Oxygen Pressure Aging. Improved Equipment

1938 ◽  
Vol 11 (4) ◽  
pp. 722-727
Author(s):  
L. M. Freeman
Keyword(s):  
Oxygen Pressure ◽  
Pressure Vessel ◽  
Large Scale ◽  
Oxygen Supply ◽  
Pressure Vessels ◽  
Water Bath ◽  
Aging Test ◽  
Constant Temperature Water Bath ◽  
Temperature Water ◽  
Continuous Source

Abstract Since the introduction of the oxygen pressure-aging test by Bierer and Davis, prevailing standard conditions for the test have been 70° C. (158° F.) and 300 pounds per square inch oxygen pressure. Various types of equipment have been used; usually the equipment has consisted of a pressure vessel immersed in a constant-temperature water bath to which is connected an oxygen supply. In the majority of instances the equipment has been difficult to operate and maintain for several reasons: Immersion of pressure vessels in a water bath made handling difficult. Corrosion was a continuous source of trouble, causing “freezing” of cover bolts and making it difficult to obtain a leakproof oxygen seal between cover and vessel. This caused loss of oxygen. Each time the pressure vessel was removed from the bath it was necessary to disconnect the oxygen supply and make the connection again when the test was started. This also caused loss of oxygen. If more than one pressure vessel was connected to the oxygen supply and a safety released, the entire oxygen supply was exhausted. The original pressure vessels were relatively large. Since the use of age resistors on a large scale, smaller units have been desirable in order to decrease migration of age resistors and eliminate erroneous results. Some of these operation difficulties were outlined by Ingmanson and Kemp, who also emphasized the importance of temperature control to obtain reproducible results. It is the purpose of this paper to describe an improved oxygen pressure installation which avoids some of these difficulties.

Research of Artificial Rumen Constant Temperature Water Bath Based on Fuzzy Logic Controller

2014 ◽  
Vol 602-605 ◽  
pp. 2487-2490
Author(s):  
Xi Wu Li ◽  
Bo Xu
Keyword(s):  
Fuzzy Control ◽  
Constant Temperature ◽  
Fuzzy Logic Controller ◽  
Control Unit ◽  
Bath Temperature ◽  
Water Bath ◽  
Dynamic Responses ◽  
Test Operation ◽  
Constant Temperature Water Bath ◽  
Temperature Water

In the artificial rumen device constant temperature water bath temperature control for model and parameter uncertainty is proposed that 89S51 microcontroller as the control core, using fuzzy control algorithm, realized thermostatically control of water bath temperature. This paper presents the overall system architecture and design philosophy of fuzzy control unit and associated circuits. Systematic simulation and test operation showed that: the good dynamic responses of the system, high precision control, strong robustness, achieve better control of the water bath temperature.

The Consequences of Macroscopic Segregation on the Transformation Behavior of a Pressure-Vessel Steel

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
E. J. Pickering ◽  
H. K. D. H. Bhadeshia
Keyword(s):  
Mechanical Properties ◽  
Pressure Vessel ◽  
Large Scale ◽  
Pressure Vessels ◽  
Pressure Vessel Steel ◽  
Vessel Steel ◽  
Chemical Segregation ◽  
Compositional Variations ◽  
Grade 3 ◽  
Kinetics Of

It is important that the material used to produce high-integrity pressure vessels has homogeneous properties which are reproducible and within specification. Most heavy pressure vessels comprise large forgings derived from ingots, and are consequently affected by the chemical segregation that occurs during ingot casting. Of particular concern are the compositional variations that arise from macrosegregation, such as the channels of enriched material commonly referred to as A-segregates. By causing corresponding variations in microstructure, the segregation may be detrimental to mechanical properties. It also cannot be removed by any practically feasible heat treatments because of the large scale on which it forms. Here we describe an investigation on the consequences of macrosegregation on the development of microstructure in a pressure-vessel steel, SA508 Grade 3. It is demonstrated that the kinetics of transformation are sensitive to the segregation, resulting in a dramatic spatial variations in microstructure. It is likely therefore that some of the scatter in mechanical properties as observed for such pressure vessels can be attributed to macroscopic casting-induced chemical segregation.

scholarly journals Adaptive temperature control of a constant-temperature water bath by multi-variable STC.

1988 ◽  
Vol 108 (1) ◽  
pp. 31-38
Author(s):  
Sigeru Omatu ◽  
Toru Yamamoto ◽  
Haruyoshi Maruyama ◽  
Norio Yoshikawa
Keyword(s):  
Constant Temperature ◽  
Temperature Control ◽  
Water Bath ◽  
Constant Temperature Water Bath ◽  
Temperature Water

Investigation on the Effects of Carbon Macro-Segregation of Mechanical Properties Using a Large-Scale Forged Low Alloy Steel for a BWR Reactor Pressure Vessel

2020 ◽  
Author(s):  
Takahiro Hayashi ◽  
Takuya Ogawa ◽  
Rie Sumiya ◽  
Tetsushi Yamaoka ◽  
Shigeaki Tanaka ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Content ◽  
Pressure Vessel ◽  
Material Properties ◽  
Large Scale ◽  
Structural Reliability ◽  
Pressure Vessels ◽  
Reactor Pressure Vessel ◽  
Steel Making ◽  
Reactor Pressure

Abstract Control of carbon macro-segregation in the steel-making process for large steel forgings is of great importance in order to achieve the material properties and structural reliability required for the pressure vessels of nuclear power plant components. It is well known that high carbon content due to carbon macro-segregation can affect the mechanical properties of steels, leading to decreases in ductility and fracture toughness. In this study, possible effects of carbon macro-segregation have been examined using a large-scale forged steel “bottom head dome” of a reactor pressure vessel (RPV) manufactured for a recent BWR. Material testing conducted included chemical analyses, tensile tests and Charpy impact tests. In the center part of the concave disk-shaped forged material, carbon content varied slightly in the material thickness direction within the range of carbon content requirement, as expected from the relationship between the solidification and the resultant segregation process in the cast ingot material and the forging process from the ingot to the dome material. The results of each mechanical test also showed full compliance with the properties required in the code regardless of the carbon content at each of the thickness locations examined. All the tests results demonstrated that with the steel-making technology and practice employed, carbon macro-segregation is well controlled to achieve the required material properties even in large-scale forged materials used in BWRs.

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