The thermography is an attractive technique to record the real-time temperature during the continuous welding processes. The temperature distribution during the weld zone is essential for understanding and evaluating the metallurgical properties of the joints. The knowledge of the material emissivity curve is necessary for the precise acquisition of thermography data. This emissivity value is usually assumed constant in the thermography software data acquisition, resulting in inaccurate thermographic data. The surface emissivity usually depends on the temperature. Thus, the values obtained in the literature may not be valid for materials of interest under the process’s conditions. Especially in the case of the low carbon steels, the emissivity data available are scarce and frequently obtained at low temperatures (below 200oC). Therefore, we proposed a methodological procedure to measure the effective surface emissivity, which considers the effect of temperatures and surface conditions. This research was focused on the development of an experimental methodology for determining the emissivity curve, using as the sample, a low carbon steel (0.07% C) with 0.21 mm thickness obtained from the productive stock of a continuous annealing line in the steel plant of the Companhia Siderurgica Nacional (CSN). The normal sample emissivity was evaluated in the temperature range from 100oC to 800oC. It was proposed a model based on a sigmoid function to represent the effective emissivity during temperature rise. The sigmoid model parameters were obtained by a fitting procedure using temperature measurements obtained by thermocouples. The results showed an effective emissivity variation as a function of temperature, where emissivity values raged in the interval of 0.09 to 0.83. Thus, the useful emissivity curve was used to correct the thermography data obtained in electrical resistance seam welding (RSEW) with three levels of heats inputs. The correlation for the emissivity curve incorporated in the thermography software was applied to the thermal profiles of the welds analyzed from 441oC to 713oC. These values are consistent with the welding process used. The developed methodology can be applied, in a similar way, in the correction of profiles in other types of welding processes.
热成像技术是一种记录连续焊接过程中实时温度的有吸引力的技术。焊接区的温度分布对于了解和评价接头的冶金性能至关重要。材料发射率曲线的知识是精确获取热成像数据所必需的。在热成像软件数据采集中,通常假设该发射率值为常数,导致热成像数据不准确。表面发射率通常取决于温度。因此,在该工艺条件下,文献中获得的值可能对感兴趣的材料无效。特别是在低碳钢的情况下,可用的发射率数据很少,并且经常在低温(低于200℃)下获得。因此,我们提出了一种考虑温度和表面条件影响的有效表面发射率测量方法。本研究的重点是开发一种用于确定发射率曲线的实验方法,以一种厚度为0.21 mm的低碳钢(0.07% C)为样本,该低碳钢来自Companhia Siderurgica Nacional (CSN)钢厂连续退火生产线的生产原料。在100 ~ 800℃的温度范围内测量了正常样品的发射率。提出了一种基于s型函数的有效发射率模型。利用热电偶测得的温度,通过拟合程序获得了s型模型参数。结果表明,辐射率随温度的变化是有效的,辐射率值在0.09 ~ 0.83之间波动。因此,利用有用的发射率曲线对电阻缝焊(RSEW)中三阶热输入的热成像数据进行了校正。将热像仪软件中包含的发射率曲线的相关性应用于从441oC到713oC分析的焊缝热剖面。这些值与所使用的焊接工艺一致。所开发的方法可以以类似的方式应用于其他类型焊接工艺的轮廓校正。
{"title":"Prediction of the Emissivity Curve at High Temperatures of Low Carbon Steel","authors":"Vinicius Santos de Deus, J. A. Castro, S. Correa","doi":"10.5539/jmsr.v9n2p59","DOIUrl":"https://doi.org/10.5539/jmsr.v9n2p59","url":null,"abstract":"The thermography is an attractive technique to record the real-time temperature during the continuous welding processes. The temperature distribution during the weld zone is essential for understanding and evaluating the metallurgical properties of the joints. The knowledge of the material emissivity curve is necessary for the precise acquisition of thermography data. This emissivity value is usually assumed constant in the thermography software data acquisition, resulting in inaccurate thermographic data. The surface emissivity usually depends on the temperature. Thus, the values obtained in the literature may not be valid for materials of interest under the process’s conditions. Especially in the case of the low carbon steels, the emissivity data available are scarce and frequently obtained at low temperatures (below 200oC). Therefore, we proposed a methodological procedure to measure the effective surface emissivity, which considers the effect of temperatures and surface conditions. This research was focused on the development of an experimental methodology for determining the emissivity curve, using as the sample, a low carbon steel (0.07% C) with 0.21 mm thickness obtained from the productive stock of a continuous annealing line in the steel plant of the Companhia Siderurgica Nacional (CSN). The normal sample emissivity was evaluated in the temperature range from 100oC to 800oC. It was proposed a model based on a sigmoid function to represent the effective emissivity during temperature rise. The sigmoid model parameters were obtained by a fitting procedure using temperature measurements obtained by thermocouples. The results showed an effective emissivity variation as a function of temperature, where emissivity values raged in the interval of 