QATAR ENGINEERING & CONSTRUCTION COMPANY WLL(Qcon)

Gate 69, Street 48, Salwa Industrial Area, Qatar

Mailing Address;PO Box 24491, Doha, QatarTel: (+974) 458 7200, Fax: (+974) 458 7201e-mail: qcon@qcon.com.qaweb site: www.qcon.com..qa

Welding CALIBRATION PROCEDUREDocument numberQCON-P&M-08

026-08-2014DraftSudath Sanjeewa

Rev.DateDescriptionORIGINATED BY CHECKED BY APPROVED BY

IMPORTANTHard copy of this document shall be considered uncontrolled unless signed and stamped as Controlled Copy by DCC with copy number and issue date. Current revision of this document is available in the Network Shared Folder. It is the responsibility of the user to verify that this copy is of the latest revision.

REVISION RECORD

REVDATEDESCRIPTION

026-08-2014Draft

INDEX

SECTIONTITLEPAGE

-REVISION RECORD2

-INDEX3

1.0PURPOSE4

2.0SCOPE4

3.0DEFINITION4

4.0DIVERSION4

5.0RESPONSIBILITIES4

6.0CALIBRATION5

7.0REGISTRATION & CONTROL OF CALIBRATION6

8.0ACCEPTANCE CRITERIA6

9.0DOCUMENTS6

1. PURPOSE

1.1. To established technical guidelines to perform and calibrate inverter welding machine, rectifier welding machine, A/C transformer welding machine, an engine driven welding machine. And to ensure that only those calibrated welding machines will produce acceptable quality professional weld as per national and international standards. 1.2. To minimize the current and voltage deviations between welding machine set parameters and work piece and certify the welding machine.1.3. Several national and international standards specify that the welding machine to be used for welding machine products shall be calibrated. 1.4. Welding machine current / voltage is an essential variable in all of the national and International Standards. A change in current / voltage can change weld joint properties and introduce unacceptable discontinuities. Hence having correct current / voltage reading on the welding machine is very vital to produce acceptable quality welds.

2. SCOPE

This procedure details the requirement that is required to be implemented for the welding machine calibration.

3. EXPLANATION / DEFINITIONS

Metrological comparison between a measurement device or an instrument with their respective benchmarks, certificates and their accuracy, in order to detect, report or eliminate by adjustment any inaccuracy of the instrument.

4. DIVERSION

It is the difference in magnitude between the current rating of the welding machine and the actual value measured in amperage volt ammeter clamp, taking as basis the corresponding nominal value.

5. RESPONSIBILITIES

5.1. Production Supervisor and / or Sr. Foreman responsible for :5.1.1. Use only calibrated welding machines.5.1.2. Advice the staff involved and apply the requirements of this procedure5.1.3. Arrange and meet with the minimum premises and equipment calibration.5.1.4. Notify the Quality Control prior to the date for the calibration of welding machine.

5.2. The Section of the Quality / Welding Inspector responsible for 5.2.1. Notify the Technical Dept. prior to the date for the calibration of welding machine.5.2.2. Receive the welding machine calibration certificates from Technical Dept. and inspect, the welding machine calibration certificate in acceptable criteria, 5.2.3. Calibration certificate to be stamped, sign and authorized to use the welding machine. 5.2.4. Verify the validity of the calibration time.(As per Client requirement)5.2.5. Affix labels on the welding machine indicating the calibration.5.2.6. Maintain proper inventory and calibration records.

5.3. The Section of the Technical / Electrical responsibility for:5.3.1. Receive the notification for welding machine calibration.5.3.2. Test the welding machine prior to calibration and certification.5.3.3. Assigning competent technician to perform welding machine calibration. 5.3.4. Perform and calibrate the welding machine, utilizing calibrated master instrument.(Calibration standards traceable to Internal standards)5.3.5. Adjust and minimise the parameter deviation. 5.3.6. Verify the validity of the calibration time.(As per Client requirement) 5.3.7. Issue welding machine calibration certificate.5.3.8. Issue labels to stick on the welding machine indicating the calibration.5.3.9. Maintain proper inventory and calibration records.

6. CALIBRATION

6.1. Calibration and certification of welding machine.6.2. Technical staff required for welding machine calibration.6.2.1. Welding inspector.(Witness)6.2.2. An Electrician.6.2.3. Qualified Welder6.2.4. Document controller

6.3. Materials required for welding machine Calibration6.3.1. Welding PPE.6.3.2. Welding Consumable.6.3.3. Steel plate appropriate.6.3.4. Accessory.6.3.5. Master instrument. (Third party Calibrated certify and valid ( traceable to internal standards) (properly protected from damage and deterioration during handling, maintenance and storage)6.3.6. Suitable and standard welding cables.6.3.7. Suitable and standard welding cable connectors.6.3.8. Suitable and standard welding earth clamp.6.3.9. Suitable and standard welding electrode holder

6.4. Frequency of Calibration.

6.4.1. All welding machine such as inverter welding machine, rectifier welding machine, A/C transformer welding machine, an engine driven welding machine should be Calibrated and certify before use, and thereafter every six months.6.4.2. All Master instruments should be Calibrated and certify before use, and thereafter every six months.

Note: This period can be set by the contractor (CLIENT) but not higher than that specified above.

6.4.3. Welding machine Calibration Technique.

6.4.3.1. Welding Electrode cable clamp connect to the positive terminal of the welding machine to be test and calibrate.6.4.3.2. Welding ground cable clamp connector to the negative terminal of the welding machine to be test and calibrate.6.4.3.3. Energize the welding machine. ((ON)Electrically or (Start)Engine driven)6.4.3.4. Test and record welding machine OCV (Open Circuit Voltage) and verify with the welding machine name plate.6.4.3.5. Set the welding parameter positioning liver in the desired position.(Set point)6.4.3.6. Engage with the volt ammeter clamp the cable clamp electrode.6.4.3.7. Carry out the reading of the clamp volt ampere ammeter, comparing it with the values shown on the recorder panel of the welding machine.(Welding machine Dial)

Note; Evidence records calibration results of deviations in from. Calibrations should happen in bands of every (It should indicate the calibration bands for gradual measurement are taken e.g. every 40A, 60A, 80ANumbering is the same numbering allocated as indicated in the procedure)

7. REGISTRATION AND CONTROL OF CALIBRATION.

7.1. The results of the calibration process must be registered in the Control of Calibration of welding machine. It should be kept track of time calibration, so no equipment is used with their deadlines expired.

7.2. The equipment may only be labelled when they are approved.

8. ACCEPTANCE CRITERIA

The maximum permissible deviations for calibration are: + / - 20% on the Set point.

Note: The maximum deviation is in accordance with the criteria established by Client. Porum not exceeding the amount fixed by the Standard.

9. DOCUMENTS

1. Master instrument Calibration Certificate. (Sample)

2. Electric Welding machine Calibration Certificate. (Sample]

3. Engine Driven Welding machine Calibration Certificate. (Sample)

4. Electrode oven Calibration Certificate. (Sample)