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André Paulo Tschiptschin - One of the best experts on this subject based on the ideXlab platform.
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Scratch test of active screen low temperature plasma Nitrided AISI 410 martensitic stainless steel
Wear, 2017Co-Authors: L.a Espitia, Hanshan Dong, Carlos Eduardo Pinedo, André Paulo TschiptschinAbstract:Abstract A Nitrided Case composed of expanded martensite and small quantities of hexagonal e-Fe 24 N 10 iron nitrides was formed in a martensitic stainless steel by means of active screen plasma nitriding process. Nanoindentation tests were carried out in order to assess the mechanical properties and to obtain an energy dissipation coefficient defined as the ratio of plastic to total deformation energy. Friction coefficient, mechanical failure mode and critical load for damaging the Nitrided Case were determined using linear scratch tests performed at both linearly-increased normal force and constant normal force according to ASTM C1624 standard. The scratch test results showed that the groove features and the friction coefficient could be well correlated to the energy dissipation coefficient. The expanded martensite strongly decreased the friction coefficient in comparison to the non-Nitrided martensitic stainless steel. The critical load was 14 N and tensile cracking was the mechanical failure mode of the Nitrided Case.
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cavitation erosion resistance and wear mechanisms of active screen low temperature plasma Nitrided aisi 410 martensitic stainless steel
Wear, 2015Co-Authors: L.a Espitia, Hanshan Dong, Carlos Eduardo Pinedo, Xiaoying Li, André Paulo TschiptschinAbstract:Abstract Quenched and tempered AISI 410 martensitic stainless steel specimens were active screen plasma Nitrided in a mixture of 75% of nitrogen and 25% of hydrogen during 20 h at 400 °C. The microstructure of the Nitrided Case was characterized by optical microscopy, scanning electron microscopy and microhardness measurements. The phases were identified by X-ray diffraction and the nitrogen content as a function of depth was measured using wavelength dispersive X-ray spectrometer coupled to SEM. Nanoindentation tests were carried out in order to assess hardness ( H ), Young modulus ( E ), H / E and H 3 / E 2 ratios and the elastic recovery ( W e ) of the Nitrided layer. Cavitation erosion tests were carried out according to ASTM G32 standard during 20 h, with periodical interruptions for registering the mass losses. Additional cavitation erosion tests were performed to identify the wear mechanisms in both specimens, through assessment of the evolution of the damage on the surface, in a scanning electron microscope. A ~28 µm thick, 1275 HV hard Nitrided Case formed at the surface of the martensitic stainless steel, composed of nitrogen supersaturated expanded martensite and hexagonal e-Fe 24 N 10 iron nitrides. The expanded martensite decreased 27 times the mass loss shown by the non-Nitrided stainless steel and the erosion rate decreased from 2.56 mg/h to 0.085 mg/h. The increase in cavitation erosion resistance can be mainly attributed to the increase in hardness and to the elastic response of the expanded martensite. The non-Nitrided specimen changed from initially ductile to brittle behavior, exhibiting two different modes of material detachment. The first mode was characterized by a great degree of plastic deformation, fatigue and ductile fracture. The second failure mode could be associated to brittle fracture by cleavage mechanisms. In contrast, the wear mechanism observed in the Nitrided specimen was brittle fracture without evident plastic deformation.
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estrutura e propriedades do aco inoxidavel austenitico aisi 316l grau astm f138 nitretado sob plasma a baixa temperatura structure and properties of an austenitic stainless steel aisi 316l grade astm f138 after low temperature plasma nitriding
2010Co-Authors: André Paulo Tschiptschin, Carlos Eduardo PinedoAbstract:Austenitic stainless steels cannot be conventionally Nitrided at temperatures near 550°C due to the intense precipitation of chromium nitrides in the diffusion zone. The precipitation of chro-mium nitrides increases the hardness but severely impairs corrosion resistance. Plasma nitriding allows introducing nitrogen in the steel at temperatures below 450°C, forming pre-dominantly expanded austenite ( N ), with a crystalline structure best represented by a special triclin-ic lattice, with a very high nitrogen atomic concentration promoting high compressive residual stresses at the surface, increasing substrate hardness from 4 GPa up to 14 GPa on the Nitrided Case.
