Re: [MW:27814] AWS D 1.1 interpretation on Increase in Preheat / Interpass temperature

hello,

The subject under discussion is Max. preheat..It is 173 °c 

( Preheat/Interpass Temperature

7) An increase of more than 100°F [56°C] in the maximum preheat or interpass temperature qualified ) 

Max. preheat = Interpass temperature...

So anything between 30°c to 173°c is ok.

On Tue 8 May, 2018, 7:27 PM 'james gerald' via Materials & Welding, <materials-welding@googlegroups.com> wrote:

Moreover though maximum Interpass temperature controls the Austenitic Grain size and thus the Charpy values and Preheat controls the Temperature between 800-500 degC , but under ideal conditions using ASME Materials.

But below also have a effect

Chemical comp, method of maufacture, product form, Hardness, strength, Heat Treatment, microstructure, uniformity, homogenity, Grain size etc.. which are mostly controlled in the ASME Materials since its low temperature properties are controlled whereas material used in AWS D 1.1 have a effect.

Thanks & Regards

J.Gerald Jayakumar

0091-9344954677

On Tuesday, May 8, 2018, 1:10:17 PM GMT+4, Kannayeram Gnanapandithan <kgpandithan@gmail.com> wrote:

In ASME, % carbon is restricted to max 0.35%, where as in AWS it is more and properties will be deteriorated if use higher Pre Heat than qualified. That is why it is restricted.

THANKS & BEST REGARDS,

KG.PANDITHAN, BE, IWE,  AWS-CWI, CSWIP 3.1,

CONSULTANT-WELDING & QUALITY

Mobile no: +919940739349

On Tue, May 8, 2018 at 1:03 PM, George Dilintas <dilintas@gmail.com> wrote:

in ASME IX also the increase is only for the interpass temperature and the decrease for the preheat.

The increase of interpass is a supplementary essential variable

the decrease of preheat is an essential one

2018-05-02 6:54 GMT+03:00 N VENKATESWARA PRASAD <weldengr.velosi@gmail.com>:

Dear Experts,

We have received a comment on Increase in Preheat temperature greater than 56°C is essential variable as per AWS D.1 from our client.

My interpretation is the increase in 56°C is applicable only for inter pass temperature.  The details are as given below. 

 

PQR   Test coupon thickness        :  30 mm

PQR   Preheat temperature          :  30°C

PQR Inter pass temperature        :  173°C

 

Job Thickness                                   : > 38 mm  to 65 mm  ( As per Table 3.3)

Preheat temperature                    :  110°C

Inter pass temperature                 :  220°C

MDMT                                                :  -40 °C

 

As per AWS D 1.1  Table 4.6  Point no. 7   an increase more than 56°C in max preheat or interpass temperature is essential variable  for CVN testing applications.

 

Based on the above clause, the client is insisting that the Qualified Range for  thickness in WPS shall be restricted to 38 mm as the preheat is increased from 30°C to 110°C which is not acceptable .

 

Please provide me if you any interpretation on it from AWS.

Regards

Prasad

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