The tensile strength and ductility of a high nitrogen nickel-free austenitic stainless steel with solution and cold rolling treatment were investigated by performing tensile tests at different strain rates and at room...The tensile strength and ductility of a high nitrogen nickel-free austenitic stainless steel with solution and cold rolling treatment were investigated by performing tensile tests at different strain rates and at room temperature. The tensile tests demonstrated that this steel exhibits a significant strain rate and cold rolling dependence of the tensile strength and ductility.With the increase of the strain rate from 10^-4s^-1to 1 s^-1, the yield strength and ultimate tensile strength increase and the uniform elongation and total elongation decrease. The analysis of the double logarithmic stress–strain curves showed that this steel exhibits a two-stage strain hardening behavior, which can be well examined and analyzed by using the Ludwigson equation. The strain hardening exponents at low and high strain regions(n2and n1) and the transition strain(εL) decrease with increasing strain rate and the increase of cold rolling RA. Based on the analysis results of the stress–strain curves, the transmission electron microscopy characterization of the microstructure and the scanning electron microscopy observation of the deformation surfaces, the significant strain rate and cold rolling dependence of the strength and ductility of this steel were discussed and connected with the variation in the work hardening and dislocation activity with strain rate and cold rolling.展开更多
Problems encountered in the production of low nickel austenitic stainless steel have been studied. These problems primarily include the changes to the microstructure of the slab during the heating process, the formati...Problems encountered in the production of low nickel austenitic stainless steel have been studied. These problems primarily include the changes to the microstructure of the slab during the heating process, the formation and removal of deformation - induced martensite during cold rolling, and the effects of the annealing process on the surface oxide structure. A reasonable manufacturing process has been proposed on the basis of the research results and high-quality cold-rolled strips of low nickel austenitic stainless steel have been produced.展开更多
The key manufacturing technologies associated with composition, microstructure, mechanical properties, casting quality and key process control for large martensitic stainless steel castings are involved in this paper....The key manufacturing technologies associated with composition, microstructure, mechanical properties, casting quality and key process control for large martensitic stainless steel castings are involved in this paper. The achievements fully satisfeid the technical requirements of the large 700 MW stainless steel hydraulic turbine runner for the Three Gorges Hydropower Station, and become the major technical support for the design and manufacture of the largest 700 MW hydraulic turbine generator unit in the world developed through our own efforts. The characteristics of a new high yield to tensile strength (R p0.2/R m ) ratio and high obdurability martensitic stainless steel with ultra low carbon and high cleanliness are also described. Over the next ten years, the large martensitic stainless steel castings and advanced manufacturing technologies will see a huge demand in clean energy industry such as nuclear power, hydraulic power at home and abroad. Therefore, the new high yield o tensile strength (R p0.2/R m ) ratio and high obdurability martensitic stainless steel materials, the fast and flexible manufacturing technologies of large size castings, and new environment friendly sustainable process will face new challenges and opportunities.展开更多
SAW308L submerged arc welding wire and SJ601A submerged arc welding flux were selected to weld the 12 mm 08Cr19MnNi3Cu2N low nickel and high nitrogen austenitic stainless steel plates with three different welding heat...SAW308L submerged arc welding wire and SJ601A submerged arc welding flux were selected to weld the 12 mm 08Cr19MnNi3Cu2N low nickel and high nitrogen austenitic stainless steel plates with three different welding heat input,and microstructure,tensile properties,microhardness and corrosion properties of the welded joints were studied.The results show that no defects are found in the three groups of welded joints,and the welded joints have better performance.The tensile strength of 08Cr19MnNi3Cu2N stainless steel welded joints with different heat input is slightly lower than that of the base metal,and fracture occurs in the weld zone,and the hardness of the weld zone is lower than that of the base metal.The weld microstructure of stainless steel welded joints with different heat input is composed of austenite+δferrite,and ferrite is uniformly distributed in austenite.With the increase of the welding heat input,the ferrite content in the weld zone decrease gradually,the grain size in the thermal affected zone increase gradually,and the impact toughness reduce.展开更多
