Step Tube Solder Joint Calculation Formulas

Allowable stress

Joint shear stress

Minimum step depth

Strength check

σ σ A

Design of optimum step depth

Anticipates that a joint is designed so that any breakage occurs in the joint itself, and not in the basic material.

L opt = max {L min , L 1 }

where:

and the joint factor f:

 

for h 1 < h 2 :

 
 

for h 1 > h 2 :

 

Meaning of used variables for metric units:

S US

Joint strength in shear [MPa]

k S

Shear safety factor

S Ub

Tensile strength of basic material [MPa]

d

Diameter of inner tube or step diameter [mm]

L

Step depth [mm]

h 1

Tube thickness of inner tube [mm]

h 2

Tube thickness of outer tube [mm]

Meaning of used variables for English units:

S US

Joint strength in shear [psi]

k S

Shear safety factor

S Ub

Tensile strength of basic material [psi]

d

Diameter of inner tube or step diameter [in]

L

Step depth [in]

h 1

Tube thickness of inner tube [in]

h 2

Tube thickness of outer tube [in]

Guiding values for solder joint strength

Soft solder alloys

Brazing filler metals