Non-destructive Eddy current (EC) technique has long been used to detect discontinuities in materials. Recently, its application has been extended to characterize materials microstructure. In order to identify different microstructures, four plain carbon steel bars with different chemical compositions (AISI 1015, 1035, 1045 and 1080) were used in annealed condition. The pearlite percentage, car...

A study for optimizing of siliconizing and borosiliconizing processes on carbon steels has been carried out. The process parameters, i.e, time and powder mixture, were considered for optimization of the case depth, surface quality and the hardness profile.&#10Time and temperature of the processes were 4 hr and 950˚C, respectively. Powder mixture in siliconizing process was 2.5% ferrosilicon, 2....

LOW-TEMPERATURE CARBURIZATION is a gaseous carburization process performed at atmospheric pressure, at temperatures where the kinetics of substitutional diffusion are very slow. Low-temperature carburization hardens the surface of austenitic stainless steels through the diffusion of interstitial carbon, without the formation of carbides. The surface must be activated, by modification and remova...

This paper discusses the use of laser-ultrasonics to monitor the metallurgical transformations of advanced high-strength steels. In this technique, acoustic waves are generated and detected in the material by use of lasers. The ultrasonic velocity can sense the austenite formation/decomposition in real time. Unlike dilatometric measurements the ultrasonic velocity measurements show little influ...

The redistribution of carbon after tempering of a novel nanocrystalline bainitic steel consisting of a mixture of supersaturated ferrite and retained austenite has been analyzed by atom probe tomography. No direct evidence supporting the additional carbon enrichment of austenite beyond that initially achieved during the bainite heat treatment was obtained during subsequent tempering of this hig...

Most new materials are introduced by selectively comparing their properties against those of steels. Steels set this standard because iron and its alloys have so much potential that new concepts are discovered and implemented with notorious regularity. In this 52nd Hatfield Memorial Lecture, a remarkably beautiful microstructure consisting of slender crystals of ferrite, whose controlling scale...

The different techniques available for the accurate measurement of lattice fringe spacings are discussed and their relative merit under different circumstances assessed. The relationship between the lattice fringe spacing and the lattice parameter is further examined for both uniform and chemically inhomogeneous material. The techniques described were also applied to an investigation of carbon ...

Diamond-like carbon deposition techniques, characterization techniques and processing parameters, such as gas ratio, bias voltage, gas pressure, type of precursor gas used, temperature, gas total flow, substrate material, among others are reviewed. Mostly silicon substrates have been employed, but also metallic materials such as titanium and aluminum alloys or steels have been used as well. Imp...

Low carbon ferritic steel alloyed with Ti, Mo and Cu was hot rolled and interrupt cooled to produce nano-sized precipitates of copper and (Ti,Mo)C carbides. The steel had a tensile strength of 840 MPa, an increase in yield strength of 380 MPa over that of the plain carbon steel and reasonable ductility. Transmission electron microscopy and small angle neutron scattering were used to characteriz...

This paper discusses the influence of Particle Stimulated Nucleation (PSN) on the overall process of nucleation and subsequent grain growth in low carbon (LC) steels and proposes a global recrystallisation kinetics model based on fundamental physical metallurgy principles. The model takes into account the cementite content, which is dependent on the nominal carbon content, and the second phase ...