Using an arc atmosphere controlling chamber, effects of the welding conditions and atmosphere on the nitrogen content of the stainless steel weld metal by gas tungsten arc welding were investigated in comparison with those on the iron weld metal. The results are as follows:(1) The temperatures of stainless steel and iron molten pools were measured as about 1530°C and 1630°C, respectively.(2) The nitrogen content of stainless steel weld metal decreased with increasing the welding current, as well as that of iron weld metal.(3) The nitrogen content of stainless steel weld metal hardly depended on the arc length, as well as that of iron weld metal.(4) The nitrogen content of stainless steel weld metal increased with increasing the travel speed, while that of iron weld metal hardly depended on the travel speed.(5) The nitrogen content of stainless steel weld metal increased with the nitrogen partial pressure at low nitrogen partial pressure region, and was constant at the nitrogen partial pressure region above 0.2 atm in N2-Ar gas mixture atmosphere, as well as that of iron weld metal.(6) The nitrogen absorption by stainless steel weld metal was discussed with equilibrium data.
{"title":"The Nitrogen Absorption of Stainless Steel Weld Metal during Gas Tungsten Arc Welding","authors":"T. Kuwana, H. Kokawa, Kensuke Naitoh","doi":"10.2207/QJJWS.2.669","DOIUrl":"https://doi.org/10.2207/QJJWS.2.669","url":null,"abstract":"Using an arc atmosphere controlling chamber, effects of the welding conditions and atmosphere on the nitrogen content of the stainless steel weld metal by gas tungsten arc welding were investigated in comparison with those on the iron weld metal. The results are as follows:(1) The temperatures of stainless steel and iron molten pools were measured as about 1530°C and 1630°C, respectively.(2) The nitrogen content of stainless steel weld metal decreased with increasing the welding current, as well as that of iron weld metal.(3) The nitrogen content of stainless steel weld metal hardly depended on the arc length, as well as that of iron weld metal.(4) The nitrogen content of stainless steel weld metal increased with increasing the travel speed, while that of iron weld metal hardly depended on the travel speed.(5) The nitrogen content of stainless steel weld metal increased with the nitrogen partial pressure at low nitrogen partial pressure region, and was constant at the nitrogen partial pressure region above 0.2 atm in N2-Ar gas mixture atmosphere, as well as that of iron weld metal.(6) The nitrogen absorption by stainless steel weld metal was discussed with equilibrium data.","PeriodicalId":273687,"journal":{"name":"Transactions of the Japan Welding Society","volume":"4 10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128791590","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}
H. Okamura, Hideki Shinohara, Takao Funamoto, T. Shida
Metallization and bonding of AIN ceramics were made using active brazing metal (Ti-AgCu). Active brazing metal used in metallization and bonding was in paste form prepared by adding Ti powder and organic solvent in to eutectic silver brazing metal powder.Characterization and bonding mechanism of the bonded layer, and relation between the thichness of the reacted layer and bonding strength were studied.The results of this study are as follows :(1) The microstructure of the bonded layer between AIN ceramics and Ti-AgCu brazing metal is found to be TiN layer of about 0.2 to 0.8 μm in thickness at the AIN interface, a composite layer of TiC, AICu as a middle layer and Ag-Cu alloy layer at the surface side.(2) Thickness of TiN layer did not change by the amount of Ti addition in silver brazing metal but the thicness of TiCu and AlCu layers are increased with increase of Ti addition in silverbrazing metal. Activation energy of growth of TiN layer is found to be 20 kJ/mol.(3) When the amount of Ti addition is more than 15 mass%, the bonding strength is decresed and the bonded layer is broken. Because the thickness of brittle TiCu layer increases with the increase of the Ti cotent in silver brazing metal.
