The microstructure obtained as the weld cools from the liquid phase to ambient temperature is called the as–deposited or primary microstructure. Its major components include allotriomorphic ferrite, Widmanstätten ferrite, and acicular ferrite (Fig. 1). There may also be some martensite, retained austenite or degenerate pearlite. These latter phases occur in very small fractions, and are known b...

transformation induced plasticity (trip) steels have a vast application in automotive industry because of theirhigh strength, high ductility and hence excellent energy absorption capacity. these characteristics of tripsteels are due to the existence of retained austenite in their microstructures in the ambient temperature, whichtransforms to the martensite phase during deformation. the microstr...

Little is known about the effect of stress on the development of microstructure in steel welds. This paper contains an assessment of published data together with a description of the theory that is available for dealing with stress–affected transformations in steels. Attention is focused on those transformations which have the greatest potential for interaction with an externally applied stress...

Strong steels also have to be tough and hence rely on fine microstructures such as bainite or martensite, produced commercially by continuous cooling transformation. Depending on the detailed requirements, the steel-design process may explicitly require other higher temperature phases to be absent in the final microstructure. Such a procedure can be made easier by the availability of a good met...

Transformation induced plasticity (TRIP) steels have a vast application in automotive industry because of theirhigh strength, high ductility and hence excellent energy absorption capacity. These characteristics of TRIPsteels are due to the existence of retained austenite in their microstructures in the ambient temperature, whichtransforms to the martensite phase during deforma...

In this work, three low-carbon bainitic steels, with different Mo contents, were designed to investigate the effects of Mo addition on microstructure and mechanical properties. Two-step cooling, i.e., initial accelerated cooling and subsequent slow cooling, was used to obtain the desired bainite microstructure. The results show that the product of strength and elongation first increases and the...

X90 pipeline steel was processed with the simulated coarse grain heat affect zone (CGHAZ) thermal cycle with heat input varying from 30 kJ/cm to 60 kJ/cm, the microstructures were investigated by means of optical microscope (OM), scanning electron microscope (SEM), electron backscattering diffraction (EBSD), and transmission electron microscope (TEM), and the impact properties were evaluated fr...

The thermo-mechanical controlled process (TMCP) of 800-MPa-grade non-quenched tempered steel used for penstocks was simulated on a Gleeble-3500 thermo-mechanical simulator. The effect of the finish cooling temperature (FCT) which ranged from 350–550 ◦C on the microstructure and mechanical properties was studied. The microstructure of TMCP specimens is primarily composed of lath bainite (LB) and...

Coalesced bainite is a coarse constituent recently found to develop along with the classical martensite, lower and upper bainite in steel weld metals. Its crystallography has been characterised using electron backscattering diffraction in combination with field emission gun scanning electron microscopy. It is confirmed that coalesced bainite grains are crystallographically homogeneous but do co...