminum alloy printing.

[0070] Specifically, after removing the substrate for additive manufacturing, the aluminum alloy automobile crash box obtained in step 6 can also be subjected to 2-3 times of sandblasting treatment to obtain an aluminum alloy automobile crash box with a smooth surface; for the aluminum alloy automobile crash box that does not have special requirements for surface smoothness, this step can be omitted.

[0071] It is emphasized that the forming process does not need to heat treat the aluminum alloy powder, and the automobile crash box meeting the performance requirements can be formed; the process is simple, the machining cycle of the automobile crash box is greatly shortened while the weight of the automobile crash box is reduced, and the equipment demand is reduced; compared with the existing stamping technology forming the aluminum alloy automobile crash box, the machining cycle is shortened from more than one month to one week.

[0072] The aluminum alloy automobile crash box prepared by the method has no crack, the microstructure morphology is fish scale shape, and the grain is bimodal grain distribution; the bimodal grain distribution of the aluminum alloy in the application is mainly related to Zr, Al3Zr, Al3(Sc, Zr) and other particles are precipitated at the boundary of the molten pool during the printing process, which provides nucleation sites and promotes the formation of equiaxed grains, which can improve the strength of the alloy and inhibit the propagation of cracks; the synergistic effect of Mg element and Mn element can improve the strength and plasticity matching performance of the aluminum alloy, improve the yield strength of the aluminum alloy, so that the yield strength requirement of the aluminum alloy can be met without heat treatment in the forming process, and the material suitable for powder forming of the aluminum alloy crash box can be obtained and the performance requirements of the crash box can be met.

[0073] The mechanical properties of the automobile crash box in China are usually required to be: tensile strength 220-400 MPa, yield strength 200-300 MPa, elongation ≥12%, the tensile strength of the aluminum alloy crash box prepared by the application is 280-380 MPa, the yield strength is 240-310 Mpa, and the elongation is ≥21%, which is better than the performance requirements of the automobile industry in China for the crash box; at the same time, the single crash box can absorb energy ≥4 KJ, which can meet the low-speed crash energy absorption requirement.

[0074] Example 1

[0075] An aluminum alloy automobile crash box powder forming process, comprising the following steps:

[0076] Step 1: a certain amount of pure metal ingot and / or alloy ingot is weighed according to the aluminum alloy component ratio;

[0077] The component ratio of the target aluminum alloy automobile crash box is 3.5% of Mg, 1.2% of Zr, 0.74% of Mn, 0.5% of Si, 0.03% of Fe, 0.02% of Ti, and the rest is Al and non-removable impurity elements.

[0078] According to the component ratio, Al ingot, Mg ingot, Zr ingot, Mn ingot, Ti ingot and Al-Si ingot with a purity of more than 99% are weighed, a total of 12 kg.

[0079] Step 2: pure metal ingot and alloy ingot are melted by vacuum melting to obtain pre-alloyed ingot;

[0080] S21: Place the weighed aluminum ingots into the crucible of the vacuum intermediate frequency induction furnace, evacuate the furnace, and when the vacuum degree is less than 1*10... -2 When Pa, heating begins and argon gas is introduced to create a positive pressure environment inside the furnace; the heating rate is 15℃ / s, and heating is stopped after the furnace temperature reaches 700~850℃, and the furnace is held at that temperature for 1 hour.

[0081] S22: According to the melting point of the billet, other pure metal ingots and alloy ingots are added in order from high to low. After the alloy ingot is completely melted, hexachloroethane is added to degas it. The mixture is stirred by electromagnetic stirring at a speed of 200 r / min to make the elements evenly mixed. After holding and calming for 30 minutes, the casting begins. The casting temperature is 750℃ and the casting alloy flow rate is 5 kg / min to obtain the pre-alloyed ingot.

[0082] Step 3: The pre-alloyed ingot is powdered using argon atomization at a pressure of 2.5 MPa and a temperature of 750°C. Pre-alloyed powder is obtained.

[0083] Step 4: The pre-alloyed powder is processed through a mesh sieve to obtain pre-alloyed powder with a size of 15-53 μm and a powder shape of near-spherical or spherical.

[0084] Step 5: Vacuum dry the pre-alloyed powder with a size of 15-53 μm and a powder shape of near-spherical or spherical obtained by sieving; the drying temperature is 100℃ and the drying time is 6h.