Stainless steel crude alloy recovery from direct smelting of low-grade chromite, nickel laterite and manganese ores was investigated. The mixed low-grade ores were directly smelted in an elevator furnace at smelting t...Stainless steel crude alloy recovery from direct smelting of low-grade chromite, nickel laterite and manganese ores was investigated. The mixed low-grade ores were directly smelted in an elevator furnace at smelting temperatures ranging from 1550 to 1600 ℃. Smelting experiments were conducted in a laboratory elevator furnace equipped with 8 U-shaped high- quality molybdenum disilicide heating elements. A low-grade coal was used as the reductant. Experimental results showed that the recovery of Fe, Cr, Ni, Mn and Si within the alloy increased from 34.22, 60.27, 57.14, 25.42 and 13.02% to 69.91, 99.26, 86.02, 60.8 and 34.21%, respectively, when the temperature was increased from 1550 to 1600 ℃. There was a general increase in the total recoveries of Fe, Cr, and Ni in the alloy with CaO addition increasing from 0.4 g up to 1.2 g. However, the recoveries of Mn and Si vividly decreased as the CaO contents were increased. In general, the recoveries of the metal contents of the crude alloy increase with the increase in the amount of manganese ore. Compared to the recoveries of Fe, Cr, and Ni when CaO was added, the recoveries of Fe, Cr and Ni were lower when manganese ore was used as an additive.展开更多
The influence of cerium(Ce)treatment on the morphologies,size and distributions of Al_2O_3 inclusions in low carbon high manganese steel was investigated by OM,SEM-EDS and theoretical calculation.The results showed ...The influence of cerium(Ce)treatment on the morphologies,size and distributions of Al_2O_3 inclusions in low carbon high manganese steel was investigated by OM,SEM-EDS and theoretical calculation.The results showed that Ce can modify the morphologies and types of Al_2O_3 inclusions.After Ce treatment,the irregular Al_2O_3 inclusions were replaced by smaller and dispersive spherical cerium oxysulfides.The effects of treatment time and Ce content on the evolution of Al_2O_3 inclusions were examined.It indicated that Al_2O_3 inclusions were wrapped by rare earth inclusions to form a ring like shape Ce-enriched band around the inclusions.Model was established to elucidate the evolution mechanism of Al_2O_3 inclusions.Evolution kinetics of inclusions was discussed qualitatively to analyze the velocity controlled step.It was found that diffusion of Ce^(3+)and Al^(3+)in solid inclusion core and the formed intermediate layer would be the limited step during the evolution process.展开更多
Austenitic stainless steel(ASS) and High nickel steel(HNS) welding consumables are being used for welding Q&T steels, as they have higher solubility for hydrogen in austenitic phase, to avoid hydrogen induced crac...Austenitic stainless steel(ASS) and High nickel steel(HNS) welding consumables are being used for welding Q&T steels, as they have higher solubility for hydrogen in austenitic phase, to avoid hydrogen induced cracking(HIC) but they are very expensive. In recent years, the developments of low hydrogen ferritic steel(LHF) consumables that contain no hygroscopic compounds are utilized for welding Q&T steels. Heat affected zone(HAZ) softening is another critical issue during welding of armour grade Q&T steels and it depends on the welding process employed and the weld thermal cycle. In this investigation an attempt has been made to study the influence of welding consumables and welding processes on metallurgical characteristics of armour grade Q&T steel joints by various metallurgical characterization procedures. Shielded metal arc welding(SMAW) and flux cored arc welding(FCAW) processes were used for making welds using ASS, LHF and HNS welding consumables. The joints fabricated by using LHF consumables offered lower degree of HAZ softening and there is no evidence of HIC in the joints fabricated using LHF consumables.展开更多
Most commercialized coronary stents are made of 316L stainless steels due to its good combination of properties, and currently some new stents are made of cobalt-based alloy owing to its higher mechanical properties. ...Most commercialized coronary stents are made of 316L stainless steels due to its good combination of properties, and currently some new stents are made of cobalt-based alloy owing to its higher mechanical properties. However, the presence of high quantity of nickel and/or cobalt elements in these materials, which are known to trigger the toxic and allergic responses, has caused many concerns. Nickel-free austenitic stainless steels have been developed in order to solve these problems. In this paper, based on the development of a new Fe- Cr-Mn-Mo-N type high nitrogen nickel-free austenitic stainless steel, properties such as mechanical property, corrosion resistance in Hankls solution, and in vitro blood compatibility including the kinetic clotting time and the platelets adhesion, were investigated in comparison to the above two conventional materials, a 316L stainless steel and a Co-28Cr-6Mo alloy. The results showed that the new high nitrogen steel possessed better combination of mechanical properties, corrosion resistance and blood compatibility than those of 316L steel and the Co-28Cr-OMo alloy, and can be a promising alternative material for manufacture of coronary stents.展开更多
