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Quick Search     Adv Search   2019 Vol. 29, No. 05 Published: 2019-10-10   1 Technology and application of metal 3D printing Hot! ZONG Gui-sheng, ZHAO Hao DOI: 10.13228/j.boyuan.issn1006-6543.20190187 In the recent decades, the comprehensive advancements in new material, new process and new equipment have together promoted the additive manufacturing (AM) technology and industry. Focusing on the utilization of AM in metal manufacturing, this article summarizes the progresses in the mainstream direct-metal and in-direct-metal printing technologies, that include Selective Laser Sintering (SLS), Binder Jetting (BJ), Directed Fusion Deposition (DFD), Selective Laser Melting (SLM) and Directed Energy Deposition (DED), etc. 2019 Vol. 29 (05): 1-6 [Abstract] ( 5 ) HTML (1 KB)  PDF (1935 KB)  ( 10 ) 7 Study on rheological properties of polyoxymethylene 17-4PH stainless steel feedstocks Hot! DING Chu-xiong， LI Du-xin，ZHANG Chen-ming，LU Ren-wei，YANG Zhong-chen DOI: 10.13228/j.boyuan.issn1006-6543.20180036 The effects of three kinds of flow addition reagent on the rheological properties of POM based 17-4PH stainless steel feed were analyzed by PH-7D capillary rheometer. The results show that three kinds of feedstocks are pseudoplastic fluid, the selection of flow addition reagent influence the rheological properties of feedstocks, and at the temperature of 185 ℃, the shear rate of 965 /s ,the feedstock which adding flow addition reagent PTHF in POM based binder system presents a better comprehensive rheological property while the non-Newton index n, the viscous flow activation energy E and the comprehensive rheological index αSTV are 0.387, 21.49 KJ/mol  and 2.364×10-4. 2019 Vol. 29 (05): 7-11 [Abstract] ( 6 ) HTML (1 KB)  PDF (1483 KB)  ( 4 ) 12 Effect of oxygen content on mechanical properties of hot isostatic pressing TC4 titanium alloy Hot! LIANG Chao, LIU Wen-bin, WANG Tie-jun, CHEN Wei, CHE Hong-yan DOI: 10.13228/j.boyuan.issn1006-6543.20180038 In this paper, the mechanical properties, microstructures and fracture surfaces of TC4 powder titanium alloy prepared by hot isostatic pressing were compared and analyzed, and the effect of oxygen content on its mechanical properties was studied. The results show that the microstructures of TC4 titanium alloys as hot isostatic pressing and annealing have no obvious difference and are lamellar; the oxygen content increases from 0.11% to 0.17%, the strength and plasticity of titanium alloys increase obviously, and the fracture toughness KIC of TC4 titanium alloys decreases from 101 MPa·m1/2 to 95 101 MPa·m1/2; the fracture mechanism of TC4 titanium alloys under room temperature tension is typical microporous aggregation fracture. The mechanism is that cleavage facets appear on the tough section with the increase of oxygen content. 2019 Vol. 29 (05): 12-17 [Abstract] ( 6 ) HTML (1 KB)  PDF (2422 KB)  ( 3 ) 18 Effect of sintering process on properties of Cu-based pre-alloyed powder Hot! XIAO Chang-jiang, DOU Zhi-qiang，LI juan DOI: 10.13228/j.boyuan.issn1006-6543.20180033 The effects of sintering temperature, holding time and sintering pressure on the properties of Cu-Fe-Sn-Ni quaternary Cu-based pre-alloyed powder with particle size of about 500 nm were studied by three-factor and three-level orthogonal experiments. The density, flexural strength and hardness of the samples under different sintering conditions were tested, and the samples were observed by scanning electron microscope. The results show that the influence of various factors on the properties is different, the best mechanical properties is obtained under the temperature 820 ℃，pressure 25 MPa and holding time 5 min, and its mechanical properties of the density, the bending strength and the hardness are 8.21 g/cm3, 1 335 MPa and 112.5HRB, respectively. Under the bonding condition, the sample is the densest and the bonding between the powders is the best. 2019 Vol. 29 (05): 18-21 [Abstract] ( 3 ) HTML (1 KB)  PDF (1380 KB)  ( 4 ) 22 Effects of different gas conditions on sintering of 3D printing molding Hot! WANG Chuan-sheng,CAI Ning, WANG Hu-Zi, CHAO Yu-Qi, ZHANG Wei DOI: 10.13228/j.boyuan.issn1006-6543.20180052 Based on the powder feeding 3D printer forming technology, the particles are pressed into the screw-screw conveyor to generate pressure-extrusion material extrusion nozzles, which are then processed by the slicing software and transferred to the powder feeding 3D printer on the upper layer of the printing platform. The stacked body is formed into a green body structure, and then the product is obtained through a degreasing-sintering process. In the sintering process, three different atmospheres, N2, N2+H2, and vacuum, are introduced to influence the density, yield strength, hardness, elongation, sintering density, and relative density of the metal body. Experiments show that the vacuum sintering atmosphere is good for the density, sintered density, elongation, and hardness of the metal products. And N2 and N2+H2 atmospheres have good effects for the hardness of metal products, but products are easy to be damaged. 