[0085] Step 6: The pre-alloyed powder is shaped into the target aluminum alloy car crash box shape using a selective laser melting (SLM) additive manufacturing process;

[0086] Shape like Figure 1 As shown, the structure is an approximate negative Poisson structure, which can significantly improve energy absorption and reduce the mass of the device; no support structure needs to be designed during the additive manufacturing process; the numerical parameters of the structure are 95 (length) * 95 (width) * 100 (height) mm, the inner diameter of the hole is 3 mm, the outer diameter is 3.8 mm, and the weight is approximately 250 g.

[0087] The selective laser melting (SLM) additive manufacturing process parameters are as follows: scanning power of 200W, scanning speed of 500mm / s, powder thickness of 0.03mm, and scanning spacing of 0.09mm. The substrate is preheated to 50℃.

[0088] Step 7: Perform three sandblasting processes on the obtained aluminum alloy car crash box to obtain a smooth surface target aluminum alloy car crash box.

[0089] The embodiment can form the automobile crash box meeting the performance requirements without heat treatment. The obtained target aluminum alloy part has no crack, the microstructure morphology is fish scale shape, and the grain is bimodal grain distribution, as shown in Figure 2

[0090] The obtained target aluminum alloy automobile crash box has a tensile strength of 330 MPa, a yield strength of 260 MPa, and an elongation of 26.5%, and the single automobile crash box absorbs energy of 4.5 KJ.

[0091] Embodiment 2

[0092] An aluminum alloy automobile crash box powder forming process comprises the following steps:

[0093] Step 1: A certain amount of pure metal ingot and / or alloy ingot is weighed according to the component proportion of the aluminum alloy.

[0094] The component proportion of the target aluminum alloy automobile crash box is as follows in terms of mass percentage: Mg: 3.5%, Zr: 0.15%, Mn: 0.6%, Si: 0.8%, Sc: 0.25%, Fe: 0.03%, Ti: 0.02%, and the rest is Al and non-removable impurity elements.

[0095] According to the component proportion, Al ingot, Mg ingot, Zr ingot, Mn ingot, Ti ingot, Al-Si ingot and Al-Sc ingot with a purity of more than 99% are weighed, and the total weight is 15 Kg.

[0096] Step 2: The pure metal ingot and the alloy ingot are melted by vacuum melting to obtain a pre-alloyed ingot.

[0097] S21: The weighed aluminum ingot is placed in the crucible of the vacuum medium-frequency induction furnace, vacuum is extracted, and argon is filled when the vacuum degree is less than 1*10 -2 Pa to make the furnace in a positive pressure environment; wherein the heating rate is 15℃ / s, the furnace temperature is stopped at 700-850℃, and the temperature is kept for 1.5h.

[0098] S22: Other pure metal ingots and alloy ingots are sequentially placed according to the melting point of the ingot blank from high to low, and after the alloy ingot is completely melted, hexachloroethane is added for degassing, and electromagnetic stirring is performed at a speed of 300r / min to uniformly mix the elements, and after keeping for 30min, pouring is started, the pouring temperature is 800℃, the pouring alloy flow rate is 6Kg / min, and the pre-alloyed ingot is obtained.

[0099] Step 3: The pre-alloyed ingot is powdered by argon gas atomization method, the atomization pressure is 2.5MPa, and the atomization temperature is 760℃. The pre-alloyed powder is obtained.

[0100] ​Step 4: The pre-alloyed powder is processed through a mesh screen to obtain a pre-alloyed powder with a size of 15-53 μm and a powder shape of near-spherical or spherical;

[0101] Step 5: The pre-alloyed powder with a size of 15-53 μm and a powder shape of near-spherical or spherical obtained by screening is subjected to vacuum drying treatment; the drying temperature is 100°C, and the drying time is 6h;

[0102] Step 6: The pre-alloyed powder is shaped into a target aluminum alloy automobile crash box shape by a selective laser melting (SLM) additive manufacturing process;

[0103] The target aluminum alloy automobile crash box shape obtained in this embodiment is the same as that in Embodiment 1, and the selective laser melting (SLM) additive manufacturing process parameters are as follows: a scanning power of 200W, a scanning speed of 500mm / s, a powder laying thickness of 0.03mm, and a scanning interval of 0.09mm. The substrate is preheated, and the preheating temperature is 50°C.

[0104] Step 7: The obtained aluminum alloy automobile crash box is subjected to 2 times of sandblasting treatment to obtain a target aluminum alloy automobile crash box with a smooth surface.

[0105] The automobile crash box shaped in this embodiment without heat treatment meets the performance requirements. The target aluminum alloy part obtained is crack-free, and the microstructure is similar to that in Embodiment 1, which is fish scale-shaped, and the grains are bimodal grain distribution.

[0106] The target aluminum alloy automobile crash box obtained in this embodiment has a tensile strength of 380MPa, a yield strength of 275MPa, an elongation of 30%, and a single automobile crash box energy absorption of 5.5KJ.

