scholarly journals Discussion: “A Comparison of Charpy V-Notch, Dynamic Tear, and Precracked Charpy Impact Transition-Temperature Curves for AAR Grades of Cast Steel” (Sharkey, R. L., and Stone, D. H., 1976, ASME J. Eng. Ind., 98, pp. 446–452)

1976 ◽  
Vol 98 (2) ◽  
pp. 452-452
Author(s):  
J. A. Cran
Keyword(s):  
Transition Temperature ◽  
Cast Steel ◽  
Charpy Impact ◽  
Impact Transition Temperature

A Comparison of Charpy V-Notch, Dynamic Tear, and Precracked Charpy Impact Transition-Temperature Curves for AAR Grades of Cast Steel

1976 ◽  
Vol 98 (2) ◽  
pp. 446-452
Author(s):  
R. L. Sharkey ◽  
D. H. Stone
Keyword(s):  
Fracture Toughness ◽  
Transition Temperature ◽  
Cast Steel ◽  
Charpy Impact ◽  
High Strength ◽  
Temperature Data ◽  
Transition Temperatures ◽  
Strength Alloy ◽  
Impact Transition Temperature ◽  
Alloy Cast

Impact tests using Charpy V-notch, Dynamic Tear and Precracked Charpy samples were conducted on AAR-B, AAR-C (several compositions and heat treatments), and AAR-E cast grades of steel and on a high-strength, alloy cast steel. Graphical presentations of the transition-temperature data are given. Differences in the relative shapes of the curves and the locations of the NDT temperatures with respect to the transition temperatures are discussed. Fracture toughness, KId, values are also presented.

Notch Effects on Impact and Bending Characteristics of Spheroidal Graphite and Compacted Vermicular Graphite Cast Irons with Various Matrices

2010 ◽  
Vol 457 ◽  
pp. 392-397 ◽  
Author(s):  
Tohru Nobuki ◽  
Minoru Hatate ◽  
Toshio Shiota
Keyword(s):  
Cast Iron ◽  
Transition Temperature ◽  
Brittle Fracture ◽  
Cast Steel ◽  
Charpy Impact ◽  
Spheroidal Graphite ◽  
Buffer Effect ◽  
Cast Irons ◽  
Type Specimens ◽  
The Impact

The object of this study is to find out and evaluate systematically how the basic factors such as graphite-shape, external notch and matrix-characteristic affect the impact and bending characteristics of cast irons. The Spheroidal Graphite (SG) and Compacted Vermicular graphite (CV) cast iron samples were prepared, and their matrixes were modified into ferritic, pearlitic and bainitic in order to make the various kinds of samples whose graphite-shape and matrix vary widely. From each sample we produced five kinds of Charpy-type specimens by adding five kinds of notches whose stress concentration factor (α) varied from 1.0 (un-notched) to 4.8. The Charpy impact value decreases greatly in the range of α from 1 to 2.3 but decreases slightly in the range of α larger than 2.3. No influence to the fracture energy in the range of α larger than 2.3. Increasing of α results in moderate elevation of transition temperature of Charpy impact value and the transition temperature of CV cast ion is lower than that of SG one. The impact value in brittle fracture region of the cast iron samples were recognized to be a little bit larger than that of cast steel sample, and it was considered to be caused by graphite which act as a kind of buffer effect against crack growth in brittle fracture.

scholarly journals Toughness Property Control by Nb and Mo Additions in High-Strength Quenched and Tempered Boron Steels

Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 95
Author(s):  
Irati Zurutuza ◽  
Nerea Isasti ◽  
Eric Detemple ◽  
Volker Schwinn ◽  
Hardy Mohrbacher ◽  
...  
Keyword(s):  
Solid Solution ◽  
Transition Temperature ◽  
High Strength ◽  
Unit Size ◽  
Tempered Martensite ◽  
Size Refinement ◽  
Direct Quenching ◽  
Property Control ◽  
The Impact ◽  
Impact Transition Temperature

The synergetic effect on hardenability by combining boron with other microalloying elements (such as Nb, Mo and Nb + Mo) is widely known for high-strength medium carbon steels produced by direct quenching and subsequent tempering treatment. The improvement of mechanical properties could be reached through optimization of different mechanisms, such as solid solution hardening, unit size refinement, strain hardening, fine precipitation hardening and the effect of carbon in solid solution. The current study proposes a procedure for evaluating the contribution of different microstructural aspects on Charpy impact toughness. First, the effect that austenite conditioning has on low-temperature transformation unit sizes and microstructural homogeneity was analysed for the different microalloying element combinations. A detailed crystallographic characterization of the tempered martensite was carried out using electron backscattered diffraction (EBSD) in order to quantify the effect of unit size refinement and dislocation density. The impact of heterogeneity and presence of carbides was also evaluated. The existing equations for impact transition temperature (ITT50%) predictions were extended from ferrite-pearlite and bainitic microstructures to tempered martensite microstructures. The results show that microstructural refinement is most beneficial to strength and toughness while unit size heterogeneity has a particularly negative effect on ductile-to-brittle transition behaviour. By properly balancing alloy concept and processing, steel having a yield strength above 900 MPa and low impact transition temperature could be obtained by direct quenching and tempering.

