Velocity compensation and practical aspects for high-temperature ultrasonic testing

2021 ◽  
Vol 63 (11) ◽  
pp. 641-647
Author(s):  
T Stevenson ◽  
Chuangnan Wang
Keyword(s):  
High Temperature ◽  
Ultrasonic Testing ◽  
Elevated Temperatures ◽  
Accurate Determination ◽  
Carbon Steels ◽  
International Standards ◽  
Internal Corrosion ◽  
Measured Time ◽  
Tools And Techniques ◽  
Thickness Measurements

Increasingly, the need for on-stream asset integrity, where inspections are carried out while components are still operating to reduce the disruption and impact of outages, is required at elevated temperatures. For example, a typical hydrocarbon refinery has process units with surface temperatures in excess of 500°C, where internal corrosion of the typically steel components needs to be monitored by testing, to maintain safe and reliable operation. This is ubiquitously carried out by means of ultrasonic testing (UT). As high-temperature tools increasingly become available, the accuracy of thickness measurements is often questioned due to the intrinsic link between the measured time-of-flight (TOF) and the characteristic speed of sound of the material. The velocity, in turn, is a factor of the elastic modulus of the material, which is inversely proportional to temperature in steel. Historically, international standards and practices publish correction factors for generic steel materials, but increasingly the desire for more accurate determination is required with more advanced tools and techniques. Here, the velocity as a function of temperature is determined through experimental study for two common carbon steels that may see service at elevated temperatures, and the correction factor is shown by application to a typical corrosion mapping survey at elevated temperature. The errors associated with variable velocity are shown to be effectively minimised below the normal variability of ultrasonic testing.

Properties of Steels as a Basis for Design for High-Temperature Service. Part I: Carbon Steels

1940 ◽  
Vol 144 (1) ◽  
pp. 97-106 ◽  
Author(s):  
H. J. Tapsell ◽  
A. E. Johnson
Keyword(s):  
High Temperature ◽  
Carbon Content ◽  
Elevated Temperatures ◽  
National Physical Laboratory ◽  
Carbon Steels ◽  
Research Association ◽  
Physical Laboratory

The paper gives a brief account of the influence of stress, temperature, and time on the behaviour of carbon steels of about 0·15 to 0·50 per cent carbon content, and provides data as a basis for design purposes. The data given are derived from investigations carried out at the National Physical Laboratory, largely on behalf of the British Electrical and Allied Industries Research Association. Although practice has established satisfactory working stresses for carbon steels at moderately elevated temperatures—possibly up to 425 deg. C. (800 deg. F.)—it may serve a useful purpose to include herein particulars of the strength of carbon steels up to 800 deg. F. The chief purpose of the paper, however, is to assist the reader in appreciating the factors involved in estimating the useful strength of steels at higher temperatures extending to about 1,000 deg. F.

High-Temperature Instability of A Cr2Nb-Nb(Cr) Microlaminate Composite

1996 ◽  
Vol 54 ◽  
pp. 374-375
Author(s):  
M. Larsen ◽  
R.G. Rowe ◽  
D.W. Skelly
Keyword(s):  
Heat Treatment ◽  
Solid Solution ◽  
High Temperature ◽  
Elevated Temperatures ◽  
Aircraft Engine ◽  
Lattice Parameter ◽  
Microstructural Stability ◽  
Elevated Temperature Strength ◽  
Cross Sectional ◽  
Bcc Structure

