Abstract
A guideline for bolted flange joint assembly has been published as an HPIS technical report, in which bolts are tightened in the clockwise-pattern sequence and the tightening torque is 100% of the target torque in all steps except for an install step. This paper describes analytical and experimental backgrounds of the guideline. Numerical simulations of bolt-up procedure by using three-dimensional finite element analysis are systematically executed for JPI flange joints of various nominal sizes and classes. The number of bolt-up passes required to achieve uniform bolt preloads is determined in order to avoid excessive iterations of tightening operation. Tightening tests using various sizes of the flange joint demonstrate that HPIS procedure achieves comparable uniformity in bolt preload and in flange alignment with ASME PCC-1 procedure. The guideline developed is able to achieve accurate preloads consisting with assembly efficiency for practical use.