scholarly journals A New Method for Determining the Brittle-to-Ductile Transition Temperature of a TiAl Intermetallic

Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1550
Author(s):  
Sarper Nizamoglu ◽  
Karl-Heinz Lang ◽  
Stefan Guth ◽  
Martin Heilmaier
Keyword(s):  
Transition Temperature ◽  
Charpy Impact ◽  
Plastic Strain Amplitude ◽  
Bending Tests ◽  
Brittle To Ductile Transition ◽  
Intermetallic Materials ◽  
Different Temperatures ◽  
Specific Temperature ◽  
Increasing Temperature ◽  
Fully Lamellar

Intermetallic materials typically change their deformation behavior from brittle to ductile at a certain temperature called the Brittle-to-Ductile Transition Temperature (BDTT). This specific temperature can be determined by the Charpy impact, tensile or bending tests conducted at different temperatures and strain rates, which usually requires a large number of specimens. In order to reduce the number of necessary specimens for finding the BDTT, a new methodology comprising cyclic loadings as the crucial step was studied on a fully lamellar TiAl alloy with composition Ti-48Al-2Nb-0.7Cr-0.3Si. The loading blocks are applied isothermally under strain control and repeated on the same specimen at different temperatures. The development of plastic strain amplitude with increasing temperature is analyzed to determine the BDTT of the specimen. The BDTTs found with the described method agree well with literature data derived with conventional methods. With the loading strategy presented in this study, the BDTT and additionally the effect of strain rate on it can be found by using a single specimen.

Microstructure-Toughness Relationship in AISI4340 Steel

2011 ◽  
Vol 312-315 ◽  
pp. 110-115
Author(s):  
N. Saeidi ◽  
A. Ekrami
Keyword(s):  
Transition Temperature ◽  
Charpy Impact ◽  
Brittle Transition ◽  
Hardness Tests ◽  
Ductile Brittle Transition Temperature ◽  
Different Temperatures ◽  
Ferrite Steel ◽  
Brittle Transition Temperature ◽  
Impact Data ◽  
Aisi4340 Steel

To improve the strength and toughness of AISI 4340 steel, different microstructures, containing full bainite, bainite-ferrite, martensite-ferrite and full martensite were produced by different heat treatment cycles. Tensile, impact and hardness tests were carried out at room temperature. The ductile-brittle transition temperature was determined from impact data at different temperatures. The results showed that steel with bainite - 0.34 ferrite microstructure has the highest elongation and charpy impact energy, while its tensile strength and yield stress decreased in comparison to other microstructures. This increment was noticeable when bainite - 0.34 ferrite steel was tempered. The ductile-brittle transition temperature decreased with tempering of bainite -0.34 steel. The fracture surface analysis of charpy specimens also showed an increase in toughness of tempered bainite-ferrite in comparison to other microstructures.

Predicting the Brittle-to-Ductile Fracture Initiation Transition Temperature for Surface-Cracked Pipe From Charpy Data

2005 ◽  
Author(s):  
Gery Wilkowski ◽  
Dave Rudland ◽  
Richard Wolterman
Keyword(s):  
Transition Temperature ◽  
Ductile Fracture ◽  
Failure Modes ◽  
Charpy Impact ◽  
Fracture Initiation ◽  
Evaluation Procedures ◽  
Balance Of Plant ◽  
Constraint Effects ◽  
Impact Data ◽  
Ductile Fracture Initiation

Much work has been done to assess constraint effects on the crack-driving force for specimens and cracks in pipes. The material’s transition temperature where the fracture process changes from ductile tearing to cleavage fracture at crack initiation is affected by the constraint conditions, but is a material property that cannot be determined analytically. This paper presents a methodology to account for constraint effects to predict the lowest temperature for ductile fracture initiation and relates that temperature to Charpy impact data for typical ferritic pipe materials. It involves a series of transition temperature shifts to account for thickness, strain-rate, and constraint to give a master curve of transition temperatures from Charpy data to through-wall-cracked or surface-cracked pipes (with various a/t values) under quasi-static loading. These transition temperature shifts were based on hundreds of pipe tests and thousands of specimen tests over several decades of work by numerous investigators. It is equally applicable to ferritic nuclear pipe for Class 2, 3, or balance of plant piping, or for older linepipe materials. If found to be reasonable, then the procedure could be used in the ASME pipe flaw evaluation procedures as a screening criterion between LEFM and EPFM failure modes.

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