NON-DESTRUCTIVE EXAMINATIONS AND METHODS USED FOR VALVES

NON-DESTRUCTIVE EXAMINATIONS AND METHODS USED FOR VALVES
1.1 Hardness Testing
1.1.1 Perform hardness tests at or near the centre of the weld or surface to be tested on the side exposed to the process environment. Prepare the surface in accordance with ASTM E-10. Use a Telebrineller portable tester to measure hardness.
One hardness test for each 10 feet, or fraction thereof, for each longitudinal seam of each course. One hardness test for each 10 feet, or fraction thereof, for each vessel circumferential seam. One hardness test for each nozzle to shell weld.
One test on each surface cut with oxy-fuel or Arc-Air which is left unwelded on the finished part. One test on each area where a temporary weld was made and removed.
1.1.2 Brinell hardness test of the deposited weld, and heat affected zone shall be required for procedure qualifications of every welding process used. On production welds hardness test shall be obtained form the weld metal and heat affected zone.
Material Group Maximum Brinell Hardness
Carbon steel P-1 200
Carbon-molybdenum P-3 215
Chrome-molybdenum P-4, P-5 225
Chrome stainless stee P-6 225
Chrome stainless steel P-7 235
Report all hardness readings in excess of values shown above to Owner. Review any
corrective action with Owner before proceeding.
1.1.3 Non-ferrous materials and austenitic stainless steel welds shall not require hardness testing.
1.1.4 If post-weld heat treatment (PWHT) is applied for valves , perform the hardness test after PWHT.
1.2 Ultrasonic Examination (UT)
1.2.1 Ultrasonic examination and the acceptance criteria shall be in accordance with Section VIII, Division 1, Appendix 12.
1.2.2 Where full radiography of nozzle attachment welds is specified on vessel data sheet and radiographic interpretation is questionable owing to weld configuration, then such areas shall be UT examined.
1.2.3 When nozzles require ultrasonic examination, weldment shall be examined prior to fitting the reinforcement pad.
1.3 Magnetic Particle and Liquid Penetrant Examination (MT) & (PT)
1.3.1 Magnetic particle examination procedure shall be in accordance with ASME Code Section V, Article 7.
1.3.2 The elevation of indications and acceptance criteria for magnetic particle
examination shall be in accordance with ASME Code Section VIII, Division 1, Appendix 6.
1.3.3 Where magnetic particle examination is called for and material is not magnetic,
liquid penetrant examination shall be substituted.
1.3.4 Liquid penetrant examination procedure shall be in accordance with ASME Code Section V, Article 6.
1.3.5 The elevation of indications and the acceptance criteria for liquid penetrant examination shall be in accordance with ASME Code Section VIII, Division 1, Appendix 8.
1.3.6 Where stainless steel equipment is intended to inspect by liquid penetrant
technique, all dyes, developers and cleaners used for such inspection shall be
essentially free of halogen and sulphur compounds.
1.3.7 The maximum acceptable levels by weight of halogen and sulphur are as follows:
(1) Water Soluble Dye - Halogen 0.08%
- Sulphur 0.008%
(2) Developer - Halogen 0.07%
- Sulphur 0.011%
(3) Chemical Cleaner - Halogen 0.05%
- Sulphur 0.006%
Vendor shall furnish test results for approval in accordance with paragraph 2.3.
1.3.8 All root passes in materials P3 and higher shall be magnetic particle examined.
This includes back-chipped root passes to be welded from the second side.
1.3.9 All finished pressure welds in materials P3 and higher and in vessels designed with full radiography, regardless of material, shall be examined by magnetic particle or liquid penetrant after PWHT.
1.3.10 Welds between external and internal attachments and pressure parts in
materials P3 and higher shall be examined by magnetic particle or liquid penetrant after PWHT.
1.3.11 When magnetic particle examination is required, the DC prod or the DC yoke
method shall be used prior to PWHT while the AC yoke method shall be used after
PWHT.
1.3.12 The skirt to shell weld shall be magnetic particle or liquid penetrant examined all around.
1.3.13 Base metal sections shall be 100% examined by Magnetic Particle Examination prior to weld overlay and clad restoration.
1.3.14 All surfaces of weld overlaid and clad restoration sections as well as attachment
welds to lining or cladding shall be examined by Liquid Penetrant Examination.
1.3.15 All surfaces of each layer of weld overlay and clad restoration shall be examined by PT when using different welding materials.
1.4 Impact Testing
1.4.1 Charpy impact tests, when required shall comply with ASME Section VIII,
Division 1 requirements.
1.4.2 Impact tests shall be conducted at the minimum design metal temperature or at a lower temperature and shall meet or exceed energy absorption values required by Section VIII, Division 1.
1.5 Radiographic Examination (RT)
1.5.1 Radiographic examination of welded joints shall be performed when required by the Code or additionally when specified in this specification.
1.5.2 The minimum requirement for Code vessels is spot radiography plus the
additional requirements of this specification.
1.5.3 Radiographic examination procedures shall be submitted and shall be in
accordance with code Section V, Article 2 and Section VIII, Division 1.
1.5.4 Acceptance criteria shall be in accordance with ASME Code Section VIII,
Division 1, Appendix 4.
 UW 51(b) for full radiography
 UW 52(c) for spot radiography
1.5.5 Only lead screens should be used.
1.5.6 All radiographs taken during fabrication shall be available for examination by OWNER.
1.5.7 Where nozzles and manways necks are fabricated from rolled plate the
longitudinal seam weld shall be 100% radiographed.
1.5.8 Where spot radiography is required all joint intersections shall be radiographed and one additional spot shall be radiographed in each longitudinal and circumferential seam.
1.5.9 For unfired seam drums, nozzle-to-nozzle weld shall also be radiographed. Fine grain film such as Kodak AA shall be placed to cover the entire periphery of nozzle-tonozzle attachment weld area. Where radiographed interpretation is questionable owing to weld configuration then such areas shall be UT examined.
1.5.10 All butt weld in material P3 and higher shall be fully radiographed after PWHT.

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