Effect of Ce Content on Microstructure-Toughness Relationship in the Simulated Coarse-Grained Heat-Affected Zone of High-Strength Low-Alloy Steels

The study aimed to identify a moderate degree of Ce addition to improve the toughness in the simulated coarse-grained heat-affected zone (CGHAZ) of high-strength low-alloy steels, based on the effect of the Ce content on particle characteristics, microstructure and impact toughness. Three steels with 0.012 wt.%, 0.050 wt.% and 0.086 wt.% Ce content were subjected to 100 kJ/cm heat input in their thermal welding cycles. The particles and microstructures in the simulated CGHAZ of each steel were characterized and the impact-absorbance energy levels were measured at −20 °C. The results indicated that Ce2O2S inclusion compounds were gradually modified to CexSy-CeP and CeP with the increasing of the Ce content. A higher fraction of acicular ferrite was formed in the 0.012 wt.%-Ce-treated steel due to the lower mismatch between Ce2O2S and α-Fe. Furthermore, a lower fraction of M-A constituent was obtained in the 0.012 wt.%-Ce-treated steel. As a result, superior toughness and a typical amount of ductile fracture were detected in the simulated CGHAZ of the 0.012 wt.%-Ce-treated steel. Compared with the 0.012 wt.%-Ce-treated steel, a smaller prior austenite grain was observed in the 0.086 wt.%-Ce-treated steel because of the segregation of CeP at the grain boundary. However, the larger size and density of CeP led to poor toughness in the CGHAZ of the 0.086 wt.%-Ce-treated steel.

Evaluation of inclined crack in mixed mode I and II

In this work,we tented to study the mixed mode of failure with two angles of inclination, of a treated steel, for that we tried to determine the parameters of failure as the stress intensity factor, tenacity and the critical energy in mixed mode of a rupture and see the criterion of rupture and seeing the effect of the angles evolution applied for all parameters. of in our close there is a fragile and less ductile rupture.

Effect of Sub-Zero Treatments and Tempering on Corrosion Behaviour of Vanadis 6 Tool Steel

Sub-zero treatment of Vanadis 6 steel resulted in a considerable reduction of retained austenite amount, refinement of martensite, enhancement of population density of carbides, and modification of precipitation behaviour. Tempering of sub-zero-treated steel led to a decrease in population density of carbides, to a further reduction of retained austenite, and to precipitation of M3C carbides, while M7C3 carbides precipitated only in the case of conventionally quenched steel. Complementary effects of these microstructural variations resulted in more noble behaviour of sub-zero-treated steel compared to the conventionally room-quenched one, and to clear inhibition of the corrosion rate at the same time.