Microstructure and Fracture Toughness of Cast and Forged Ultra-High-Strength, Low-Alloy (UHSLA) Steels

Microstructure and Fracture Toughness of Cast and Forged Ultra-High-Strength, Low-Alloy (UHSLA) Steels PDF Author: J. Buchar
Publisher:
ISBN:
Category : Effective stress intensity factor
Languages : en
Pages : 23

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Book Description
This paper describes the fracture toughness and microstructure relations for ultra-high-strength, low-alloy (UHSLA) steels corresponding to AISI 4340 composition. The steels were either cast or forged, heat treated at austenitizing temperatures from 840 to 1100°C, oil quenched and tempered at 180 and 650°C. Fracture toughness, tensile, and Charpy impact toughness tests, and testing of apparent fracture toughness under the influence of notch root radius, were performed simultaneously. Investigation of microstructures and corresponding mechanical properties, as well as fractographic examinations and evaluation of chemical heterogeneity, made it possible to elucidate the alteration of fracture behavior.

Microstructure and Fracture Toughness of Cast and Forged Ultra-High-Strength, Low-Alloy (UHSLA) Steels

Microstructure and Fracture Toughness of Cast and Forged Ultra-High-Strength, Low-Alloy (UHSLA) Steels PDF Author: J. Buchar
Publisher:
ISBN:
Category : Effective stress intensity factor
Languages : en
Pages : 23

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Book Description
This paper describes the fracture toughness and microstructure relations for ultra-high-strength, low-alloy (UHSLA) steels corresponding to AISI 4340 composition. The steels were either cast or forged, heat treated at austenitizing temperatures from 840 to 1100°C, oil quenched and tempered at 180 and 650°C. Fracture toughness, tensile, and Charpy impact toughness tests, and testing of apparent fracture toughness under the influence of notch root radius, were performed simultaneously. Investigation of microstructures and corresponding mechanical properties, as well as fractographic examinations and evaluation of chemical heterogeneity, made it possible to elucidate the alteration of fracture behavior.

Microstructure and Fracture Toughness of a High-strength Low-alloy Steel

Microstructure and Fracture Toughness of a High-strength Low-alloy Steel PDF Author: Marie Therese Miglin
Publisher:
ISBN:
Category : Steel, High strength
Languages : en
Pages : 308

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Metallurgical Origins of Fracture Toughness and Microstructure and Fracture Toughness of an HSLA (High-Strength/Low-Alloy) Steel

Metallurgical Origins of Fracture Toughness and Microstructure and Fracture Toughness of an HSLA (High-Strength/Low-Alloy) Steel PDF Author: A. R. Rosenfield
Publisher:
ISBN:
Category :
Languages : en
Pages : 11

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Book Description
The report discusses effects of composition and heat treatment on the fracture behavior of a group of steels based on ASTM A712A. Very low transition temperatures were observed in a number of cases. However, adverse effects of Cu on the K sub Ic value for cleavage and on the sharpness of the ductile/brittle transition are noted. At ambient temperatures, overaged Cu particles are beneficial for ductile fracture resistance. A new experimental method of evaluating the relative contributions of opening and shear to ductile crack growth was developed, along with a superdislocation model of the process. Keywords: Steel, high-strength/low alloy; Microstructural effects; Compositional effects; Fracture statistics; Constitutive Modelling.

Processing, Microstructure and Properties of HSLA Steels

Processing, Microstructure and Properties of HSLA Steels PDF Author: Anthony J. DeArdo
Publisher:
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 534

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Book Description


Analysis of Fracture Toughness Mechanism in Ultra-fine-grained Steels

Analysis of Fracture Toughness Mechanism in Ultra-fine-grained Steels PDF Author: Toshihiro Hanamura
Publisher: Springer
ISBN: 4431544992
Category : Technology & Engineering
Languages : en
Pages : 71

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Book Description
In this book, advanced steel technologies mainly developed at the National Institute for Materials Science (NIMS), Japan, for structure control, mechanical properties, and the related mechanisms are introduced and discussed. NIMS has long worked on developing advanced steel techniques, namely, producing advanced steels by using only simple alloying elements such as carbon, manganese, and silicon, and also by utilizing steel scrap. The hope is that this approach will lead to a technology of a so-called steel-to-steel recycling process, with the ultimate goal of a recycling process such as an automotive-steel-to-automotive-steel recycling process to take the place of the current cascade-type recycling system. The main idea is to utilize ultra-grain refining structures and hetero structures as well as martensite structures. In particular, the focus of this book is on tensile strength and toughness of advanced steels from both the fundamental and engineering points of view. Fundamentally, a unique approach to analysis is taken, based on fracture surface energy as effective grain size is employed to better understand the mechanism of property improvement. From the engineering point of view, in fracture toughness such factors as crack tip opening displacement (CTOD) of advanced steels are evaluated in comparison with those of conventional steels.