L.a Espitia - One of the best experts on this subject based on the ideXlab platform.
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Scratch test of active screen low temperature plasma Nitrided AISI 410 martensitic stainless steel
Wear, 2017Co-Authors: L.a Espitia, Hanshan Dong, Carlos Eduardo Pinedo, André Paulo TschiptschinAbstract:Abstract A Nitrided Case composed of expanded martensite and small quantities of hexagonal e-Fe 24 N 10 iron nitrides was formed in a martensitic stainless steel by means of active screen plasma nitriding process. Nanoindentation tests were carried out in order to assess the mechanical properties and to obtain an energy dissipation coefficient defined as the ratio of plastic to total deformation energy. Friction coefficient, mechanical failure mode and critical load for damaging the Nitrided Case were determined using linear scratch tests performed at both linearly-increased normal force and constant normal force according to ASTM C1624 standard. The scratch test results showed that the groove features and the friction coefficient could be well correlated to the energy dissipation coefficient. The expanded martensite strongly decreased the friction coefficient in comparison to the non-Nitrided martensitic stainless steel. The critical load was 14 N and tensile cracking was the mechanical failure mode of the Nitrided Case.
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cavitation erosion resistance and wear mechanisms of active screen low temperature plasma Nitrided aisi 410 martensitic stainless steel
Wear, 2015Co-Authors: L.a Espitia, Hanshan Dong, Carlos Eduardo Pinedo, Xiaoying Li, André Paulo TschiptschinAbstract:Abstract Quenched and tempered AISI 410 martensitic stainless steel specimens were active screen plasma Nitrided in a mixture of 75% of nitrogen and 25% of hydrogen during 20 h at 400 °C. The microstructure of the Nitrided Case was characterized by optical microscopy, scanning electron microscopy and microhardness measurements. The phases were identified by X-ray diffraction and the nitrogen content as a function of depth was measured using wavelength dispersive X-ray spectrometer coupled to SEM. Nanoindentation tests were carried out in order to assess hardness ( H ), Young modulus ( E ), H / E and H 3 / E 2 ratios and the elastic recovery ( W e ) of the Nitrided layer. Cavitation erosion tests were carried out according to ASTM G32 standard during 20 h, with periodical interruptions for registering the mass losses. Additional cavitation erosion tests were performed to identify the wear mechanisms in both specimens, through assessment of the evolution of the damage on the surface, in a scanning electron microscope. A ~28 µm thick, 1275 HV hard Nitrided Case formed at the surface of the martensitic stainless steel, composed of nitrogen supersaturated expanded martensite and hexagonal e-Fe 24 N 10 iron nitrides. The expanded martensite decreased 27 times the mass loss shown by the non-Nitrided stainless steel and the erosion rate decreased from 2.56 mg/h to 0.085 mg/h. The increase in cavitation erosion resistance can be mainly attributed to the increase in hardness and to the elastic response of the expanded martensite. The non-Nitrided specimen changed from initially ductile to brittle behavior, exhibiting two different modes of material detachment. The first mode was characterized by a great degree of plastic deformation, fatigue and ductile fracture. The second failure mode could be associated to brittle fracture by cleavage mechanisms. In contrast, the wear mechanism observed in the Nitrided specimen was brittle fracture without evident plastic deformation.
K Hock - One of the best experts on this subject based on the ideXlab platform.
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properties of duplex treated gas nitriding and pvd tin cr2n low alloy steel
Surface & Coatings Technology, 1998Co-Authors: M Bader, Erhard Broszeit, K Hock, H J Spies, H J SchroderAbstract:Abstract Gas-nitriding of low-alloy steel as a pretreatment for hard-coating deposition by hollow cathode discharge evaporation is well established. Above all, the produced Nitrided Case leads to a distinct increase in the resistance of the coating towards mechanical and chemical stress. Gas-Nitrided samples of 31CrMoV9 coated with TiN and Cr 2 N were objects of extensive investigations to characterize their properties. The description of coating-substrate adhesion and the behaviour of the sample surface under tribological stress were the main subject of the experiments. The investigation of rolling wear with different geometries of contact and slips confirms the statement at the beginning. It was found that the bearable Hertz'ian contact stress is within the known range of bearing steels. The results are discussed from the viewpoint of stress field parameters (geometry of contact, slip) and Case structure (for example, residual stress and the gradient of hardness).
