Welding Grade 350 to 450

[tiggerfaebigger]

Hi Lads,
I have been dropped in the deep end and would like to ask a few questions if you do not mind. When welding grade Q345B (350) to TMCP 450 steel, does the welding consumable need to match the 350 or 450. I am thinking that it must be based on the lower strength steel as the mechanicals are only going to provide the minimum based on grade 350 and because of this, would a 350 grade weld procedure cover the welding?

My second question is the grade 450 has impact properties of -40 degrees. I take it we do not need to meet this also as it is welded to grade 350 and all we need to meet is the design service temperature which is in a WA coastal region which should not go below zero.

My third question, these steels are from abroad, china (we have procedures for) and Japan, so on the weld procedure can we still compare these to AU grades?
Thanks,

[Ballbearing]

TFB,
Sorry for the delayed response.
1  Yes, you will need to match or exceed the lower tensile material.
2  No, impact testing is only required if it is listed as a requirement in your fabrication code or project specifications.
3  You will need to qualify your procedures for the Chinese and Japanese materials,

Regards,
BB

[Author]

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