E. Jonda

Laser Alloying with WC Ceramic Powder in Hot Work Tool Steel Using a High Power Diode Laser (HPDL)

Investigations include alloying the X38CrMoV5-3 hot-work tool steel surface layer with the tungsten carbide, using the high power diode laser (HPDL). The tungsten carbide ceramic particles of the medium grain size according to FSSS = 50 /m were introduced using the rotor conveyer to improve the properties of the surface layer. The powder feed rate was set at the steady level of 8.64g/min. Remelting and alloying were carried out several times in the laser power range of 1.2 – 2.3 kW in the remelting/alloying, alloying/remelting sequences. The structural mechanism was determined of gradient layer development, effect was studied of alloying parameters, gas protection method, and powder feed rate on its mechanical properties, and especially on its hardness, abrasive wear resistance, and roughness. Structure changes were revealed consisting, in particular, in its refining, and also hardness and microhardness changes in comparizon to the nonremelted steel. Examination results obtained with the EDX microanalysis, surface and linear analysis of the chemical composition, as well as the X-ray qualitative phase analysis are presented.

Structures, properties and development trends of laser-surface-treated hot-work steels, light metal alloys and polycrystalline silicon

Several examples have been chosen for presentation from a broad array of laser surface treatment technologies currently researched into and used in industry and the examples are distinguished by their extensive possibilities of future and current applications, especially in the tooling, automotive, and power industry. A newly developed methodology has been employed in order to make an objectivized assessment of the relevant laser surface treatment technologies. Contextual matrices and roadmaps and technology information sheets allowing for the mainly qualitative comparisons of the individual technologies according to harmonized criteria were created as a result of employing the methodology.

Diode Laser Modification of Surface Gradient Layer Properties of a Hot-Work Tool Steel

The objective of the present work was to study the modification of the microstructure of hot-work tool steels X40CrMoV5-1 and X38CrMoV5-3 during the surface modifying by means of laser technology. This treatment aims to harden and alloy the steel surface which had been previously coated with tungsten carbide (WC) and were introduced using the rotor conveyer to improve the properties of the surface layer. The fine grained, dendritic structure occurs in the remelted and alloyed zone with the crystallization direction connected with the dynamical heat abstraction from the laser beam influenced zone. The fine grained martensite structure is responsible for the hardness increase of the alloyed layer.

Modelling of properties of the alloy tool steels after laser surface treatment

This paper presents the investigation results of the computer modelling of the surface layer hardness of hot work tool alloy steel alloyed with the ceramic powders using the High Power Diode Laser (HPDL). Laser treatment by remelting or alloying with the carbides was employed for improvement of the surface layer properties of tools made from the hot work tool steels. The developed model of the neural network make predicting possible for the surface layer hardness values. Further investigations should be concentrated on computer modelling of microhardness and resistance wear abrasion using the artificial neural networks. The surface layer of the hot work steel alloyed with ceramic powder using the HPDL have good properties and makes it possible for using in various technical and industrial applications. The artificial neural networks were used to determine the technological effect of laser alloying on hardness of the hot work tool steels. [Received 10 January 2007; Accepted 12 July 2007]

Microstructure and properties of the hot work tool steel gradient surface layer obtained using laser alloying with tungsten carbide ceramic powder

Purpose: The aim of the paper is to present the innovatory investigation results of the impact of laser treatment consisting of multiple remelting and alloying using tungsten carbide ceramic powder on the microstructure and properties of hot work tool steel X40CrMoV5-1 surface layer. Design/methodology/approach: Laser heat treatment allows the production of gradient surface layer with a thickness reaching from of tenths of a millimetre even to few millimetres with specific functional properties, including high hardness and abrasion resistance, while maintaining the properties of the substrate material. Findings: Preliminary investigations of the effects of laser radiation on steel surface have showed, that in the surface layer there occur changes concerning the microstructure as well as in the chemical composition different from those occurring during conventional heat treatment. Research limitations/implications: There was determined the effect of laser power on the remelting depth, the depth of the heat affected zone and the width of the laser tray face. There was also measured and compared to the hardness and roughness of the steel processed by remelting with different process parameters. Practical implications: The current application areas for hot work tool steels are constantly growing, and the intensive development of techniques requires the use of new technologies, what leads to production of specific surface layer on materials, in order to meet the extremely difficult working conditions of modern tools. Originality/value: The effect of a HPDL laser melting on the hot work tool steel, especially on their structure and hardness has been studied.

Electron Microscopy Investigation of Cast Aluminium Alloy after Laser Feeding with Ceramic Powder

This paper presents the results of an investigation using transmission electron microscopy concerning the structure of AlSi7Cu2 cast aluminium alloy after alloying and remelting with a high power diode laser (HPDL). In particular, the changes in the particle/precipitation type, size and shape were determined, concerning especially the SiC and TiC particles added to the initial material. The aim of this work was also to present the laser treatment technology which will be used for further alloying and remelting with ceramic powders – especially carbides and oxides. The innovatory arrangement of this investigation is based on the mixing of two different powders, which were fed simultaneously to the laser-treated aluminium surface. The overview focuses on the laser power required to achieve good layer hardness to prevent hot work tool steel from losing its work stability and to make the tool surface more resistant to action in external conditions.

Surface laser alloying with ceramic powders of the X40CrMoV5-1 tool steel

This paper presents the results of laser treatment influence on structure and properties of the surface of the X40CrMoV5-1 hot work tool steel, using the high power diode laser (HPDL) for remelting and alloying. In this work structure changes as well as hardness and roughness are investigated. The goal of this work was also to determine technological conditions for remelting of surface layer with HPDL laser.This paper presents the results of laser treatment influence on structure and properties of the surface of the X40CrMoV5-1 hot work tool steel, using the high power diode laser (HPDL) for remelting and alloying. In this work structure changes as well as hardness and roughness are investigated. The goal of this work was also to determine technological conditions for remelting of surface layer with HPDL laser.