These are reformer tubes to header under B 31.3.
As per design wall temperature are forecasted 200 to 220 degree
centigrade. Considering that the elastic range of of P-11 material in
ASME 31.3 is defined upto 482 degree centigrade & creep range goes
upto 649 degree centigrade. The operating temp can not taken as high.
In our application hydrogen partial pressure is 14 bar.
ASME 31.3 allows to weld 7.5 mm thickness without PWHT.
If we increase preheat temperature we will get any benefit.
Guide me how can i control hardness in these case.
Regards
Pradip
On 4/14/12, james gerald <gerry_tup@yahoo.com> wrote:
> 225BHN hardness specified is for Weldment which includes weld metal, HAZ &
> BM. PWHT is one of the method of reducing hardness.
>
> Other methods are Controlled cooling t8/5 which can be achieved by
> increasing the preheat. Preheat can be increased
> just below Mf temperature and try the Hardness values.
>
> You could try with a temper bead welding technique. There are different
> methods of temper bead welding technique and you can select the suitable one
> for your case eg a half bead technioque.
>
> Thanks & Regards
>
>
> J.Gerald Jayakumar
> 0091-9344954677
>
>
> ________________________________
> From: Ramchandra vichare <vicharerke@indiatimes.com>
> To: materials-welding@googlegroups.com
> Cc: pgoswami <pgoswami@quickclic.net>
> Sent: Friday, April 13, 2012 2:43 PM
> Subject: [SUSPECTED SPAM] Re: [MW:14106] Hardness value without PWHT
>
>
> ----- Original Message -----
>
>
> Dear friend,
> First of all pl confirm which welding procedure you used (i.e.GTAW+SMAW),or
> any one?
>
> See if you use welding technique GTAW by ER80SB2 + SMAW by E8018B2 hardness
> value will may be in controll.
> Pl try & revert.
>
> Regards,
> RK Vichare
>
>
> From: pradip kumar sil <pradipsil@gmail.com>
> To: materials-welding@googlegroups.com
> Cc: pgoswami <pgoswami@quickclic.net>
> Sent: Thu, 12 Apr 2012 10:50:16 +0530 (IST)
> Subject: [MW:14104] Hardness value without PWHT
>
> Dear experts,
> I have faced regarding hardness issue on ASTM A 335 GR P-11 material.
> Pipe thickness is 7.5mm. Without PWHT hardness is coming around 275
> to 289 BHN on weld zone & 250 260 BHN on HAZ zone & parent material
> hardness is 197 to 204 BHN. Due to inside refractory material PWHT is
> not possible.
> My question is as per ASME B-31.3/ ASME SEC II PART A hardness value
> of this material is 225 BHN ( MAX). There is any specification for
> weld zone / HAZ zone hardness value.
> Can anybody give an idea to reduce the hardness without PWHT if it is
> not acceptable limit.
> Thanx in advance.
>
> Regards
> Pradip
>
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