Welding to N80 Casing
Welding to N80 Casing
(OP)
Looking to use N80 casing pipe ~8"x1/2" thick in a structural application. From published specs, Fy ranges from min 80 to 110ksi, Fu is minimum 100ksi.
Casing would be used as soldier piling for earth retention and will be installed by drilling using flush-threaded connections. This application is very restricted in terms of headroom and access otherwise I would do something different.
I'd need to weld studs and plates to connect wood lagging and ground anchors.
Normally, these connections are not that demanding when attaching to A572-50 rolled sections - typically 3/16 fillet SMAW (all-around on the 5/8" UNC allthread studs). Studs are typically spaced 9" vertically apart. In this application, I'd likely need to have pairs installed on one side of the pipe at a few inches spacing horizontally. Plates would get a 3/16 fillet weld on each side for about 9in/side.
I have some telling me that this welding could embrittle or even crack the casing, and others saying they've never had brittle issues with this kind of casing.
I will be cross-posting in the petroleum fora. All answers appreciated.
JTD
Casing would be used as soldier piling for earth retention and will be installed by drilling using flush-threaded connections. This application is very restricted in terms of headroom and access otherwise I would do something different.
I'd need to weld studs and plates to connect wood lagging and ground anchors.
Normally, these connections are not that demanding when attaching to A572-50 rolled sections - typically 3/16 fillet SMAW (all-around on the 5/8" UNC allthread studs). Studs are typically spaced 9" vertically apart. In this application, I'd likely need to have pairs installed on one side of the pipe at a few inches spacing horizontally. Plates would get a 3/16 fillet weld on each side for about 9in/side.
I have some telling me that this welding could embrittle or even crack the casing, and others saying they've never had brittle issues with this kind of casing.
I will be cross-posting in the petroleum fora. All answers appreciated.
JTD
RE: Welding to N80 Casing
RE: Welding to N80 Casing
Some of it can be rather high hardenability so watch out.
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P.E. Metallurgy, Plymouth Tube
RE: Welding to N80 Casing
@weldstan, @EdStainless: I will speak to my people about preheat.
I have seen suggestions elsewhere to use cellulosic E80 electrodes for the initial pass. Can you comment on this?
Please let me know if you think that there are other things we should consider to use SMAW process.
RE: Welding to N80 Casing
RE: Welding to N80 Casing
In this situation all that is required is for the weld strength to match that of the lower strength base metal. 70 ksi class fillers are often more than adequate.
"Everyone is entitled to their own opinions, but they are not entitled to their own facts."
RE: Welding to N80 Casing
Based on carbon equivalent, I estimate that a preheat of 300F is warranted. Thanks to all who replied.
RE: Welding to N80 Casing
RE: Welding to N80 Casing
"Everyone is entitled to their own opinions, but they are not entitled to their own facts."
RE: Welding to N80 Casing
RE: Welding to N80 Casing
RE: Welding to N80 Casing