A grade 30 cast iron pressure vessel has a sealed head diameter of 20 inches. It
ID: 1857218 • Letter: A
Question
A grade 30 cast iron pressure vessel has a sealed head diameter of 20 inches. It uses ten 1 1/4 UNF steel studs that are fully threaded and have an effective grip length of 6 inches.
The studs are made of grade 8 material. find the torque 9in-lb) necessary to tighten to 90 percent of the proof strength, assuming plated threads.
This is my answer but I think I have done something wrong....any idea?
1 1/4 UNF steel studs
threads/inch= 12
At= 1.073 inches squared
major=1.250 inches
Grade 8 Proof strength = 120ksi
90% of proof strength = .9 x 120 ksi = 108 ksi
F= 108 kips/inches squared x 1.073 inches squared
=115.884 kips
Since there are 10 bolts, force on each bolt 115.884 kips/10 =11.5884 kips
T= K x D x P
T = .16 x 1.250in x 11588.4 lb.
T= 2317.68 in lb.
Explanation / Answer
NO the solution is correct,there is no mistake in this solution..!!!
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