Re: [MW:17346] Difference Between SA 266 Gr.2 and SA 266 Gr.4

ASTM A266/A266M-11 specification for carbon steel forging fir pressure vessels components gives SA 266 in 4 grades and doest not specify the difference 

How ever I agree with comments about the ceq and fir that reason SA 266 gr2 is preferred in most cases

Sent from my iPhone 

Regards B. Alavi

On 11 Apr 2013, at 03:00, Purav Desai <puravdesai1@gmail.com> wrote:

Hi Ramdas,

 

The only difference in SA 266 Gr. 2 & SA 266 Gr. 4 is, content of Manganese is approximately double (0.8~1.35) in SA 266 Gr. 4 than SA 266 Gr. 2 (0.4~1.05). These materials are widely used for body flanges, tubesheets, backing devices of heat exchangers and vessels.

 

Hence the element that makes difference is manganese. Manganese has various advantages as below;

 

It increases tensile strength, toughness and hardenability. Manganese also tends to increase the rate of carbon penetration during carburizing and acts as a mild deoxidizing agent. Manganese is capable to form Manganese Sulphide (MnS) with sulphur, which is beneficial to machining. At the same time, it counters the brittleness from sulphur and is beneficial to the surface finish of carbon steel.

 

The disadvantage is when you use SA 266 Gr. 4, carbon equivalent will be above 0.42 which is not allowed as per most specifications and specially for HIC or Wet H2S/sour service most client prefers to maintain Ceq. below 0.40.

 

Apart from above, from the design point of view it does not make any difference because ASME has considered same allowable stress values for both the grades.

 

Hence as per me it is always good to consider SA 266 Gr. 2.

 

Please correct me if i miss some points.

 

 

Regards;

 

Purav Desai.

On Wed, Apr 10, 2013 at 3:54 PM, <ramdas.swati@gmail.com> wrote:

Hi,

Can anyone explain me what is difference between SA 266 Gr.2 and SA 266 Gr.4

When we use SA 266 Gr. 2 and when we use SA 266 Gr.4

--
To post to this group, send email to materials-welding@googlegroups.com
To unsubscribe from this group, send email to materials-welding+unsubscribe@googlegroups.com
For more options, visit this group's bolg at http://materials-welding.blogspot.com/
http://www.linkedin.com/groups/MaterialsWelding-122787?home=&gid=122787&trk=anet_ug_hm
 
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.
---
You received this message because you are subscribed to the Google Groups "Materials & Welding" group.
To unsubscribe from this group and stop receiving emails from it, send an email to materials-welding+unsubscribe@googlegroups.com.
For more options, visit https://groups.google.com/groups/opt_out.
 
 

--
Regards;

Purav DESAI

puravdesai1@gmail.com

--
To post to this group, send email to materials-welding@googlegroups.com
To unsubscribe from this group, send email to materials-welding+unsubscribe@googlegroups.com
For more options, visit this group's bolg at http://materials-welding.blogspot.com/
http://www.linkedin.com/groups/MaterialsWelding-122787?home=&gid=122787&trk=anet_ug_hm
 
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.
---
You received this message because you are subscribed to the Google Groups "Materials & Welding" group.
To unsubscribe from this group and stop receiving emails from it, send an email to materials-welding+unsubscribe@googlegroups.com.
For more options, visit https://groups.google.com/groups/opt_out.