{"title":"Bonding Mechanism and Microstructure of Bonded Zone of AIN Ceramics with Ti-AgCu Brazing Metal","authors":"H. Okamura, Hideki Shinohara, Takao Funamoto, T. Shida","doi":"10.2207/QJJWS.9.494","DOIUrl":"https://doi.org/10.2207/QJJWS.9.494","url":null,"abstract":"Metallization and bonding of AIN ceramics were made using active brazing metal (Ti-AgCu). Active brazing metal used in metallization and bonding was in paste form prepared by adding Ti powder and organic solvent in to eutectic silver brazing metal powder.Characterization and bonding mechanism of the bonded layer, and relation between the thichness of the reacted layer and bonding strength were studied.The results of this study are as follows :(1) The microstructure of the bonded layer between AIN ceramics and Ti-AgCu brazing metal is found to be TiN layer of about 0.2 to 0.8 μm in thickness at the AIN interface, a composite layer of TiC, AICu as a middle layer and Ag-Cu alloy layer at the surface side.(2) Thickness of TiN layer did not change by the amount of Ti addition in silver brazing metal but the thicness of TiCu and AlCu layers are increased with increase of Ti addition in silverbrazing metal. Activation energy of growth of TiN layer is found to be 20 kJ/mol.(3) When the amount of Ti addition is more than 15 mass%, the bonding strength is decresed and the bonded layer is broken. Because the thickness of brittle TiCu layer increases with the increase of the Ti cotent in silver brazing metal.","PeriodicalId":273687,"journal":{"name":"Transactions of the Japan Welding Society","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123659422","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}
Further examinations and considerations were carried out for Foil S of Fe-Si-B alloy, Foil A of Fe-Co-Si-B alloy, Foil B of Fe-Ni-Mo-B alloy and Foil C of Co-Fe-Ni-Mo-Si-B alloy.Tensile shear strength of Foil B single spot-welded joints somewhat increased with the increase both in electrode force and in charging voltage, but fracture modes of these joints did not change so much. This result suggests that the increased electrode force could not suppress crystallization of Foil B weld nuggets.Tensile shear strength of Foil C single spot-welded joints did not vary so much; these joints were welded at various capacitances up to 700μF and both at a constant peak welding current of 1118 A and. at a higher electrode force of 83.1 N.Crystallization temperature Tx and melting temperature Tm of these foils were estimated through DSC in the course of heating. The order of the ratio Tx/Tm fairly relates to the order of spotweldability of these foils.Weld nuggets of Foil C produced by irradiating a defocused Nd-YAG laser beam pulse maintained the amorphous state, whereas weld nuggets of the other foils crystallized under the same condition.
{"title":"Spot Welding of Iron-based and Cobalt-based Amorphous Alloy Foils (Report 2)","authors":"S. Fukushima, T. Kasugai","doi":"10.2207/QJJWS.9.457","DOIUrl":"https://doi.org/10.2207/QJJWS.9.457","url":null,"abstract":"Further examinations and considerations were carried out for Foil S of Fe-Si-B alloy, Foil A of Fe-Co-Si-B alloy, Foil B of Fe-Ni-Mo-B alloy and Foil C of Co-Fe-Ni-Mo-Si-B alloy.Tensile shear strength of Foil B single spot-welded joints somewhat increased with the increase both in electrode force and in charging voltage, but fracture modes of these joints did not change so much. This result suggests that the increased electrode force could not suppress crystallization of Foil B weld nuggets.Tensile shear strength of Foil C single spot-welded joints did not vary so much; these joints were welded at various capacitances up to 700μF and both at a constant peak welding current of 1118 A and. at a higher electrode force of 83.1 N.Crystallization temperature Tx and melting temperature Tm of these foils were estimated through DSC in the course of heating. The order of the ratio Tx/Tm fairly relates to the order of spotweldability of these foils.Weld nuggets of Foil C produced by irradiating a defocused Nd-YAG laser beam pulse maintained the amorphous state, whereas weld nuggets of the other foils crystallized under the same condition.","PeriodicalId":273687,"journal":{"name":"Transactions of the Japan Welding Society","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114688419","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}
Methods to measure the surface temperature and the velocity of thermally sprayed particles were developed and applied to plasma-sprayed Mo, Ni-Cr alloy, and alumina particles in the air.In the temperature measurement, radiation from particles within a cylindrical measurement volume is measured and its spectrum is analyzed by a monochromator. Then the spectrum is compared with the spectra of blackbody radiation to determine the surface temperature of the particles through the least squares method.Spatial filtering technique using a mask with four thin parallel slits was adopted in the velocity measurement. When a single particle travels in front of the plates, radiation passing through the spacings between the plates is detected by a photo-multiplier, which gives a signal with four peaks. Then the velocity v of the particle is given by υ=d/t, where d is the distance between the neighboring slits and t the period between the peaks. It was also found that the mean velocity of a high-density particle stream can be determined by analyzing the power spectrum of the signal by a method such as FFT.As the results of those measurements, the change in the temperature and the velocity of sprayed particles with the distance from the exit of a plasma-torch was obtained. Where as the metal powders exhibited similar history of cooling and deceleration with the distance, alumina particles were found to be accelerated to a much higher velocity close to 300 m/s but decelerated at a much faster rate. The temperature of alumina particles could be measured for only a limited region due to the weak radiation. Also the effects of particle size on the distribution of both the temperature and the velocity of sprayed Mo particles were examined.
