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L A Dobrzanski - One of the best experts on this subject based on the ideXlab platform.

  • effect of manufacturing methods on structure and properties of the gradient tool materials with the non alloy Steel matrix reinforced with the hs6 5 2 type High Speed Steel
    Materials Science Forum, 2007
    Co-Authors: A Kloc, Grzegorz Matula, L A Dobrzanski, José M. Torralba
    Abstract:

    Investigations carried out referred to obtaining material based on the High-Speed Steel and non-alloy Steel. The conventional powder metallurgy method was used for manufacturing these materials, consisting in compacting the powder in the closed die and sintering it next, the isostatic pressing method, and the modern pressureless forming powder metallurgy. Forming methods were developed during the investigations for High-Speed and non-alloy Steel powders, making it possible to obtain materials with three layers in their structure. Investigations included determining the sintering conditions, and especially the temperature and treatment cycle, as well as examining the selected mechanical properties. It was found out, basing on the comparison of structures and properties of test pieces made with the pressureless forming method, as well as with the isostatic pressing and pressing in the closed die, with further sintering, that in structures of all examined test pieces in the sintered state fine carbides occurred distributed homogeneously in the High-Speed Steel layer. It was noticed, that increase of the sintering temperature, regardless of the manufacturing method, results in the uncontrolled growth and coagulation of the primary carbides and melting up to forming of eutectics in layers consisting of the High-Speed Steel. It was found out basing on the microhardness tests that hardness of test pieces both those pressureless formed, compacted in the closed die, and isostatically cold pressed and sintered grows along with the sintering temperature. It was also noted that the sintering temperature range is bigger in case of the pressureless formed materials.

  • metal injection moulding of hs12 1 5 5 High Speed Steel using a pw hdpe based binder
    Journal of Materials Processing Technology, 2006
    Co-Authors: L A Dobrzanski, Gemma Herranz, Alejandro Várez, Grzegorz Matula, José M. Torralba
    Abstract:

    Abstract In this communication, we present the powder injection moulding (PIM) of HS12-1-5-5 High-Speed Steel parts using a wax-HDPE based binder. The injection moulding process of the feedstock (68 vol.% of metal) has been optimized to obtain High quality green parts. The elimination of organic binder was carried out by thermal debinding under inert atmosphere. In order to keep carbon in the sample that could improve the sintering process, incomplete debinding were performed between 450 and 500 °C. In this study, we have studied the effect of different atmospheres on the debinding process. Debinding was performed under nitrogen and argon. The specimens were sintered at temperatures between 1200 and 1300 °C with steps of 10 °C in following mixture N 2 –10% H 2 atmosphere. The PIM parts present Higher density than those obtained by conventional PM.

  • employment of the finite element method for determining stresses in coatings obtained on High Speed Steel with the pvd process
    Journal of Materials Processing Technology, 2005
    Co-Authors: L A Dobrzanski, A śliwa, W Kwaśny
    Abstract:

    Abstract The paper presents the possibility to employ the finite element method for evaluation of stresses in the Ti + TiN coating obtained in the magnetron PVD process on the sintered High-Speed Steel of the ASP 30 type, taking into account their deposition conditions. FEM was used to evaluate stress error in the simulated model. Computer simulation results were compared with the experimental results of stress measurement in the analysed coatings. Computer simulation of stresses was carried out in ANSYS environment, using the FEM method and the experimental values of stresses were determined basing on the X-ray diffraction patterns.

  • structure and properties of the ti ti c n coatings obtained in the pvd process on sintered High Speed Steel
    Journal of Materials Processing Technology, 2004
    Co-Authors: L A Dobrzanski, W Kwaśny, Z Brytan, R Shishkov, B Tomov
    Abstract:

    Abstract The paper presents investigation results of the effect of deposition parameters on structure and mechanical properties of the two-layer Ti + Ti(C,N) coatings obtained by magnetron sputtering in the vacuum furnace onto the ASP 30 sintered High Speed Steel. Effect of sputtering parameters on chemical and phase compositions, thickness, microhardness, Young's modulus and adhesion of coatings to the substrate material was evaluated. The characteristic structure and surface topography of the analysed coatings are presented.

