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Hardness Testing

Tesko specialise in hardness testing, examination of various materials from stainless to copper-aluminium alloys (bronze) by our portable ultrasonic hardness testers with the results given in different hardness conversions such as LD, Vickers HV, Brinell HB, Rockwell-B HRB, Rockell-C HRC and Shore HS. 

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Holiday Testing

Holiday test or a Continuity test is one of the non-destructive test methods applied on protective coatings to detect unacceptable discontinuities such as pinholes and voids. The test involves checking of an electric circuit to see if current flows to complete the electrical circuit. A Holiday test or Continuity test is performed by applying low voltage (connected in series with an LED or noise-producing component such as a piezoelectric speaker) across the chosen path. If the electrical flow is detected then the test area is termed as conductive indicating presence of discontinuities such as pinholes and voids. This test is commonly used in the offshore industries where piping and structures are coated with non-conductor coatings. Tesko professionals are trained in Holiday (Continuity) test method in accordance with AS 3894.1, ASTM G62 and similar national and international standards. 

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Heat Treatment

Heat treatment is a method used to alter the physical, and sometimes chemical, properties of a material. Heat treatment involves the use of heating or chilling, normally to extreme temperatures, to achieve a desired result such as hardening or softening of a material.


Heat  treatment  techniques  include  annealing,  case  hardening,  precipitation  strengthening, tempering and quenching. It is noteworthy that while the term heat treatment applies only to

processes where the heating and cooling are done for the specific purpose of altering properties intentionally, heating and cooling often occur incidentally during other manufacturing processes such as hot welding. Tesko provide two major heat treatment services for our clients:


  • Pre Heating Services

  • Post Weld Heat Treatment

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Coating Inspection

We document each phase of the job to help ensure the successful completion of the coating project per the specification. We are familiar with many different surface preparation and coating application procedures. We are familiar with the maintenance of many existing structures or items in new construction, whether it is in the fabricating shop or in the field. 

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Hydrogen Attack Evaluation

The presence of hydrogen in industrial plants is a potential source of damage. High partial hydrogen pressure (higher than 30 bar) and high temperature (higher than 300 ºC) can negatively influence the material’s characteristics. Such damage occurs largely in fertilizer plants and refineries. Hot Hydrogen Attack (HHA) is a form of degradation caused by carbides reacting in steel, thereby forming methane (CH4). The probability of HHA damage in industrial plants is dependent on its partial hydrogen pressure and operating temperature. In the worst cases, HHA may lead to a leak before an actual break situation, but when the damage is in the parent material, the results can be catastrophic.


Tesko provides services for customers to identify and monitor HHA. Tesko combine advanced signal processing and results imaging utilizing advanced techniques like Time of Flight Diffraction (ToFD), Automated Backscatter and Velocity Ratio Measurements. To inspect a plant for the possible occurrence of Hot Hydrogen Attack, an accurate inspection plan has to be made with the back scatter technique using Corroscan for the most critical areas, i.e., at highest temperature and/or highest partial hydrogen pressure. In order to discriminate between HHA and small inclusions and to verify any attack, additional measurements are taken with the velocity ratio technique. The approach in the field would involve complete scanning of all welds with ToFD (if accessible) and manual or automated Pulse Echo.




  • The inspection is highly reliable and reproducible

  • It is possible to detect attack at an early stage

  • The progress of attack can be monitored

  • Results can be presented clearly

  • Examination is non-intrusive, resulting in cost and time savings

  • All geometries can be examined

  • All data is stored for quick and easy reference at any time in the future.


Application Range:


  • Industrial plants

  • Fertilizer plants

  • Refineries

  • Material parts where Hot Hydrogen Attack has occurred and accurate testing is needed 

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Welding Engineering

At Tesko, we have been providing welding engineering services during all production steps:


  • Preparing Welding Procedure Specification (WPS)

  • Planning, executing and approving of Welding Procedure Qualification (WPAR/PQR) Tests

  • Welder qualifications and tests

  • Overview of contract

  • Construction control

  • Traceability and control of material (parent material and consumables)

  • Sub-contractor conformity audits

  • Production Planning (WPS, PQR, work instructions, fixturing equipment, welder certifications, welding plans, examination criteria, health and safety and environment rules)

  • Examination and inspection of welding

  • Planning and executing of inspections


As part of this enhanced service offering, Tesko undertake the following:


  • Welder Qualification Testing for performance qualification and certification of welders (a welder / welding operator performance qualification - WQT) to ASME, ANSI, AWS, API code

  • Preparation of Weld Procedure Qualification as per client or project requirements.

