The Experts below are selected from a list of 369 Experts worldwide ranked by ideXlab platform

Jianyin Chen - One of the best experts on this subject based on the ideXlab platform.

  • a study of the abrasive wear behaviour of laser Clad tool steel coatings
    Surface & Coatings Technology, 2006
    Co-Authors: Shenghui Wang, Jianyin Chen
    Abstract:

    Abstract A comparative study of the abrasive wear behaviour has been conducted on several tool steel coatings that were deposited by laser Cladding process using a CW CO 2 laser in combination with a blown powder feed technique. The laser-Clad CPM 15V and CPM 10V coatings exhibit superior abrasive wear resistance as compared with the reference material, AISI D2 tool steel. In contrast, the wear resistance of the CPM 9V and M4 coatings is inferior to that of the D2 steel. As multiple overlapping Clad-Tracks are used to produce a coating covering relatively large area, a thin layer of a pre-deposited Clad-Track will be “over-heated” while depositing the next adjacent one. Depending on the coating material, this re-heated zone (RHZ) can exhibit different wear rate compared with the other area of the Track in the as-Clad condition, which is especially significant for the CPM 10V coating. For coatings with a large proportion of retained austenite, post heat-treatment promotes the transformation of the retained austenite to martensite, improving the wear resistance. The wear resistance of tool steel coatings is dependent upon the matrix microstructure and the features of dispersed carbides, such as their type, proportion, shape, size and distribution.

Shenghui Wang - One of the best experts on this subject based on the ideXlab platform.

  • a study of the abrasive wear behaviour of laser Clad tool steel coatings
    Surface & Coatings Technology, 2006
    Co-Authors: Shenghui Wang, Jianyin Chen
    Abstract:

    Abstract A comparative study of the abrasive wear behaviour has been conducted on several tool steel coatings that were deposited by laser Cladding process using a CW CO 2 laser in combination with a blown powder feed technique. The laser-Clad CPM 15V and CPM 10V coatings exhibit superior abrasive wear resistance as compared with the reference material, AISI D2 tool steel. In contrast, the wear resistance of the CPM 9V and M4 coatings is inferior to that of the D2 steel. As multiple overlapping Clad-Tracks are used to produce a coating covering relatively large area, a thin layer of a pre-deposited Clad-Track will be “over-heated” while depositing the next adjacent one. Depending on the coating material, this re-heated zone (RHZ) can exhibit different wear rate compared with the other area of the Track in the as-Clad condition, which is especially significant for the CPM 10V coating. For coatings with a large proportion of retained austenite, post heat-treatment promotes the transformation of the retained austenite to martensite, improving the wear resistance. The wear resistance of tool steel coatings is dependent upon the matrix microstructure and the features of dispersed carbides, such as their type, proportion, shape, size and distribution.

Hau Chung Man - One of the best experts on this subject based on the ideXlab platform.

  • A preliminary study of laser Cladding of AISI 316 stainless steel using preplaced NiTi wire
    Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2004
    Co-Authors: F. T. Cheng, Hau Chung Man
    Abstract:

    Abstract NiTi wire of diameter 1 mm was preplaced on AISI 316 stainless steel samples by using a binder. Melting of the NiTi wire to form a Clad Track on the steel substrate was achieved by means of a high-power CW Nd:YAG laser using different processing parameters. The geometry and microstructure of the Clad deposit were studied by optical microscopy and scanning electron microscopy (SEM), respectively. The hardness and compositional profiles along the depth of the deposit were acquired by microhardness testing and energy-dispersive spectroscopy (EDS), respectively. The elastic behavior of the deposit was analyzed using nanoindentation, and compared with that of the NiTi wire. The dilution of the NiTi Clad by the substrate material beneath was substantial in single Clad Tracks, but could be successively reduced in multiple Clad layers. A strong fusion bonding with tough interface could be obtained as evidenced by the integrity of Vickers indentations in the interfacial region. In comparison with the NiTi Cladding on AISI 316 using the tungsten inert gas (TIG) process, the laser process was capable of producing a much less defective Cladding with a more homogeneous microstructure, which is an essential Cladding quality with respect to cavitation erosion and corrosion resistance. Thus, the present preliminary study shows that laser Cladding using preplaced wire is a feasible method to obtain a thick and homogeneous NiTi-based alloy layer on AISI 316 stainless steel substrate.

F. T. Cheng - One of the best experts on this subject based on the ideXlab platform.

  • A preliminary study of laser Cladding of AISI 316 stainless steel using preplaced NiTi wire
    Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2004
    Co-Authors: F. T. Cheng, Hau Chung Man
    Abstract:

    Abstract NiTi wire of diameter 1 mm was preplaced on AISI 316 stainless steel samples by using a binder. Melting of the NiTi wire to form a Clad Track on the steel substrate was achieved by means of a high-power CW Nd:YAG laser using different processing parameters. The geometry and microstructure of the Clad deposit were studied by optical microscopy and scanning electron microscopy (SEM), respectively. The hardness and compositional profiles along the depth of the deposit were acquired by microhardness testing and energy-dispersive spectroscopy (EDS), respectively. The elastic behavior of the deposit was analyzed using nanoindentation, and compared with that of the NiTi wire. The dilution of the NiTi Clad by the substrate material beneath was substantial in single Clad Tracks, but could be successively reduced in multiple Clad layers. A strong fusion bonding with tough interface could be obtained as evidenced by the integrity of Vickers indentations in the interfacial region. In comparison with the NiTi Cladding on AISI 316 using the tungsten inert gas (TIG) process, the laser process was capable of producing a much less defective Cladding with a more homogeneous microstructure, which is an essential Cladding quality with respect to cavitation erosion and corrosion resistance. Thus, the present preliminary study shows that laser Cladding using preplaced wire is a feasible method to obtain a thick and homogeneous NiTi-based alloy layer on AISI 316 stainless steel substrate.

Milan Brandt - One of the best experts on this subject based on the ideXlab platform.

  • parametric investigation of pulsed nd yag laser Cladding of stellite 6 on stainless steel
    Surface & Coatings Technology, 2005
    Co-Authors: Shoujin Sun, Yvonne Durandet, Milan Brandt
    Abstract:

    A systematic research into the Cladding of stellite 6 on stainless steel by pulsed Nd:YAG laser has been carried out. The effects of pulse energy, pulse frequency, powder mass flow rate and spot overlap on the Clad layer height, dilution and heat-affected zone (HAZ) have been examined. It was found that both the Clad height and penetration into the substrate increase with the pulse energy, spot overlap and pulse frequency, but the effects of these parameters on dilution are complex. The dilution reaches the lowest value (4%) at the incident energy of 18 and 25 J/ pulse, spot overlap of 89% and pulse frequency of 40 Hz. The powder mass flow rate of 22 g/min (for energy of 25 J/pulse and spot overlap of 83%) produces thick Clad layer with low dilution but results in the formation of defects. The hardness of the Clad layer decreases linearly with increasing dilution. No cracks have been found in single-Track Clad layers at a spot overlap of 89%, however, cracks occurred at lower spot overlap. These cracks were eliminated by the multi-Track Cladding when the Track increment is less than 1/3 of the width of Track, which is believed to be due to the remelting or heat treatment of the previous Clad Track by the subsequent Track. The Track bands in multi-Track Clad show coarser structure, higher element segregation and lower hardness.