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Reg. 591 c, Reg. 591 d, Reg. 591 e

Link stays

 

Link stays shall be so arranged that the angle “V”  (Fig. XII/83) is not less than 60° and the dimensions shall be such that the stress in the stay at its weakest part does not exceed one-seventh of the minimum tensile stress of the plate used.



Reg. 591 d

Anchor plates angles, link pins and the like members

The strength of anchor plates, angles and link pins calculated at the weakest section shall be as follows:-

(i)

Link pins shall be so designed that the shear stress does not exceed 8,000 pounds per square inch, the strength of pins in double shear being taken as 1.875 times the strength of pins in single shear.

(ii)

Anchor plates or angles shall be so designed that the calculated stress does not exceed one-seventh of the minimum tensile stress of the material used, but in no case shall the thickness be less than seven-eighth of the thickness of the shell plate with a minimum of ½ inch, nor the length of the portion attached to the end plate be less than the distance between the lines of end to shell flat margin and the breathing space line around the flues or tube nests.


Reg. 591 e

Weld attachment

Where gusset plates, anchor plates or angles are welded to the shell and/or end plates, the attachment shall be by means of continuous fillet welds on each side or by butt welds prepared in accordance with paragraph 2, details 1, m, n, or p of Appendix A of this Chapter.

The welds shall be of such dimensions that the stress calculated on an area equal to the effective length of the weld multiplied by the effective throat thickness shall not exceed that permitted for the parent metal multiplied by the appropriate weld factor in Table XII/7

The effective length of a weld shall be taken as that length of weld which is of the specified size throughout.

For open-ended fillet welds the effective length shall be the overall length less twice the weld size.

For the purpose of stress calculation the effective throat thickness of a butt weld shall be taken as the thickness of the gusset or anchor plate and the effective throat thickness of fillet weld shall be taken as 0.7 of the fillet size. For compound welds the effective throat thickness shall be the sum of those of the constituent parts.

TABLE XII/7
Weld Attachments

Form of weld

Weld factor

  Not stress relieved Stress relieved
Single J or bevel butt-welds (with or without superimposed fillet. Unsealed
Sealed
0.35
0.60
0.45
0.70
Double J or bevel butt-welds [with or without super-imposed fillet(s)]   0.60 0.70
Double fillet welds   0.55 0.65
 
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