-SQA- SCOTTISH QUALIFICATIONS AUTHORITY
NATIONAL CERTIFICATE MODULE: UNIT SPECIFICATION
GENERAL INFORMATION
-Module Number-
2270754
-Session- 1994-95
-Superclass-
XE
-Title-
INTRODUCTION TO GAS SHIELDED WELDING
SKILLS
-------------------------------
-DESCRIPTIONGENERAL COMPETENCE FOR UNIT: Acquiring basic welding skills in two gas
shielded metal arc processes.
OUTCOMES
1.
apply safe working practices when producing welds by gas shielded
welding processes;
2.
prepare gas shielded welding equipment prior to use;
3.
produce welded joints using gas shielded welding processes;
4.
inspect and test a completed welded joint.
CREDIT VALUE: 1 NC Credit
ACCESS STATEMENT: No formal entry qualification.
---------------------------------For further information contact: Committee and Administration Unit, SQA,
Hanover House, 24 Douglas Street, Glasgow G2 7NQ.
Additional copies of this unit may be purchased from SQA (Sales and Despatch
section). At the time of publication, the cost is £1.50 (minimum order £5).
Unit No. 2270754
Continuation
Session 1994-95
NATIONAL CERTIFICATE MODULE: UNIT SPECIFICATION
STATEMENT OF STANDARDS
UNIT NUMBER:
2270754
UNIT TITLE:
INTRODUCTION TO GAS SHIELDED WELDING
SKILLS
Acceptable performance in this unit will be the satisfactory achievement of the
standards set out in this part of the specification. All sections of the statement of
standards are mandatory and cannot be altered without reference to SQA.
OUTCOME
1.
APPLY SAFE WORKING PRACTICES WHEN PRODUCING
WELDS BY GAS SHIELDED WELDING PROCESSES
PERFORMANCE CRITERIA
(a)
(b)
(c)
Cables and hoses are routed correctly to avoid damage to
individuals and welding equipment.
Personnel are protected from hazards by the correct use of
safety equipment.
Working area is kept clean and tidy to minimise hazards.
RANGE STATEMENT
Gas shielded processes: metal arc gas shielded, tungsten arc gas shielded.
Welding equipment: welding leads; wire feed units, gas hoses, footswitches.
Safety equipment: welding helmets; protective filters; overall protection; gloves;
fume extraction.
Safety hazards: arc shielding; burns; welding fume; electric shock; welding rays.
EVIDENCE REQUIREMENTS
Performance evidence that the candidate can maintain a safe working
environment and can readily identify potential safety hazards and take corrective
action.
OUTCOME
2.
PREPARE GAS SHIELDED WELDING EQUIPMENT PRIOR TO
USE
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Unit No. 2270754
Continuation
Session 1994-95
PERFORMANCE CRITERIA
(a)
(b)
(c)
The selection of gas shielded welding equipment is correct for a
given task.
Cables and hoses are correctly assembled.
Welding parameters are correctly selected.
RANGE STATEMENT
Gas shielded processes: metal arc gas shielded; tungsten arc gas shielded.
Welding parameters: consumables; gas flow rates; voltage; current; wire feed
speed; tungsten size and type; polarity; shielding gases.
EVIDENCE REQUIREMENTS
Performance evidence that the candidate can select and prepare the appropriate
equipment to produce a weld using gas shielded welding processes.
OUTCOME
3.
PRODUCE WELDED JOINTS
WELDING PROCESSES
USING
GAS
SHIELDED
PERFORMANCE CRITERIA
(a)
(b)
(c)
(d)
Welding parameters are correctly selected.
Weld defects are minimal.
Weld profiles are correct in terms of joint requirements.
Penetration of the joint is at least 50% over the length of weld for
corner and butt.
RANGE STATEMENT
Joint types: 'T' joint; outside corner; butt.
Joint position: horizontal-vertical (T Joint); flat (butt joint and outside corner).
Materials: carbon steel up to 6mm for metal arc gas shielded; carbon steels up to
3mm for tungsten arc gas shielded.
EVIDENCE REQUIREMENTS
Performance evidence that the candidate can produce a range of welded joints
using gas shielded welding processes.
OUTCOME
4.
INSPECT AND TEST A COMPLETE WELDED JOINT
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Unit No. 2270754
Continuation
Session 1994-95
PERFORMANCE CRITERIA
(a)
(b)
The welded joints are visually inspected using
procedures.
Welds are destructive tested using correct procedures.
correct
RANGE STATEMENT
Destructive tests: root bends; face bends; macro-examination; fillet fracture.
EVIDENCE REQUIREMENTS
Performance evidence that the candidate can use inspection methods and
destructive tests to assess the quality of a welded joint.
--------------------------------ASSESSMENT
In order to achieve this unit, candidates are required to present sufficient
evidence that they have met all the performance criteria for each outcome within
the range specified. Details of these requirements are given for each outcome.
The assessment instruments used should follow the general guidance offered by
the SQA assessment model and an integrative approach to assessment is
encouraged. (See references at the end of support notes).
