[MW:22958] difference between ER70 S-6 and ER70 S-3

Dear expert ;

we have  to weld an ammonia liquid line ( temperature of service -33 °c) with ER 70 S-3 for penetration and E 7018 for filling and cap .

Our client ask to weld with ER 70 S - 6 because of better impact test proprities.

THis is true ?? please give me more details

Regards

 

SALHI Raouf

QA/QC Engineer

Tel: Morocco +212628979891

      Tunisia +21621458258