There is a crack(Not through crack) in the elbow to reducer weld joint of a 24" cold flare line (Hydrocarbon line).

Material details of reducer & elbow are --

24",SA 403 WP 304L, SCH-10S , Weld & HAZ are impact tested.

Crack details:

Length of the crack – 175 mm
Depth of the crack – 2.56 mm from OD surface ( not through crack)
Location of the crack – Weld toe


Design Conditions:

Max. Design Temperature : 130 Deg. C

Min. Design Temperature : -180 Deg. C

Pressure : 4.9 Bar

Operating conditions:

Max. Design (operating) Temperature : 65 Deg. C

Min. Design (operating) Temperture : -121 Deg. C

History :

The probable cause of the crack is due to the sudden two phase flow conditions experienced by this 24” cold flare line & this event was not considered during the pipe design conditions.

At present condition, this line cannot be isolated & the management has decided to go for online welding.

Fitness for service was conducted & as a temporary measure (Till shutdown) it was recommended to reinforce the damaged elbow by means of a fabricated sleeve.

Based on that the sleeve (SS 304L-Mechanical properties unknown) was fabricated & longitudinal welding of the sleeve with back strip was done.

Now we have to do circumferential fillet weld(Online) of the sleeve with the process pipe.

But the question is

1. Is the sleeve material required to be impact tested?

2. We are having repair welding contractors WPS without impact test. Can we proceed welding the circumferential joint using this WPS?


Regards,

_________________
Kareem

Hi Kareem. It seems you didn't mention which constructing code, although I assume B31.3?

Secondly, what are the requirements of your Project Specifications?

If your constructing code is B31.3 and it Normal Fluid Service or Cat. D (which again, making an assumption on operating pressure, also not mentioned in your enquiry), then the following is stated in Code:

(f) Impact testing is not required for the following
combinations of weld metals and design minimum
temperatures:
(1) for austenitic stainless steel base materials having
a carbon content not exceeding 0.10%, welded without
filler metal, at design minimum temperatures of
−101°C (−150°F) and higher
(2) for austenitic weld metal
(a) having a carbon content not exceeding 0.10%,
and produced with filler metals conforming to AWS
A5.4, A5.9, A5.11, A5.14, or A5.221 at design minimum
temperatures of −101°C (−150°F) and higher, or
(b) having a carbon content exceeding 0.10%, and
produced with filler metals conforming to AWS A5.4,
A5.9, A5.11, A5.14, or A5.221 at design minimum temperatures
of −48°C (−55°F) and higher