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.
Metallurgicaltechniques and principles
Corrosion and Society
definition of corrosion
environments
corrosion damage
classificiation or corrosion
cost of erosion
social implications
Corrosion Principles
Electrochemical aspects
electrochemical reactions and chemical corrosion, galvanic cells, anode reactions, cathode reactions, concentrations cells, polarisation, passivity, pourbaix diagrams (simplified Pourbaix diagrams for Al, Fe and Zn), the driving force of corrosion, the rate of corrosion
Environmental effects
oxygen and oxidisers, velocity, temperature, corrosive concentration, corrosion environments (water, soil, atmosphere, dry gasses)
Metallurgical aspects
metal structures (defects, grain boundaries, second phases, cold work, residual stress), galvanic series, immunity, passivity.
Corrosion at Elevated Temperatures
Mechanism of oxide film growth:
rate laws
oxide defect structures
Pilling-Bedworth rule
oxidation of alloys
catastrophic oxidations
de carburisation
high temperature resistent alloys
Forms of corrosion
Uniform corrosion (general corrosion)
Galvanic corrosion
Crevice corrosion
Pitting corrosion
Fretting corrosion
Selective attack (leaching)
Intergranular corrosion
Stray current corrosion (electrolysis)
Erosion corrosion and cavitation damage
Stress corrosion cracking
Corrosion fatigue
Hydrogen damage
Microbial corrosion
Basic principles of Corrosion Control
Material selection
metals and alloys, metal purification, nonmetallics, stress relief
Alteration of environment
changing media, temperature, velocity, oxygen concentration, etc.
Corrosion protection
cathodic protection, anodic, protection and passivation, corrosion inhibitors, chemical conversion coatings, metal coatings, corrosion-preventing paints, coatings of plastic and rubber, temporary corrosion prevention.
Corrosion prevented by design
wall thickness, design rules (streamlining, stagnation, crevices, metallic contact, etc.)
Corrosion Characteristics of common alloys
Steel and cast iron
Stainless steel
Aluminium and its alloys
Copper and its alloys
Methodology of corrosion investigations
Corrosions testing
Corrosion monitering
Electrochemical investigations
Physical methods
Sources of information
Reference texts
Manufacturers' catalogues and industrial magazines
Websites
Use of phone, email and fax information gathering

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 corrosion prevention strategies for metal and alloys. 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:
correctly identify metallurgical processes involved in corrosion and corrosion prevention;
select corrosion prevention strategies and techniques appropriate to metal or alloy application and client needs
prepare instructions for corrosion prevention for client and other appropriate personnel.
Relationship to other units
This unit may be assessed concurrently with other relevant units.
Assessment method and context
Assessors must be satisfied that the person can consistently perform the unit as a whole, as defined by the elements, performance criteria, skills and knowledge. A holistic approach should be taken to the assessment.
Assessors should gather sufficient, fair, valid, reliable, authentic and current evidence from a range of sources. Sources of evidence may include direct observation, reports from supervisors, peers and colleagues, project work, samples, organisation records and questioning. Assessment should not require language, literacy or numeracy skills beyond those required for the unit.
The assessee will have access to all techniques, procedures, information, resources and aids which would normally be available in the workplace.
The method of assessment should be discussed and agreed with the assessee prior to the commencement of assessment.
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 an operating plant or equipment that allows for appropriate and realistic simulation. 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.