[0107] Embodiment 3

[0108] An aluminum alloy automobile crash box powder shaping process, comprising the following steps:

[0109] Step 1: A certain amount of pure metal ingot and / or alloy ingot is weighed according to the aluminum alloy component ratio;

[0110] The component ratio of the target aluminum alloy automobile crash box is as follows: Mg: 3.5%, Zr: 0.15%, Mn: 0.6%, Si: 0.8%, Sc: 0.25%, Fe: 0.03%, Ti: 0.02%, and the rest is Al and non-removable impurity elements.

[0111] According to the component ratio, Al ingot, Mg ingot, Zr ingot, Mn ingot, Ti ingot, Al-Si ingot and Al-Sc ingot with a purity of more than 99% are weighed, and the total weight is 15Kg.

[0112] Step 2: Obtain a pre-alloy ingot by vacuum melting of pure metal ingots and alloy ingots;

[0113] S21: Put the weighed aluminum ingot into the crucible of the vacuum medium-frequency induction furnace, and vacuumize, when the vacuum degree is less than 1*10 -2 Pa, start heating and fill argon to make the furnace in a positive pressure environment; wherein the heating rate is 15℃ / s, the furnace temperature reaches 700-850℃, then stop heating, and keep warm for 1.5h.

[0114] S22: Put other pure metal ingots and alloy ingots in order from high to low according to the melting point of the ingot blank, and after the alloy ingot is completely melted, add hexachloroethane to degas, and mix the elements uniformly by electromagnetic stirring at a speed of 300r / min, keep warm and calm for 30min, then start pouring, the pouring temperature is 800℃, the pouring alloy flow rate is 6Kg / min, and the pre-alloy ingot is obtained.

[0115] Step 3: Powder the pre-alloy ingot by argon gas atomization method, the atomization pressure is 2.5MPa, and the atomization temperature is 760℃. Obtain a pre-alloy powder;

[0116] Step 4: Screen the pre-alloy powder through a mesh screen to obtain a pre-alloy powder with a size of 15-53μm and a powder shape of near-spherical or spherical;

[0117] Step 5: Perform vacuum drying treatment on the pre-alloy powder with a size of 15-53μm and a powder shape of near-spherical or spherical obtained by screening; the drying temperature is 100℃, and the drying time is 6h;

[0118] Step 6: Form the pre-alloy powder into a target aluminum alloy automobile crash box shape by a selective laser melting (SLM) additive manufacturing process;

[0119] The target aluminum alloy automobile crash box shape obtained in this embodiment has a structure as shown in Figure 3 The internal structure of the structure is a honeycomb structure, the outside is a tetrahedron, the inside is connected by regular hexagons, the radii of the circumscribed circles are 5mm and 5.4mm respectively, the outside edge length is 55(long)*50(width)*60(height)mm, the wall thickness is 1mm, and the total mass is 70g; the selective laser melting (SLM) additive manufacturing process parameters are: scanning power is 200W, scanning speed is 500mm / s, powder laying thickness is 0.03mm, and scanning spacing is 0.09mm. Preheat the substrate, and the preheating temperature is 50℃.

[0120] Step 7: Perform 2 times of sandblasting treatment on the obtained aluminum alloy automobile crash box to obtain a target aluminum alloy automobile crash box with a smooth surface.

[0121] The automobile crash box of the embodiment can be formed without heat treatment to meet the performance requirements. The target aluminum alloy part obtained has no cracks and a similar microstructure to that of the embodiment 1, i.e., a fish scale shape and a bimodal grain distribution.

[0122] The target aluminum alloy automobile crash box obtained in the embodiment has a tensile strength of 380 MPa, a yield strength of 275 MPa, an elongation of 30%, and an energy absorption of 4.4 KJ per automobile crash box.

[0123] Embodiment 4

[0124] A powder forming process for an aluminum alloy automobile crash box includes the following steps.

[0125] Step 1: A certain amount of pure metal ingots and / or alloy ingots are weighed according to the component proportions of the aluminum alloy.

[0126] The component proportions of the target aluminum alloy automobile crash box are as follows in terms of mass percentage: Mg: 3.5%, Zr: 1.2%, Mn: 0.74%, Si: 0.5%, Fe: 0.03%, Ti: 0.02%, and the rest is Al and non-removable impurity elements.

[0127] According to the component proportions, Al ingots, Mg ingots, Zr ingots, Mn ingots, Ti ingots, and Al-Si ingots with a purity of more than 99% are weighed, and the total weight is 12 Kg.

