Description

1. TASK 70-27-00-270-501 Ultrasonic Inspection - General Inspection

   

   WARNING

   IT IS THE RESPONSIBILITY OF THE OPERATOR TO OBTAIN AND OBSERVE THE MANUFACTURERS MATERIAL SAFETY DATA SHEETS FOR CONSUMABLE MATERIALS INFORMATION SUCH AS, HAZARDOUS INGREDIENTS, PHYSICAL/CHEMICAL CHARACTERISTICS, FIRE, EXPLOSION, REACTIVITY, HEALTH HAZARD DATA, PRECAUTIONS FOR SAFE HANDLING, USE AND CONTROL MEASURES AND ALSO TO TAKE LOCAL REGULATIONS INTO CONSIDERATION.

   1. Safety Precautions

   2. Definition

      Ultrasonic testing is a non destructive procedure for looking for defects or breaks within materials which can transmit sound at high frequency. In these materials, land quality, voids, cracks, inclusions, porosity can be found throughout the work piece.

   3. Principle

      In ultrasonic testing, an electrical pulse is applied to a piezo-electric crystal, which causes it to vibrate. When this vibration is applied to a sound transmitting material, a mechanical wave is caused in the material and becomes larger until stopped and/or reflected by a break or edge. The reflected energy is found by the same or a different crystal.

      These detected signals are applied to an amplifier and visually presented on a cathode ray tube. This presentation is then analysed to give the size, location and other property of the break or edge.

   4. Prepare Parts

      Parts must have such a surface finish as to make sure the correct movement of sound waves into the material at the ultrasonic properties specified in the applicable technique.

   5. Technique Preparation

      An ultrasonic instruction must be prepared for each part to be tested. The subsequent items will be included in the instruction.

      1. Scope

         A note that identifies the correct parts and materials included.

      2. Equipment

         All equipment which can do the instruction which includes flaw detection type, probes, jigs/fixtures, scanning devices, recording system etc.

      3. Surface condition

         Surface finish on parts to be tested must be specified. Also how clean and free from scale, paint, rust etc.

      4. Couplant

         Type and viscosity (if applicable) to be used must be specified.

      5. Reference standards

         Standard used for:

         1. Calibration of ultrasonic testing equipment

         2. Compare test indications of ultrasonic inspection material against defects (real or artificial) of known size rust be specified with the applicable reference number.

      6. Testing procedure

         1. Set up, which includes basic instrument positions.

         2. Inspection of parts

         3. Decrease in value correction.

         4. Distance echo correction (if applicable).

         5. Scan speed, pitch etc.

         6. Scan schedule.

         7. Final cleaning and protection (if applicable).

      7. Calibration

         Procedure of calibration and frequency.

      8. Acceptance standard

         Refer to the applicable document which specifies the correct accept/reject/report levels.

      9. Record test results

         Description/example of form or chart used to report the results.

   6. Identification

      It must be made sure that the component identification is kept on all records and reports and that all scans specified in the testing procedure have been carried out.

   7. Ultrasonic Equipment

      The equipment must be serviceable of operating to the necessary conditions of the parts specific technique.

   8. Scan Speed and Pitch

      To make sure satisfactory inspection of the necessary volume of the part, the speed and pitch at which the scan occurs must be made. The diameter of the test beam, the acceptance standard and the pulse repetition frequency must also be taken into account. A decision must also be made on if a manual or automatic system of defect detection is used.

   9. Control Checks

      Internal procedures must be specified that the control checks and their frequency to be done on the subsequent fields.

      1. Defect detection

      2. Probe and defect detection mixture

      3. Mechanical facility if applicable

      4. Ultrasonic/electronic aspects of automatic scanning if applicable.

   10. Records Held

       As specified in contractual agreements.