Can A320 L7 grade bolts be used for Slip Critical connections?
The grade of bolt used in a Slip Critical (SC) connection has no direct bearing on the connection itself, so the answer is yes. The SC connection means that it is a type of bolted structural steel connection which relies on friction between the two connected elements rather than bolt shear or bolt bearing to join two structural elements. Or to put it another way, both surfaces must be absolutely free of any impediments between the two surfaces. The most common methods to prepare the surfaces are with a wire brush, abrasive blasting or a zinc-silicate paint. Typically you would see the call out for Slip Critical connections on either an A325 or A490 structural bolt. The call out for a SC on an A320 L7 bolt is rather rare, but again has nothing to do with the actual bolt grade.