2019 Vol. 29 (05): 22-26 [Abstract] ( 4 ) HTML (1 KB)  PDF (1402 KB)  ( 3 ) 27 Preparation of Mn-Ce/AC catalyst and its catalytic properties for nitrogen oxides Hot! LI Bing-feng，CHANG Si-yuan DOI: 10.13228/j.boyuan.issn1006-6543.20180170 A series of Mn-Ce/AC catalysts were prepared by impregnation method, and their properties were investigated by changing the ratio of Mn/Ce. Thermogravimetric analysis, BET and XRD were used to determine the weight loss curves, physical properties and crystalline forms of the catalysts, in order to find the catalyst with the best ratio of active Mn/Ce. The results show that the hydrophilicity of activated carbon increased and the weight loss percentage increased with the addition of Mn-Ce mixture; the addition of Ce could reduce the aggregation of MnOx on activated carbon; when Mn/Ce was 0.5, the catalytic performance was the best, reaching 90.4%. 2019 Vol. 29 (05): 27-30 [Abstract] ( 3 ) HTML (1 KB)  PDF (1243 KB)  ( 3 ) 31 Effect of Fe content on mechanical property of TiC-based cermets Hot! YE Xuan， CHEN Shao-jun， ZHONG Yan-hui， LING Yu-xiang DOI: 10.13228/j.boyuan.issn1006-6543.20180035 TiC-based cermet materials with 8-X and X contents of Co and Fe were prepared by introducing Fe into TiC-2Mo2C-8Ni-20WC-8Co, with X as 0%、2%、4%、6%、8%. The density, hardness and transverse rupture strength of the materials were tested. The results show that it is feasible to introduce Fe as binder to replace Co partially. Compared with the samples containing 0% Fe binder, the properties of the samples containing 1:1 ratio of Co to Fe do not decrease significantly. The relative density is 95.03%, the hardness is 73.6HRC and the transverse rupture strength is 838.4 MPa, which still have high practicability. 2019 Vol. 29 (05): 31-33 [Abstract] ( 4 ) HTML (1 KB)  PDF (993 KB)  ( 6 ) 34 Research on the inlay method of stainless steel powder using metal tin Hot! HU Jia-qi，ZHANG Lei，WEI Lai，SUN Wei，LI Ning-shuan WANG Chang-jun DOI: 10.13228/j.boyuan.issn1006-6543.20180140 In order to observe the internal structure of stainless steel powder inlaid with tin, three inlaying methods were used, and stainless steel powder inlaid with tin with low melting point was used to prepare powder inlay samples with high conductivity. The results show that due to the poor wettability of stainless steel powder and liquid tin and the high surface tension of liquid tin, stainless steel powder can’t be embedded in tin by conventional inlaying method. During polishing, stainless steel powder falled off from tin surface. A layer of stainless steel powder was sprayed on the surface of solid tin at a higher temperature, and then the high temperature liquid tin was poured on the surface. The stainless steel powder was completely coated with tin by spreading the liquid tin on the surface of solid tin, and the samples of stainless steel powder inlaid with tin were prepared successfully. 2019 Vol. 29 (05): 34-37 [Abstract] ( 5 ) HTML (1 KB)  PDF (2068 KB)  ( 3 ) 38 Analysis of the microstructure of Fe-TiC-TiN cladding layer on Q235 steel surface Hot! Liu li-xin，Tang Jing，Zhang Jie-Xi DOI: 10.13228/j.boyuan.issn1006-6543.20180091 In this paper, A Fe-TiC-TiN coating is obtained on the Q235 soft steel used Plasma cladding technology using Fe310 ferrobased self-fused alloy powder + TiC powder as cladding material. At the addition ratio of 3 %, 6 %, and 10 % of TiC, the phase composition and microstructure of the cladding layer were analyzed by means of scanning electricity and X-ray diffraction experiments. The microhardness and wear resistance of the cladding layer were measured by microhardness meter and friction wear tester，The results show that the combination between the cladding layer and the matrix is metallurgical; The highest hardness of cladding layer is up to 1 643HV0.5, is 6.3 times of the substrate. The relative wear resistance is 5.8 times of the substrate. 2019 Vol. 29 (05): 38-43 [Abstract] ( 5 ) HTML (1 KB)  PDF (2209 KB)  ( 4 ) 44 System parameter optimization design of extruding grinding mill based on EDEM Hot! SHANG Zhu-xian，MA Lin，LIU Bo，ZHAO Yan-bo DOI: 10.13228/j.boyuan.issn1006-6543.20180039 This paper introduces a grinding machine based on the relative movement between the lap and the material to smash the material.And the extruding and smashing process of the material between the rotating grinding block and the fixed grinding plate is simulated in EDEM. The effects of rotor speed, relative taper between grinding block and grinding disk on grinding efficiency were discussed using orthogonal test and variance analysis method. The analysis shows that the destruction of the bond key by the rotor speed increases with the increase of the rotation speed. The larger the angle, the greater the shear friction between the particle and the grinding disk, and the better the grinding effect. The angle has the greatest impact on the grinding effect, followed by the rotational speed. Considering the stability of the system and the efficiency of the mechanical equipment，the simulation shows that the grinding machine has the best effect when the speed is 800rpm,the relative taper is 5 degrees,which provides a reference for improving the efficiency of the grinding machine. 