Correlation of Rupture Life, Creep Rate, and Microstructure for Type 304 Stainless Steel

The stress and temperature sensitivites of the rupture life and secondary creep rate were examined in detail for a single heat of type 304 stainless steel (9T2796). Assuming that the rupture life has a power law stress dependency, relatively small differences in the stress exponent were observed over a broad range of stress and temperature. In contrast, large changes were observed for equivalent parameter for secondary creep rate. As a result of these differences, the Monkman-Grant correlation was sensitive to stress and temperature below 650 C. Metallurgical studies based on light and transmission electron microscopy suggested that the temperature and stress sensitivities of secondary creep rate at temperatures below 650 C were related to features of the substructure not present at higher temperature. Specifically, the presence of a fine dislocation network stabilized by precipitates altered the stress and temperature sensitivities relative to what might be expected from high temperature studies

Correlations Between Metallurgical Characterization Studies, Exploratory Mechanical Tests, and Continuum Mechanics Approaches to Constitutive Equations

Austenitic stainless steels, such as types 316 and 304, are widely used as pressure vessel materials in the temperature range of 425 to 650 C. Stainless steel specimens were tested to rupture at two different stress levels sigma and sigma 2 sigma 1 sigma 2) to establish the normal stain-time behavior. A subsequent test was performed in which the specimen was crept at the higher stress (sigma 1) to the beginning of the secondary stage of creep, presumed to be the strain/time conditions at which a steady state microstructure is developed, and then the stress was reduced to the lower level (sigma 2). The associated microstructure, and significance of this microstructure on the creep strain-hardening model for variable uniaxial loads were assesed and found to be consistent with the use of creep-recovery models at high stresses and temperatures and strain-hardening models at low stresses and tempertures

Critical Infrastructure Security: CRS Experts

This report contains a table which provides access to names and contact information for CRS experts on policy concerns relating to critical infrastructure security. Policy areas identified include: mission; security services; and specific sectors: assessing vulnerabilities, planning and implementation

Critical Infrastructures: Background, Policy, and Implementation

The nation’s health, wealth, and security rely on the production and distribution of certain goods and services. The array of physical assets, processes and organizations across which these goods and services move are called critical infrastructures (e.g. electricity, the power plants that generate it, and the electric grid upon which it is distributed). Computers and communications, themselves critical infrastructures, are increasingly tying these infrastructures together. This report aims to address the concern that this reliance on computers and computer networks raises the vulnerability of the nation’s critical infrastructures to “cyber” attacks

CRS Issue Briefs

On June 27, the Bush Administration released an amended FY2002 budget for the Department of Defense (DOD). The amended budget requests a total of $328.9 billion for DOD, an additional$18.4 billion above the Administration’s “Blueprint” budget released in April. The amended budget included an additional 5.6 billion for DOD’s Research, Development, Test and Evaluation (RDT&E) program. This raises the FY2002 RDT&E request to 47.4 billion, $6.3 billion above the total obligational authority available for RDT&E in FY2001

DOD's Dual-Use Strategy

In an effort to reduce the costs of its military systems and gain greater access to state-of-the-art technologies, the Department of Defense is pursuing what is being called a "dual-use" strategy. This strategy seeks to make greater use of the commercial sector in developing and manufacturing military goods. This report discusses issues raised over the implementation of this strategy

Critical Infrastructure: The National Asset Database

The purpose of this report is to discuss the National Asset Database: what is in it, how it is populated, what the Database apparently is, what it is not, and how it is intended to be used. The report also discusses some of the issues on which Congress could focus its oversight, including appropriation bill language

Critical Infrastructures: Background, Policy, and Implementation

The nation’s health, wealth, and security rely on the production and distribution of certain goods and services. The array of physical assets, processes and organizations across which these goods and services move are called critical infrastructures (e.g. electricity, the power plants that generate it, and the electric grid upon which it is distributed). Computers and communications, themselves critical infrastructures, are increasingly tying these infrastructures together. This report aims to address the concern that this reliance on computers and computer networks raises the vulnerability of the nation’s critical infrastructures to “cyber” attacks

Defense Research: A Primer on the Department of Defense's Research, Development, Test and Evaluation (RDT and E) Program

This report describes the basic elements and issues of the Department of Defense's (DOD) Research, Development, Test and Evaluation (RDT&E) Program. It defines basic activities supported by the program, presents budget trends, discusses the management of program, and describes the infrastructure in which the program is implemented. This report is for staff new to the area of defense research and for senior staff interested in historical trends

Critical Infrastructures: Background and Early Implementation of PDD-63

The nation's health, wealth, and security rely on the supply and distribution of certain goods and services. The array of physical assets, processes and organizations across which these goods and services move are called critical infrastructures (e.g. electricity, the power plants that generate it, and the electric grid upon which it is distributed or financial capital, the institutions that manage it, and the record- keeping and communications that move it from one institution to another)