Accurate records should be made of the assessment instruments used showing
how evidence is generated for each outcome and giving marking schemes
and/or checklists, etc. Records of candidates' achievements should be kept.
These records will be available for external verification.
SPECIAL NEEDS
In certain cases, modified outcomes and range statements can be proposed for
certification. See references at end of support notes.
 Copyright SQA 1994
Please note that this publication may be reproduced in whole or in part for
educational purposes provided that:
(i)
(ii)
no profit is derived from the reproduction;
if reproduced in part, the source is acknowledged.
4
Unit No. 2270754
Continuation
Session 1994-95
NATIONAL CERTIFICATE MODULE: UNIT SPECIFICATION
SUPPORT NOTES
UNIT NUMBER:
2270754
UNIT TITLE:
INTRODUCTION TO GAS SHIELDED WELDING
SKILLS
SUPPORT NOTES: This part of the unit specification is offered as guidance.
None of the sections of the support notes is mandatory.
NOTIONAL DESIGN LENGTH: SQA allocates a notional design length to a unit
on the basis of time estimated for achievement of the stated standards by a
candidate whose starting point is as described in the access statement. The
notional design length for this unit is 40 hours. The use of notional design length
for programme design and timetabling is advisory only.
PURPOSE SQA publishes summaries of NC units for easy reference, publicity
purposes, centre handbooks, etc. The summary statement for this unit is as
follows:
A specialist module which introduces you to the skill requirements of gas
shielded welding processes. On completion of the module you should have
acquired a basic skill which should allow progression to higher skill which should
allow progression to higher skills in these processes. You will also have a basic
knowledge of consumables, set up, and safety requirements associated with
metal arc gas shielded welding and tungsten arc gas shielded welding.
You will also have gained a basic knowledge of simple inspection and testing
methods and be responsible for your own quality assurance.
CONTENT/CONTEXT
The following information gives further clarification
regarding the context in which the outcomes and performance criteria are to be
achieved.
1.
Importance of safety equipment for welding, shades of filter glass,
importance of fume extraction, personal safety, welding rays.
The correct routing of cables and hoses to prevent obstruction. Mounting
of welding torch after use. Care associated with filler wires. Importance
of good electrical connections. Transportation of welded specimens
(hot).
2.
Importance of shielding gas selection, wire feed speed and voltage.
Tungsten type and diameter in tags. Selecting the correct size of filler
wire for materials thickness and joint
type. Procedure for assembling equipment to gauges. Selecting gas
flow rate. Assembly of tags torch components. Changing of wire
reel/liner in mags processes. Current selection in tags.
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Unit No. 2270754
Continuation
Session 1994-95
3.
All joints should be tacked prior to welding. Each competence should be
demonstrated at least three times. All welds should be at least 150mm in
length.
4.
The first and last 15mm of the joint should not be taken into account for
inspection and testing purposes.
The use of inspection gauges can be used where appropriate.
Root bend for butt weld is taken from centre of specimen and should be
at least 25mm wide.
It is recommended that 50% of the time is spent on each process.
APPROACHES TO GENERATING EVIDENCE Assessment should be produced
in the conditions of the workplace using practical exercises and tasks related to
the production of a welded joint.
Outcome 1
Observation checklist based on a practical task where the
candidate is assessed prior to, during and after the production of
welded joints.
Outcome 2
Observation checklist based on a practical task where the
candidate prepares and selects equipment and parameters prior
to the production of a welded joint.
Outcome 3
Observation checklist based on practical exercises where the
candidate has to produce the following welded joints to the
standards stated in the performance criteria.
Reference to Outcome 3:
Process
Joint Type
Metal Arc
Outside corner
Gas Shielded joint
Tungsten
Arc
Gas Shielded
Material
Position
Carbon steel
up to 6mm
thick
Flat
'T' Joint
Carbon steel
up to 6mm
thick
Horizontal-Vertical
Outside Corner
Joint
Carbon Steels
up to 3mm
Thick
Flat
Butt Joint
Carbon Steels
up to 3mm
thick
Flat
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Unit No. 2270754
Outcome 4
Continuation
Session 1994-95
Observation checklist based on a practical exercise where the
candidate inspects and tests each of the joints produced in
Outcome 3.
RECOGNITION Many SQA NC units are recognised for entry/recruitment
purposes. For up-to-date information see the SQA guide 'Recognised and
Recommended Groupings'.
REFERENCES
1.
2.
3.
4.
5.
Guide to unit writing.
For a fuller discussion on assessment issues, please refer to SQA's
Guide to Assessment.
Procedures for special needs statements are set out in SQA's guide
'Students with Special Needs'.
Information for centres on SQA's operating procedures is contained in
SQA's Guide to Procedures.
For details of other SQA publications, please consult SQA's publications
list.
 Copyright SQA 1994
Please note that this publication may be reproduced in whole or in part for
educational purposes provided that:
(i)
(ii)
no profit is derived from the reproduction;
if reproduced in part, the source is acknowledged.
7