Question

*) (5) What is referred to as a "self-locking” power screw and what is the condition for it! b) (4) What are the two main mechanisms for "thread loosening" in a threaded connection? c) (2) If fatigue is of concer, what manufacturing process should be adopted for the bolt (Heat Treat/Roll or Roll/Heat Treat)? d) (5) Preload control (correct preload and its maintenance) is critical in maintaining a threaded connection's integrity. List the five most important factors affecting the preload control and the common abbreviation given to them. c) (4) What are two methods for mitigating corrosion?

Answer 1

(5) Hlead screw is referred cused to as a "self-locking power screw It transmit turning motion linear motion. Condition fore" self locking power Screw when d (friction angle) is greater tan or equal to a chelix angie) under this condition, the load will not turn the scrow and will not descend on its own unless an effort pis applied - Screw is self locking if the coeffi_ cient of Friction is equal to oro grea- ter than tangent helix angie. -For Serrocking

co The main mechanism for thread 'loosenina in threaded conne nreaded connection - Spontaneous loosening. Slackering for Slight rotation can be enough boited Joint to lose all its preload Slackering is caused by Settlement, creep and relaxation. (2) Heat Treat / Roll this manufacturing process Shovid be adopted for boit i F Fatigue is concern. It improved the fatigue performance Of bolt.

- five important factors affecting the preload control. The preload in threaded connection is very important factor affecting the Joint performance and reliablility. the improper preload can affect such as - life span of the Joint - material failure fastener loosening - Joint seperation leakage - fattigue Failure Common Abbrivations As - Alloy steel CH → Case Hardened 2A(3A) -class of thread fit 2R (3B) - Class of thread fit 69 - Class of thread fit for inch nuts for metric - Saxon SiegewS GH ET_ of thread Fit For Metric mots External thread - ------

athodic protection. galvanization ③ Hot Dip 100+5 pol.com v ☺ bu +00) өнө% (о дәte Ssəта! D1S 0 0UA/UJ0) o o o Чns 1okəя +40}S! Soxu0! So Lo) 050 ° 0 The methods for mitigating corrosion (4) е)