Need any one have an experience in dish end machining ?

[AhmedDeiaa]

i have a circular sheet diameter = 3700 mm ,consist of three segments as illustrated in the attachments
off course , i have two welding joints

1-can any one tell me is it okay to make a three welded segments dish end as illustrated in the attachments ? what are
the recommended dimensions for welding joint ? what is the proposed width for three segments ?


2- For crowning the dish end , i have two options in crowning process:-

i- use the maximum pressure of the hydraulic press to minimize the time
of crowning and make it in a few rounds from internal to external .


ii - use the minimum pressure of the hydraulic press in the first round and gradually increase
the pressure and no. of rounds , it takes too long time but i think the hardness will slightly increase
due to strain hardening unlike the first option where the hardness will be bigger .


just For example(may be i am wrong) :- if the raw material (circular sheet) hardness is HV = 140
then , if i follow the first option............the hardness will become 150 : 155
but , if i follow the second option.............the hardness will become 170 : 180

 

[JStephen]

First off, see the responses to your previous thread:

http://www.eng-tips.com/viewthread.cfm?qid=424093

 

[Don56]

1a)Yes
1b&c) However you wish, no Code no care. ASME Section VIII does not address this.

2) The preferred method would be to start dishing in the center. Do not use maximum power to start or you may incur bumps which are hard to remove.

Most materials work harden to some degree, some more than others.