forming head

[Navid Navidi]

Hello All,
We are going to form a head for a presser vessel. Its diameter is about 3000mm.
And it is made of A516Grade70. Unfortunately, while forming we have cracks on
the material which cause rejection of the head.
How can we form a crack-free head? Do we have to do the forming in several
steps? Do we need heat treatment between forming steps?
Thank you,
Saied

[T. Rizal H.]

Sorry, I don't answer your question but please tell the thickness and
which portion crack happened, such as on weld, on knuckle or other.

Thanks

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Regards,

T. Rizal Hidayat

[agstes]

Dear Saied,

Can we get the data, material thickness, form of the head, knuckle radius,
crown radius, straight face and location of the crack?

Shinde

[israr]

Dear Mr.
Could you provide me the thickness which you are forming? What type of
the dish head. and what is the process?

If thckness is more calculate the fiber elongation and accordignly
intermediate heat treatment is required.

Regards
Israr Ahmed
Tata Projects Ltd.
India

[Prakash Hegde]

As such there should not be problem of crack during formimg for SA 516 gr 70 material

However

i)what is the thickness of D/E if it is up to 40mm no need of intermidiate normalising or stress relieving  but higher thk D/E require intermidiate SR

ii) Forming  should be carried step wise and require slowl increase the applied force force(point pressing)

 

regards

 

Hegde

 

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From: israr <ahmedi...@gmail.com>
To: Materials & Welding <material...@googlegroups.com>
Sent: Sat, 23 October, 2010 9:18:33 PM
Subject: [MW:7747] Re: forming head

[Gopalakrishnan G]

hi sir

I have welded dish of 25 mm thick using SMAW (E-7018-1) . Hair cracks are observed after forming along the weld toe.

production weld test coupon has been cleared with impact.

Material : SA 516 Gr 70

Thickness : 25 mm

Process : SMAW

Electrode : E-7018 - 1

Code : ASME Sec 8

Please guide the method for forming.

[Prakash Hegde]

Hi!

Did you check the hardness of Weld and HAZ before Forming? If it is high needs PWHT

ii) Did you flush the weld seam before forming ? It needs to be flush ground as extra reinforcement causing stress concentration during pressing

iii)Did you had any NDT like LPT,UT/RT before pressing

Regards

Hegde

On Saturday, 23 August 2014 9:11 PM, Gopalakrishnan G <gopa...@gmail.com> wrote:

hi sir

I have welded dish of 25 mm thick using SMAW (E-7018-1) . Hair cracks are observed after forming along the weld toe.

production weld test coupon has been cleared with impact.

Material : SA 516 Gr 70

Thickness : 25 mm

Process : SMAW

Electrode : E-7018 - 1

Code : ASME Sec 8

Please guide the method for forming.

On Sunday, October 24, 2010 5:39:56 PM UTC+5:30, Prakash Hegde wrote:

As such there should not be problem of crack during formimg for SA 516 gr 70 material

However

i)what is the thickness of D/E if it is up to 40mm no need of intermidiate normalising or stress relieving  but higher thk D/E require intermidiate SR

ii) Forming  should be carried step wise and require slowl increase the applied force force(point pressing)

 

regards

 

Hegde

 

[Gopalakrishnan G]

thank u for ur kind advice.the following are problems i have faced.
1) cracks are observed along the weldtoe not continuous
cracks. 2)weld reinforcement is not flushed.
3)intermidiate normalizing during forming and complete normalizing
done after forming. 4)what abt weld cycle?
5)radiography cleared before forming. 6)plz specify
forming procedure for 25mm thick with normalizing

>>________________________________

--
*G.Gopalakrishnan
Welding Engineer
Mukand Ltd
Mumbai
Moble :+91-9833397917*

[Prakash Hegde]

On Monday, 25 August 2014 8:46 PM, Gopalakrishnan G <gopa...@gmail.com> wrote:

thank u for ur kind advice.the following are problems i have faced.
          1) cracks are observed along the weldtoe not continuous

cracks.       (This is due to stress concentration and it should have flushed before Forming )       2)weld reinforcement is not flushed.(It require to flush, Dp test,RT before Forming)

3)intermidiate normalizing during forming and complete normalizing
done after forming.           

  4)what abt weld cycle? Welding consumables are to be selected properly If weld to be normalized (It deteoriates UTS) you have to use high strength consumables likeE 9018G or E7018A1  Use gradual increase in pressure during forming and no sudden pressure increase
5)radiography cleared before forming.           

   6)plz specify forming procedure for 25mm thick with normalizing

all the edges including circumference to be ground before forming as serration of edges causing stress concentration

Above precaution will definitely avoid cracking as such 25mm is not very thk and if properly pressed no need of intermediate normalizing reqd.

Regards

Hegde