0.09 to 0.83. Thus, the useful emissivity curve was used to correct the thermography data obtained in electrical resistance seam welding (RSEW) with three levels of heats inputs. The correlation for the emissivity curve incorporated in the thermography software was applied to the thermal profiles of the welds analyzed from 441oC to 713oC. These values are consistent with the welding process used. The developed methodology can be applied, in a similar way, in the correction of profiles in other types of welding processes.","PeriodicalId":16111,"journal":{"name":"Journal of Materials Science Research","volume":"12 1","pages":"59"},"PeriodicalIF":0.0,"publicationDate":"2020-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73259353","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The adoption of inorganic fertilizer such as NPS which is concerned by development clients and government is different from one farmer to another farmer and this makes productivity of agricultural crops to vary from one plot to another plot due to socio-economic, institutional and other factors. Therefore, this study was intended to know the socio-economic factors that significantly affect utilization of inorganic fertilizer NPS. Primary data was collected from 201 sampled households of selected districts. Secondary data was collected from stakeholders related with production of sorghum and inorganic fertilizer NPS in the study areas. In the sampling procedure, two stage simple random sampling was used. In the first stage, kebeles were randomly taken from total kebeles in the two districts. In the second stage, households were randomly selected from the selected kebeles. Data was analyzed using descriptive, inferential statistics and econometric models methods of data analysis. In econometric models Double Hurdle model was use to know factors affect adoption decision of inorganic fertilizer NPS and intensity use of inorganic fertilizer NPS. Double Hurdle model result confirms that district of the household, education level, family size, extension visit, expectation of the coming rainfall by the household, number of farm plot owned, total farm land owned and off/non-farm income earned by the household significantly affect adoption decision inorganic fertilizer NPS. Double hurdle model result also reveals that, district of the household, livestock holding, number of farm plot owned, participation on agricultural training by the household significantly affect intensity use of inorganic fertilizer NPS. Government and concerned stakeholders should give attention on these significant socio-economic factors so that utilization inorganic fertilizer can be improved to sorghum crop productivity.
{"title":"Adoption of NPS Fertilizer on Sorghum Crop Production by Smallholder Farmers in Gemechis and Mieso Districts of West Hararghe Zone, Oromia Regional State, Ethiopia","authors":"Muhammed Shako Hiko","doi":"10.5539/jmsr.v9n2p46","DOIUrl":"https://doi.org/10.5539/jmsr.v9n2p46","url":null,"abstract":"The adoption of inorganic fertilizer such as NPS which is concerned by development clients and government is different from one farmer to another farmer and this makes productivity of agricultural crops to vary from one plot to another plot due to socio-economic, institutional and other factors. Therefore, this study was intended to know the socio-economic factors that significantly affect utilization of inorganic fertilizer NPS. Primary data was collected from 201 sampled households of selected districts. Secondary data was collected from stakeholders related with production of sorghum and inorganic fertilizer NPS in the study areas. In the sampling procedure, two stage simple random sampling was used. In the first stage, kebeles were randomly taken from total kebeles in the two districts. In the second stage, households were randomly selected from the selected kebeles. Data was analyzed using descriptive, inferential statistics and econometric models methods of data analysis. In econometric models Double Hurdle model was use to know factors affect adoption decision of inorganic fertilizer NPS and intensity use of inorganic fertilizer NPS. Double Hurdle model result confirms that district of the household, education level, family size, extension visit, expectation of the coming rainfall by the household, number of farm plot owned, total farm land owned and off/non-farm income earned by the household significantly affect adoption decision inorganic fertilizer NPS. Double hurdle model result also reveals that, district of the household, livestock holding, number of farm plot owned, participation on agricultural training by the household significantly affect intensity use of inorganic fertilizer NPS. Government and concerned stakeholders should give attention on these significant socio-economic factors so that utilization inorganic fertilizer can be improved to sorghum crop