Welds are associated with heavy or light fabrication. Fillet and butt welds in all positions would typically be performed on a range of materials that may include carbon steel or stainless steel, aluminium. The weld quality would meet the Australian Standard 1554 General Purpose or equivalent.
Elements and Performance Criteria | |||
Element | Performance Criteria | ||
1 | Prepare materials for gas tungsten arc welding (GTAW) | 1.1 | Weld requirements are identified from specifications and/or drawings. |
1.2 | Material is correctly prepared. | ||
1.3 | Materials are assembled/aligned to specification, where required. | ||
2 | Select welding machine components | 2.1 | Welding machine settings, accessories and consumables are identified. |
3 | Assemble and set up welding equipment | 3.1 | Welding equipment is assembled and set up. |
4 | Minimise and rectify distortion | 4.1 | Appropriate distortion prevention measures are selected for weld and material type. |
4.2 | Distortion is rectified. | ||
5 | Weld to job specification using GTAW | 5.1 | Weld deposit is to specifications. |
5.2 | Joints are cleaned to specifications. | ||
6 | Ensure weld conformance | 6.1 | Defects are removed with minimum loss of sound metal using techniques and tools appropriate to the defect, material and process. |
6.2 | Weld joints are visually inspected for conformance to specifications. | ||
7 | Maintain weld records as required | 7.1 | Weld records are completed correctly. |
The evidence guide specifies the evidence required to demonstrate achievement in the unit of competency as a whole. It must be read in conjunction with the Unit Descriptor, Performance Criteria, Range Statement and the Assessment Guidelines for the Metal and Engineering Training Package | |
Overview of assessment requirements | A person who demonstrates competency in this unit must be able to prepare materials, select and set up the welding equipment, carry out the GTAW welding and inspect for and correct defects. Competency in this unit cannot be claimed until all prerequisites have been satisfied. |
Context of assessment | This unit may be assessed on the job, off the job or a combination of both on and off the job. Where assessment occurs off the job, that is the candidate is not in productive work, then an appropriate simulation must be used where the range of conditions reflects realistic workplace situations. The competencies covered by this unit would be demonstrated by an individual working alone or as part of a team. The assessment environment should not disadvantage the candidate. |
Interdependent assessment | This unit could be assessed in conjunction with any other units addressing the safety, quality, communication, materials handling, recording and reporting associated with welding using gas tungsten arc welding process (GTAW) or other units requiring the exercise of the skills and knowledge covered by this unit. |
Method of assessment | Assessors should gather a range of evidence that is valid, sufficient, current and authentic. Evidence can be gathered through a variety of ways including direct observation, supervisor's reports, project work, samples and questioning. Questioning techniques should not require language, literacy and numeracy skills beyond those required in this unit of competency. The candidate must have access to all tools, equipment, materials and documentation required. The candidate must be permitted to refer to any relevant workplace procedures, product and manufacturing specifications, codes, standards, manuals and reference materials. |
Consistency of performance | Assessors must be satisfied that the candidate can competently and consistently perform all elements of the unit as specified by the criteria, including required knowledge, and be capable of applying the competency in new and different situations and contexts. |
Required skills | Look for evidence that confirms skills in: |
identifying and interpreting appropriate standards e.g. Australian Standard 1554 General Purpose, American Bureau of Shipping (ABS) or equivalent | |
selecting and using appropriate tools and equipment | |
using a variety of welding machines and electrodes | |
identifying and rectifying weld defects | |
applying techniques for distortion prevention and rectification | |
cleaning welds | |
reading and interpreting information on written job instructions, specifications, standard operating procedures and drawings | |
recording routine information related to GTAW onto proformas and standard workplace forms | |
following oral instructions | |
measurement skills relating to joint preparation and GTAW | |
Required knowledge | Look for evidence that confirms knowledge of: |
correct welding machine, leads, hand pieces and electrodes | |
material preparation | |
joint preparations | |
electrode classification | |
causes of distortion for materials within the scope of this unit | |
causes of defects and methods of rectification | |
the relationships between amperage, electrode and material | |
types of gases and their uses | |
types of electrodes, current settings, high frequency voltage | |
filler materials and consumables | |
safe welding practices | |
use and application of personal protective equipment for GTAW | |
The range statement provides information about the context in which the unit of competency is carried out. The variables and scope cater for different work requirements, work practices and knowledge between States, Territories and the Commonwealth, and between organisations and workplaces. The range statement relates to the unit as a whole and provides a focus for assessment. Text in italics in the performance criteria is explained here. The following variables may be present and may include, but are not limited to, the examples listed under the scope. All work is undertaken to relevant legislative requirements, where applicable | |
Variable | Scope |
Prepared | Preheating, setting up of jigs, fixtures, clamps, etc., joint preparation e.g. bevelling |
Materials | Carbon steel or stainless steel, aluminium |
Welding equipment | AC or DC welding machines |
Distortion prevention measures | Preheating, setting up of jigs, fixtures, clamps, etc. |
Rectified | Oxy acetylene and air arc equipment, grinding devices |
Defects | Porosity, slag inclusions, discontinuities, lack of penetration, undercut |
Fabrication