In order to solve the high-price and short-lifetime problems of the cutter of agricultural machinery,and improve the wear resistance of the cutter, the TiCN/Fe metal ceramic composite coating was prepared on the subst...In order to solve the high-price and short-lifetime problems of the cutter of agricultural machinery,and improve the wear resistance of the cutter, the TiCN/Fe metal ceramic composite coating was prepared on the substrate of Q235 steel by reaction nitrogen arc cladding technique. The mixture powder of titanium and graphite was preplaced on the Q235 steel surface after intensive mixing by planetary ball mill and gluing with starch binder. The microstructure and phase of the coatings, interface behavior between coatings and the substrate were investigated by scanning electronic microscope and X-ray diffractometer. The micro-hardness distribution of the coating section was tested by micro-hardness tester. Friction coefficient and wear weight loss were measured by abrasion machine. Wearing surface morphology was investigated by scanning electronic microscope. The results show that an excellent bonding between the coatings and the Q235 steel substrate is ensured by the strong metallurgical interface and phase of the coatings. The coatings are mainly composed of TiCN. The highest micro- hardness of the coatings reaches 1 089 HV0. 2, while the micro-hardness of Q235 steel substrate is only about 286 HV0. 2. The anti-abrasive test results show that the wear resistance of the cladding coating is better than that of quenched and tempered 65 Mn steel which is often used as cutter of agricultural machinery. The field test results show that the TiCN/ Fe metal ceramic composite coating prepared by reaction nitrogen arc cladding is feasible to the manufacture and remanufacture of the cutter of agricultural machinery.展开更多
Agglomerated fluxes with different basicity index designed in laboratory were used to study electrochemical reactions between slag and metal in submerged arc welding under both power polarities. The droplet metal oxyg...Agglomerated fluxes with different basicity index designed in laboratory were used to study electrochemical reactions between slag and metal in submerged arc welding under both power polarities. The droplet metal oxygen and nitrogen contents were measured using oxygen-nitrogen instrument in order to analyze indirectly metallurgy electrochemical reactions taking place in cathode and anode of welding arc. The results show that just in the period of droplet growth at the tip of consumable electrode the electrochemical oxygen contamination is produced in the case of direct current electrode positive polarity whereas electrochemical oxygen lost in electrode negative polarity. Furthermore, the results indicate that the basicity index of molten slag has great influence upon electrochemical reaction. With basicity index increasing, the effect of oxygen transferring resulted from electrochemistry becomes more evident for reacting dynamics depended on ion characteristics of molten slag. The effect of basicity index on metal-slag electrochemical reaction is contrary to traditional thermo-chemical reaction and therefore it is necessary to be considered as a metallurgy factor.展开更多
Plasma methane (CH_4) conversion in gliding arc discharge was examined. Theresult data of experiments regarding the performance of gliding arc discharge were presented in thispaper. A simulation which is consisted som...Plasma methane (CH_4) conversion in gliding arc discharge was examined. Theresult data of experiments regarding the performance of gliding arc discharge were presented in thispaper. A simulation which is consisted some chemical kinetic mechanisms has been provided toanalyze and describe the plasma process. The effect of total gas flow rate and input frequencyrefers to power consumption have been studied to evaluate the performance of gliding arc plasmasystem and the reaction mechanism of decomposition. Experiment results indicated that the maximumconversion of CH_4 reached 50% at the total gas flow rate of 1 L/min. The plasma reaction wasoccurred at the atmospheric pressure and the main products were C (solid), hydrogen, and acetylene(C_2H_2). The plasma reaction of methane conversion was exothermic reaction which increased theproduct stream temperature around 30-50℃.展开更多
Decomposition of chlorinated hydrocarbons, CCl4 and CHCl3, in gliding plasma was examined. The effects of initial concentrations, total gas flow rates, and power consumption have been investigated. The conversion resu...Decomposition of chlorinated hydrocarbons, CCl4 and CHCl3, in gliding plasma was examined. The effects of initial concentrations, total gas flow rates, and power consumption have been investigated. The conversion result was relatively high. It reached 80% for CCl4 and 97% for CHCl3. Using atmospheric air as the carrier gas, the plasma reaction occurred at exothermic reaction and the main products were CO2, CO, and Cl2. Transformation into CCl4 was also detected for CHCl3 decomposition reaction. The conversion of CCh and CHCl3 were increased with the increasing applied frequency and decreasing total gas flow rate.展开更多
The influence of arc current and pressure on the non-chemical equilibrium （non-CE） air arc behavior of a nozzle structure was investigated based on the self-consistent non-chemical equilibrium model. The arc behavio...The influence of arc current and pressure on the non-chemical equilibrium （non-CE） air arc behavior of a nozzle structure was investigated based on the self-consistent non-chemical equilibrium model. The arc behavior during both the arc burning and arc decay phases were discussed at different currents and different pressures. We also devised the concept of a non- equilibrium parameter for a better understanding of non-CE effects. During the arc burning phase, the increasing current leads to a decrease of the non-equilibrium parameter of the particles in the arc core, while the increasing pressure leads to an increase of the non-equilibrium parameter of the particles in the arc core. During the arc decay phase, the non-CE effect will decrease by increasing the arc burning current and the nozzle pressure. Three factors together-- convection, diffusion and chemical reactions--influence non-CE behavior.展开更多