productivity.","PeriodicalId":16111,"journal":{"name":"Journal of Materials Science Research","volume":"378 1","pages":"46"},"PeriodicalIF":0.0,"publicationDate":"2020-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80629971","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Innovative bio-based composites combining humins as biorefinery by-product with keratin or lignin as wastes or industrial side-products were developed. The bio-composites were prepared using three types of matrix formulations allowing the synthesis of elastic to rigid thermosets. These matrices were combined with chicken feathers powder, non-woven chicken feathers mat or lignin to produce bio-composites. A maximum quantity of bio-fillers was used, around 10 wt.%. The effect of the bio-fillers on the matrix’s crosslinking was studied by rheology and DSC. Then, the obtained materials were analyzed by TGA, DMA, tensile tests, water absorption and SEM. The results show a very good compatibility of the humins matrix with the bio-fillers, without any preliminary modification of the matrix, that is exceptional for the point of view of a composite. The overall performances of the neat matrix were maintained or improved through the composites. Therefore, bio-composites with potentially interesting thermal and mechanical properties have been synthesized. In the case of the elastic ductile matrix the Young’s modulus value was improved from 1 to 22 MPa, while for the rigid matrix the increase was from 106 to 443 or 667 MPa, in the case of composites with non-woven chicken feathers mat or lignin. To our knowledge this is the first study combining humins matrix with keratin. The obtained bio-composites are sustainable materials linked via the used raw materials to the circular economy and biomass valorization.
{"title":"Bio-Based Composites from Industrial By-products and Wastes as Raw Materials","authors":"R. Dinu, A. Mija","doi":"10.5539/jmsr.v9n2p29","DOIUrl":"https://doi.org/10.5539/jmsr.v9n2p29","url":null,"abstract":"Innovative bio-based composites combining humins as biorefinery by-product with keratin or lignin as wastes or industrial side-products were developed. The bio-composites were prepared using three types of matrix formulations allowing the synthesis of elastic to rigid thermosets. These matrices were combined with chicken feathers powder, non-woven chicken feathers mat or lignin to produce bio-composites. A maximum quantity of bio-fillers was used, around 10 wt.%. The effect of the bio-fillers on the matrix’s crosslinking was studied by rheology and DSC. Then, the obtained materials were analyzed by TGA, DMA, tensile tests, water absorption and SEM. The results show a very good compatibility of the humins matrix with the bio-fillers, without any preliminary modification of the matrix, that is exceptional for the point of view of a composite. The overall performances of the neat matrix were maintained or improved through the composites. Therefore, bio-composites with potentially interesting thermal and mechanical properties have been synthesized. In the case of the elastic ductile matrix the Young’s modulus value was improved from 1 to 22 MPa, while for the rigid matrix the increase was from 106 to 443 or 667 MPa, in the case of composites with non-woven chicken feathers mat or lignin. To our knowledge this is the first study combining humins matrix with keratin. The obtained bio-composites are sustainable materials linked via the used raw materials to the circular economy and biomass valorization.","PeriodicalId":16111,"journal":{"name":"Journal of Materials Science Research","volume":"29 1","pages":"29"},"PeriodicalIF":0.0,"publicationDate":"2020-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88263047","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The environmental pollution is growing continuously - causing a worldwide problem. Production and use of petroleum-based materials but also huge quantities of industrial wastes are important factors that affect the well-being of the environment. New scientific researches place great emphasis on waste valorization, and also on developing new environmentally friendly bio-based materials. In this work we focus on the valorization of humins, a biorefinery side product, by its copolymerization with a bio-based triepoxide. In this manner we produce materials with a very high bio-based carbon content (BCC) » 94%. The physico-chemical and mechanical properties of the cured bio-based resins were investigated using different technics as TGA, DMA, Shore hardness test, water absorption and solvents resistance. It was revealed that the obtained materials present very good mechanical properties with values of E’ in glassy region » 3.7–5 GPa. The tan δ – maxima of the three humins-based resins are ranging from 122 to 154 °C. The thermosets’ hardness values » 82–85 SD confirm the stiffness of these materials.
