Faculty of Technology The Characteristic of Cold Metal Transfer (CMT) and its application For Cladding Nelson Edoh Imoudu Master’s thesis in Technology and Safety in the High North, June 2017 i Table of Contents Basic Definition ...................................................................................................................................... vi Abstract .................................................................................................................................................. ix 1 Introduction .................................................................................................................................... 1 1.1 Research Background .............................................................................................................. 1 1.1.1 Motivation for the Research Project ................................................................................ 3 1.1.2 Research Question ........................................................................................................... 4 1.1.3 Research Purpose and Objectives .................................................................................... 4 1.1.4 Research Outline ............................................................................................................. 4 2 Research Methodology ................................................................................................................... 5 2.1 Research Purpose .................................................................................................................... 5 2.2 Research Approach .................................................................................................................. 6 2.3 Research Strategy .................................................................................................................... 7 2.4 Data Collection ........................................................................................................................ 7 2.5 Data Analysis .......................................................................................................................... 8 3 Theoretical Framework ................................................................................................................... 9 3.1 Welding Processes ................................................................................................................... 9 3.1.1 Laser light ........................................................................................................................ 9 3.1.2 Laser Welding ............................................................................................................... 10 3.1.3 Gas Tungsten Arc Welding – GTAW ........................................................................... 11 3.1.4 Gas Metal Arc Welding – GMAW ................................................................................ 11 3.1.5 Typical Hardfacing Materials ........................................................................................ 13 3.2 CMT – Cold Metal Transfer .................................................................................................. 15 3.2.1 CMT Pulse ..................................................................................................................... 17 3.2.2 CMT Advanced ............................................................................................................. 18 3.2.3 CMT Pulse Advance ..................................................................................................... 19 3.2.4 CMT Dynamic ............................................................................................................... 20 3.3 The Use of CMT process in Cladding ................................................................................... 20 3.4 Synergic Lines ....................................................................................................................... 22 3.4.1 CMT – Process Correction Parameters ......................................................................... 23 3.4.2 Wire Feed Speed ........................................................................................................... 24 3.4.3 Welding Power .............................................................................................................. 24 3.4.4 Shielding Gas ................................................................................................................ 25 3.5 Pros and Cons of CMT Cladding .......................................................................................... 26 ii 3.6 The Major Characteristics Distinguishing CMT from the GMWA conventional Welding Process. ............................................................................................................................................. 26 3.7 Pros and Cons of CMT/Conventional Welding process ........................................................ 27 3.7.1 The Limitation of CMT process .................................................................................... 27 3.8 Weld Bead Geometries .......................................................................................................... 28 3.8.1 Weld Imperfections and Defects ................................................................................... 29 3.8.2 Weld Bead Humping ..................................................................................................... 29 3.9 Failure Analysis ..................................................................................................................... 31 3.9.1 FTA – Fault Tree Analysis ............................................................................................ 31 4 Equipment and Experiment .......................................................................................................... 33 4.1 CMT Welding Equipment ..................................................................................................... 33 4.2 Experiment 1 ......................................................................................................................... 34 4.2.1 Test 1: Weaving on top of mild steel, Synergy line 1357 ............................................. 35 4.2.2 Test 2: Stringer motion, Single and Adjacent beads, Synergy line 1357 ...................... 36 4.2.3 Test 3: Stringer Motion, adjacent beads on top of Mild Steel, 1357 ............................. 37 4.2.4 Test 4 Single Bead, line 1657 ........................................................................................ 38 4.2.5 Test 5 Line 1657, MAG, MAG-Pulse, Mison 18 .......................................................... 40 4.3 Experiment 2 ......................................................................................................................... 42 4.3.1 Test Methods ................................................................................................................. 43 5 Results and Discussion ................................................................................................................. 47 5.1 Experiment 1 ......................................................................................................................... 47 5.2 Experiment 2 ......................................................................................................................... 48 5.3 Case study of fault tree analysis for cladding process ........................................................... 50 6 Conclusion .................................................................................................................................... 53 6.1 Corocarb Ni-WC facing ........................................................................................................ 53 6.2 Inconel 625 ............................................................................................................................ 53 7 Research Contribution .................................................................................................................. 54 8 Suggestion for further research ..................................................................................................... 55 Works cited ........................................................................................................................................... 56 iii List of Tables Table 1: Different kind of research purposes adapted from Neuman (2003) .......................................... 6 Table 2 : Arc Characteristic values. ........................................................................................................ 8 Table 3 – Hardfacing materials and properties, adapted from DEARNLEY (1988) ........................... 13 Table 4 – Pros and cons of CMT/Conventional welding process. ........................................................ 27 Table 5 – Shielding gas recommended .................................................................................................. 34 Table 6 – Parameter of test 1 ................................................................................................................. 35 Table 7 – Test 2 data stringer movement. ............................................................................................. 36 Table 8 –Test 3 parameter of adjacent bead on top of mild steel, 1357 ................................................ 38 Table 9 – Parameter test of single bead on top of mild steel of 20mm (80mm).