ASME PCC-2 Repair of Pressure Equipment and Piping

1. Butt-Welded Insert Plates in Pressure Components

DESCRIPTION The repair of pressure components by butt-welded insert plates involves the replacement of pressure boundary material in a pressure component with an insert plate attached by full penetration butt welds.

DESIGNInsert plates and welds should be of the same material as the existing pressure component, or of another material that has at least equal notch toughness and allowable stress,Rectangular and square insert plates shall have corners rounded to a radius 13 mm (12 in.) thick up to 25 mm (1 in.) 75 mm (3 in.) or a larger.Over 25 mm (1 in.) thick 150 mm (6 in.) or a larger.Less than 13 mm (12 in.) thick may have smaller corner radii. (Normally 1 inch or greater)Minimum Size of Insert Plates. ( non-postweld heat-treated). lesser of 12t or 380 mm (15 in.) (where t is the thickness of the parent material).Flush Insert Plate (With or WithoutNozzle/Manway) With Its Butt Weld IntersectingExisting Butt Weld in Shells or HeadsNOTES:(1) Existing butt weld in vessel shell or head. (Fig. 2 shows buttweld in a cylindrical shell.)(2) Thirty deg minimum angle.(3) Full RT or UT, or MT or PT both sides of existing butt weld,100 mm (4 in.) min. each side of intersection with insert plate.(4) Insert plate butt weld. Full RT or UT, or MT or PT both sides ofweld.(5) For nonpostweld heat-treated carbon and low alloy steelnozzle/manway assemblies, 150 mm (6 in.) minimum betweenthe toe of the nozzle fillet weld and the nearest edge of theinsert plate butt weld (see para. 3.8).

Intersecting "Doghouse" Type Insert PlateButt Weld (With or Without Nozzle/Manway)With Shell Butt Weld in Vessel Shells and HeadsNOTES:(1) Existing butt weld in vessel shell or head. (Fig. 3 shows buttweld in a cylindrical shell.)(2) Length of cut in shell butt weld, 150 mm (6 in.) minimum oneach side of intersecting insert plate butt weld.(3) Insert plate butt weld.(4) Cut existing shell butt weld to 150 mm (6 in.) minimum oneach side of intersecting insert plate butt weld and beveledges (or arc gouge edges) to the desired edge bevels. Reweldafter completion of insert plate butt weld. Full RT or UT, or MTor PT both sides of new weld.(5) For nonpostweld heat-treated carbon and low alloy steelnozzle/manway assemblies, 150 mm (6 in.) minimum betweenthe toe of the nozzle fillet weld and the nearest edge of theinsert plate butt weld (see para. 3.8).

FABRICATIONOne-Sided Welds. For flush inserts in pipe ortube or other pressure components that do not allowtwo-sidedwelding, gas tungsten arcwelding, or anotherwelding process that provides an acceptable weld onthe opposite side should be used for the initial passjoining the insert to the pipe wall.

Weld Spacing Between Nonintersecting AdjacentButt Welds in Carbon Steel and Low Alloy SteelPressure Components4.3.1 Minimum Spacing Between Non-PostweldHeat-Treated Butt Welds. Non-postweld heat-treatedbutt welds around the periphery of insert plates shallbe spaced no closer to existing non-postweld heattreatedbutt welds or reinforcing plate attachmentwelds than(a) for tw 13 mm (12 in.), 150 mm (6 in.)(b) for tw > 13 mm (12 in.), the greater of 250 mm(10 in.) and 8twwheretw p thickness of the thicker of the two adjacent buttwelds, mm (in.)4.3.2 Alternative Spacing Between Non-PostweldHeat-Treated ButtWelds. The spacing between adjacentnon-postweld heat-treated carbon and low alloy steelbutt welds may be reduced to the lesser of 8tw or 200mm(8 in.) for tw 40 mm (112 in.), provided both butt weldsare ground smooth, 100% RT or UT examined and100% MT or PT examined after completion of weldingin areas where the spacing between the adjacent buttwelds is less than that specified in para. 4.3.1. As analternative, the root pass and the weld, after half of thegroove is filled, may be either 100% MT or PT examinedin place of the 100% RT or UT examination requirementabove. The butt welds with thicknesses less than 13 mm(12 in.) need only be MT or PT examined. See para. 5.1.4.3.3 Spacing Betwen Stress-Relieved Butt Welds.The spacing between the adjacent butt welds shall benot less than 2tw if the first butt weld has been

EXAMINATION OF WELDS5.1 Insert Plate WeldsAll insert plate welds to the existing pressure componentin pressure vessels shall be examined by radiographic(RT) or ultrasonic (UT) examination methods tothe extent required by the applicable code of constructionor post-construction code for the pressure component.Where UT is used, examination of the root passby either magnetic particle (MT) or liquid-penetrant (PT)methods is recommended. The procedures, personnelqualifications, and acceptance criteria shall be in accordancewith the applicable code of construction or theapplicable post-construction code.5.2 Finished Welded SurfacesUnless 100% RT or UT examination is required, allfinished welded surfaces shall be examined by magneticparticle (MT) or liquid-penetrant (PT) methods. Examinationby the MT or PT methods is recommended forthe root pass of single-groove welds and for the backgougeof double-groove welds. No crack-like indications,incomplete fusion, or incomplete penetration arepermissible.Additional Examination Requirements for Carbonand Low Alloy Steels5.4.1 Rectangular and Square Insert Plates. Forrectangular or square insert plates, the welds aroundthe rounded corners, as a minimum, shall be either spotRT or UT examined. As an alternative, the root pass,the weld after half of the groove is filled, and the completedweld shall be either MT or PT examined.5.4.2 Closely Spaced and Intersecting Welds. Seeparas. 4.3 and 4.4 for additional examination requirementsfor closely spaced welds and intersecting welds.

5.4.1 Rectangular and Square Insert Plates. Forrectangular or square insert plates, the welds around the rounded corners, as a minimum, shall be either spotRT or UT examined. As an alternative, the root pass,the weld after half of the groove is filled, and the completedweld shall be either MT or PT examined.5.4.2 Closely Spaced and Intersecting Welds. Seeparas. 4.3 and 4.4 for additional examination requirementsfor closely spaced welds and intersecting welds.