{"title":"Sustainable Thermosets Obtained by Copolymerization of Humins with Triglycidyl Ether of Phloroglucinol","authors":"R. Dinu, A. Mija","doi":"10.5539/jmsr.v9n2p1","DOIUrl":"https://doi.org/10.5539/jmsr.v9n2p1","url":null,"abstract":"The environmental pollution is growing continuously - causing a worldwide problem. Production and use of petroleum-based materials but also huge quantities of industrial wastes are important factors that affect the well-being of the environment. New scientific researches place great emphasis on waste valorization, and also on developing new environmentally friendly bio-based materials. In this work we focus on the valorization of humins, a biorefinery side product, by its copolymerization with a bio-based triepoxide. In this manner we produce materials with a very high bio-based carbon content (BCC) » 94%. The physico-chemical and mechanical properties of the cured bio-based resins were investigated using different technics as TGA, DMA, Shore hardness test, water absorption and solvents resistance. It was revealed that the obtained materials present very good mechanical properties with values of E’ in glassy region » 3.7–5 GPa. The tan δ – maxima of the three humins-based resins are ranging from 122 to 154 °C. The thermosets’ hardness values » 82–85 SD confirm the stiffness of these materials.","PeriodicalId":16111,"journal":{"name":"Journal of Materials Science Research","volume":"33 1","pages":"1"},"PeriodicalIF":0.0,"publicationDate":"2020-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81256958","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The problem of climate change, coupled to the propagation of wood diseases (bark beetles for example), is leading to a shortage in softwood supply for the particleboard industries. Furthermore, the recent changes in the German forest policies which promote the conversion of coniferous forest into mixed stands are likely to enhance this phenomenon. There is, therefore, a growing need for research on possibilities of substituting the softwood with hardwood and other alternative material. For the first time, young six to seven years old Black locust (Robinia pseudoaccacia) stems from a short-rotation plantation were used at a laboratory scale with the objective of assessing the suitability of particleboard production. Four different variants were produced using different resin types: UF K350, UF K340, albumin, and PMDI, with a target density and thickness of 650 kg/m3 and 20 mm respectively for each board. The boards were tested regarding their mechanical (modulus of rupture, modulus of elasticity and internal bonding), physical (water absorption and thickness swelling) properties according to the European standard (EN 310, EN 317 and EN 319), and their formaldehyde content and emission following the EN 120 and EN 717. Industrial particles were used as reference material for the purpose of comparison. Promising bending strength was obtained with UF resins-bonded boards. The modulus of elasticity of all four variants fulfilled the EN 2003 requirements. The internal bond of the UF resins-bonded boards also met the general product standard, with values above 0.35 N/mm2. The bending strength and the internal bonding strength properties of the UF-bonded boards were superior to that of the reference boards produced with the industrial particles. Based on these results, black locust is a potential substitute for softwood in particleboard production and can be used in the industry as alternative raw material for panel production.
{"title":"Use of Hardwood Species (Robinia pseudoaccacia from Short-rotation Plantations as Raw Material in Particleboards","authors":"J. Tayo, Achale Travolta Achale, M. Euring","doi":"10.5539/jmsr.v9n2p18","DOIUrl":"https://doi.org/10.5539/jmsr.v9n2p18","url":null,"abstract":"The problem of climate change, coupled to the propagation of wood diseases (bark beetles for example), is leading to a shortage in softwood supply for the particleboard industries. Furthermore, the recent changes in the German forest policies which promote the conversion of coniferous forest into mixed stands are likely to enhance this phenomenon. There is, therefore, a growing need for research on possibilities of substituting the softwood with hardwood and other alternative material. For the first time, young six to seven years old Black locust (Robinia pseudoaccacia) stems from a short-rotation plantation were used at a laboratory scale with the objective of assessing the suitability of particleboard production. Four different variants were produced using different resin types: UF K350, UF K340, albumin, and PMDI, with a target density and thickness of 650 kg/m3 and 20 mm respectively for each board. The boards were tested regarding their mechanical (modulus of rupture, modulus of elasticity and internal bonding), physical (water absorption and thickness swelling) properties according to the European standard (EN 310, EN 317 and EN 319), and their formaldehyde content and emission following the EN 120 and EN 717. Industrial particles were used as reference material for the purpose of comparison. Promising bending strength was obtained with UF resins-bonded boards. The modulus of elasticity of all four variants fulfilled the EN 2003 requirements. The internal bond of the UF resins-bonded boards also met the general product standard, with values above 0.35 N/mm2. The bending strength and the internal bonding strength properties of the UF-bonded boards were superior to that of the reference boards produced with the industrial particles. Based on these results, black locust is a potential substitute for softwood in particleboard production and can be used in the industry as alternative raw material for panel production.","PeriodicalId":16111,"journal":{"name":"Journal of Materials Science Research","volume":"17 1","pages":"18"},"PeriodicalIF":0.0,"publicationDate":"2020-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91260637","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Phthalic anhydride-glycerol Resin(PAGR) increase the flexibility of paint, resist to acid rain effect, increases the adhesiveness, brushing power, film hardness, layer flexibility, durability, gloss retention, resistance to abrasion also helps to decrease the overall drying time of paints. Phthalic anhydride-glycerol Resin is produced by reacting polyfunctional alcohol with the poly basic and monofunctional acid by Alcoholysis process. Moreover, Phthalic anhydride-glycerol Resin (PAGR) is a major raw material for coatings, varnishes and binders. Phthalic anhydride-glycerol Resin (PAGR) is used in paints coating compositions, adhesive, plastics, varnishes, printing ink, floor coverings. In the present research work, Phthalic anhydride-glycerol Resin is synthesized using soybean oil, pentaerythritol, phthalic anhydride and litharge (PbO). It was further characterized by FTIR, DSC TGA and acid value.