[0128] Step 2: The pure metal ingots and alloy ingots are melted by vacuum melting to obtain pre-alloyed ingots.

[0129] S21: The weighed aluminum ingots are placed in the crucible of the vacuum medium-frequency induction furnace, vacuum is drawn, and argon is filled when the vacuum degree is less than 1*10 -2 Pa to make the furnace in a positive pressure environment; wherein the heating rate is 20 ℃ / s, the furnace temperature is stopped at 700-850 ℃ after heating, and the temperature is maintained for 1 h.

[0130] S22: The other pure metal ingots and alloy ingots are sequentially placed according to the melting point of the ingot blank from high to low, and after the alloy ingots are completely melted, hexachloroethane is added for degassing, and electromagnetic stirring is performed at a speed of 300 r / min to uniformly mix the elements. After maintaining and quieting for 30 min, pouring is started, the pouring temperature is 800 ℃, the pouring alloy flow rate is 10 Kg / min, and pre-alloyed ingots are obtained.

[0131] Step 3: The pre-alloyed ingots are powdered by argon gas atomization method, the atomization pressure is 3 MPa, and the atomization temperature is 780 ℃. Pre-alloyed powder is obtained.

[0132] Step 4: The pre-alloyed powder is treated by mesh screen to obtain pre-alloyed powder with a size of 15-53 μm and a nearly spherical or spherical shape.

[0133] Step 5: The pre-alloyed powder with a size of 15-53 μm and a powder shape of near-spherical or spherical obtained by screening is subjected to vacuum drying treatment; the drying temperature is 100°C, and the drying time is 6h;

[0134] Step 6: The pre-alloyed powder is shaped into a target aluminum alloy automobile crash box shape by a selective laser melting (SLM) additive manufacturing process; the crash box structure is consistent with that of Embodiment 1;

[0135] The selective laser melting (SLM) additive manufacturing process parameters are: a scanning power of 250W, a scanning speed of 800mm / s, a powder laying thickness of 0.03mm, and a scanning interval of 0.09mm. The substrate is preheated, and the preheating temperature is 50°C.

[0136] Step 7: The obtained aluminum alloy automobile crash box is subjected to 3 times of sand blasting treatment to obtain a target aluminum alloy automobile crash box with a smooth surface.

[0137] The automobile crash box shaped in this embodiment does not need heat treatment and meets the performance requirements. The target aluminum alloy part obtained has no cracks and a microstructure similar to that of Embodiment 1, which is fish scale-shaped and has a bimodal grain distribution.

[0138] The target aluminum alloy automobile crash box obtained in this embodiment has a tensile strength of 310MPa, a yield strength of 255MPa, an elongation of 25%, and a single automobile crash box energy absorption of 4.3KJ.

[0139] Embodiment 5

[0140] An aluminum alloy automobile crash box powder shaping process, comprising the following steps:

[0141] Step 1: A certain amount of pure metal ingot and / or alloy ingot is weighed according to the aluminum alloy component ratio;

[0142] The component ratio of the target aluminum alloy automobile crash box is, in terms of mass percentage: Mg: 3.5%, Zr: 1.2%, Mn: 0.74%, Si: 0.5%, Fe: 0.03%, Ti: 0.02%, and the rest is Al and non-removable impurity elements.

[0143] According to the component ratio, Al ingot, Mg ingot, Zr ingot, Mn ingot, Ti ingot, and Al-Si ingot with a purity of more than 99% are weighed, and the total weight is 12Kg.

[0144] Step 2: The pure metal ingot and the alloy ingot are subjected to vacuum melting to obtain a pre-alloyed ingot;

[0145] S21: The weighed aluminum ingot is placed in the crucible of the vacuum medium-frequency induction furnace, vacuum is drawn, and when the vacuum degree is less than 1*10 -2Pa, start heating and filling argon to make the furnace in a positive pressure environment; wherein the heating rate is 20℃ / s, the furnace temperature reaches 700-850℃, then stop heating, and keep warm for 1.5h.

[0146] S22: Put other pure metal ingots and alloy ingots into the furnace according to the melting point of the ingot from high to low, and after the alloy ingot is completely melted, add hexachloroethane to degas, pass through electromagnetic stirring at a speed of 400r / min, so that the elements are uniformly mixed, keep warm and calm for 40min, then start pouring, the pouring temperature is 800℃, the pouring alloy flow rate is 8Kg / min, and the pre-alloy ingot is obtained.

