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Calculation formula for flattening, bending and hydraulic test of low-medium pressure boiler tube
- Jul 19, 2018 -

(1) Flattening test

External diameter d>22 mm, wall thickness s≤10 mm steel tube, should be flattened test, plate spacing H value According to the calculation h= (1+α) s/(α+s/d) type S ——— steel pipe wall thickness, mm, D ——— pipe diameter, mm;α ——— unit length 

The coefficient of deformation is 0.08 when the s/d≥0.125 is 0.07. 

(2) Bending test

For d≤22mm steel pipe with external diameter should be carried out. The bending angle is 90°, and the bending radius is 6 times times the diameter of the steel pipe. 

Cracks and slits shall not occur at the bend. 

(3) Hydraulic test should be carried out all tube. The test pressure P (MPa)should be in accordance with the calculation, but the maximum pressure of 10 steel 7 mpa;20 steel maximum pressure of MPa, the regulator time of not less than 5 s. 

P=2SR/D type S ——— steel pipe nominal wall thickness, mm, D ——— pipe diameter, mm, R ——— allowable stress, specify the yield point of the 60%,mpa. The supplier can replace the hydraulic test with Eddy current testing.