  • Coupon testing as per Weld Procedure Qualification which includes visual examination, mechanical testing, metallographic examination and non destructive testing.

  • Documentation of the Procedure Qualification Record as per ASME, ANSI, AWS, API codes

  • In depth weld inspection to include review of the applicable qualification e.g. weld procedure specification, welder performance qualification and validity for process materials and consumable items, equipment, set up and other factors, including certificates of calibration and/or conformity governing the work.

  • Check safety of set up and operation having due regard for self, welder and other workers invicinity, particular in respect of ultraviolet radiation from arc during welding.


The welding inspector deployed at a site from Tesko will be responsible for monitoring and verifying that the following functions of the work conform in all aspects to the specific requirements of the relevant code, specification and/or standard:


  • Check correct weld procedure(s) employed.

  • Check weld procedure and welder qualifications.

  • Inspect weld profile preparation.

  • Inspect joint fit-up

  • Check filler metals and consumable materials

  • Check correct welding performance parameters observed

  • Perform visual examination upon completion of welding

  • Monitor pre and post weld heat treatment, where specified.

  • Monitor the physical examination including non-destructive test, hydrostatic test, mechanical test etc. If needed, the inspector may choose to send test coupons to the material testing laboratory.

  • Ensure that all necessary visual inspection is completed and verify that all other necessary non-destructive examinations are executed in the specified manner for the method and overage by appropriately qualified personnel.


The inspector shall employ the following equipment to aid in the performance of duties:


  • Inspection mirrors

  • Torch or other electrical lighting facilities (permitted by safety codes eg. 24V system etc.)     

  • Physical size measuring instruments such as welding gauge, rule, vernier etc.

  • Electrical parameter measuring instruments such as ammeter, voltmeter etc.

  • Temperature measuring instruments (thermometer)/aids (thermochalk).


All Tesko welding inspectors are generally certified in accordance with the requirements of at least one of the following schemes; Certification Scheme for Weld Inspection Personnel (CSWIP), American Welding Society (AWS), BGAS (previously British Gas ERS), and/or ASNT Level II VT. All inspectors have the ability to interpret various standards including ASME B&PV Code, Section IX, API Std. 1104 and ANSI / AWS D1.1. 

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Vacuum Test

Vacuum box bubble test is one of the safest and reliable non-destructive test method. The vacuum box bubble test can locate leaks in the test area that cannot be directly pressurized. The test is performed by applying a detergent solution on the test area and creating a vacuum around the test surface by external mechanism e.g. vacuum box. The detergent solution will bubble if there is any leakage through the test area. Liquid or vacuum systems tests are performed and reported for detecting leakages in pressure vessels, storage tanks, pipelines. Tesko professionals are trained and experienced in vacuum box bubble test method in accordance with ASME V, Appendix II and API standards. 


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Metallographic Examination

Analysis of macro/micro structure, designation of material, creep and defect analysis and reporting is performed with our competent metallurgical engineers. All examination process can be performed by Tesko.

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Corrosion Examination

Corrosion controls are carried out by competent engineers with advanced corrosion mapping equipment (video tracking), visual inspection, replica test methods. Tesko supplies detailed evaluation and reporting services.

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Replica Test

Replica test is applied on in-service pressure vessels, boilers, rotors, pipe-lines, ships, all kind of materials and welded structures for determination of the creep and fatigue condition. Test is applied by taking image of micro structure non-destructively and analysing, without blocking running of the equipment or facility. There is no need for cutting specimens. Necessary preparation is made with mobile devices.

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Manpower Recruitment

Tesko provide a comprehensive manpower supply service. Resourcing individuals and/or project teams who are fully trained and qualified to our clients' specific requirements. We have a large core team of personnel on which to draw. The service is further enhanced by access to our extensive computerised database; holding personnel covering a vast range of disciplines who are based throughout the world.


Tesko offer an extensive base of indigenous and ex-patriot technical personnel who can be mobilised rapidly on a temporary or long-term basis. We have considerable experience of providing reliable project support worldwide at short notice.

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