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# Min and Max Bend Radius4

## Min and Max Bend Radius

(OP)
Hi , All

What s the min and max radius of cold bending for Size 6" Sch40

### RE: Min and Max Bend Radius

That's neat, MJ. Can you give me a bit of a hint how you develope that method/animation? ...and why would you have a max radius? a fabrication issue? Do different schedules have different radii?

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

### RE: Min and Max Bend Radius

(OP)
in Asme code B31.8 mentioned min radius is 18D Not 1D TO 10D also max angle depend on design pressure

### RE: Min and Max Bend Radius

"in Asme code B31.8 mentioned min radius is 18D Not 1D TO 10D also max angle depend on design pressure"

Aaahhh ..... and we take another tiny step forward in this third world guessing game !!!

Now, Najeeb, can you try to state your entire question, in english, so that we may have some hope of answering it ?

Most of the engineering seniors have dropped out of eng-tips because they grow sick and tired of trying to tease details out of hostile newbies who either cannot use the language, or feels.... somhow .... a compete explanation is "kowtowing" to the man.

I am on the edge ....

Now, restate your entire question with all appicable details necesary to formulate an accurate and complete answer ..... You can do it !!!

MJCronin
Sr. Process Engineer

### RE: Min and Max Bend Radius

Dik....couldn't resist :)

#### Quote:

Can you give me a bit of a hint how you develope that method/animation?

### RE: Min and Max Bend Radius

ASME B31.3, Section 304.2.1 has the minimum bend radius. Max bend radius is easy, 179.999999° because at 180° there is no bend.

### RE: Min and Max Bend Radius

(OP)
I=(4(R1/D)−1)/( 4(R1/D)−2) ~1D ?

### RE: Min and Max Bend Radius

that is the intrados (inside bend radius), you will have to rearrange t = (P*D)/(2*((S*E*W)/I)+P*Y)where 't' is the pipe wall thickness minus undertolerance & corrosion & thinout of the pipe from bending

Where:
R1 = bend radius at center of pipe
D = OD of pipe
nt = nominal pipe thickness - undertolerance - corrosion - mechanical allowances.

Thinning Due To Bending:
Ro [in] = R1+(D/2) ~ outside radius
Pt [%] = (Ro-R1)/Ro ~ thin out
tmin = nt*(1-Pt) ~ minimum outside radius thickness

Required Thickness: 304.2
tinside [in] = (P*D)/(2*((S*E*W)/Intra) + P*Y) ~ 304.2.1(3c)
Checktinside = nt>=tinside
toutside [in] = (P*D)/(2*((S*E*W)/Extra) + P*Y) ~ 304.2.1(3c)
Checktmin = tmin>=toutside
tcenter [in] = (P*D)/(2*((S*E*W)/1) + P*Y) ~ 304.2.1(3c)
Checkt = t>=tcenter

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