2019 Vol. 29 (05): 44-48 [Abstract] ( 3 ) HTML (1 KB)  PDF (1555 KB)  ( 3 ) 49 Development of single dynamic horizontal planetary ball mill and the analysis of milling efficiency Hot! XIE Zheng-chuan，LIU Meng-ru，YANG Song DOI: 10.13228/j.boyuan.issn1006-6543.20180031 In view of the shortcomings of conventional horizontal planetary ball mill, a single power horizontal planetary ball mill was developed, and the calculation formula of critical speed was given. The ball milling experiments of limestone and granite were carried out by using the developed experimental prototype. It was found that the ball milling efficiency was positively correlated with the filling rate when the filling rate was 2019 Vol. 29 (05): 49-52 [Abstract] ( 3 ) HTML (1 KB)  PDF (1344 KB)  ( 6 ) 53 Effect of reinforcing iron powder on the friction and wear performance of the copper base friction plate for truck brake Hot! YANG?Bin-bin, ZHANG?Jing-kai DOI: 10.13228/j.boyuan.issn1006-6543.20180153 Fe powder was added to the copper matrix by hot pressing sintering, and its reinforcement effect on the matrix was tested. The microstructure and friction properties of the friction samples were tested by experiments. The results show that the friction coefficients of A1 and A2 specimens increase obviously with the increase of load, and the friction coefficients of A3 and A4 increase with the increase of load. The friction stability of A2 is better than A1. The friction coefficient of A3 and A4 decreases with the increase of braking speed. A1 has a smaller wear rate than A2. The wear rate of A3 and A4 increases with the increase of braking speed, and achieves a higher wear rate at high speed. A2 has a more compact mechanical mixing layer, which forms many adhesion pits on the friction surface, showing the characteristics of adhesion wear. The surface of A3 specimen has more cracks and debris than that of A4 specimen. 2019 Vol. 29 (05): 53-57 [Abstract] ( 1 ) HTML (1 KB)  PDF (1494 KB)  ( 2 ) 58 Microstructure and mechanical properties of 3D-print 4J32 alloys fabricated by selective laser melting Hot! WU Kai, ZHANG Jing-lin, WU Bin, FENG Hai-bo , ZHANG Jian-fu DOI: 10.13228/j.boyuan.issn1006-6543.20180053 Selective laser melting is a rapid prototyping technology, which employs high energy laser beam on melting metal powder then fast cooling to manufacture high-density and high-precision metal part. The 4J32 alloy powder was manufactured using gas atomization for SLM. In this research, the molding process parameters, XRD, microstructure and mechanical properties of SLM samples have been studied. The results show that the microstructure of SLM samples is composed of fine dendrites, which axial size is less than 2μm.There is mass density dislocation inside the grains. After the fast cooling process, the mechanical properties of the SLM samples, with even and fine grain sizes, are superior to the as-forged alloys. Due to residual stress the plastic strength has reduced, but it enhanced sharply after the heat treatments. Interestingly, an anisotropy of mechanical properties has found between building and scanning direction in SLM and SLM-HT samples. 2019 Vol. 29 (05): 58-62 [Abstract] ( 3 ) HTML (1 KB)  PDF (2107 KB)  ( 5 ) 63 Design and process research of vacuum hot pressing device for bimetallic inner bushing base on TRIZ theory Hot! QI Cui-fen，LI Xiu-min，CHEN Cun-guang, SHI Yong-liang DOI: 10.13228/j.boyuan.issn1006-6543.20190003 In order to prepare the inner bushing with the wear resistant metal layer of the inner wall for the double helix extruder,?the vacuum sintering device was designed. The TRIZ theory was introduced for the design innovation of the device.?The vacuum loose sintering was changed to vacuum hot pressing sintering. The double C type pressure head was designed with ceramic material, and the pressure head was fixed to the top of the furnace which had the hydraulic lifting device. The high frequency induction heating device was designed?which was fixed to furnace body. The furnace bottom which had the inner bushing fixture and hydraulic lifting device was designed?divided with furnace body. The device can be quickly heated and pressurized to complete sintering after filling the "8" font gap of the?inner bushing?with alloy powder. The furnace body was designed with cyclic cooling to achieve rapid cooling. As the hydraulic device descends, the prepared inner bushing was quickly removed from the bottom of the furnace. The next inner bushing was re-entered from the bottom of the furnace to complete the continuous preparation. The device had the characteristics of high efficiency and low cost, and it also can satisfy continuous production, by which the metal lining?or metal ceramic composite lining can be prepared. 