Cone to Weld Neck Flange Junction in ASME Sec VIII Div-1 1

[cak4Engg]

Hi Guys,

The Question here is whether code restricts welding of a flange directly to a Conical section without knuckle?

Based on my understanding the following are the clauses applicable as per ASME Sec VIII Div-1,

Figure UG-28.1(Notes)- Lays the requirement of the junctures under the external pressure if it is the lines of support(LOS)(Note-3) and if not(Note-1).
UG-32(f)-Cone thickness calculation under internal pressure.
UG-33(f)-Cone thickness under external pressure.

​

-Junction does not act as a LOS As per Fig UG-28(Note-1) the required thickness of the cone shall not be less than that of the adjacent cylindrical shell (in this case-weld neck).

​

-Junction does act as LOS UG-33(f)(1)shall be followed for thickness calculation.
Appendix 1-5(d)(2) and (e)(2)- Lays The requirement of reinforcement in Cone to flange joints when under internal pressure.
Appendix 1-8(b)(2) and (c)(2)- Lays The requirement of reinforcement in Cone to flange joints when under External pressure.
Appendix 1-8(b)(3) and (c)(3)- If junction acts as a LOS under external pressure then the junction must meet the stiffness requirements of Appendix 1-8.

Please give thoughts on the same, a software vendor says that the welding a cone directly is not acceptable as per code, he was not able to give any code reference.
Based on my understanding it is totally possible as per above-given clauses.

If any of my above inerpetataion is wrong or any more clauses are applicable also please do let me know.

Cak

 

[SnTMan]

cak4Engg, per my reading of the Code, it is permitted to attach a weld neck flange directly to a cone without a knuckle, provided the rules of 1-5(d)(2) & (e)(2) and 1-8(b)(2) & (3) and (c)(2) & (c)(3), as applicable, are met.

I am not certain, but I think these Appendices were changed to allow this practice, fairly recently, in Code terms.

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[Jano6924]

Mike is correct, take a look into following interpretation, question 2:

Interpretation: VIII-1-83-131
Subject: Section VIII, Division 1; 1-5 and 1-8
Date Issued: June 20, 1983
File: BC82-209
Question (1): If reinforcement is required at the cylinder-to-cone junction and a compression ring is not used, is it the intent of 1-5 and 1-8 of Section VIII, Division 1 that reinforcement may be provided by thickening the shell only, or can both the cylinder and cone thickness be increased?
Reply (1): Either the cylinder, the cone, or both thicknesses may be increased.
Question (2): Is it permissible to weld a weld neck flange directly to the cone at either end without a transition shell?
Reply (2): Yes.

Hope this helps.

 

[cak4Engg]

@Jano6924 SnTMan

Gentleman,

Thanks so much for your response... all of us are on the same page.