{"title":"Synthesis and Study of Thermo Physical Properties of Phthalic anhydride glycerol Resin (PAGR) from Soybean Oil","authors":"Shafqat Abbas, Zaheer Ahmad","doi":"10.5539/jmsr.v9n1p42","DOIUrl":"https://doi.org/10.5539/jmsr.v9n1p42","url":null,"abstract":"Phthalic anhydride-glycerol Resin(PAGR) increase the flexibility of paint, resist to acid rain effect, increases the adhesiveness, brushing power, film hardness, layer flexibility, durability, gloss retention, resistance to abrasion also helps to decrease the overall drying time of paints. Phthalic anhydride-glycerol Resin is produced by reacting polyfunctional alcohol with the poly basic and monofunctional acid by Alcoholysis process. Moreover, Phthalic anhydride-glycerol Resin (PAGR) is a major raw material for coatings, varnishes and binders. Phthalic anhydride-glycerol Resin (PAGR) is used in paints coating compositions, adhesive, plastics, varnishes, printing ink, floor coverings. In the present research work, Phthalic anhydride-glycerol Resin is synthesized using soybean oil, pentaerythritol, phthalic anhydride and litharge (PbO). It was further characterized by FTIR, DSC TGA and acid value.","PeriodicalId":16111,"journal":{"name":"Journal of Materials Science Research","volume":"61 1","pages":"42"},"PeriodicalIF":0.0,"publicationDate":"2019-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88167096","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Luiz Fernando Cursino Briet de Almeida, J. C. Lourenço, M. Faria, D. Vieira, A. Robin, C. A. Nunes
ASTM A743 CA6NM steel is used in the manufacturing of hydraulic turbines components. Multipass welding is commonly used for their fabrication or repairing. In this work, two different vibratory welding procedures were studied: vibration applied during welding (VWC) and vibration applied after welding (VSR). Results have shown that in both conditions, CA6NM steel presented a martensitic microstructure, in which the VSR welded joint presented column-shaped packets and fine martensite delineating the individual beads, while VWC joint presented grain refinement. Heat affected zones (HAZ) presented δ-phase in small amounts for both conditions in the regions which reached higher temperatures. VSR and VWC conditions presented similar behavior in terms of hardness, HAZ hardness values being close to those of the weld metal, except for the root regions, where higher values were obtained. Charpy-V results showed that HAZs presented higher impact values than those of the weld metal. The low impact values of the weld metal were attributed to presence of inclusions from the welding electrode.