2019 Vol. 29 (05): 63-67 [Abstract] ( 1 ) HTML (1 KB)  PDF (1809 KB)  ( 4 ) 68 A powder injection molding debinding process for iron-based alloys Hot! Luo Meng，Zhou Fen，Song Xi-wen DOI: 10.13228/j.boyuan.issn1006-6543.20180037 Three different debinding processes of wax based binder were studied . Heating rate, insulation points and debinding temperature of thermal debinding process were determined by TG-DSC thermogravimetric analysis.The effect of temperature and debinding time on the debinding rate during the debinding process of two solvents was analyzed with scanning electron microscopy. And the advantages and disadvantages of different debinding processes were compared in this paper. Anhydrous ethanol was first used as a debinding solvent, and a solvent debinding + low temperature thermal debinding method was successfully used to prepare the defect free samples. 2019 Vol. 29 (05): 68-73 [Abstract] ( 1 ) HTML (1 KB)  PDF (1793 KB)  ( 4 ) 74 The research progress of powder preparation technology by gas atomization Hot! WANG Bo-ya，LU Lin，WU Wen-heng，WANG Bin DOI: 10.13228/j.boyuan.issn1006-6543.20180063 Gas atomization technology can prepare metal and alloy powders with small particle size, good sphericity and high purity. After a long period of development, this technology has become the main preparation method for large-scale preparation of powders, especially for metal and alloy powders for material addition manufacturing. In this paper，the nozzle structure and corresponding technological characteristics of air atomization pulverizing technology in different periods and the mechanism of air atomization technology were summarized, the new atomization technology in recent years was introduced.With the emergence of new methods of air atomization, the further study of atomization mechanism and the technology of air atomization will be greatly improved. 2019 Vol. 29 (05): 74-80 [Abstract] ( 2 ) HTML (1 KB)  PDF (1871 KB)  ( 6 ) 81 Structural analysis and improvement of the die set of a type of powder forged connecting rod press Hot! WANG Ji-zhong，GAO Li，MA Yu-yue DOI: 10.13228/j.boyuan.issn1006-6543.20180014 The smoothness of powder forming press in the production process directly affects the product quality and production efficiency. Aiming at the problems of large deformation in the die frame of a powder forging connecting rod press, which affects the working stability and product consistency of the press, the assembly model of the die frame is established by using Pro/E three-dimensional modeling software, and the finite element analysis model of the die frame is established by introducing it into ABAQUS finite element analysis software. The stress distribution and displacement of the die frame of the press are analyzed, and the weak links of the structure are found out. On this basis, considering the principle of economy and applicability, a scheme for optimizing and improving the die frame size structure is determined. The distance between the negative template and the lower template is reduced, the size of the lower template and the distance between the guide pillars are appropriately increased, and the diameter of the washer in the die-punching template assembly is increased. After the structure is improved, the maximum stress of the lower one, the lower two and the lower three die punching template components is reduced by 33%, 21% and 43% respectively, and the maximum overall displacement of the mould frame is reduced by 64% compared with that before the improvement. The strength and overall stiffness of the improved die frame have been greatly improved, and the working stability can be effectively improved, which provides a feasible scheme for the actual improvement of the die frame of this press. 2019 Vol. 29 (05): 81-85 [Abstract] ( 3 ) HTML (1 KB)  PDF (1503 KB)  ( 3 ) 86 Extraction of zinc slag with titanium sulfate by reduction of iron powder for titanium dioxide via sulfate process Hot! Xian Zhong-ju DOI: 10.13228/j.boyuan.issn1006-6543.20180004 After the pretreatment of zinc tail slags by crushing, ball milling and magnetic separation, the iron concentrate with MFe of more than 45% can be obtained. Then the iron concentrate is subjected to secondary ball milling, primary magnetic separation, primary rolling and baking. The iron powder for reduction which all the indexes meet the standard can be obtained. The samples are sent for the reduction test of titanium dioxide powder production, which is approved by the users. 2019 Vol. 29 (05): 86-89 [Abstract] ( 2 ) HTML (1 KB)  PDF (930 KB)  ( 5 )

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