  • ti tin ti ti cxn1 x ti tic pvd coatings on the asp 30 sintered High Speed Steel
    Journal of Materials Processing Technology, 2004
    Co-Authors: W Kwaśny, L A Dobrzanski, S Bugliosi
    Abstract:

    Abstract The work presents the investigation results of the effect of coating process parameters structure, erosion resistance, and mechanical properties of the two-layer Ti + TiN, Ti + Ti(CxN1−x), and Ti + TiC coatings obtained using magnetron sputtering in the chamber with the controlled temperature on the substrate from the ASP 30 sintered High-Speed Steel. Test results of the mechanical properties tests of the obtained coatings are presented, depending on the specimen distance from the magnetron disk, working atmosphere, and chamber temperature. The effect was evaluated of the vapour deposition parameters on micro-hardness, adhesion to the substrate material, and erosion resistance of the coatings. Characteristic structure and surface topography of the mentioned coatings are presented.

I Iturriza - One of the best experts on this subject based on the ideXlab platform.

  • microstructural characterisation of vacuum sintered t42 powder metallurgy High Speed Steel after heat treatments
    Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2009
    Co-Authors: V Trabadelo, S Gimenez, I Iturriza
    Abstract:

    Abstract High-Speed Steel powders (T42 grade) have been uniaxially cold-pressed and vacuum sintered to full density. Subsequently, the material was heat treated following an austenitising + quenching + multitempering route or alternatively austenitising + isothermal annealing. The isothermal annealing route was designed in order to attain a hardness value of ∼50 Rockwell C (HRC) (adequate for structural applications) while the multitempering parameters were selected to obtain this value and also the maximum hardening of the material (∼66 HRC). Microstructural characterisation has been carried out by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The microstructure consists of a ferrous (martensitic or ferritic) matrix with a distribution of second phase particles corresponding to nanometric and submicrometric secondary carbides precipitated during heat treatment together with primary carbides. The identification of those secondary precipitates (mainly M 3 C, M 6 C and M 23 C 6 carbides) has allowed understanding the microstructural evolution of T42 High-Speed Steel under different processing conditions.

  • sintering behaviour and microstructure development of t42 powder metallurgy High Speed Steel under different processing conditions
    Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2008
    Co-Authors: S Gimenez, V Trabadelo, C Zubizarreta, I Iturriza
    Abstract:

    Abstract High Speed Steel powders (T42 grade) have been uniaxially cold-pressed and subsequently densified through different sintering routes including: supersolidus liquid phase sintering (SLPS) under vacuum and different nitrogen pressures (0.2, 0.9, and 8 bar) and through solid state sintering (SSS) by hot isostatic pressing (HIP). HIP temperatures as low as 850 °C led to near full densification of the material (>98% theoretical density) with average size of M6C and MC carbides lower than 1 μm and grain size ≈3 μm. Pressureless sintering under different nitrogen pressures (up to 0.39 wt.%N absorption) led to a significant reduction of the optimum sintering temperature (OST) and a pronounced increase in the sintering window (SW) as compared to vacuum sintering. Pressureless sintering under 8 bar N2 led to a further reduction in OST together with the precipitation of massive eutectic structures. Therefore, the SW was judged to be negligible. The response of the as-sintered materials to the heat treatment is basically determined by the amount of C available in the matrix prior to quenching and the grain size. The Highest hardness achievable for the sintering conditions evaluated ranges 700–1100 HV2 after austenitizing at 1100 °C, oil quenching and multitempering at 500–550 °C.

Liu Jie Xu - One of the best experts on this subject based on the ideXlab platform.