{"title":"Measurement of temperature and velocity of thermally sprayed particles using thermal radiation.","authors":"S. Kuroda, H. Fujimori, T. Fukushima, S. Kitahara","doi":"10.2207/QJJWS.8.132","DOIUrl":"https://doi.org/10.2207/QJJWS.8.132","url":null,"abstract":"Methods to measure the surface temperature and the velocity of thermally sprayed particles were developed and applied to plasma-sprayed Mo, Ni-Cr alloy, and alumina particles in the air.In the temperature measurement, radiation from particles within a cylindrical measurement volume is measured and its spectrum is analyzed by a monochromator. Then the spectrum is compared with the spectra of blackbody radiation to determine the surface temperature of the particles through the least squares method.Spatial filtering technique using a mask with four thin parallel slits was adopted in the velocity measurement. When a single particle travels in front of the plates, radiation passing through the spacings between the plates is detected by a photo-multiplier, which gives a signal with four peaks. Then the velocity v of the particle is given by υ=d/t, where d is the distance between the neighboring slits and t the period between the peaks. It was also found that the mean velocity of a high-density particle stream can be determined by analyzing the power spectrum of the signal by a method such as FFT.As the results of those measurements, the change in the temperature and the velocity of sprayed particles with the distance from the exit of a plasma-torch was obtained. Where as the metal powders exhibited similar history of cooling and deceleration with the distance, alumina particles were found to be accelerated to a much higher velocity close to 300 m/s but decelerated at a much faster rate. The temperature of alumina particles could be measured for only a limited region due to the weak radiation. Also the effects of particle size on the distribution of both the temperature and the velocity of sprayed Mo particles were examined.","PeriodicalId":273687,"journal":{"name":"Transactions of the Japan Welding Society","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115368717","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}
Pub Date : 1900-01-01DOI: 10.2207/QJJWS1943.49.462
A. Suzumura, T. Onzawa, H. Tamura
The TLP (Transient Liquid Phase) weldability of nickel-base heat-resistant alloys (Hastelloy X, Inconel X-750 and Udimet 500) have been studied by microscopy, electron-probe-microanalysis, tensile tests and stress-rupture tests of the joints.The major cause to restrict the TLP weldability was the formation during welding of a continuous array of stable Ti, Al and/or Nb compounds at the joint interface, which produce a weak plane joint grain boundary. In order to prevent this phenomenon, it was found important for interlayer alloys to melt moderately the base metal surface at the joint interface. For this purpose it was indicated that such interlayer alloys as including both boron and silicon which lower the melting point of the interlayer were more effective for TLP welding.