Microlaminate composites consisting of alternating layers of a high temperature intermetallic compound for elevated temperature strength and a ductile refractory metal for toughening may have uses in aircraft engine turbines. Microstructural stability at elevated temperatures is a crucial requirement for these composites. A microlaminate composite consisting of alternating layers of Cr2Nb and Nb(Cr) was produced by vapor phase deposition. The stability of the layers at elevated temperatures was investigated by cross-sectional TEM.The as-deposited composite consists of layers of a Nb(Cr) solid solution with a composition in atomic percent of 91% Nb and 9% Cr. It has a bcc structure with highly elongated grains. Alternating with this Nb(Cr) layer is the Cr2Nb layer. However, this layer has deposited as a fine grain Cr(Nb) solid solution with a metastable bcc structure and a lattice parameter about half way between that of pure Nb and pure Cr. The atomic composition of this layer is 60% Cr and 40% Nb. The interface between the layers in the as-deposited condition appears very flat (figure 1). After a two hour, 1200 °C heat treatment, the metastable Cr(Nb) layer transforms to the Cr2Nb phase with the C15 cubic structure. Grain coarsening occurs in the Nb(Cr) layer and the interface between the layers roughen. The roughening of the interface is a prelude to an instability of the interface at higher heat treatment temperatures with perturbations of the Cr2Nb grains penetrating into the Nb(Cr) layer.

Phase transformation and layer evolution in molybdenum disilicide-silicon carbide nanolayered coatings

1994 ◽  
Vol 52 ◽  
pp. 538-539
Author(s):  
H. Kung ◽  
T. R. Jervis ◽  
J.-P. Hirvonen ◽  
M. Nastasi ◽  
T. E. Mitchell ◽  
...  
Keyword(s):  
Phase Transformation ◽  
High Temperature ◽  
Oxidation Resistance ◽  
Elevated Temperatures ◽  
Matrix Material ◽  
Molybdenum Disilicide ◽  
High Temperature Strength ◽  
Cross Sectional ◽  
Good Oxidation Resistance ◽  
Structural Applications

MoSi2 is a potential matrix material for high temperature structural composites due to its high melting temperature and good oxidation resistance at elevated temperatures. The two major drawbacksfor structural applications are inadequate high temperature strength and poor low temperature ductility. The search for appropriate composite additions has been the focus of extensive investigations in recent years. The addition of SiC in a nanolayered configuration was shown to exhibit superior oxidation resistance and significant hardness increase through annealing at 500°C. One potential application of MoSi2- SiC multilayers is for high temperature coatings, where structural stability ofthe layering is of major concern. In this study, we have systematically investigated both the evolution of phases and the stability of layers by varying the heat treating conditions.Alternating layers of MoSi2 and SiC were synthesized by DC-magnetron and rf-diode sputtering respectively. Cross-sectional transmission electron microscopy (XTEM) was used to examine three distinct reactions in the specimens when exposed to different annealing conditions: crystallization and phase transformation of MoSi2, crystallization of SiC, and spheroidization of the layer structures.

WIELAND-K88

Alloy Digest ◽  
2005 ◽  
Vol 54 (12) ◽  
Keyword(s):  
Thermal Conductivity ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Stress Relaxation ◽  
Copper Alloy ◽  
Elevated Temperatures ◽  
Heat Treating ◽  
Relaxation Resistance ◽  
Temperature Performance ◽  
Very High

Abstract Wieland K-88 is a copper alloy with very high electrical and thermal conductivity, good strength, and excellent stress relaxation resistance at elevated temperatures. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: CU-738. Producer or source: Wieland Metals Inc.

DOWMETAL HZ32XA

Alloy Digest ◽  
1956 ◽  
Vol 5 (7) ◽  
Keyword(s):  
High Temperature ◽  
Physical Properties ◽  
Creep Resistance ◽  
Zirconium Alloy ◽  
Elevated Temperatures ◽  
Heat Treating ◽  
High Temperature Creep ◽  
Aged Condition ◽  
Chemical Company ◽  
Temperature Performance

Abstract DOWMETAL HZ32XA is a magnesium-thorium-zinc-zirconium alloy having good high temperature creep resistance, and is recommended for applications at elevated temperatures. It is used in the artificially aged condition (T5). This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as creep. It also includes information on high temperature performance as well as heat treating, machining, and joining. Filing Code: Mg-26. Producer or source: The Dow Chemical Company.