[0147] Step 3: The pre-alloy ingot is powdered by argon atomization method, the atomization pressure is 3MPa, and the atomization temperature is 780℃. The pre-alloy powder is obtained;

[0148] Step 4: The pre-alloy powder is treated by mesh screen to obtain a pre-alloy powder with a size of 15-53μm and a powder shape of near-spherical or spherical;

[0149] Step 5: The pre-alloy powder with a size of 15-53μm and a powder shape of near-spherical or spherical obtained by screening is subjected to vacuum drying treatment; the drying temperature is 100℃, and the drying time is 6h;

[0150] Step 6: The pre-alloy powder is formed into a target aluminum alloy automobile crash box shape by a selective laser melting (SLM) additive manufacturing process; the crash box structure is consistent with that of Example 1;

[0151] The selective laser melting (SLM) additive manufacturing process parameters are: scanning power is 220W, scanning speed is 200mm / s, powder laying thickness is 0.01mm, and scanning spacing is 0.05mm. The substrate is preheated, and the preheating temperature is 50℃.

[0152] Step 7: The obtained aluminum alloy automobile crash box is subjected to 3 times of sandblasting treatment to obtain a target aluminum alloy automobile crash box with a smooth surface.

[0153] The automobile crash box of the present embodiment can be formed without heat treatment to meet the performance requirements. The obtained target aluminum alloy part has no cracks, and the microstructure is similar to that of Example 1, which is fish scale-shaped, and the grain is bimodal grain distribution.

[0154] The target aluminum alloy automobile crash box obtained in the present embodiment has a tensile strength of 355MPa, a yield strength of 265MPa, an elongation of 30%, and a single automobile crash box absorption energy of 5.4KJ.

[0155] Example 6

[0156] An aluminum alloy automobile crash box powder forming process, wherein the component ratio of the target aluminum alloy automobile crash box in step 1 is as follows in terms of mass percentage: Mg: 3.0%, Zr: 1.25%, Mn: 1.2%, Si: 0.1%, Fe: 0.04%, Ti: 0.01%, Er: 0.25%, Y: 0.15%, Er+Y: 0.4%, and the rest is Al and non-removable impurity elements.

[0157] According to the component ratio, Al ingots, Mg ingots, Zr ingots, Mn ingots, Er ingots, Y ingots and Ti ingots with a purity of more than 99% are weighed, and the total weight is 12 kg. The remaining steps and process parameters are the same as in Example 1.

[0158] The target aluminum magnesium alloy automobile crash box obtained in this example has the same shape as in Example 1, and the automobile crash box meeting the performance requirements can be formed without heat treatment. The target aluminum alloy part obtained has no cracks, and the microstructure is similar to that in Example 1, which is fish scale-shaped, and the grain is bimodal grain distribution.

[0159] The target aluminum alloy automobile crash box obtained in this example has a tensile strength of 350 MPa, a yield strength of 260 MPa, an elongation of 26%, and a single automobile crash box energy absorption of 4.5 KJ.

[0160] Comparative Example 1

[0161] An aluminum alloy automobile crash box powder forming process, comprising the following steps:

[0162] Step 1: weighing a certain amount of pure metal ingots and / or alloy ingots according to the aluminum alloy component ratio;

[0163] The component ratio of the target aluminum alloy automobile crash box is as follows in terms of mass percentage: Mg: 3.5%, Zr: 1.2%, Mn: 0.74%, Si: 0.5%, Fe: 0.03%, Ti: 0.02%, and the rest is Al and non-removable impurity elements.

[0164] According to the component ratio, Al ingots, Mg ingots, Zr ingots, Mn ingots, Ti ingots and Al-Si ingots with a purity of more than 99% are weighed, and the total weight is 12 kg.

[0165] Step 2: obtaining pre-alloyed ingots by vacuum melting pure metal ingots and alloy ingots;

[0166] S21: placing the weighed aluminum ingots into the crucible of the vacuum medium-frequency induction furnace, and vacuumizing; when the vacuum degree is less than 1*10 -2 Pa, starting heating and filling argon to make the furnace in a positive pressure environment; wherein the heating rate is 15℃ / s, the furnace temperature is stopped at 700-850℃, and the temperature is kept for 1h.

[0167] S22: Put the other pure metal ingots and alloy ingots into the ingots according to the melting point of the ingots from high to low, and after the alloy ingots are completely melted, add hexachloroethane to degas, pass through electromagnetic stirring at a speed of 200 r / min, so that the elements are uniformly mixed, and after 30 min of heat preservation and calming, start pouring at a pouring temperature of 750 ℃ and a pouring alloy flow rate of 5 Kg / min to obtain a pre-alloy ingot.

