大于等于1/2”(13mm)才可以使用。注意TOFD的合格指标一定要用code case 2235的表不能和附录12混用。
TOFD可以代替RT在标准的解释中,解释了很多次,摘录几条比较典型的问题和回复见下文。
Interpretation:VIII-1-98-41Question: Is it permissibleto use the Ultrasonic Time-of-Flight-Diffraction (TOFD) Technique whenimplementing Code Case 2235?Reply: Yes.Interpretation:VIII-1-04-95Question (1): Is it theintent of Code Case 2235-6 (2235-7) that when portions of the vessel meet the requirementsof UW-11(a) for full radiography and portions meet the requirements of CodeCase 2235-6 for using ultrasonic examination in lieu of radiography, the vesselnameplate be stamped with “RT-1”?
Reply (1): Yes, providedthe extent of examination, joint efficiencies, and the Code Case are noted onthe Manufacturer’s Data Report and the nameplate is marked under the CodeSymbol stamp by applying "UT."
Question (2): May a vesselnameplate be stamped “RT-2” per the rules of UG -116 of Section VIII, Division1, when a complete vessel satisfies the requirements of UW-11(a)(5) and whenthe spot radiography requirements of UW-11(a)(5)(b) have been applied but whenultrasonic examination in accordance with the provisions of Code Case 2235-6has been used in lieu of radiography?Reply (2): Yes, providedthe extent of examination, joint efficiencies, and the Code Case are noted onthe Manufacturer’s Data Report and the nameplate is marked under the CodeSymbol stamp by applying "UT."Interpretation:VIII-1-07-68
Question (1): Does CodeCase 2235-9 require an ultrasonic examination plan capable of detectingindications transverse as well as parallel to the weld centerline?Reply (1): Yes.Question (2): Are theacceptance criteria specified in Tables 1, 2 and 3 of Code Case 2235-9 applicableto indications oriented transverse as well as parallel to the weld centerline?Reply