A709 grd hps 70 steel

Date 08-15-2011 12:33 Edited 08-15-2011 13:13

according to AWS table 3.2 for max preheat and interpass temp shall not exceed 450 f for mat over 1 1/2 inch .

say for instance a WF beam has a 3" thick flange that needs to be prepped for a full pen weld

if this were to be done with a oxy acetelyne torch would not the temp of the steel surpass the 450Deg .? By quite a substantial amount

Is this acceptable or does the bevel need to be machined. Thank s Joe

By Superflux (****)

Date 08-15-2011 14:11 Edited 08-15-2011 14:16

joe pirie,
5.6 says to maintain preheat and interpass temps for "not less than 3"/75mm in all directions from the point of welding".
Unless the specs specifically prohibit O/A cutting, I would accept what ever is the most efficient for Production.
The arguement could be made that the welding process is going to violate the maximum interpass temperature a certain distance from the toe of the weld as will be documented by oxidation colors.

I'll be up all night trying to rationalize this one to myself.

By joe pirie (***)

Date 08-15-2011 19:04

I just find it odd that AWS makes such a big deal about interpass temps but its ok
to use a cutting process that im guessing is around 2200 deg when that portion of the
steel is going to be welded so if its already been heated that hot what difference is
the
interpass temp going to make

By DaveBoyer (*****)

Date 08-16-2011 02:29

As I sometimes do, I will add My 2 cents without knowing all I should. The area of the parent metal that excedes the allowed temperature does not extend real far from the cut, and does not stay at that temperature long. Some of this material will be ground off, some more will be melted in with the rod and alloyed to give more ductility and better grain structure.

As mentioned, close to the edge of the puddle [in the HAZ] the part will excede maximum interpass temperature as well, but that is not where You are instructed to measure it.

Time at elevated temperature is what You are keeping under control by following the max interpass restrictions.

By joe pirie (***)

Date 08-16-2011 10:08

Please add in your two cents, just for the hell of it i used a 1100 d
temp stick highest i had and checked the area 3" away from the front edge
of the bevel . it was hotter than 1100 but we are beveling 3" thick steel
i'll check again when we cut some 1 1/2 thick. sometimes ones mind starts
to think in directions it shouldn't go this just got me real curious lol