Preparing ultrasonic flaw detection equipment for testing activities
Overview
This standard identifies the competencies you need to prepare manual, semi-automatic or fully automatic ultrasonic flaw detection equipment, in readiness for the testing activities, in accordance with approved procedures/techniques. Obtaining the correct outcome of ultrasonic testing demands great care in setting up the equipment, in order that the tests indications may be confidently interpreted. The use of both contact and non-contact ultrasonic flaw detector equipment is covered in this standard.
You will be required to check that the flaw detector, its probes and calibration blocks, are as specified in the non-destructive testing (NDT) instructions. You will be required to check that the equipment is in a safe and usable condition and that all electrical connections, cables and fittings are securely connected and fit for purpose. You will also be expected to check the performance of the equipment and to calibrate the probe flaw detector system for range, sensitivity and beam spread, distance-amplitude correction (DAC) curves will be generated when required.
Your responsibilities will require you to comply with organisational policy and procedures for the setting up of the ultrasonic test equipment, and to report any problems with the equipment in use, or the setting up activities, that you cannot personally resolve, or are outside your permitted authority, to the relevant people. You will be expected to work with a minimum of supervision, taking personal responsibility for your actions and for the quality and accuracy of the work that you carry out.
Your underpinning knowledge will provide a good understanding of your work, and will provide an informed approach to the setting up of the ultrasonic equipment being used. You will have a good understanding of the principles of the pulse-echo system, and of the transmission/reflection characteristics of ultrasonic waves. You will have an understanding of how the properties of materials will affect wave propagation and the response of different types of reflector formed by internal features and defects/flaws. You will have a good knowledge of flaw detectors and their characteristics and of the different types of probes, their application and calibration requirements. Your knowledge will include an appreciation of the hazards and safe working practices for ultrasonic flaw detection and you will understand the risks posed by casting defects/flaws and the consequences of component failure.
You will understand the safety precautions required when setting up the ultrasonic flaw detection equipment and when using the associated tools and equipment. You will be required to demonstrate safe working practices throughout and will understand the responsibility you owe to yourself and others in the workplace.
Performance criteria
You must be able to:
- work safely at all times, complying with health and safety legislation, regulations, directives and other relevant guidelines
- follow relevant job instructions and specifications for testing
- obtain all the required equipment and ensure that it is in safe and usable condition
- prepare, set up and check the equipment for testing activities to specification
- report completion of preparations in line with organisational procedures
- deal promptly and effectively with problems within your control and report those that cannot be solved
- ensure that work records are completed, stored securely and available to others, as per organisational requirements
- leave the work area in a safe condition on completion of the activities, as per organisational and legal requirements
Knowledge and Understanding
You need to know and understand:
- the specific safety precautions to be taken whilst carrying out the activities (including any specific legislation, regulations or codes of practice relating to the activities, equipment or materials)
- the health and safety requirements of the work area and the activities, and the responsibility these requirements place on you
- the hazards associated with the activities, and how to minimise them and reduce risks
- the personal protective equipment and clothing (PPE) to be worn during the activities
- how to obtain the job instructions/techniques, equipment setting up procedures and testing specifications and how to interpret the information
- the basic principles of ultrasonic flaw detection testing (including sound transmission and reflection; the echo principle; ultrasound; pulse echo system; pitch catch; defects as reflectors and transmission time as a measuring system)
- the basic components of the ultrasonic flaw detection equipment ( use of pulse generators; transducers to transmit and receive ultrasound; the receiver to recognise echo signals; the amplifier and signal display panel)
- the generation of ultrasonic waves (to include types of transducer, pulse length, frequency and bandwidth, and the coupling of the transducer to the casting)
- the ultrasonic beam (to include beam diameter and spread; intensity versus radius; near field and far field; the influence of frequency, velocity and transducer size)
- factors which will affect the selection of suitable probes (type, frequency, size, angle and product to be tested, the influence of expected defects on the probe selection)
- how to use manual, semi-automatic and automatic probe manipulation systems (including multiple probe systems)
- how the properties of the materials to be tested will affect the way the equipment performs (flat, curved, smooth or rough surface conditions and the size of the object) and any heat treatment or repairs to the castings
- how to setup and calibrate the ultrasonic flaw detection equipment (using specified calibration blocks; setting range appropriate to the castings being inspected; the effect of different sound velocities in calibration block and material of castings being inspected; the effect of casting shape and surface finish on range, sensitivity and signal-to-noise ratio)
- how to recognise defects (the various signals received from flaws); equipment response to probe manipulation and measurement of defect/flaw size
- care and control of the equipment (to include checking condition of insulation, all electrical cables and connections, equipment operating controls and displays, mechanical functions and probes)
- the extent of your own responsibility and whom you should report to if you have problems that you cannot resolve
- how to access, use and maintain information to comply with organisational requirements and legislation
Scope/range
Scope Performance
Prepare the ultrasonic equipment for testing, carrying out all of the following activities:
- comply with job instructions/techniques, equipment setting up documentation, NDT testing specifications
- adhere to health and safety regulations, systems and procedures to realise a safe system of work
- follow the defined setting up procedures/techniques
- leave the work area in a safe condition on completion of the activities
Prepare one of the following types of ultrasonic flaw detection equipment:
- analogue
- digital
Prepare one of the following types of ultrasonic testing equipment in readiness for use:
- manual
- semi-automatic
- fully automatic
Set up, check and adjust the equipment, carrying out all of the following activities:
- obtaining all necessary cables and fittings
- checking that all electrical connections, cables and fittings are secure and in a safe condition
- ensuring probes are of the required type, size, frequency and angle
- ensuring that the probe is in good condition and that the contact faces are undamaged
- obtaining appropriate reference and calibration blocks
- obtaining the required couplant (as appropriate)
Check the performance of the ultrasonic flaw detector, using the correct reference block for both of the following:
- timebase linearity
- amplifier
Calibrate the probe flaw detector system, using the specified calibration block(s) for all of the following:
- range
- sensitivity
- beam spread
- DAC curves (where appropriate)