PSI - Issue 33

Singgih Dwi Prasetyo et al. / Procedia Structural Integrity 33 (2021) 43–50 Prasetyo et al. / Structural Integrity Procedia 00 (2019) 000–000

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 Welding results are inspected by visuals, measurements, penetrants, and radiographs according to design requirements. Tolerance of weld results is as follows: welding face height (bead) max. 2.4 – 3.2 mm, undercut max. 0.5 mm, overlap max. 0.5 mm, cracked 0 mm.  Fittings and all welding results must comply with tolerance.  Cross joint (welding meeting from 4 directions) is avoided with a distance of at least five times of the thickness of the used plate. Butt fitting is done, which in the process must always consider the shape/angle of the seam, straightness, tenuous weld roots, and others. Tolerance of miss alignment is directed to the root gap and the angle of the seam. The permitted tolerance in welding is shown in Table 2.

Table 2. Welding tolerance. Thickness, t (mm)

Joint Category

Longitudinal weld

Circum weld, Weld connection Flange, Weld nozzle to the main shell

≤ 13

1/4 x t 3 mm 3 mm 3 mm

1/4 x t 1/4 x t 5 mm 1/8 x t

13

> 51

<1/6 x t or 10 mm

1/8 x t or 19 mm

3.4. Inspection and final the assembled design Inspection of the sulfur melter heating coil is a mandatory, which aims to make the parts that have been done by fabrication following the specified standards. The inspection process is carried out in several stages, namely dimensional inspections, penetrant test and full annealing. Dimensional inspection is an examination carried out to check all dimensions of the components. Dimensional checks must be performed on every piece of equipment that made by referring to approved work drawings, by following the adjusted dimensional tolerances as shown in Fig. 9a. Results of welding inspection and dimensional inspection can be seen in Tables 3 and 4, which dimensional check is concluded as acceptable.

(a) (b) Fig. 9. Inspection process: (a) Dimensional check; (b) Penetrant test.

Table 3. Welding inspection.

Table 4. Dimensional check (unit: mm).

Welding Inspection

Dimensional Check

Description

Design

Actual

Description

Design

Actual 152 2896 1443 1360 85-100

Deviation

Visual

Visual Check

Visual Check

A B C D E

150 2896 110 1440 1360

2 0 3 0

-25 ~ -10

Penetrant tests are performed to determine whether cracks occur in the sulfur melter heating coil components or the welding results. If there is a crack, then repair process will be conducted. This inspection is carried out by a certified welding inspector. The process of this inspection is conducted by penetrating the colored penetrant on all surfaces of the sulfur melter heating coil. The inspection process is described as follows with standard in Table 5 while