Elements and Performance Criteria

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

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