{"title":"TLP Weldability of Nickel-Base Superalloys","authors":"A. Suzumura, T. Onzawa, H. Tamura","doi":"10.2207/QJJWS1943.49.462","DOIUrl":"https://doi.org/10.2207/QJJWS1943.49.462","url":null,"abstract":"The TLP (Transient Liquid Phase) weldability of nickel-base heat-resistant alloys (Hastelloy X, Inconel X-750 and Udimet 500) have been studied by microscopy, electron-probe-microanalysis, tensile tests and stress-rupture tests of the joints.The major cause to restrict the TLP weldability was the formation during welding of a continuous array of stable Ti, Al and/or Nb compounds at the joint interface, which produce a weak plane joint grain boundary. In order to prevent this phenomenon, it was found important for interlayer alloys to melt moderately the base metal surface at the joint interface. For this purpose it was indicated that such interlayer alloys as including both boron and silicon which lower the melting point of the interlayer were more effective for TLP welding.","PeriodicalId":273687,"journal":{"name":"Transactions of the Japan Welding Society","volume":"457 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116770410","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}
Laser heating was applied for the desensitization heat-treatment of the surface layer in the sensitized HAZ of Type 304 stainless steel. The degree of sensitization was examined by EPR technique and the 10% oxalic acid electrolytic etch test. The CO2 laser with maximum power of 1.5kW was used for heat-treatment. Time-Temperature-Desensitization diagram (TTDS diagram) for sensitized Type 304 stainless steels were developed by calculation assuming the chromium diffusion control for desensitization which might occur when the chromium depleted zone was healed up due to dissolution of chromium carbide and chromium diffusion from the matrix being heated at the solution annealing temperatures. TTDS diagrams calculated agree fairly well with ones determined by corrosion tests. Laser irradiation conditions (e.g., Laser power, beam diameter and traveling velocity )required for desensitization of sensitized Type 304 stainless steels were calculated using additivity rule from the TTDS diagram calculated and theoretical thermal curve of laser heating derived from the heat conduction theory. After laser beam irradiated under an optimum condition predicted by calculation, the sensitized HAZ of Type 304 stainless steel restored complete resistance to intergranular corrosion.
{"title":"Desensitization of Stainless Steels by Laser Surface Heat-Treatment","authors":"Y. Nakao, K. Nishimoto","doi":"10.2207/QJJWS.5.445","DOIUrl":"https://doi.org/10.2207/QJJWS.5.445","url":null,"abstract":"Laser heating was applied for the desensitization heat-treatment of the surface layer in the sensitized HAZ of Type 304 stainless steel. The degree of sensitization was examined by EPR technique and the 10% oxalic acid electrolytic etch test. The CO2 laser with maximum power of 1.5kW was used for heat-treatment. Time-Temperature-Desensitization diagram (TTDS diagram) for sensitized Type 304 stainless steels were developed by calculation assuming the chromium diffusion control for desensitization which might occur when the chromium depleted zone was healed up due to dissolution of chromium carbide and chromium diffusion from the matrix being heated at the solution annealing temperatures. TTDS diagrams calculated agree fairly well with ones determined by corrosion tests. Laser irradiation conditions (e.g., Laser power, beam diameter and traveling velocity )required for desensitization of sensitized Type 304 stainless steels were calculated using additivity rule from the TTDS diagram calculated and theoretical thermal curve of laser heating derived from the heat conduction theory. After laser beam irradiated under an optimum condition predicted by calculation, the sensitized HAZ of Type 304 stainless steel restored complete resistance to intergranular corrosion.","PeriodicalId":273687,"journal":{"name":"Transactions of the Japan Welding Society","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131072843","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}
Generally, in TIG arc welding method, the ratio of penetration depth (D) to bead width (W) is small and the deep penetration cannot be obtained comparatively. But in the case of using the stationary TIG arc when the welding conditions were set to the suitable range, the value of D/W is closer to unity and the penetration depth becomes deep. Paying attention to the above mentioned phenomenon, the authors have made researches into the practical application of the stationary TIG arc.In this paper, the welding conditions which we obtained from the above mentioned penetration forms were investigated using SUS304. It was found out that when suffer (S) content of the base metal is more than 0.005 mass%, both the method of using the electrode with at vertex angle above 60° or with in argon shielding gas and the method of using helium to shielding gas are successful to increase the penetration depth.In the case of using the base metal which contains sulfer about 0.001 mass%, the method of using the tip-cutting electrode in argon shielding gas is more effective for same purpose.
