JLA Vol:15 Iss:3 (Three-dimensional finite element modeling of laser cladding by powder injection: Effects of powder feedrate and travel speed on the process)

Authors:
Ehsan Toyserkani
Amir Khajepour
Steve Corbin
University of Waterloo, Department of Mechanical Engineering, Waterloo, Ontario N2L 3G1, Canada

This article addresses a novel three-dimensional transient finite element model of the laser cladding by powder injection process. The proposed model can predict clad geometry as a function of time and process parameters including beam velocity, laser power, powder jet geometry, laser pulse shaping, and material properties. In the proposed method, the interaction between powder and melt pool are assumed to be decoupled and as a result, the melt pool boundary is first obtained in the absence of powder spray....

JLA Vol:19 Iss:3 (Characteristics of the laser clad metal made with powder mixture of Co-based alloy and vanadium carbide)

Authors:
Guojian Xu
Munaharu Kutsuna
Zhognjie Liu
Graduate School of Engineering, Nagoya University, 1 Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan

A powder mixture of Co-based alloy (Stellite-6) and vanadium carbide (VC) was deposited to substrates of SM400B mild steel and SUS304 stainless steel using a 2.4 kW cw CO₂ laser. The mechanism of crack for clad metal was investigated by changing the VC weight fraction in the range of 0%–56%. The microstructures of the clad layer for matrix of Co-based alloy can be classified into two types—hypoeutectic structure (0–12 wt % VC) and hypereutectic structure (13–56&ens...

JLA Vol:23 Iss:3 (Spatter in laser welding)

Authors:
A. F. H. Kaplan
J. Powell
Department of Engineering Sciences and Mathematics, Luleå University of Technology, SE-971 87 Luleå, Sweden

Spatter, the ejection of melt from a weld pool, is a major problem whenever it occurs in a welding process. The ejection of droplets from the weld metal results in a weld with underfill, undercuts, craters, blowholes, or blowouts—all of which can have a detrimental effect on the mechanical properties of the weld. This paper presents a systematic description of the different types of spatter phenomena which occur during laser welding. A categorization system is proposed to facilitate the comparison and combination ...

JLA Vol:6 Iss:1 (Mass transport during laser welding of stainless steels and alloys used by US Navy)

Authors:
Anand J. Paul
Parwaiz A. A. Khan
Manufacturing and Materials Division, Concurrent Technologies Corporation, 1450 Scalp Avenue, Johnstown, PA 15904, U.S.A.

Lasers, though developed only about a quarter century ago, are now being routinely used in the automotive, aerospace and other industries to produce superior quality, high‐speed autogenous welds with narrow heat‐affected zones in a number of alloys. However, they cannot at present be used to successfully weld certain important structural alloys due to a change in weld composition resulting from selective mass transport of certain alloying elements from the laser‐melted region. The loss of a...

JLA Vol:18 Iss:1 (Cladding of Stellite-6 and vanadium carbide on carbon steel using a yttrium–aluminum–garnet laser robot system)

Authors:
Guojian Xu
Graduate School of Engineering, Nagoya University, 1 Furo-cho Chikusa-ku, Nagoya 464-8603, Japan

Muneharu Kutsuna
Manoj Rathod
School of Engineering, Nagoya University, 1 Furo-cho Chikusa-ku, Nagoya 464-8603, Japan

In the present work, a laser robot system was setup for cladding and repairing machinery parts using pulsed 300 W Nd:yttrium–aluminum–garnet laser facility, six-axis robot, optical fiber, powder feeding system with a special nozzle for powder supply. A mild steel plate was deposited with powder mixtures of Stellite-6 alloy and vanadium carbide (VC). The shape of clad layer, microstructure, and its wear perfo...

JLA Vol:25 Iss:4 (Complex analysis of elaboration of steel–TiC composites by direct metal deposition)

JLA Vol:24 Iss:2 (Energetic efficiency of remote cutting in comparison to conventional fusion cutting)

Authors:
M. Lu¨tke
J. Hauptmann
A. Wetzig
Fraunhofer IWS, Winterbergstraße 28, 01277 Dresden, Germany

E. Beyer
Fraunhofer IWS, Winterbergstraße 28, 01277 Dresden, Germany and University of Technology Dresden, 01062 Dresden, Germany

The remote cutting technique provides an enormous potential in terms of cutting speeds when working on thin sheets. Even on contour cutting speeds about 100 m/min are realizable. Working without any cutting gas, the material of the cutting kerf must be vaporized partially. It is evident that the energy input must be higher than for pure melting of the cutting kerf’s material. In order to ...

JLA Vol:6 Iss:4 (Hazardous chemicals produced by laser materials processing)

Authors:
John M. Kokosa
GMI Engineering & Management Institute, Flint, MI, U.S.A.

Despite evidence to the contrary, until recently many laser operators believed, or at least stated, that the only chemical by‐products of laser processing of any consequence were water and CO₂. During the last eight years, especially, several investigations have shown that hazardous materials are produced when cutting or welding nearly all substrates. In the following paper, the major chemical hazards associated with processing metals, inorganics, biomaterials, and polymers are outlined.

JLA Vol:14 Iss:2 (Thermomechanical effects in laser microprocessing for dieless metal wire drawing)

Authors:
Yonggang Li
School of Optic/CREOL (Center for Research and Education of Optics and Lasers), Mechanical, Materials and Aerospace Engineering Department, University of Central Florida, Orlando, Florida, 32816-2700

Nathaniel R. Quick
USF Filtration and Separations Group, Inc., 1750 Filter Drive, DeLand, Florida 32724-2045

Aravinda Kar
School of Optic/CREOL (Center for Research and Education of Optics and Lasers), Mechanical, Materials and Aerospace Engineering Department, University of Central Florida, Orlando, Florida, 32816-2700

A new dieless metal fiber drawing process is developed in which a high-precision laser is used to heat the...

JLA Vol:18 Iss:3 (Thermal and microstructural aspects of the laser direct metal deposition of waspaloy)

Authors:
Andrew J. Pinkerton
Laser Processing Research Centre, School of Mechanical, Aerospace and Civil Engineering, The University of Manchester, PO Box 88, Manchester M60 1QD, United Kingdom

Mallikarjun Karadge
Manchester Materials Science Centre, School of Materials, The University of Manchester, Grosvenor Street, Manchester M1 7HS, United Kingdom

Waheed Ul Haq Syed
Lin Li
Laser Processing Research Centre, School of Mechanical, Aerospace and Civil Engineering, The University of Manchester, PO Box 88, Manchester M60 1QD, United Kingdom

A potential problem in applying the laser direct metal deposition (LDMD) technique to the f...