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wear resistance of preNitrided hardcoated steels for tools and machine components
Surface & Coatings Technology, 1997Co-Authors: K Hock, H J Spies, G Leonhardt, Barbara Larisch, B BueckenAbstract:Abstract Hardened and tempered low-alloy steel 31CrMoV9 and the high-alloy tool steels S 6-5-2 and X155CrMoV121 were Nitrided to form a varied structure of the substrate for the subsequent hardcoating. The tool steels were Nitrided and hardcoated in a continuous process in a modified commercial PVD plant. The duplex treatment of the low-alloy steel was realized by separate nitriding and hardcoating in different plants. The TiN and CrN were deposited with a thickness of approx. 3 μm by hollow cathode discharge evaporation. The composition and structure of the Nitrided Case, the interstage treatment before deposition, as well as the deposition parameters influence the properties of the composite. The adhesion can be improved essentially by prenitriding and deposition of a gradient interlayer system. The resistance of the tool steels to metal cutting and forming increases due to the production of an application-specific duplex layer. The resistance to sliding wear and contact fatigue was investigated on various duplex-treated low-alloy steel by nitriding the substrate. Whereas the Nitrided Case has a very high influence on the contact fatigue limit, the hardcoating reduces the wear by sliding and abrasion, which is of special interest for machine components with higher slip.
C X Li - One of the best experts on this subject based on the ideXlab platform.
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corrosion properties of plasma Nitrided aisi 410 martensitic stainless steel in 3 5 nacl and 1 hcl aqueous solutions
Corrosion Science, 2006Co-Authors: C X Li, T BellAbstract:Abstract Samples of an AISI 410 martensitic stainless steel were plasma Nitrided at a temperature of 420 °C, 460 °C or 500 °C for 20 h. The composition, microstructure and hardness of the Nitrided samples were characterised using a variety of analytical techniques. In particular, the corrosion properties of the untreated and plasma Nitrided samples were evaluated using anodic polarisation tests in 3.5% NaCl solution and immersion tests in 1% HCl acidic water solution. The results showed that plasma nitriding produced a relatively thick Nitrided Case consisting of a compound layer and a nitrogen diffusion layer on the 410 stainless steel surface. Plasma nitriding not only increased the surface hardness but also improved the corrosion resistance of the martensitic stainless steel. In the immersion test, Nitrided samples showed lower weight loss and lower corrosion rate than untreated one. In the electrochemical corrosion tests, the Nitrided samples showed higher corrosion potentials, higher pitting potentials and greatly reduced current densities. The improved corrosion resistance was believed to be related to the iron nitride compound layer formed on the martensitic stainless steel surface during plasma nitriding, which protected the underlying metal from corrosive attack under the testing conditions.
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corrosion properties of active screen plasma Nitrided 316 austenitic stainless steel
Corrosion Science, 2004Co-Authors: C X Li, Thomas BellAbstract:Abstract AISI 316 austenitic stainless steel has been plasma Nitrided using the active screen plasma nitriding (ASPN) technique. Corrosion properties of the untreated and AS plasma Nitrided 316 steel have been evaluated using various techniques, including qualitative evaluation after etching in 50%HCl + 25%HNO 3 + 25%H 2 O, weight loss measurement after immersion in 10% HCl, and anodic polarisation tests in 3.5% NaCl solution. The results showed that the untreated 316 stainless steel suffered severe localised pitting and crevice corrosion under the testing conditions. AS plasma nitriding at low temperature (420 °C) produced a single phase Nitrided layer of nitrogen expanded austenite (S-phase), which considerably improved the corrosion properties of the 316 austenitic stainless steel. In contrast, AS plasma nitriding at a high temperature (500 °C) resulted in chromium nitride precipitation so that the bulk of the Nitrided Case had very poor corrosion resistance. However, a thin deposition layer on top of the Nitrided Case, which seems to be unique to AS plasma nitriding, could have alleviated the corrosion attack of the higher temperature Nitrided 316 steel.