{"title":"Study on Penetration Form Using Stationary TIG Arc : Study on Low Speed DC-TIG Welding Method","authors":"T. Hinata, K. Yasuda, Yukio Kasuga, T. Onzawa","doi":"10.2207/QJJWS.10.353","DOIUrl":"https://doi.org/10.2207/QJJWS.10.353","url":null,"abstract":"Generally, in TIG arc welding method, the ratio of penetration depth (D) to bead width (W) is small and the deep penetration cannot be obtained comparatively. But in the case of using the stationary TIG arc when the welding conditions were set to the suitable range, the value of D/W is closer to unity and the penetration depth becomes deep. Paying attention to the above mentioned phenomenon, the authors have made researches into the practical application of the stationary TIG arc.In this paper, the welding conditions which we obtained from the above mentioned penetration forms were investigated using SUS304. It was found out that when suffer (S) content of the base metal is more than 0.005 mass%, both the method of using the electrode with at vertex angle above 60° or with in argon shielding gas and the method of using helium to shielding gas are successful to increase the penetration depth.In the case of using the base metal which contains sulfer about 0.001 mass%, the method of using the tip-cutting electrode in argon shielding gas is more effective for same purpose.","PeriodicalId":273687,"journal":{"name":"Transactions of the Japan Welding Society","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132866702","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}
Mild steel sheets with V-groove were welded in pressurized Ar-CO2 gas mixture atmospheres up to 2.0 MPa, using a 1.6 mm diameter solid wire. The effect of ambient gas pressure and gas composition on the mechanical properties of weld metals were studied. The Vickers hardness and tensile properties of weld metals were varied with the ambient gas composition but did not depend on the ambient gas pressure. The Charpy V notch toughness of weld metal was changed markedly with CO2 partial pressure in the atmosphere, and showed a maximum at 0.1-0.2 MPa CO2 partial pressure which resulted in about 0.03% oxygen content of weld metal having a fine ferrite microstructure. This suggests that toughness is strongly influenced by the oxygen content of weld metal. Mechanical properties of pressurized steel weld metal can be controlled by CO2% in the welding atmosphere, because the oxygen content of weld metal is determined by CO2 partial pressure.
{"title":"Mechanical Propertics of Mild Steel Weld Metals Produced in Pressurized Ar-CO_2 Atmospheres","authors":"T. Kuwana, H. Kokawa, R. Kiguchi","doi":"10.2207/QJJWS.9.233","DOIUrl":"https://doi.org/10.2207/QJJWS.9.233","url":null,"abstract":"Mild steel sheets with V-groove were welded in pressurized Ar-CO2 gas mixture atmospheres up to 2.0 MPa, using a 1.6 mm diameter solid wire. The effect of ambient gas pressure and gas composition on the mechanical properties of weld metals were studied. The Vickers hardness and tensile properties of weld metals were varied with the ambient gas composition but did not depend on the ambient gas pressure. The Charpy V notch toughness of weld metal was changed markedly with CO2 partial pressure in the atmosphere, and showed a maximum at 0.1-0.2 MPa CO2 partial pressure which resulted in about 0.03% oxygen content of weld metal having a fine ferrite microstructure. This suggests that toughness is strongly influenced by the oxygen content of weld metal. Mechanical properties of pressurized steel weld metal can be controlled by CO2% in the welding atmosphere, because the oxygen content of weld metal is determined by CO2 partial pressure.","PeriodicalId":273687,"journal":{"name":"Transactions of the Japan Welding Society","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130571064","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}
Pub Date : 1900-01-01DOI: 10.2207/QJJWS1943.50.465
Y. Kikuta, T. Araki, M. Yoneda, K. Yasuda, K. Matsueda
When tensile tests on mild steel are carried out at various temperatures, the serrated yielding and flow are observed at a certain testing temperature range, specially 100-300°C, and the consequent em-brittlement occurs. This phenomenon is generally known as a blue brittleness or a dynamic strain aging and is related to testing temperature, solute atom contents (carbon and/or nitrogen contents), strain rate and so forth.On the other hand, for base metal of QT-type high strength low alloy steels in which solute atoms such as carbon and nitrogen are fixed as carbide, nitride or carbo-nitride by heat treatment, such embrit-tlement seems to be not apt to occur comparatively. But, even if QT-type steels, there is a possibility of dynamic strain aging in heat-affected zone (HAZ) because of the above carbide, nitride or carbo-nitride dissolving by welding heats, and the consequent embrittlernent.This study was investigated about the ductility loss due to dynamic strain aging in HAZ of a 80 kg/mm2 class high strength low alloy steel.It is found by this study that dynamic strain aging and, thus, the ductility loss can occur in HAZ even if QT-type steels. The degree of ductility loss is increased in the order of upper bainite, lower bainite and martensite structure.These results can be qualitatively interpreted by considering as interaction between dislocations and solute atoms, specifically nitrogen atoms rather than carbon atoms.Transformed HAZ, which is heated above 1200°C and has martensite structure and, thus, a high content of free nitrogen atoms, is sensitive to ductility loss due to dynamic strain aging as well as the deterioration of grain coarsened HAZ toughness.
