IPC04-0561 ASSESSMENT OF PIPELINE STATION FACILITIES INTEGRITY

ABSTRACT This paper describes an approach for assessing the integrity of pipeline station facilities, excluding the transmission pipeline itself. It includes the development and implementation of an integrity management plan, an inspection plan, and a fitness-for-service assessment plan. These plans are adapted from accepted industry standards and implemented in accordance with accepted industry recommended practices. Risk-based assessment is used to prioritize inspections and schedule mitigation actions, including repairs and replacements. Anomalies and defects in equipment are assessed using fitness-for-service procedures. Application of the approach to station and terminal facilities is discussed

Influence of temperature on reversed creep

Several investigators have reported an acceleration of creep in metals due to repeated stress reversals. In order to determine the temperature dependence of this acceleration, reversed creep experiments have been carried out on commercially pure aluminum at temperatures from 300 to 510 K and shear stresses between ±2500 to ±6000 psi. The data show a transition from deceleration at the lowest temperatures to significant acceleration at the highest temperatures. This transition occurs at an homologous temperature of about 0.45, but the transition point is not well-defined because the behavior is also slightly dependent upon the stress and strain range. Cyclic creep acceleration or deceleration tends to approach a dynamic equilibrium, and it is shown that this state of equilibrium can be mathematically approximated by a function of the four important variables in reversed creep tests - stress amplitude, strain range, strain rate and temperature. Also, the stress dependence of the average creep rate at equilibrium is found to be similar to that of the minimum tensile creep rate.National Aeronautics & Space Administration 67/08 NGR 14 005 025 67/0

Monotonic and cyclic stress-strain response of annealed 2 1/4 Cr--1 Mo steel

The stress-strain response of isothermally annealed 2$sup 1$/$sub 4$ Cr-- 1 Mo steel under monotonic and cyclic loadings was characterized at 21 to 593$sup 0$C. Monotonic stress-strain curves were developed for uniaxial tensile loading of speciments at strain rates of 8.33 x 10$sup -5$ and 8.33 x 10$sup -6$ s$sup -1$. The cyclic stress-strain response was measured for the first 100 fully reversed strain cycles at strain ranges between 0.4 and 3.0 percent under uniaxial loading at a strain rate of 8.33 x 10$sup -5$ s$sup -1$. The effects of creep, stress-relaxation, and thermal-exposure hold periods on the cyclic stress- strain behavior were also investigated at 510$sup 0$C. Monotonic stress-strain curves were quantified using a power law relation between stress range and plastic-strain range. Cyclic hardening was observed at temperatures up to 427$sup 0$C. A mixture of initial cyclic hardening followed by later cyclic softening was seen at temperatures from 482 to 538$sup 0$C, and cyclic softening was observed at 593$sup 0$C. One measure of the cyclic stress-strain response was characterized by the ascending path of the stress-strain hysteresis loop for the tenth cycle. The reported results form part of the data base to be used by others in formulating similar general inelastic constitutive equations for analysis of 2$sup 1$/$sub 4$ Cr-1 Mo steel components. (auth