The fine grained structures of nickel-free high nitrogen austenitic stainless steels had been obtained by means of cold rolling and subsequent annealing. The relationship between microstructure and mechanical properti...The fine grained structures of nickel-free high nitrogen austenitic stainless steels had been obtained by means of cold rolling and subsequent annealing. The relationship between microstructure and mechanical properties and gain size of nickel-free high nitrogen austenitic stainless steels was examined. High strength and good ductility of the steel were found. In the grain size range, the Hall-Petch dependency for yield stress, tensile strength, and hardness was valid for grain size ranges for the nickel-free high nitrogen austenitic stainless steel. In the present study, the ductility of cold rolled nickel-free high nitrogen austenitic stainless steel decreased with annealing time when the grain size was refined. The fracture surfaces of the tensile specimens in the grain size range were covered with dimples as usually seen in a ductile fracture mode.展开更多
Three forged low-density high manganese steels Mn28Al10,Mn28Al8 and Mn20Al10 were used as experimental materials in this study.The forged microstructure and external oxidation characteristics at 1323 K and 1373 K for ...Three forged low-density high manganese steels Mn28Al10,Mn28Al8 and Mn20Al10 were used as experimental materials in this study.The forged microstructure and external oxidation characteristics at 1323 K and 1373 K for 5-25 h in air were investigated by microstructural observation and X-ray diffraction(XRD)technique.The phase compositions and abundance in the forged and oxidized samples were quantitatively obtained by Rietveld method on the basis of XRD pattern analysis.The results showed that an austenitic microstructure formed in steels Mn28Al10 and Mn28Al8,and 18.02 wt%ferrite could be found in Mn20Al10.The relative amount of ~5.28 wt%-carbide(Fe_3AlC_(0.5))in Mn28Al10 was far greater than that in Mn28Al8 and Mn20Al10.The oxidation kinetics of forged steels oxidized at 1323 K for 5-25 h had two-stage parabolic rate laws;and the oxidation rate of the first stage was lower than that of the second stage.When they were oxidized at 1373 K for 5-25 h,the oxidation kinetics followed only a parabolic law and the oxidation rates were respectively greater than those at 1323 K for 5-25 h.When they were oxidized at 1323 K for 25 h,detached external scales contained Fe_2MnO_4and-Fe_2O_3oxides.-Al_2O_3and(Fe,Mn)_2O_3oxides could only be indexed in steels Mn28Al8 and Mn28Al10,respectively.When they were oxidized at 1373 K for 25 h,Fe_2MnO_4,Fe_3O_4,-Fe_2O_3 and-Al_2O_3oxides could all be indexed in the external detached scales.The main phase of detached external scales was Fe_2MnO_4;and the relative amount of-Al_2O_3in steel Mn28Al8 was higher than that in steels Mn28Al10 and Mn20Al.The external oxidation layers of these three forged steels oxidized at 1323 K and 1373 K for 25 h were essentially followed the sequence of-Al_2O_3,Fe_2MnO_4,Fe_3O_4,FeMnO_3,and Fe_2O_3from the substrate to the outside surface.The forged Mn28Al10 steel with austenitic microstructure and a certain amount of-carbide(~5.28 wt%in the present work)possessed a better combination of strength,ductility,specific strength,and oxidation rate when compared to that of the forged Mn28Al8 and Mn20Al10 steels.展开更多
The microstructural,mechanical and corrosion properties of different cold-rolled biomedical nickel-free highnitrogen stainless steels(NFHNSSs) were investigated to study the effect of cold deformation on its dry wea...The microstructural,mechanical and corrosion properties of different cold-rolled biomedical nickel-free highnitrogen stainless steels(NFHNSSs) were investigated to study the effect of cold deformation on its dry wear resistance as well as corrosion–wear behaviors in distilled water and Hank's solution. The results indicated that NFHNSS was characterized by stable austenite and possessed excellent work-hardening capacity; due to increasing cold deformation,the corrosion resistance just decreased very slightly and the dry wear rate decreased initially but subsequently increased,while the corrosion–wear resistance was improved monotonically in both distilled water and Hank's solution in spite of the presence of corrosive ions. The friction coefficients for different cold-rolled NFHNSSs were very close under the same lubricating condition,but they were the largest in distilled water compared to that in dry wear tests and Hank's solution.展开更多