UDIMET 105

Alloy Digest ◽  
1972 ◽  
Vol 21 (7) ◽  
Keyword(s):  
Corrosion Resistance ◽  
High Temperature ◽  
Physical Properties ◽  
Surface Treatment ◽  
Elevated Temperatures ◽  
Base Alloy ◽  
Heat Treating ◽  
Nickel Base Alloy ◽  
Temperature Performance ◽  
Nickel Base

Abstract UDIMET 105 is a nickel-base alloy which was developed for service at elevated temperatures. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as creep. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: Ni-175. Producer or source: Special Metals Corporation.

CARPENTER L-605 ALLOY

Alloy Digest ◽  
1987 ◽  
Vol 36 (8) ◽  
Keyword(s):  
Corrosion Resistance ◽  
High Temperature ◽  
Elevated Temperatures ◽  
Base Alloy ◽  
High Strength ◽  
Heat Treating ◽  
Temperature Performance ◽  
Cobalt Base Alloy ◽  
Cobalt Base ◽  
Oxidation And Corrosion

Abstract CARPENTER L-605 alloy is a nonmagnetic cobalt-base alloy that has good oxidation and corrosion resistance and high strength at elevated temperatures. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as creep and fatigue. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Co-81. Producer or source: Carpenter.

FANSTEEL 85 METAL

Alloy Digest ◽  
1981 ◽  
Vol 30 (6) ◽  
Keyword(s):  
High Temperature ◽  
Physical Properties ◽  
Creep Strength ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Base Alloy ◽  
Heat Treating ◽  
Good Combination ◽  
Bend Strength ◽  
Temperature Performance

Abstract FANSTEEL 85 METAL is a columbium-base alloy characterized by good fabricability at room temperature, good weldability and a good combination of creep strength and oxidation resistance at elevated temperatures. Its applications include missile and rocket components and many other high-temperature parts. This datasheet provides information on composition, physical properties, microstructure, hardness, elasticity, tensile properties, and bend strength as well as creep. It also includes information on low and high temperature performance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: Cb-7. Producer or source: Fansteel Metallurgical Corporation. Originally published December 1963, revised June 1981.

INCONEL ALLOY N06230

Alloy Digest ◽  
2009 ◽  
Vol 58 (3) ◽  
Keyword(s):  
Fracture Toughness ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
Elevated Temperatures ◽  
Heat Treating ◽  
Inconel Alloy ◽  
Temperature Performance ◽  
Resistance To Oxidation

Abstract Inconel Alloy N06230 is a Ni-Cr-W alloy with excellent strength and resistance to oxidation at elevated temperatures. This alloy offers good metallurgical stability and is readily fabricated by conventional processes and procedures. This datasheet provides information on composition, physical properties, microstructure, elasticity, and tensile properties as well as fracture toughness. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Ni-667. Producer or source: Special Metals Corporation.

ELEKTRON QH21A

Alloy Digest ◽  
1979 ◽  
Vol 28 (1) ◽  
Keyword(s):  
Fracture Toughness ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Physical Properties ◽  
Surface Treatment ◽  
Elevated Temperatures ◽  
Heat Treating ◽  
Casting Alloy ◽  
Casting Alloys ◽  
Temperature Performance

Abstract ELEKTRON QH21A is a magnesium-base casting alloy developed to meet the ever increasing requirements for casting alloys to operate at elevated temperatures. It is of particular interest to designers and stress engineers for highly stressed components operating at temperatures up to 480 F (250 C), especially where pressure tightness is a requirement. This datasheet provides information on composition, physical properties, and tensile properties as well as fracture toughness, creep, and fatigue. It also includes information on high temperature performance and corrosion resistance as well as casting, heat treating, machining, joining, and surface treatment. Filing Code: Mg-72. Producer or source: Magnesium Elektron Inc..

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