PSI - Issue 33

J.L. González-Velázquez et al. / Procedia Structural Integrity 33 (2021) 221–228 J.L. González-Velázquez et al. / Structural Integrity Procedia 00 (2021) 000–000

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Table 1. Technical data of the pressure vessel Type of component

Cylindrical horizontal, torispherical heads, welded

Service

Sour gas/condensate separator

Design code

ASME Sec. VIII, Div. 1

Material specification Operating pressure

SA 516 Gr. 70

14.2 psi Maximum Allowable Working Pressure ( MAWP ) 42.6 psi Service temperature 95  F External diameter ( D ) 122 in Nominal thickness ( t nom ) 1 in Minimum required wall thickness ( t min) 0.130 in Future Corrosion Allowance ( FCA ) 0.125 in

Fig. 3. The typical aspect of inclusions in the vessel shell. As-polished sample, bright field metallographic microscope.

SC: Circumferential weld SL: Longitudinal weld CS: Head to shell weld

Fig. 4. Pressure vessel design drawing, indicating the identification tags of the shell plates.

The zones of NMI were detected by phased array ultrasonic testing (PAUT) in Scan-C mode. Fig 5 shows two examples of the detected zones of non-metallic inclusions, along with the corresponding PAUT screen record; one is close to a weld joint (ENV-3.2) and one is isolated (TP-1.6). It is observed that the indications are planar and not interconnected and spread across a significant portion of the thickness.