5.3.3 Service
Conditions
The Purchaser shall specify any applicable special metallurgical requirements. When the service conditions might include the presence of hydrogen sulfide or other conditions that could promote hydrogen-induced cracking, notably near the bottom of the shell at the shell-to-bottom connections, care should be taken for materials and welding to resist hydrogen-induced cracking. The weld metal and adjacent heat-affected zone often contain a zone of hardness well in excess of Rockwell C 22(248HV) and can be expected to be more susceptible to cracking than unwelded metal is. Any hardness criteria should be a matter of agreement between the Purchaser and the Manufacturer and should be based on an evaluation of the expected hydrogen sulfide concentration in the product, the possibility of moisture being present on the inside metal surface, and the strength and hardness characteristics of the base metal and weld metal.
From: Perumal Govindan [mailto:perumalgovindan@gmail.com]
Sent: Tuesday, June 17, 2014 1:52 AM
To: pgoswami
Subject: Re: [MW:21144] Reasons for High Hardness on WM and HAZ
Dear Sir,
Thank you very much for your reply.
Further, the electrode was selected based on the requirements of API 650:2013 Edition, Clause 4.8.2
(API 650: 2013, Clause 4.8.2 ( on page 49 of 514): For the welding of materials with a minimum tensile strength of 550 MPa to 585 MPa (80 ksi to 85 ksi), the manual arc-welding electrodes shall conform to the E80XX-CX classification series in AWS A5.5.)
Please find the attached copy of API 650:2013 and MTCs of ASTM A537 Class 1, hence once again request your good self kindly review and provide your feed back as early as possible.
--
Thank You and Regards
P Govindan
Mobile: +919643152414
Direct : +911294291200
On Tue, Jun 17, 2014 at 8:38 AM, pgoswami <pgoswami@quickclic.net> wrote:
Hi Govindan,
Why did you choose E 8018-C3 electrode for SA 537 Cl1 plates. SA 537 Cl1 is almost back to back to SA 515 Gr70 Steel. Based on the impact requirement as indicated below, E-7018-1 would have been appropriate. I would say that E 8018-C3 would have been advisable if the welds would have undergone enhanced heat treatment e.g Normalizing.
The high hardness in the weld and HAZ is due to the use of overalloyed electrode .E-8018C3/Tenacito 70 contains typically 1.005 Nickel.Nickel causes to form acicular ferrite in the weld/HAZ , which in turn causes higher hardness.
Thanks
Pradip Goswami, P.Eng,IWE
Welding & Metallurgical Specialist
Ontario, Canada
Date: Mon, 16 Jun 2014 20:22:33 +0530
Subject: [MW:21143] Reasons for High Hardness on WM and HAZ
From: perumalgovindan@gmail.com
To: materials-welding@googlegroups.com
Dear Experts,
We have conducted PQR and measured the hardness values between 248 HV to 269 HV:
Material Specification and Parameters:
Material Specification: ASTM A537 Class 1,Plate 12.8 mm thickness, SMAW process, 4G position
Electrode Used: AWS / SFA: 5.5, E 8018-C3, Brand Name: TENALLOY-70/ADOR welding limited.
Electrode baking Temp.: 350 deg. C for 2 hours
Electrode Holding temp.: 150 deg. C
Preheat: Ambient temperature (surrounding temp. was 40 deg. Centigrade)
Interpass temp.: 150 deg. C to 185 deg.C
Travel Speed: 70 to 80 mm/min
Voltage: 20 to 24V
Current: 70 to 79A
Heat input: 1.45 KJ/mm to 2.27 KJ/mm
Lab test Results:
UTS: 571 MPa
Bend test; Accepted
Impact test at 0 deg. C:WM - Average 102J and HAZ: 234J
Hardness Value: 248HV to 269HV.
Request to provide the reasons for high hardness
--
Thank You and Regards
P Govindan
Mobile: +919643152414
Direct : +911294291200
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