Heat Treatment Requirement after Cold Bending 2

[Asadullahkhan]

Dear All,

We have performed Cold Bending on SA213 T11 (P4) Material for Superheater tubes.
Dia of Tube is 31.8mm and Thickness in 3mm

Now what does the code say about Heat Treatment. Either we should perform heat treatment or not. If yes then please specify reference and what will be Temperature and Soaking Time.

 

[metengr]

If you are using Section I, no post bend thermal treatment is required. If you are under B31.1/Section I, even B31.1 does not require post bend thermal treatment as long as the OD is less than 4" and the wall thickness is below 0.50".

 

[Asadullahkhan]

Thank you for your reply.

(c) Cold bending and forming of carbon steel having a wall thickness of three-fourths of an inch and heavier, and all ferritic-alloy pipe in nominal pipe sizes of 4 inches and larger, or one-half-inch wall thickness or heavier, will require a stress-relieving treatment.

(d) Cold bending of carbon-steel and ferritic-alloy steel pipe in sizes and wall thicknesses less than specified in 129.3.3 of ASME B31.1 (incorporated by reference; see 46 CFR 56.01-2) may be used without a postheat treatment.

THIS IS WHAT I FOUND ON INTERNET. I AM CONFUSED AS I THINK MY CASE COMES UNDER THE 2ND CRITERIA BECUASE THE MATERIAL I AM USING IN FERRITIC ALLOY STEEL.

 

[Asadullahkhan]

The specification of ASME B31.1 (129.3.3)
129.3.3 A postforming or postbending heat treat-
ment as defined below is required for all ferritic alloy
steel (excluding P-No. 1) materials with a nominal pipe
size 4 in. and larger or with a nominal thickness of 12 in.
(13.0 mm) or greater.
(A) If hot bending or forming is performed, the mate-
rial shall receive a full anneal, normalize and tempel~
or tempering heat treatment as specified by the designer.
(B) If cold bending or forming is performed, a heat
treatment is required at the time and temperature cycle
listed for the material in Table 132.

NOW HERE I AM AGAIN CONFUSED AS IT STATES IN POINT B THAT H.T IS REQUIRED WHEN DOING COLD BENDING OR FORMING AND IT FURTHER REFER TO TABLE 132

 

[metengr]

Based on the material, OD and wall thickness NO post bend thermal treatment is required.

You have 31.8 mm OD
3 mm wall thickness
Grade T11 material

 

[Asadullahkhan]

Alright. I have got your point.
Thank you.

 

[Asadullahkhan]

Can you please look in to the matter again. As our client is still asking for Heat Treatment.
He says "Stress Relieving is required due to short radius of bends. As per ASME Sec I (PG-19) H.T is required after cold forming if the %strain is more than 20 %"

The radius Coil's U-Bend is 42mm.

When I review PG-19, it states about "Austenitic Steel Materieals" not Alloy Steels.
My question is if the specification of my client really makes a sense?

Your advice is needed.

 

[metengr]

Asadullahkhan
First, in Section I, Table PG-19 applies to austenitic and nickel-base alloys and not low alloy steels. Second, your client is trying to make code rules apply to a situation where there are no code rules to require a post forming thermal treatment.

Just tell the client if they want a post forming thermal treatment it can be easily done, but they have to pay for it because it is not a code requirement based on material, OD and wall thickness.