基金financially supported by the Natural Science Foundation of Hebei Province for Distinguished Young Scientists(No.E2011204036)the Natural Science Foundation of Hebei Province(No.E2014204028)the Youth Fund of Hebei Education Department(No.QN2014100)
文摘In order to solve the high-price and short-lifetime problems of the cutter of agricultural machinery,and improve the wear resistance of the cutter, the TiCN/Fe metal ceramic composite coating was prepared on the substrate of Q235 steel by reaction nitrogen arc cladding technique. The mixture powder of titanium and graphite was preplaced on the Q235 steel surface after intensive mixing by planetary ball mill and gluing with starch binder. The microstructure and phase of the coatings, interface behavior between coatings and the substrate were investigated by scanning electronic microscope and X-ray diffractometer. The micro-hardness distribution of the coating section was tested by micro-hardness tester. Friction coefficient and wear weight loss were measured by abrasion machine. Wearing surface morphology was investigated by scanning electronic microscope. The results show that an excellent bonding between the coatings and the Q235 steel substrate is ensured by the strong metallurgical interface and phase of the coatings. The coatings are mainly composed of TiCN. The highest micro- hardness of the coatings reaches 1 089 HV0. 2, while the micro-hardness of Q235 steel substrate is only about 286 HV0. 2. The anti-abrasive test results show that the wear resistance of the cladding coating is better than that of quenched and tempered 65 Mn steel which is often used as cutter of agricultural machinery. The field test results show that the TiCN/ Fe metal ceramic composite coating prepared by reaction nitrogen arc cladding is feasible to the manufacture and remanufacture of the cutter of agricultural machinery.
基金This work is supported by the National Natural Science Foundation of China （No. 51075197）, Jiangsu Province Science and Technology Support Program （ No. BE2012186）.
文摘Agglomerated fluxes with different basicity index designed in laboratory were used to study electrochemical reactions between slag and metal in submerged arc welding under both power polarities. The droplet metal oxygen and nitrogen contents were measured using oxygen-nitrogen instrument in order to analyze indirectly metallurgy electrochemical reactions taking place in cathode and anode of welding arc. The results show that just in the period of droplet growth at the tip of consumable electrode the electrochemical oxygen contamination is produced in the case of direct current electrode positive polarity whereas electrochemical oxygen lost in electrode negative polarity. Furthermore, the results indicate that the basicity index of molten slag has great influence upon electrochemical reaction. With basicity index increasing, the effect of oxygen transferring resulted from electrochemistry becomes more evident for reacting dynamics depended on ion characteristics of molten slag. The effect of basicity index on metal-slag electrochemical reaction is contrary to traditional thermo-chemical reaction and therefore it is necessary to be considered as a metallurgy factor.
文摘Plasma methane (CH_4) conversion in gliding arc discharge was examined. Theresult data of experiments regarding the performance of gliding arc discharge were presented in thispaper. A simulation which is consisted some chemical kinetic mechanisms has been provided toanalyze and describe the plasma process. The effect of total gas flow rate and input frequencyrefers to power consumption have been studied to evaluate the performance of gliding arc plasmasystem and the reaction mechanism of decomposition. Experiment results indicated that the maximumconversion of CH_4 reached 50% at the total gas flow rate of 1 L/min. The plasma reaction wasoccurred at the atmospheric pressure and the main products were C (solid), hydrogen, and acetylene(C_2H_2). The plasma reaction of methane conversion was exothermic reaction which increased theproduct stream temperature around 30-50℃.
文摘Decomposition of chlorinated hydrocarbons, CCl4 and CHCl3, in gliding plasma was examined. The effects of initial concentrations, total gas flow rates, and power consumption have been investigated. The conversion result was relatively high. It reached 80% for CCl4 and 97% for CHCl3. Using atmospheric air as the carrier gas, the plasma reaction occurred at exothermic reaction and the main products were CO2, CO, and Cl2. Transformation into CCl4 was also detected for CHCl3 decomposition reaction. The conversion of CCh and CHCl3 were increased with the increasing applied frequency and decreasing total gas flow rate.
基金supported by the National Key Basic Research Program of China (973 Program) (No. 2015CB251002)National Natural Science Foundation of China under grant Nos. 51521065, 51577145 and 51707144the State Key Laboratory of Electrical Insulation and Power Equipment (No. EIPE17305)
文摘The influence of arc current and pressure on the non-chemical equilibrium （non-CE） air arc behavior of a nozzle structure was investigated based on the self-consistent non-chemical equilibrium model. The arc behavior during both the arc burning and arc decay phases were discussed at different currents and different pressures. We also devised the concept of a non- equilibrium parameter for a better understanding of non-CE effects. During the arc burning phase, the increasing current leads to a decrease of the non-equilibrium parameter of the particles in the arc core, while the increasing pressure leads to an increase of the non-equilibrium parameter of the particles in the arc core. During the arc decay phase, the non-CE effect will decrease by increasing the arc burning current and the nozzle pressure. Three factors together-- convection, diffusion and chemical reactions--influence non-CE behavior.