  • effects of carbon content and sliding ratio on wear behavior of High vanadium High Speed Steel hvhss under High stress rolling sliding contact
    Tribology International, 2014
    Co-Authors: Liu Jie Xu, Jiandong Xing, Rui Long
    Abstract:

    Abstract This study developed a wear tester to investigate the wear properties of High-vanadium High-Speed Steel (HVHSS) with approximately 9% vanadium and different carbon contents under rolling–sliding condition. The carbon content significantly affected microstructure of matrix and mechanical properties of HVHSS, and therefore played an important role in wear resistance. Nevertheless, the wear failure mode was mainly related to sliding ratio, which varied from fatigue wear to sliding wear with increasing sliding ratio. The wear behavior was affected by the interaction of carbon content and sliding ratio. The High-stress rolling–sliding contact not only caused severe wear but transformed austenite to martensite.

  • research on frictional wear property of the High vanadium High Speed Steel in conditions of low slip roll ratio
    Key Engineering Materials, 2010
    Co-Authors: Hui-min Chen, Liu Jie Xu, Hui Wang
    Abstract:

    The frictional resistance and abrasion mechanism of High vanadium High Speed Steel were studied by the self-made friction wear testing machine under the conditions of 0.5% slip-roll ratio. Results show that the frictional resistance increases with the increase of carbon content. The retained austenite and the shapes of carbides will change when the carbon content alters, which make the frictional resistance of the material change, and the proper quantities of retained austenite makes the impact toughness the matrix better; The spherical VC can prevent the initiation and expansion of cracks forming and make the frictional resistance increase. The abrasion mechanism is fatigue flake under the condition of rolling and sliding.

  • study on frictional wear property of the High vanadium High Speed Steel
    Key Engineering Materials, 2010
    Co-Authors: Hui-min Chen, Liu Jie Xu
    Abstract:

    The frictional resistance and abrasion mechanism of High vanadium High Speed Steel were studied by the self-made friction wear testing machine under the conditions of 10% slip-roll ratio. Results show that the frictional resistance increases with the increase of carbon content and is optimal when the carbon content is 2.92%. The carbon content affect the wear resistance by changing the amount of the retained austenite and the shapes of carbides, the moderate quantities of retained austenite makes the matrix have better impact toughness and hardness; The spherical VC can prevent the initiation and expansion of cracks forming and make the frictional resistance increase. The abrasion mechanism is fatigue flake under the condition of rolling and sliding.

  • effects of vanadium and carbon on microstructures and abrasive wear resistance of High Speed Steel
    Tribology International, 2006
    Co-Authors: Liu Jie Xu
    Abstract:

    Abstract The effects of vanadium and carbon on microstructures and abrasive wear resistance of High Speed Steel were studied. The results show that the microstructures are characterized by VC, M 7 C 3 and Mo 2 C in the martensite and austenite matrix. Typical morphologies of vanadium carbides are found to be spherical, lumpy, strip, and short rod. On the other hand, the vanadium carbides have three kinds of distributions, i.e. grain boundary, chrysanthemum-like, and homogeneous distributions. The abrasive wear resistance of High Speed Steel depends on the hardness and microstructures. When the hardness is lower than HRC58, the abrasive wear resistance of the High Speed Steel mainly depends on its hardness. But when the hardness is Higher than HRC58, it mainly depends on the amount, morphology and distribution of VC in the matrix. Many spherical or lumpy VC carbides are obtained when vanadium and carbon content is up to 8.15–10.20 and 2.70–3.15%. The excellent abrasive wear resistance would be obtained if such VC carbides disperse uniformly in the hardened matrix of High Speed Steel after quenched at 1050 °C and tempered at 550 °C.

Rui Long - One of the best experts on this subject based on the ideXlab platform.

  • effects of carbon content and sliding ratio on wear behavior of High vanadium High Speed Steel hvhss under High stress rolling sliding contact
    Tribology International, 2014
    Co-Authors: Liu Jie Xu, Jiandong Xing, Rui Long
    Abstract:

    Abstract This study developed a wear tester to investigate the wear properties of High-vanadium High-Speed Steel (HVHSS) with approximately 9% vanadium and different carbon contents under rolling–sliding condition. The carbon content significantly affected microstructure of matrix and mechanical properties of HVHSS, and therefore played an important role in wear resistance. Nevertheless, the wear failure mode was mainly related to sliding ratio, which varied from fatigue wear to sliding wear with increasing sliding ratio. The wear behavior was affected by the interaction of carbon content and sliding ratio. The High-stress rolling–sliding contact not only caused severe wear but transformed austenite to martensite.

