Elements and Performance Criteria

RANGE STATEMENT
The range statement relates to the unit of competency as a whole. It allows for different work environments and situations that may affect performance. Bold italicised wording, if used in the performance criteria, is detailed below. Essential operating conditions that may be present with training and assessment (depending on the work situation, needs of the candidate, accessibility of the item, and local industry and regional contexts) may also be included.
Codes of practice/standards
Where reference is made to industry codes of practice, and/or Australian/international standards, it is expected the latest version will be used.
Sources of information
reference texts
manufacturers' catalogues and industrial magazines
websites
use of phone, email and fax information gathering
Scientific techniques and principles of heat treatment relate to:
Ferrous heat treatment
the iron-carbon equilibrium and plain carbon steels.
iron-carbon phase equilibrium
austenite-ferrite transformation
austenite-pearlite steels
influence of grain size and carbide distribution on mechanical properties.
microstructure and properties of slowly cooled steels.
effect of temperature and composition on structure and properties.
effects of alloying elements in iron-carbon alloys.
the gamma and sigma phase fields
distribution of alloying elements in steel.
effects of alloying elements in the kinetics of gamma and sigma transformations.
structural changes resulting for alloying additions.
transformation diagrams for alloy steels.
isothermal transformation of austenite.
austenite grain size
formation of pearlite
formation of bainite
role of alloying elements
mechanical properties of pearlite and bainite
Temperature Time Transformation (TTT) diagrams.
quenching treatments.
formation of martensite
morphology and crystallography of ferrous martensites
mechanical properties of martensites
retained austenite
quenching media - stages of quenching, effect of variables
thermal and transformation stresses, quenching defects.
transformation of austenite continuous cooling
cooling curves
Continuous Cooling Transformation (CCT) diagrams
hardening and heat treatment.
factors affecting how well a metal responds to hardening processes
use of TTT and CCT diagrams
hardenability testing e.g. Jominy
hardenability and heat treatment
tempering
tempering of irons and steels.
tempering of non ferrous metals and alloys
mechanical properties of tempered irons and steels
mechanical properties of non ferrous metals and alloys
Special heat treatments
austempering
martempering (marquenching)
maraging steels
high-strength, low-alloy (HSLA) steels.
surface treatments
carburising
carbonitriding
nitriding
induction and flame hardening
other methods
heat treatment defects
nature and prevention of defects
surface
structural and property
stress related
dimensional
embrittlement
Non-ferrous heat treatments
aluminium alloys
solutions treatments
quenching
precipitation hardening
coldworking
temper designations
copper alloys
solution annealing
age hardening
precipitation hardening
coldworking
quenching and tempering
miscellaneous non-ferrous
Significant figures
Are those relevant to accuracy and are appropriate to the process, data and desired range of results
Risks and safety procedures
biological factors in quench tank fluids
carcinogenic oil fumes,
flash point of oils and risk of fire in oil quenching
inert atmospheres and their potential to cause asphyxiation
specification and use of personal protective equipment (PPE)
location of emergency switches
tagging and isolation procedures
atmosphere control
identification of high risk alloys and metals
appropriate transfer times to quench and from quench to temper furnace

EVIDENCE GUIDE
The Evidence Guide provides advice on assessment and must be read in conjunction with the Performance Criteria, Required Skills and Knowledge, the Range Statement and the Assessment Guidelines for the Training Package.

Overview of assessment
A person who demonstrates competency in this unit must be able to determine and supervise heat treatment of metal. Critical aspects for assessment and evidence are required to demonstrate competency in this unit.
Critical aspects for assessment and evidence required to demonstrate competency in this unit
It is essential that competence is demonstrated in the ability to:
Select the appropriate heat treatment cycle(s) for nominated materials, so that they meet the required physical properties.
Relationship to other units
This unit could be assessed in conjunction with any other units addressing the safety, quality, communication, materials handling, recording and reporting associated with applying basic scientific principles and techniques in mechanical engineering situations or other units requiring the exercise of the skills and knowledge covered by this unit.
Assessment method and context
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.
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.
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.
Resource implications
This section should be read in conjunction with the range of variables for this unit of competency. Resources required include suitable access to a situation where heat treatment of metal is undertaken. A bank of case studies/scenarios and questions will also be required to the extent that they form part of the assessment method. Questioning may take place either in the workplace, or in an adjacent, quiet facility such as an office or lunchroom. No other special resources are required.