In the present study, fracture toughness of functionally graded steels in crack divider configuration has been modeled. By utilizing plain carbon and austenitic stainless steels slices with various thicknesses and arrangements as electroslag remelting electrodes, functionally graded steels were produced. The fracture toughness of the functionally graded steels in crack divider configuration has...

Much of the recent research at the NDE Centre at UCL has revolved round the study of the scattering of thin skin electromagnetic fields by a fatigue crack. The early work concentrated on the perturbations to the surface electric field (ACPD), while the more recent work involved the scattered magnetic field (ACFM). The Centre has recently become involved in a collaborative project, a part of whi...

It has been possible in recent times to make large quantities of steels in which the controlling scale is 20 nm or less, i.e., comparable to that of carbon nanotubes. The mechanical properties of such steels are abnormal. For example, in some cases the ductility vanishes as the strength increases, whereas in others the ductility almost entirely consists of uniform plastic strain. Some of the st...

In this work, tensile and yield stress and tensile and yield strain of oblique layer functionally graded steels produced by electroslag remelting were investigated. Functionally graded steels containing ferrite, austenite, bainite, and/or martensite layers may be fabricated via diffusion of alloying elements during the remelting stage. Tensile and yield stress and tensile and yield strain of fu...

The elastic-plastic fracture toughness JIc tests by the stretched zone method were performed to obtain JIc values for machine structural steels. The validity of the JIc values obtained was evaluated, and the effects of the heat treatment conditions and microstructure of steels on the JIc values were investigated by use of streched zone width, SZW. The results obtained are summarized as follows....

SEM in-situ investigations of the micromechanisms of damage initiation and fracture in tool steels are described. The critical state of the material and the damage growth were observed in the tests. It was shown that the initial microcracks in the steels are formed in primary carbides and then join together. A hierarchical finite element model of damage initiation, which included a macroscopic ...

The understanding of the hardenability is important in steel development with respect to weldability of steels as well as to the design of quenched and tempered steels. The common way to judge if steel is suitability to welding is the use of a carbon equivalent, which reflects the alloy content to the hardenability of the heat affected zone (HAZ). Most common of these equivalents is the IIW car...

Adding a large amount of light elements such as aluminum to steels is not a new concept recalling that several Fe-Al-Mn-C alloys were patented in 1950s for replacement of nickel or chromium in corrosion resistance steels. However, the so-called lightweight steels or low-density steels were revisited recently, which is driven by demands from the industry where steel has served as a major structu...

This work considers use neurofuzzy set theory for estimate abrasion wear resistance of steels based on chemical composition, heat treatment (austenitising temperature, quenchant and tempering temperature), hardness after hardening and different tempering temperature and volume loss of materials according to ASTM G 65-94. Testing of volume loss for the following group of materials as fuzzy data ...

A computational approach to the optimization of service properties of two-phase materials (in this case, fracture resistance of tool steels) by varying their microstructure is developed. The main points of the optimization of steels are as follows: (1) numerical simulation of crack initiation and growth in real microstructures of materials with the use of the multiphase finite elements (MPFE) a...