[0168] Step 3: The pre-alloy ingot is powdered by an argon atomization method, the atomization pressure is 2.5 MPa, and the atomization temperature is 750℃. The pre-alloy powder is obtained;

[0169] Step 4: The pre-alloy powder is treated by a mesh screen to obtain a pre-alloy powder with a size of 15-53 μm and a powder shape of near-spherical or spherical;

[0170] Step 5: The pre-alloy powder with a size of 15-53 μm and a powder shape of near-spherical or spherical obtained by screening is subjected to vacuum drying treatment; the drying temperature is 100℃, and the drying time is 6h;

[0171] Step 6: The pre-alloy powder is formed into a target aluminum alloy automobile crash box shape by a selective laser melting (SLM) additive manufacturing process; the crash box structure is consistent with that of Example 1;

[0172] The selective laser melting (SLM) additive manufacturing process parameters are: a scanning power of 200 W, a scanning speed of 500 mm / s, a powder laying thickness of 0.03 mm, and a scanning spacing of 0.09 mm. The substrate is preheated at a preheating temperature of 50℃.

[0173] Step 7: The obtained aluminum alloy automobile crash box is subjected to heat treatment at a heat treatment temperature of 400℃ for 2h and air cooling.

[0174] Step 8: The obtained aluminum alloy automobile crash box is subjected to 3 times of sandblasting treatment to obtain a target aluminum alloy automobile crash box with a smooth surface.

[0175] In the process of forming the target aluminum alloy automobile crash box, a heat treatment process is added, and the obtained target aluminum alloy automobile crash box has a tensile strength of 450 MPa, a yield strength of 380 MPa, an elongation of 12%, and an absorbed energy of 4.3 KJ. The alloy strength of this example is relatively high, which will increase the response time and is not suitable for use as an automobile crash box.

[0176] Comparative Example 2

[0177] An aluminum alloy automobile crash box powder forming process, comprising the following steps:

[0178] Step 1: A certain amount of pure metal ingots and alloy ingots are weighed according to the aluminum alloy composition ratio;

[0179] The target aluminum alloy automobile crash box raw material is a conventional aluminum alloy with a brand of 5083, and the component proportions are as follows in terms of mass percentage: Mg: 4.78%, Mn: 0.73%, Si: 0.02%, Fe: 0.03%, Ti: 0.005%, and the rest is Al and non-removable impurity elements.

[0180] According to the component proportions, Al ingots, Mg ingots, Zr ingots, Mn ingots, Ti ingots, and Al-Si ingots with a purity of more than 99% are weighed, with a total of 12 Kg.

[0181] Step 2: Pure metal ingots and alloy ingots are melted by vacuum melting to obtain pre-alloyed ingots;

[0182] S21: Put the weighed aluminum ingots into the crucible of the vacuum medium-frequency induction furnace, and vacuumize. When the vacuum degree is less than 1*10 -2 Pa, start heating and fill argon to make the furnace in a positive pressure environment; wherein the heating rate is 15℃ / s, the furnace temperature reaches 700-850℃, and then the heating is stopped, and the temperature is kept for 1h.

[0183] S22: Put other pure metal ingots and alloy ingots in order from high to low according to the melting point of the ingot blank. After the alloy ingots are completely melted, add hexachloroethane to degas, and mix the elements uniformly by electromagnetic stirring at a speed of 200r / min. After keeping still and quiet for 30min, start pouring. The pouring temperature is 750℃, the pouring alloy flow rate is 5Kg / min, and the pre-alloyed ingots are obtained.

[0184] Step 3: The pre-alloyed ingots are powdered by argon gas atomization method, the atomization pressure is 2.5MPa, and the atomization temperature is 750℃. The pre-alloyed powder is obtained;

[0185] Step 4: The pre-alloyed powder is treated by mesh screen to obtain pre-alloyed powder with a size of 15-53μm and a powder shape of near-spherical or spherical;

[0186] Step 5: The pre-alloyed powder with a size of 15-53μm and a powder shape of near-spherical or spherical obtained by screening is subjected to vacuum drying treatment; the drying temperature is 100℃, and the drying time is 6h;

[0187] Step 6: The pre-alloyed powder is formed into the shape of the target aluminum alloy automobile crash box by the selective laser melting (SLM) additive manufacturing process; the crash box structure is consistent with that of Embodiment 1;

[0188] The selective laser melting (SLM) additive manufacturing process parameters are as follows: scanning power is 200W, scanning speed is 500mm / s, powder laying thickness is 0.03mm, and scanning spacing is 0.09mm. The substrate is preheated, and the preheating temperature is 50℃.

[0189] Step 7: The obtained aluminum alloy automobile crash box is subjected to 3 times of sand blasting treatment to obtain a target aluminum alloy automobile crash box with a smooth surface.

