Sunday, August 29, 2010

Re: [MW:6763] Re: What is SR(PWHT) thickness requirements by AWS D1.1

Not like  construction codes like asme sec1, 8 ect on Thickness restriction for PWHT, in AWS there is no set rules on thickness, but it is ur requirement like in  ASME sec IX( applicable or not)
kgp

On Sun, Aug 29, 2010 at 12:27 PM, Srinivas Engr <srinivas.gmsrini@gmail.com> wrote:
Dear Karthik,

section 5.8 is ok.
What i am asking is for a 30 mm CS plate is my job,?
where i to refer this thickness of CS plate either has to be done for
SR  or not in AWS D1.1?
In asme b31.3 there is one chart is for Piping tat for cs >20mm we
have to do PWHT?
Like tat any chart is available in AWS D1.1 or not?
Either how can we refer for thickness? by AWS D1.1
Pl clear me...........


Thanks



On Aug 28, 2:47 pm, Karthik <karthik6...@yahoo.com> wrote:
> Hi Srinivas,
> Pls.refer to AWS D1.1-Section 5.8 for SR.Also Pls.find below the extraction of that.
>  
> 5.8 Stress-Relief Heat Treatment
> Where required by the contract documents, welded assemblies
> shall be stress relieved by heat treating. Final
> machining after stress relieving shall be considered when
> needed to maintain dimensional tolerances.
> 5.8.1 Requirements. The stress-relief treatment shall
> conform to the following requirements:
> (1) The temperature of the furnace shall not exceed
> 600°F [315°C] at the time the welded assembly is placed
> in it.
> (2) Above 600°F, the rate of heating shall not be more
> than 400°F per hour divided by the maximum metal thickness
> of the thicker part, in inches, but in no case more than
> 400°F per hour. Above 315°C, the rate of heating in °C/hr
> shall not exceed 5600 divided by the maximum metal
> thickness, in millimeters, but not more than 220°C/hr.
> During the heating period, variations in temperature
> throughout the portion of the part being heated shall be no
> greater than 250°F [140°C] within any 15 ft [5 m] interval
> of length. The rates of heating and cooling need not be
> less than 100°F [55°C] per hour. However, in all cases,
> consideration of closed chambers and complex structures
> may indicate reduced rates of heating and cooling to avoid
> structural damage due to excessive thermal gradients.
> (3) After a maximum temperature of 1100°F [600°C]
> is reached on quenched and tempered steels, or a mean
> temperature range between 1100°F and 1200°F [600°C
> and 650°C] is reached on other steels, the temperature of
> the assembly shall be held within the specified limits for
> a time not less than specified in Table 5.2, based on weld
> thickness. When the specified stress relief is for dimensional
> stability, the holding time shall be not less than
> specified in Table 5.2, based on the thickness of the
> thicker part. During the holding period there shall be no
> difference greater than 150°F [85°C] between the highest
> and lowest temperature throughout the portion of the
> assembly being heated.
> (4) Above 600°F [315°C], cooling shall be done in a
> closed furnace or cooling chamber at a rate no greater
> than 500°F [260°C] per hour divided by the maximum
> metal thickness of the thicker part in inches, but in no
> case more than 500°F [260°C] per hour. From 600°F
> [315°C], the assembly may be cooled in still air.
> 5.8.2 Alternative PWHT. Alternatively, when it is impractical
> to PWHT to the temperature limitations stated
> in 5.8.1, welded assemblies may be stress-relieved at
> lower temperatures for longer periods of time, as given in
> Table 5.3.
> 5.8.3 Steels Not Recommended for PWHT. Stress relieving
> of weldments of ASTM A 514, ASTM A 517,
> ASTM A 709 Grades 100 (690) and 100W (690W), and
> ASTM A 710 steels is not generally recommended.
> Stress relieving may be necessary for those applications
> where weldments shall be required to retain dimensional
> stability during machining or where stress corrosion may
> be involved, neither condition being unique to weldments
> involving ASTM A 514, ASTM A 517, ASTM A 709
> Grades 100 (690) and 100W (690W), and ASTM A 710
> steels. However, the results of notch toughness tests have
> shown that PWHT may actually impair weld metal and
> HAZ toughness, and intergranular cracking may sometimes
> occur in the grain-coarsened region of the weld
> HAZ.
>  
> Thanks & Regards,
>  
> (Karthik)
>
> Karthikeyan.S
> QA/QC Manager
> Getabec Energy Co.,Ltd.
> 379,Moo6,Soi8,Nikhomphatana,
> Rayong-21180,
> Thailand.
> Phone: 0066 38 897035-8 (Off)
> Fax: 0066 38 897034
> Hand Phone: 0066 892512282
>
> --- On Sat, 8/28/10, Srinivas Engr <srinivas.gmsr...@gmail.com> wrote:
>
> From: Srinivas Engr <srinivas.gmsr...@gmail.com>
> Subject: [MW:6753] What is SR(PWHT) thickness requirements by AWS D1.1
> To: "Materials & Welding" <materials-welding@googlegroups.com>
> Date: Saturday, August 28, 2010, 11:46 AM
>
> Dear all,
>
> what r thickness to be done for SR(PWHT) for CS according to AWS D1.1
> structural steel code?
> Where to refer in AWS D1.1? for thickness requirements for PWHT?
>
> Thanks
> Srinivas
>
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The views expressed/exchnaged in this group are members personel views and meant for educational purposes only, Users must take their own decisions w.r.t. applicable code/standard/contract documents.

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