625 Weld Overlay on SA516 Gr70 plate in 3G position

[Mohmmed Dudhiyawala]

Hi Everyone,

We have encountered as PQR for Inconel-625 WOL on SA516 Grade 70 Normalized plate in 3G position.

Two Anomalies were observed: 

1. After PWHT of 120 mins, Hardness in base metal dropped from average 164 HV to average 108 HV! Has anyone observed such a drop in hardness? Is it possible? 

2. 625 WOL is done using SMAW electrode from Special Metals, the Nickel content as per consumable TC is 65%. While in WOL chemistry, 1.5mm from Top, Nickel % came around 68%. 3% Higher!! Is this possible, in any case?

Thanks in advance from your expert views.

Regards,
Mohammed Dudhiyawala, IWE