[0190] The comparative example does not contain Zr element, and the contents of Mg and Si elements and the content of Mg+Mn do not meet the requirements of the present application. The obtained target aluminum alloy automobile crash box has partial micro-cracks in the alloy structure, as shown in Figure 4 The tensile strength is 257 MPa, the yield strength is 163 MPa, and the elongation is 10%, which does not meet the performance requirements of the automobile crash box.

[0191] Comparative Example 3

[0192] An aluminum alloy automobile crash box powder forming process, comprising the following steps:

[0193] Step 1: A certain amount of pure metal ingots and alloy ingots are weighed according to the aluminum alloy component ratio;

[0194] The component ratio of the target aluminum alloy automobile crash box is: Mg: 3.5%, Zr: 1.2%, Mn: 0.74%, Si: 0.5%, Fe: 0.03%, Ti: 0.02%, and the rest is Al and non-removable impurity elements.

[0195] According to the component ratio, Al ingots, Mg ingots, Zr ingots, Mn ingots, Ti ingots and Al-Si ingots with a purity of more than 99% are weighed, a total of 12Kg.

[0196] Step 2: Pure metal ingots and alloy ingots are melted by vacuum melting to obtain pre-alloyed ingots;

[0197] S21: The weighed aluminum ingots are placed in the crucible of the vacuum medium frequency induction furnace, vacuum is extracted, and when the vacuum degree is less than 1*10 -2 Pa, heating is started and argon is filled to make the furnace in a positive pressure environment; wherein the heating rate is 15℃ / s, the furnace temperature is stopped at 700-850℃, and the temperature is kept for 1h.

[0198] S22: Other pure metal ingots and alloy ingots are sequentially placed according to the melting point of the ingot blank from high to low, after the alloy ingots are completely melted, hexachloroethane is added for degassing, and electromagnetic stirring is performed at a speed of 200r / min to make the elements uniformly mixed, and after keeping for 30min, pouring is started, the pouring temperature is 750℃, the pouring alloy flow rate is 5Kg / min, and pre-alloyed ingots are obtained.

[0199] Step 3: The pre-alloyed ingots are powdered by argon gas atomization method, the atomization pressure is 2.5MPa, and the atomization temperature is 680℃. Pre-alloyed powder is obtained.

[0200] Step 4: The pre-alloy powder is treated by a mesh screen to obtain a pre-alloy powder with a size of 15-53 μm and a powder shape of near-spherical or spherical;

[0201] Step 5: The pre-alloy powder with a size of 15-53 μm and a powder shape of near-spherical or spherical obtained by screening is subjected to vacuum drying treatment; the drying temperature is 100°C, and the drying time is 6 h;

[0202] Step 6: The pre-alloy powder is formed into a target aluminum alloy automobile crash box shape by a selective laser melting (SLM) additive manufacturing process; the crash box structure is consistent with that of Example 1.

[0203] The selective laser melting (SLM) additive manufacturing process parameters are as follows: a scanning power of 150 W, a scanning speed of 1000 mm / s, a powder laying thickness of 0.1 mm, and a scanning interval of 0.2 mm.

[0204] Step 7: The obtained aluminum alloy automobile crash box is subjected to 3 times of sandblasting treatment to obtain a target aluminum alloy automobile crash box with a smooth surface.

[0205] The selective laser melting (SLM) additive manufacturing process parameters of the present comparative example do not meet the requirements of the present application, and the target aluminum alloy automobile crash box obtained has a tensile strength of 260 MPa, a yield strength of 195 MPa, and an elongation of 18%. In the present comparative example, the yield strength of the target aluminum alloy automobile crash box is too low to meet the requirements for use of an automobile crash box.

[0206] Table 1 Aluminum alloy components (wt, %) of Examples and Comparative Examples

[0207] Number Mg Zr Mn Si Sc Er Y Ti Fe Mg+Mn Sc+Er+Y Example 1 3.5 1.2 0.74 0.5 - - - 0.02 0.03 4.24 - Example 2 3.5 0.15 0.6 0.8 0.25 - - 0.02 0.03 4.10 0.25 Example 3 3.5 0.15 0.6 0.8 0.25 - - 0.02 0.03 4.10 0.25 Example 4 3.5 1.2 0.74 0.5 - - - 0.02 0.03 4.24 - Example 5 3.5 1.2 0.74 0.5 - - - 0.02 0.03 4.24 - Example 6 3.0 1.25 1.2 0.1 - 0.25 0.15 0.01 0.04 4.20 0.4 Comparative Example 1 3.5 1.2 0.74 0.5 - - - 0.02 0.03 4.24 - Comparative Example 2 4.78 - 0.73 0.02 - - - 0.005 0.03 5.51 - Comparative Example 3 3.5 1.2 0.74 0.5 - - - 0.02 0.03 4.24 -