Carlos Eduardo Pinedo - One of the best experts on this subject based on the ideXlab platform.
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Scratch test of active screen low temperature plasma Nitrided AISI 410 martensitic stainless steel
Wear, 2017Co-Authors: L.a Espitia, Hanshan Dong, Carlos Eduardo Pinedo, André Paulo TschiptschinAbstract:Abstract A Nitrided Case composed of expanded martensite and small quantities of hexagonal e-Fe 24 N 10 iron nitrides was formed in a martensitic stainless steel by means of active screen plasma nitriding process. Nanoindentation tests were carried out in order to assess the mechanical properties and to obtain an energy dissipation coefficient defined as the ratio of plastic to total deformation energy. Friction coefficient, mechanical failure mode and critical load for damaging the Nitrided Case were determined using linear scratch tests performed at both linearly-increased normal force and constant normal force according to ASTM C1624 standard. The scratch test results showed that the groove features and the friction coefficient could be well correlated to the energy dissipation coefficient. The expanded martensite strongly decreased the friction coefficient in comparison to the non-Nitrided martensitic stainless steel. The critical load was 14 N and tensile cracking was the mechanical failure mode of the Nitrided Case.
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cavitation erosion resistance and wear mechanisms of active screen low temperature plasma Nitrided aisi 410 martensitic stainless steel
Wear, 2015Co-Authors: L.a Espitia, Hanshan Dong, Carlos Eduardo Pinedo, Xiaoying Li, André Paulo TschiptschinAbstract:Abstract Quenched and tempered AISI 410 martensitic stainless steel specimens were active screen plasma Nitrided in a mixture of 75% of nitrogen and 25% of hydrogen during 20 h at 400 °C. The microstructure of the Nitrided Case was characterized by optical microscopy, scanning electron microscopy and microhardness measurements. The phases were identified by X-ray diffraction and the nitrogen content as a function of depth was measured using wavelength dispersive X-ray spectrometer coupled to SEM. Nanoindentation tests were carried out in order to assess hardness ( H ), Young modulus ( E ), H / E and H 3 / E 2 ratios and the elastic recovery ( W e ) of the Nitrided layer. Cavitation erosion tests were carried out according to ASTM G32 standard during 20 h, with periodical interruptions for registering the mass losses. Additional cavitation erosion tests were performed to identify the wear mechanisms in both specimens, through assessment of the evolution of the damage on the surface, in a scanning electron microscope. A ~28 µm thick, 1275 HV hard Nitrided Case formed at the surface of the martensitic stainless steel, composed of nitrogen supersaturated expanded martensite and hexagonal e-Fe 24 N 10 iron nitrides. The expanded martensite decreased 27 times the mass loss shown by the non-Nitrided stainless steel and the erosion rate decreased from 2.56 mg/h to 0.085 mg/h. The increase in cavitation erosion resistance can be mainly attributed to the increase in hardness and to the elastic response of the expanded martensite. The non-Nitrided specimen changed from initially ductile to brittle behavior, exhibiting two different modes of material detachment. The first mode was characterized by a great degree of plastic deformation, fatigue and ductile fracture. The second failure mode could be associated to brittle fracture by cleavage mechanisms. In contrast, the wear mechanism observed in the Nitrided specimen was brittle fracture without evident plastic deformation.
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estrutura e propriedades do aco inoxidavel austenitico aisi 316l grau astm f138 nitretado sob plasma a baixa temperatura structure and properties of an austenitic stainless steel aisi 316l grade astm f138 after low temperature plasma nitriding
2010Co-Authors: André Paulo Tschiptschin, Carlos Eduardo PinedoAbstract:Austenitic stainless steels cannot be conventionally Nitrided at temperatures near 550°C due to the intense precipitation of chromium nitrides in the diffusion zone. The precipitation of chro-mium nitrides increases the hardness but severely impairs corrosion resistance. Plasma nitriding allows introducing nitrogen in the steel at temperatures below 450°C, forming pre-dominantly expanded austenite ( N ), with a crystalline structure best represented by a special triclin-ic lattice, with a very high nitrogen atomic concentration promoting high compressive residual stresses at the surface, increasing substrate hardness from 4 GPa up to 14 GPa on the Nitrided Case.