{"title":"Vibratory Stress Relief and Vibratory Weld Conditioning of Flux cored arc welded CA6NM steel","authors":"Luiz Fernando Cursino Briet de Almeida, J. C. Lourenço, M. Faria, D. Vieira, A. Robin, C. A. Nunes","doi":"10.5539/jmsr.v9n1p32","DOIUrl":"https://doi.org/10.5539/jmsr.v9n1p32","url":null,"abstract":"ASTM A743 CA6NM steel is used in the manufacturing of hydraulic turbines components. Multipass welding is commonly used for their fabrication or repairing. In this work, two different vibratory welding procedures were studied: vibration applied during welding (VWC) and vibration applied after welding (VSR). Results have shown that in both conditions, CA6NM steel presented a martensitic microstructure, in which the VSR welded joint presented column-shaped packets and fine martensite delineating the individual beads, while VWC joint presented grain refinement. Heat affected zones (HAZ) presented δ-phase in small amounts for both conditions in the regions which reached higher temperatures. VSR and VWC conditions presented similar behavior in terms of hardness, HAZ hardness values being close to those of the weld metal, except for the root regions, where higher values were obtained. Charpy-V results showed that HAZs presented higher impact values than those of the weld metal. The low impact values of the weld metal were attributed to presence of inclusions from the welding electrode.","PeriodicalId":16111,"journal":{"name":"Journal of Materials Science Research","volume":"6 1","pages":"32"},"PeriodicalIF":0.0,"publicationDate":"2019-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82127424","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
G. S. Fonseca, Silvana Carreiro de Oliveira, Jéssica Gadêlha Chaves, Pedro Pena Leite, F. Silva, L. Lopes
There are many studies on austenitic stainless steels with transformation induced plasticity (TRIP). Basically, in these steels, there is a significant increase in strength and toughness with the transformation of austenite to martensite. 304L steel finds extensive application in industry. Studies relating to martensitic transformation with plastic deformation are quite common. Many studies involve monotonic loading relating to the martensite formed. In practice, 304L steels are subject to distinct types of loading and possibly with stress concentrators. Thus, also in smaller quantities, it is possible to find in the literature studies involving cyclic loading with the TRIP effect. To contribute to the literature on the analysis of the TRIP effect on these steels, 304L steel samples with stress concentrators underwent interrupted monotonic tensile tests. Optical microscopy (OM) and x-ray diffraction (XRD) technique characterized the martensitic transformation. Other 304L steel samples with a stress concentrator underwent a low cycle fatigue test. The martensitic transformation, in this case, was possible to follow with the electron backscatter diffraction technique (EBSD). The samples after the interrupted monotonic tests show a high martensite volume fraction formed 1mm away from the notch (30% to 50%), due to the plastic deformation suffered. From 5.5mm of the notch, the samples again display a microstructure like that of the as-received (AR) sample. For the low cycle fatigue tested sample, the high concentration of deformation-induced martensite was within 15mm of the discontinuity. Approximately 0.5mm from the circular discontinuity, the sample again has a microstructure like the initial sample (IS).
{"title":"Study of Martensitic Transformation in 304L Austenitic Stainless Steel after Tensile and Low Cycle Fatigue Tests","authors":"G. S. Fonseca, Silvana Carreiro de Oliveira, Jéssica Gadêlha Chaves, Pedro Pena Leite, F. Silva, L. Lopes","doi":"10.5539/jmsr.v9n1p22","DOIUrl":"https://doi.org/10.5539/jmsr.v9n1p22","url":null,"abstract":"There are many studies on austenitic stainless steels with transformation induced plasticity (TRIP). Basically, in these steels, there is a significant increase in strength and toughness with the transformation of austenite to martensite. 304L steel finds extensive application in industry. Studies relating to martensitic transformation with plastic deformation are quite common. Many studies involve monotonic loading relating to the martensite formed. In practice, 304L steels are subject to distinct types of loading and possibly with stress concentrators. Thus, also in smaller quantities, it is possible to find in the literature studies involving cyclic loading with the TRIP effect. To contribute to the literature on the analysis of the TRIP effect on these steels, 304L steel samples with stress concentrators underwent interrupted monotonic tensile tests. Optical microscopy (OM) and x-ray diffraction (XRD) technique characterized the martensitic transformation. Other 304L steel samples with a stress concentrator underwent a low cycle fatigue test. The martensitic transformation, in this case, was possible to follow with the electron backscatter diffraction technique (EBSD). The samples after the interrupted monotonic tests show a high martensite volume fraction formed 1mm away from the notch (30% to 50%), due to the plastic deformation suffered. From 5.5mm of the notch, the samples again display a microstructure like that of the as-received (AR) sample. For the low cycle fatigue tested sample, the high concentration of deformation-induced martensite was within 15mm of the discontinuity. Approximately 0.5mm from the circular discontinuity, the sample again has a microstructure like the initial sample (IS).","PeriodicalId":16111,"journal":{"name":"Journal of Materials Science Research","volume":"9 1","pages":"22"},"PeriodicalIF":0.0,"publicationDate":"2019-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88580747","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}