Based on the time-dependent strain cyclic characteristics and fatigue behaviors of SS304 stainless steel under multi-axial cyclic loading at 700 ? C, and in the frame of unified visoco-plastic cyclic constitutive mod...Based on the time-dependent strain cyclic characteristics and fatigue behaviors of SS304 stainless steel under multi-axial cyclic loading at 700 ? C, and in the frame of unified visoco-plastic cyclic constitutive model and continuum damage mechanics theory, the damage-coupled multi-axial time-dependent constitutive model and fatigue failure model were proposed. In the model, the evolution equation of damage was introduced in and the time-dependent effects, e.g. holding time, loading rate, were taken into account. The model was applied to the simulation of whole-life cyclic deformation behaviors and prediction of LCF life for SS304 stainless steel in multiaxial time-dependent low cycle fatigue tests. It is shown that the simulated results agree well with experimental ones.展开更多
基金Project supported by the National Natural Science Foundations of China(Grant Nos.51371089 and 51401083)
文摘The tensile strength and ductility of a high nitrogen nickel-free austenitic stainless steel with solution and cold rolling treatment were investigated by performing tensile tests at different strain rates and at room temperature. The tensile tests demonstrated that this steel exhibits a significant strain rate and cold rolling dependence of the tensile strength and ductility.With the increase of the strain rate from 10^-4s^-1to 1 s^-1, the yield strength and ultimate tensile strength increase and the uniform elongation and total elongation decrease. The analysis of the double logarithmic stress–strain curves showed that this steel exhibits a two-stage strain hardening behavior, which can be well examined and analyzed by using the Ludwigson equation. The strain hardening exponents at low and high strain regions(n2and n1) and the transition strain(εL) decrease with increasing strain rate and the increase of cold rolling RA. Based on the analysis results of the stress–strain curves, the transmission electron microscopy characterization of the microstructure and the scanning electron microscopy observation of the deformation surfaces, the significant strain rate and cold rolling dependence of the strength and ductility of this steel were discussed and connected with the variation in the work hardening and dislocation activity with strain rate and cold rolling.
文摘Problems encountered in the production of low nickel austenitic stainless steel have been studied. These problems primarily include the changes to the microstructure of the slab during the heating process, the formation and removal of deformation - induced martensite during cold rolling, and the effects of the annealing process on the surface oxide structure. A reasonable manufacturing process has been proposed on the basis of the research results and high-quality cold-rolled strips of low nickel austenitic stainless steel have been produced.
文摘The key manufacturing technologies associated with composition, microstructure, mechanical properties, casting quality and key process control for large martensitic stainless steel castings are involved in this paper. The achievements fully satisfeid the technical requirements of the large 700 MW stainless steel hydraulic turbine runner for the Three Gorges Hydropower Station, and become the major technical support for the design and manufacture of the largest 700 MW hydraulic turbine generator unit in the world developed through our own efforts. The characteristics of a new high yield to tensile strength (R p0.2/R m ) ratio and high obdurability martensitic stainless steel with ultra low carbon and high cleanliness are also described. Over the next ten years, the large martensitic stainless steel castings and advanced manufacturing technologies will see a huge demand in clean energy industry such as nuclear power, hydraulic power at home and abroad. Therefore, the new high yield o tensile strength (R p0.2/R m ) ratio and high obdurability martensitic stainless steel materials, the fast and flexible manufacturing technologies of large size castings, and new environment friendly sustainable process will face new challenges and opportunities.
文摘SAW308L submerged arc welding wire and SJ601A submerged arc welding flux were selected to weld the 12 mm 08Cr19MnNi3Cu2N low nickel and high nitrogen austenitic stainless steel plates with three different welding heat input,and microstructure,tensile properties,microhardness and corrosion properties of the welded joints were studied.The results show that no defects are found in the three groups of welded joints,and the welded joints have better performance.The tensile strength of 08Cr19MnNi3Cu2N stainless steel welded joints with different heat input is slightly lower than that of the base metal,and fracture occurs in the weld zone,and the hardness of the weld zone is lower than that of the base metal.The weld microstructure of stainless steel welded joints with different heat input is composed of austenite+δferrite,and ferrite is uniformly distributed in austenite.With the increase of the welding heat input,the ferrite content in the weld zone decrease gradually,the grain size in the thermal affected zone increase gradually,and the impact toughness reduce.