  • study on relative wear resistance and wear stability of High Speed Steel with High vanadium content
    Wear, 2007
    Co-Authors: Jiandong Xing, Shizhong Wei, Yongzhe Zhang, Rui Long
    Abstract:

    Abstract In this work, a new concept of wear stability was put forward by authors, and it was quantitatively expressed by factor of wear stability. Different hardness, impact toughness and retained austenite content High-Speed Steel with High vanadium content samples were obtained by varying heat treatment conditions. The effects of hardness, impact toughness and retained austenite content on relatively wear resistance and wear stability were studied under abrasive wear condition. Results show that relative wear resistance increases with increasing hardness or decreasing impact toughness, whereas the wear stability rises with the increasing of hardness or impact toughness. The analyzing results reveal that mechanical behaviors are only apparent factors to influence wear behaviors. Relative wear resistance substantially depends on retained austenite content (Ar). At retained austenite content of about 30 vol.%, the relative wear resistance is optimal. However, wear stability is scarcely influenced by retained austenite content, which depends on the maximum changing amount of retained austenite under certain condition (ΔAr) in essence. With increasing ΔAr, wear stability linearly decreases.

V Trabadelo - One of the best experts on this subject based on the ideXlab platform.

  • microstructural characterisation of vacuum sintered t42 powder metallurgy High Speed Steel after heat treatments
    Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2009
    Co-Authors: V Trabadelo, S Gimenez, I Iturriza
    Abstract:

    Abstract High-Speed Steel powders (T42 grade) have been uniaxially cold-pressed and vacuum sintered to full density. Subsequently, the material was heat treated following an austenitising + quenching + multitempering route or alternatively austenitising + isothermal annealing. The isothermal annealing route was designed in order to attain a hardness value of ∼50 Rockwell C (HRC) (adequate for structural applications) while the multitempering parameters were selected to obtain this value and also the maximum hardening of the material (∼66 HRC). Microstructural characterisation has been carried out by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The microstructure consists of a ferrous (martensitic or ferritic) matrix with a distribution of second phase particles corresponding to nanometric and submicrometric secondary carbides precipitated during heat treatment together with primary carbides. The identification of those secondary precipitates (mainly M 3 C, M 6 C and M 23 C 6 carbides) has allowed understanding the microstructural evolution of T42 High-Speed Steel under different processing conditions.

  • sintering behaviour and microstructure development of t42 powder metallurgy High Speed Steel under different processing conditions
    Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2008
    Co-Authors: S Gimenez, V Trabadelo, C Zubizarreta, I Iturriza
    Abstract:

    Abstract High Speed Steel powders (T42 grade) have been uniaxially cold-pressed and subsequently densified through different sintering routes including: supersolidus liquid phase sintering (SLPS) under vacuum and different nitrogen pressures (0.2, 0.9, and 8 bar) and through solid state sintering (SSS) by hot isostatic pressing (HIP). HIP temperatures as low as 850 °C led to near full densification of the material (>98% theoretical density) with average size of M6C and MC carbides lower than 1 μm and grain size ≈3 μm. Pressureless sintering under different nitrogen pressures (up to 0.39 wt.%N absorption) led to a significant reduction of the optimum sintering temperature (OST) and a pronounced increase in the sintering window (SW) as compared to vacuum sintering. Pressureless sintering under 8 bar N2 led to a further reduction in OST together with the precipitation of massive eutectic structures. Therefore, the SW was judged to be negligible. The response of the as-sintered materials to the heat treatment is basically determined by the amount of C available in the matrix prior to quenching and the grain size. The Highest hardness achievable for the sintering conditions evaluated ranges 700–1100 HV2 after austenitizing at 1100 °C, oil quenching and multitempering at 500–550 °C.