[0208] Table 2 Aluminum alloy forming process parameters of Examples and Comparative Examples

[0209]

[0210] Table 3 Mechanical properties of aluminum alloys of Examples and Comparative Examples

[0211] Number Yield strength MPa Tensile strength MPa Elongation % Single impact box absorption capacity KJ Example 1 260 330 26.5 4.5 Example 2 275 380 30 5.5 Example 3 275 380 30 4.4 Example 4 255 310 25 4.3 Example 5 265 355 30 5.4 Example 6 260 350 26 4.5 Comparative Example 1 380 450 12 4.3 Comparative Example 2 163 257 10 - Comparative Example 3 195 260 18 -

[0212] The above description is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and any changes or replacements within the technical scope disclosed by the present application can be easily thought of by those skilled in the art, and should be covered within the protection scope of the present application.

Claims

1. A powder forming process for an aluminum alloy automotive crash box, characterized by, The method comprises the following steps: Step 1: according to the aluminum alloy component ratio, a certain amount of pure metal ingot and / or alloy ingot is weighed; Step 2: the pure metal ingot and the alloy ingot are vacuum melted to obtain a pre-alloy ingot; Step 3: the pre-alloy ingot is atomized to obtain a pre-alloy powder; Step 4: the pre-alloy powder is screened through a screen to obtain a pre-alloy powder meeting the size and shape requirements; Step 5: the pre-alloy powder meeting the size and shape requirements obtained by screening is subjected to vacuum drying treatment; Step 6: the pre-alloy powder is formed into a target aluminum alloy automobile crash box shape through an additive manufacturing process; In step 2, the vacuum melting comprises the following steps: S21: Put the weighed Al ingot into the crucible of the vacuum medium frequency induction furnace, vacuumize, when the vacuum degree is less than 1*10 -2 Pa, start heating and fill argon to make the furnace in positive pressure environment; S22: the other pure metal ingot and / or alloy ingot is sequentially placed according to the melting point of the ingot from high to low, and after complete melting, degassing, stirring and pouring are performed to obtain a pre-alloy ingot; In step S21, the heating rate is 5-20℃ / s, the heating temperature is 700-850℃, and the holding time is 0.5-2h; In step S22, the stirring speed is 200-500r / min, the pouring temperature is 700-850℃, and the alloy flow rate is 5-10Kg / min; In step 3, the atomization is completed by an argon atomization method, the atomization pressure is 1.5-4.5MPa, and the atomization temperature is 700-850℃; The component ratio of the target aluminum alloy automobile crash box is as follows in terms of mass percentage: Mg: 3.0-3.5%, Zr: 0.15-1.2%, Mn: 0.6-1.2%, Si: 0.5-0.8%, Sc≤0.25%, Ti: 0.01-0.02, Fe: 0.03-0.04%, Er≤0.25%, Y≤0.15%, Sc+Er+Y: 0-0.4%, Mg+Mn: 4.10-4.24%, and the rest is Al and non-removable impurity elements; The powder forming process of the aluminum alloy automobile crash box does not require a heat treatment process in the forming process, the automobile crash box has a tensile strength of 280-380MPa, a yield strength of 240-310MPa, an elongation of ≥21%, and an individual automobile crash box absorbs energy of ≥4KJ.

2. Powder forming process according to claim 1, characterized in that The powder forming process further comprises 2-3 times of sand blasting treatment on the target aluminum alloy automobile crash box obtained in step 6.

3. The powder forming process of claim 1, wherein, In step 3, the atomization is completed by an argon atomization method, the atomization pressure is 2.5-4.5MPa, and the atomization temperature is 700-850℃.

4. The powder forming process of claim 1, wherein, In step 4, the size of the pre-alloy powder is 15-105μm, and the powder shape is near-spherical or spherical.

5. The powder forming process of claim 1, wherein, In step 5, the vacuum drying has a drying temperature of 100-140℃ and a drying time of 2-8h.

6. The powder forming process of claim 1, wherein, The additive manufacturing process is selective laser melting, and the substrate of the selective laser melting equipment is preheated, and the preheating temperature is 25-350℃.

7. Powder forming process according to claim 6, characterized in that The selective laser melting parameters are as follows: the scanning power is 190-350W, the scanning speed is 200-800mm / s, the powder laying thickness is 0.01-0.05mm, and the scanning interval is 0.05-0.1mm.

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