IIW 2012 - 23

Session 2 Automated Repair Procedures
Paper 1: Advanced Programming Techniques for Robotic Weld Repair of Worn Components
By: John Norrish, Zengxi Pan, Nathan Larkin, University of Wollongong, Australia Abstract: Repair and reclamation of engineering components by weld deposition is often a desirable economic and logistical alternative to replacement. Due to the nature of wear damage it is common for reclamation operations to be carried out by manual welding in restricted or poor access situations on site. The operating environment of the component may also dictate the use of highly alloyed welding consumables and there are commonly fairly tight constraints on welding procedures to ensure adequate wear performance and avoid damage to the original component. Robotic welding offers an attractive alternative to manual operations, removing the operator from a potentially hazardous environment and allowing much better control of welding procedures. The problem with the application of industrial robots in these situations is the need to re-program the robot for each repair. Manual programming would not be feasible since the programming operation would take longer than the manual repair. Conventional off-line programming is similarly time consuming, but by automating the program generation and incorporating vision system and laser measuring techniques it is possible to achieve very rapid and accurate program execution. The paper describes some of the techniques which have been developed for robotic weld reclamation using these advanced programming approaches.

narrower heat-affected zone, smaller dilution, and less tendency to form cracks. Moreover, the laser power-off period between two pulses allows the molten pool to solidify; therefore, the higher cooling rate results in a finer microstructure. Multiple pulses were found to remelt and partially heal microfissures formed during the previous pulse deposit (Fig. 1).

Fig. 1 Top-down view of a patch deposit of RENE80 on GTD-111 (top). The fusion lines produced by multiple pulses (bottom). Notice the microfissure is associated with dark-etched stray grains, and is melted by the pulse marked by the dashed line. Epitaxial solidification of the deposit was achieved in the <100> crystallographic direction. The grain size was uniform throughout multiple layers of deposit and appeared to be of cellular dendritic morphology. The heataffected zone was nearly undetectable by microstructure: there was no change in the morphology of the gamma prime precipitates in the HAZ region close to the fusion boundary (Figure 2). The cusp angle of the adjacent deposit passes was less than 30 degrees. This shallow and wide profile of the deposit did not allow for stray grain formation. The cracking tendency was kept to a minimum in the deposits without preheating or post heating. Unmelted carbides from the base material were found in the deposit matrix even after multiple melting cycles.

Paper 2: Effect of Process Parameters on Pulsed-Laser Repair of Directionally Solidified Superalloy
By: Dr. Leijun Li, Andrew Deceuster, and Chunbo (Sam) Zhang, Utah State University, USA Abstract: Pulsed-laser repair technology for directionally solidified nickel-based superalloys has been investigated both experimentally and numerically. Compared with the continuous laser deposition, the pulsed Nd:YAG laser deposition offers a number of advantages due to its significantly lowered heat input to the workpiece and therefore a much
23

www.iiw2012.com www.iiw2012.com



http://www.iiw2012.com

IIW 2012

Table of Contents for the Digital Edition of IIW 2012

IIW 2012
Contents
Welcome Message
Annual Assembly Location
Colorado
Denver
General Information
IIW 65th Annual Assembly
IIW International Conference 2012 - Program
IIW International Conference 2012 - Abstracts
Speaker Bio Information
Smartphone App
Social Program
Technical Visits
Social Tours
Tour Schedule
Advertising Sponsor Profiles
Commission XIII Fracture Mechanics Seminar
IIW 2012 Sponsors
IIW 2012 - IIW 2012
IIW 2012 - Cover2
IIW 2012 - Contents
IIW 2012 - Welcome Message
IIW 2012 - 3
IIW 2012 - Annual Assembly Location
IIW 2012 - 5
IIW 2012 - Colorado
IIW 2012 - 7
IIW 2012 - Denver
IIW 2012 - 9
IIW 2012 - General Information
IIW 2012 - 11
IIW 2012 - 12
IIW 2012 - IIW 65th Annual Assembly
IIW 2012 - 14
IIW 2012 - 15
IIW 2012 - IIW International Conference 2012 - Program
IIW 2012 - 17
IIW 2012 - 18
IIW 2012 - 19
IIW 2012 - IIW International Conference 2012 - Abstracts
IIW 2012 - 21
IIW 2012 - 22
IIW 2012 - 23
IIW 2012 - 24
IIW 2012 - 25
IIW 2012 - 26
IIW 2012 - 27
IIW 2012 - 28
IIW 2012 - 29
IIW 2012 - 30
IIW 2012 - 31
IIW 2012 - 32
IIW 2012 - 33
IIW 2012 - 34
IIW 2012 - 35
IIW 2012 - 36
IIW 2012 - 37
IIW 2012 - 38
IIW 2012 - Speaker Bio Information
IIW 2012 - 40
IIW 2012 - 41
IIW 2012 - 42
IIW 2012 - 43
IIW 2012 - 44
IIW 2012 - 45
IIW 2012 - 46
IIW 2012 - 47
IIW 2012 - Smartphone App
IIW 2012 - Social Program
IIW 2012 - Technical Visits
IIW 2012 - 51
IIW 2012 - Social Tours
IIW 2012 - 53
IIW 2012 - 54
IIW 2012 - Tour Schedule
IIW 2012 - Advertising Sponsor Profiles
IIW 2012 - 57
IIW 2012 - 58
IIW 2012 - 59
IIW 2012 - 60
IIW 2012 - Commission XIII Fracture Mechanics Seminar
IIW 2012 - IIW 2012 Sponsors
IIW 2012 - 63
IIW 2012 - 64
IIW 2012 - Cover3
IIW 2012 - Cover4
https://www.nxtbookmedia.com