Ultrahigh Strength, High Fracture Toughness Low-alloy Steel

Ultrahigh Strength, High Fracture Toughness Low-alloy Steel PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 300

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The Relationship of Microstructure to Strength and Toughness in High-strength Steel

The Relationship of Microstructure to Strength and Toughness in High-strength Steel PDF Author: John Henry Bucher
Publisher:
ISBN:
Category : Fractography
Languages : en
Pages : 138

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Book Description
This report deals with the relationship of elements of microstructure to the fracture characteristics of a group of commercially produced steels, heat-treated to ultra-high strength levels. The microstructures were characterized in terms of optical microscopy, electron diffraction, and electron fractography. Fractographic studies were made of fractured surfaces broken in impact at +25 and -196 C as a function of tempering temperature, in slow bending at ambient temperature, in a modified bend test in which slow and fast propagation stages were effected, and on surfaces produced in tensile fractures. The fracture characteristics were studied by means of an instrumented bend test and in terms of the plastic instability generated in the torsion test. The instrumented bend test yielded data on criteria for the onset of slow crack propagation and for the onset of rapid propagation, including the effect of the total stored energy in the system. Plastic instability in torsion was studied as a function of specimen section size in AISI 4340 steel. A 250,000 psi yield strength Maraging steel was studied in a standard size test bar. (Author).

Fracture Toughness Characteristics of the New Weldable Steels of 180- to 210-Ksi Yield Strengths

Fracture Toughness Characteristics of the New Weldable Steels of 180- to 210-Ksi Yield Strengths PDF Author: Peter P. Puzak
Publisher:
ISBN:
Category : Steel
Languages : en
Pages : 36

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Book Description
The yield strength range for steels from 180 to 210 ksi is currently covered by four weldable alloys of the following nominal chemical analysis: 18%Ni-8%Co-3%Mo maraging steel, 12%Ni-5%Cr-3%Mo maraging steel, 9%Ni-4%Co-0.20%C quenched and tempered (Q and T) steel, and 10%Ni-8%Co-2%Cr-1%Mo-0.10%C Q and T steel. Broad ranges of fracture resistance have been reported for these materials based on various fracture tests, and this report presents information for material selection and design guidance by providing an analysis of the interactions between the metallurgical and mechanical parameters that contribute to the fracture resistance of plate products. Definitions of the interaction between the metallurgical and the mechanical aspects are developed with the use of the Dynamic Tear (DT) test and the Ratio Analysis Diagram (RAD). (Author).

Structure and Properties of Ultrahigh-strength Steels

Structure and Properties of Ultrahigh-strength Steels PDF Author:
Publisher:
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 236

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Book Description


The Effect of Microstructure on the Fracture Toughness of Low-alloy Steels

The Effect of Microstructure on the Fracture Toughness of Low-alloy Steels PDF Author: Syavash Ensha
Publisher:
ISBN:
Category : Steel
Languages : en
Pages : 198

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Book Description
A theoretical model has been used to relate the cleavage fracture toughness of the low-alloy steels to their microstructure. The cleavage fracture toughness of low-alloy steels depends upon three metallurgical parameters: the microscopic cleavage strength, the yield strength, and the effective root radius. Variations in fracture toughness with microstructure can be explained through the effect of the microstructure on these parameters. The major objective of this investigation has been the study of the effect of microstructural variables on these parameters, and hence the effect of microstructure on fracture toughness. The theoretical model for the cleavage fracture toughness of the low-alloy steels can be successfully applied provided the assumptions are not strongly violated. This requires low microscopic cleavage strength/yield strength ratio values and low work-hardening rates. Lower temperatures and higher strain rates both favor these conditions. (Modified author abstract).