文摘Stainless steel crude alloy recovery from direct smelting of low-grade chromite, nickel laterite and manganese ores was investigated. The mixed low-grade ores were directly smelted in an elevator furnace at smelting temperatures ranging from 1550 to 1600 ℃. Smelting experiments were conducted in a laboratory elevator furnace equipped with 8 U-shaped high- quality molybdenum disilicide heating elements. A low-grade coal was used as the reductant. Experimental results showed that the recovery of Fe, Cr, Ni, Mn and Si within the alloy increased from 34.22, 60.27, 57.14, 25.42 and 13.02% to 69.91, 99.26, 86.02, 60.8 and 34.21%, respectively, when the temperature was increased from 1550 to 1600 ℃. There was a general increase in the total recoveries of Fe, Cr, and Ni in the alloy with CaO addition increasing from 0.4 g up to 1.2 g. However, the recoveries of Mn and Si vividly decreased as the CaO contents were increased. In general, the recoveries of the metal contents of the crude alloy increase with the increase in the amount of manganese ore. Compared to the recoveries of Fe, Cr, and Ni when CaO was added, the recoveries of Fe, Cr and Ni were lower when manganese ore was used as an additive.
基金financially sponsored by Nature Science Foundation of Shanxi Province of China(No.2015011068)Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi(Grant No.2017138)
文摘The influence of cerium(Ce)treatment on the morphologies,size and distributions of Al_2O_3 inclusions in low carbon high manganese steel was investigated by OM,SEM-EDS and theoretical calculation.The results showed that Ce can modify the morphologies and types of Al_2O_3 inclusions.After Ce treatment,the irregular Al_2O_3 inclusions were replaced by smaller and dispersive spherical cerium oxysulfides.The effects of treatment time and Ce content on the evolution of Al_2O_3 inclusions were examined.It indicated that Al_2O_3 inclusions were wrapped by rare earth inclusions to form a ring like shape Ce-enriched band around the inclusions.Model was established to elucidate the evolution mechanism of Al_2O_3 inclusions.Evolution kinetics of inclusions was discussed qualitatively to analyze the velocity controlled step.It was found that diffusion of Ce^(3+)and Al^(3+)in solid inclusion core and the formed intermediate layer would be the limited step during the evolution process.
基金Armament Research Board (ARMREB), New Delhi for funding this project work (Project no. MAA/03/ 41)
文摘Austenitic stainless steel(ASS) and High nickel steel(HNS) welding consumables are being used for welding Q&T steels, as they have higher solubility for hydrogen in austenitic phase, to avoid hydrogen induced cracking(HIC) but they are very expensive. In recent years, the developments of low hydrogen ferritic steel(LHF) consumables that contain no hygroscopic compounds are utilized for welding Q&T steels. Heat affected zone(HAZ) softening is another critical issue during welding of armour grade Q&T steels and it depends on the welding process employed and the weld thermal cycle. In this investigation an attempt has been made to study the influence of welding consumables and welding processes on metallurgical characteristics of armour grade Q&T steel joints by various metallurgical characterization procedures. Shielded metal arc welding(SMAW) and flux cored arc welding(FCAW) processes were used for making welds using ASS, LHF and HNS welding consumables. The joints fabricated by using LHF consumables offered lower degree of HAZ softening and there is no evidence of HIC in the joints fabricated using LHF consumables.
基金supported by the National Natural Science Foundation of China (No. 31000428)a funding from Chinese Academy of Sciences (No.KGCX2-YW-207)
文摘Most commercialized coronary stents are made of 316L stainless steels due to its good combination of properties, and currently some new stents are made of cobalt-based alloy owing to its higher mechanical properties. However, the presence of high quantity of nickel and/or cobalt elements in these materials, which are known to trigger the toxic and allergic responses, has caused many concerns. Nickel-free austenitic stainless steels have been developed in order to solve these problems. In this paper, based on the development of a new Fe- Cr-Mn-Mo-N type high nitrogen nickel-free austenitic stainless steel, properties such as mechanical property, corrosion resistance in Hankls solution, and in vitro blood compatibility including the kinetic clotting time and the platelets adhesion, were investigated in comparison to the above two conventional materials, a 316L stainless steel and a Co-28Cr-6Mo alloy. The results showed that the new high nitrogen steel possessed better combination of mechanical properties, corrosion resistance and blood compatibility than those of 316L steel and the Co-28Cr-OMo alloy, and can be a promising alternative material for manufacture of coronary stents.
基金Item Sponsored by Key Program of National Natural Science Foundation of China (50534010)
文摘The fine grained structures of nickel-free high nitrogen austenitic stainless steels had been obtained by means of cold rolling and subsequent annealing. The relationship between microstructure and mechanical properties and gain size of nickel-free high nitrogen austenitic stainless steels was examined. High strength and good ductility of the steel were found. In the grain size range, the Hall-Petch dependency for yield stress, tensile strength, and hardness was valid for grain size ranges for the nickel-free high nitrogen austenitic stainless steel. In the present study, the ductility of cold rolled nickel-free high nitrogen austenitic stainless steel decreased with annealing time when the grain size was refined. The fracture surfaces of the tensile specimens in the grain size range were covered with dimples as usually seen in a ductile fracture mode.