{"title":"Ductility Loss due to Dynamic Strain Aging in Heat-Affected Zone of High Strength Low Alloy Steel","authors":"Y. Kikuta, T. Araki, M. Yoneda, K. Yasuda, K. Matsueda","doi":"10.2207/QJJWS1943.50.465","DOIUrl":"https://doi.org/10.2207/QJJWS1943.50.465","url":null,"abstract":"When tensile tests on mild steel are carried out at various temperatures, the serrated yielding and flow are observed at a certain testing temperature range, specially 100-300°C, and the consequent em-brittlement occurs. This phenomenon is generally known as a blue brittleness or a dynamic strain aging and is related to testing temperature, solute atom contents (carbon and/or nitrogen contents), strain rate and so forth.On the other hand, for base metal of QT-type high strength low alloy steels in which solute atoms such as carbon and nitrogen are fixed as carbide, nitride or carbo-nitride by heat treatment, such embrit-tlement seems to be not apt to occur comparatively. But, even if QT-type steels, there is a possibility of dynamic strain aging in heat-affected zone (HAZ) because of the above carbide, nitride or carbo-nitride dissolving by welding heats, and the consequent embrittlernent.This study was investigated about the ductility loss due to dynamic strain aging in HAZ of a 80 kg/mm2 class high strength low alloy steel.It is found by this study that dynamic strain aging and, thus, the ductility loss can occur in HAZ even if QT-type steels. The degree of ductility loss is increased in the order of upper bainite, lower bainite and martensite structure.These results can be qualitatively interpreted by considering as interaction between dislocations and solute atoms, specifically nitrogen atoms rather than carbon atoms.Transformed HAZ, which is heated above 1200°C and has martensite structure and, thus, a high content of free nitrogen atoms, is sensitive to ductility loss due to dynamic strain aging as well as the deterioration of grain coarsened HAZ toughness.","PeriodicalId":273687,"journal":{"name":"Transactions of the Japan Welding Society","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133611840","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}
This paper deals with the singularity of residual stress arising at the interface corner of sprayed substrates and the effects of specimen size, mechanical and physical properties on residual stress distributions using the theory of elasticity and a boundary element method (BEM).The residual stress distribution is not only defined by one singular term, then it is difficult to use a stress intensity factor as the parameter to define the strength of sprayed substrate.The residual stress distribution of test specimen satisfying following conditions are the same as that of sprayed substrate in a working field : The test specimen is composed of the substrate with the thickness being 4 times, and the length and the width being 8 times as large as a thickness of sprayed coating.The preheat temperature TB of substrate in order to make a residual stress zero is given by the temperature of sprayed coating and the ratio of linear thermal expansions of coating and substrate materials.
{"title":"Study of Residual Stress in the Vicinity of Interface Corner of Sprayed Coatings.","authors":"T. Terasaki, T. Akiyama, T. Hirai, K. Seo","doi":"10.2207/qjjws.9.430","DOIUrl":"https://doi.org/10.2207/qjjws.9.430","url":null,"abstract":"This paper deals with the singularity of residual stress arising at the interface corner of sprayed substrates and the effects of specimen size, mechanical and physical properties on residual stress distributions using the theory of elasticity and a boundary element method (BEM).The residual stress distribution is not only defined by one singular term, then it is difficult to use a stress intensity factor as the parameter to define the strength of sprayed substrate.The residual stress distribution of test specimen satisfying following conditions are the same as that of sprayed substrate in a working field : The test specimen is composed of the substrate with the thickness being 4 times, and the length and the width being 8 times as large as a thickness of sprayed coating.The preheat temperature TB of substrate in order to make a residual stress zero is given by the temperature of sprayed coating and the ratio of linear thermal expansions of coating and substrate materials.","PeriodicalId":273687,"journal":{"name":"Transactions of the Japan Welding Society","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116598502","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}
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