I attached some information on Code required impact values for E-7018 C1L and E-7018C3L electrodes for your reference.
E-7018 C1L is typically 2.5% Ni electrodes designed for impact down up to minus 750C hence passing impact should not be a problem, while the other electrode E-7018C3L ( Ni-0.8-1.1%) is designed for impact up to minus 500C. Some batches of this electrode could be excellent some may produce erratic results.
There could be problems in passing impact tests on ASME Sec-IX PQR and one has to be carful about:-
- All weld impact values as per Sec-II Part-C, electrode manufacturer may impact test in 1G position ( Refer SFA-5.5 Fig-2 ).Same electrode may not produce satisfactory results, when tested in 3G-Upwards position. If there is a specific requirement fabricator may ask electrodes to be impact tested in 3G-Upwards position.
- Electrode manipulation in 3G-up position. Usually for consistent impact test results, 3/32”, 1/8” and 5/32” are reliable. Handling 3/16” electrode in any positional welding would require welder’s training.
- Control heat input, typically 2.5 KJ/mm max to start with. Depending on the results you may allow higher heat inputs, however advisable would not to exceed 3.0-3.2Kj/mm.
- Impact results in HAZ and base metal:- SA- 537Cl-1 is a C-Mn steel .The major alloying element for notch toughness is Mn. It has some Ni ,0.25% max. Hence for consistent impact results one has to be very careful. The values mentioned below for SA-537 Cl1 (extract from SA-20) are for base metal. Generally impact values would be lower after welding and PWHT.
My opinion would be to talk with Advani, may be keeping the above points in mind and stick to a specific batch/es of E-7018 C1L electrodes. In absence of the same pursue welding with E-7018C3L with a strict control.
Pradip Goswami, P.Eng
88,Garth Trails Crescent
Impact Test Requirements:-
From: email@example.com [mailto:firstname.lastname@example.org] On Behalf Of amarjit Singh
Sent: Tuesday, January 12, 2010 11:49 AM
Subject: [Norton AntiSpam] [MW:4032] Impact
I am facing the problem of impact test at -60 deg C in welding.
The material is SA 537 Cl 1 and welding consumable used is E7018 C1L ( Advani make). as C1L contain Ni its weld should pass impact but the same is not. where as impact is OK with E-7018 C3L electrodes.
can any body suggest ????