基金financially supported by the National Natural Science Foundation of China(Grant No.51674004)the Education Department of Anhui Province of China(No.KJ2016A104,KJ2017A805)
文摘Three forged low-density high manganese steels Mn28Al10,Mn28Al8 and Mn20Al10 were used as experimental materials in this study.The forged microstructure and external oxidation characteristics at 1323 K and 1373 K for 5-25 h in air were investigated by microstructural observation and X-ray diffraction(XRD)technique.The phase compositions and abundance in the forged and oxidized samples were quantitatively obtained by Rietveld method on the basis of XRD pattern analysis.The results showed that an austenitic microstructure formed in steels Mn28Al10 and Mn28Al8,and 18.02 wt%ferrite could be found in Mn20Al10.The relative amount of ~5.28 wt%-carbide(Fe_3AlC_(0.5))in Mn28Al10 was far greater than that in Mn28Al8 and Mn20Al10.The oxidation kinetics of forged steels oxidized at 1323 K for 5-25 h had two-stage parabolic rate laws;and the oxidation rate of the first stage was lower than that of the second stage.When they were oxidized at 1373 K for 5-25 h,the oxidation kinetics followed only a parabolic law and the oxidation rates were respectively greater than those at 1323 K for 5-25 h.When they were oxidized at 1323 K for 25 h,detached external scales contained Fe_2MnO_4and-Fe_2O_3oxides.-Al_2O_3and(Fe,Mn)_2O_3oxides could only be indexed in steels Mn28Al8 and Mn28Al10,respectively.When they were oxidized at 1373 K for 25 h,Fe_2MnO_4,Fe_3O_4,-Fe_2O_3 and-Al_2O_3oxides could all be indexed in the external detached scales.The main phase of detached external scales was Fe_2MnO_4;and the relative amount of-Al_2O_3in steel Mn28Al8 was higher than that in steels Mn28Al10 and Mn20Al.The external oxidation layers of these three forged steels oxidized at 1323 K and 1373 K for 25 h were essentially followed the sequence of-Al_2O_3,Fe_2MnO_4,Fe_3O_4,FeMnO_3,and Fe_2O_3from the substrate to the outside surface.The forged Mn28Al10 steel with austenitic microstructure and a certain amount of-carbide(~5.28 wt%in the present work)possessed a better combination of strength,ductility,specific strength,and oxidation rate when compared to that of the forged Mn28Al8 and Mn20Al10 steels.
基金supported by the National Natural Science Foundation of China(No.31370976)the National Basic Research Program of China(No.2012CB619101)
文摘The microstructural,mechanical and corrosion properties of different cold-rolled biomedical nickel-free highnitrogen stainless steels(NFHNSSs) were investigated to study the effect of cold deformation on its dry wear resistance as well as corrosion–wear behaviors in distilled water and Hank's solution. The results indicated that NFHNSS was characterized by stable austenite and possessed excellent work-hardening capacity; due to increasing cold deformation,the corrosion resistance just decreased very slightly and the dry wear rate decreased initially but subsequently increased,while the corrosion–wear resistance was improved monotonically in both distilled water and Hank's solution in spite of the presence of corrosive ions. The friction coefficients for different cold-rolled NFHNSSs were very close under the same lubricating condition,but they were the largest in distilled water compared to that in dry wear tests and Hank's solution.
基金supported by the Fundamental Research Funds for the Central Universities (No.SWJTU09ZT35)National Science Fund for Distinguished Young Scholars of China (No.11025210)
文摘Based on the time-dependent strain cyclic characteristics and fatigue behaviors of SS304 stainless steel under multi-axial cyclic loading at 700 ? C, and in the frame of unified visoco-plastic cyclic constitutive model and continuum damage mechanics theory, the damage-coupled multi-axial time-dependent constitutive model and fatigue failure model were proposed. In the model, the evolution equation of damage was introduced in and the time-dependent effects, e.g. holding time, loading rate, were taken into account. The model was applied to the simulation of whole-life cyclic deformation behaviors and prediction of LCF life for SS304 stainless steel in multiaxial time-dependent low cycle fatigue tests. It is shown that the simulated results agree well with experimental ones.