API PUBL 939-B-2002 pdf free download

API PUBL 939-B-2002 pdf free download.API Publication 939-B, Repair and Remediation Strategies for Equipment Operating in Wet H2S Service.
Following PWHT, the remaining eight attachments were welded onto the test panel using the same conventional weld- ing technique described previously. The four unrepaired grooves were repaired using a temper bead welding technique, as was done for the Exposure 1 test panel. The technique con- sisted of depositing an E7018 filler in multiple passes (6 total) in specific sequencing steps to temper back the bead hardness and HAZ produced by the previous bead(s). A schematic of the full penetration circumferential weld in the as-welded condition is shown in Figure 14. The bead hardness was approximately HRB 87 (converted from 500 gram Vickers). The HAZ hardness was approximately HRB 97 and HRB 98 at the I.D. surface. A schematic of the full penetration longitudinal weld, which was subjected to a PWHT, is shown in Figure 15. The bead hardness was approximately HRB 83. The HAZ hardness was approxi- mately HRE3 85 throughout the thickness. Hence PWHT reduced the bead hardness approximately 5 HRB points and the HAZ regions approximately 15 HRB points. Schematics of actual sections for the conventional (with PWHT) and temper bead weld (as-welded) repairs are shown in Figures 16 and 17, respectively.
The corresponding HAZ hardnesses were approximately HRB 85 throughout the extent of the repair. The temper bead repair produced bead hardnesses of approximately HRB 92. The corresponding HAZ hardnesses ranged from HRB 86 subsurface to HRB 93 at the surface. Hence, the temper bead technique produced higher hardness than the conventional weld repair with subsequent PWHT; however, hardnesses for both repairs were considered soft from the standpoint of SSC susceptibility. In addition to the above variables, the serviceability of unrepaired groovedlocal thin areas (LTAs) was also evalu- ated. The profiles were derived using a remaining strength factor (RSF) of 0.8. A schematic representation of the three profiles is provided in Figure 18. Profile 1 was positioned on one side of each fillet attachment. Profile 2 was centered at two places on the longitudinal weld and Profile 3 was posi- tioned at two places on the circumferential weld. The position of Profile 3 was such that one-half the metal removed was in the as-welded circumferential weld and the other half in the PWHT circumferential weld. Based on the width and length of the profiles, Profile 1 would be classified as a groove and Profiles 2 and 3 would each be classified as an LTA. Note: All three profiles would be acceptable per API EW 579 Fitness- For-Service procedure.
The use of strip lining the I.D. surface was also investi- gated in this test panel. AISI 304L sheet, 0.109-in. thick was welded on the I.D. in two places across the circumferential weld using an AISI 309L filler. The objective of this test panel was not to evaluate the ability of the liner to reduce hydrogen permeation. Experience has proven that this method provides adequate protection to the underlying base metal thereby pre- venting or minimizing further damage. The variable under evaluation with this surface treatment was the interaction/ behavior of the lining attachment welds. Detailed sectioning schematics and cracking results for the Exposure 2 test panel can be found in Appendix B. 5.2.3 Large-scale Exposure 3 Test Panel Configuration The test panel utilized for the third exposure in this study is shown in Figure 19. It consisted of four quarter panels cold-rolled to the appropriate radius for welding together and subsequent welding of the completed panel into the body of the test vessel. Each quarter panel mea- sured approximately l ft by l ft (0.3 m by 0.3 m). The typ- ical structure of InterCorr 2289 (CS) is shown in Figure 5. The typical structure for InterCorr 2099 (LSCS), 3247 (HRS) and 3250 (Th4CP) are shown in Figures 20,21, and 22, respectively.