Mechanical stress-strain hysteresis, temperature and electrical resistance measurements were performed for the detailed characterisation of the fatigue behaviour of the quenched and tempered steel SAE 4140 (42CrMo4) under constant amplitude loading and service loading. On the basis of generalised Morrow and Basquin equations the fatigue life calculation method “PHYBAL” was developed. Short cons...

A heat transfer study of resistance spot welding has been conducted both theoretically and experimentally. A numerical solution based on a finite difference formulation of the heat equation has been developed to predict temperature distributions as a function of both time and position during the welding process. The computer model also predicts the temperature distribution through the copper el...

In this paper, a fracto-metallographic analysis was performed on the cracked specimens of cold drawn pearlitic steel subjected to fatigue tests. Fatigue cracks are transcollonial and exhibit a preference for fracturing pearlitic lamellae, with non-uniform crack opening displacement values, micro-discontinuities, branchings, bifurcations and frequent local deflections that create microstructural...

In this study the effects of surface texture on the fatigue life of a high-strength low-alloy steel were evaluated in terms of the apparent fatigue stress concentration. An abrasive waterjet was used to machine uniaxial dogbone fatigue specimens with specific surface quality from a rolled sheet of AISI 4130 CR steel. The surface texture resulting from machining was characterized using contact p...

Fatigue is one of the main factors that cause the collapse of steel bridges. Anti-fatigue design therefore draws close attention all over the world. The design must have a fatigue load model based upon native traffic load conditions. But the Chinese steel bridge design specification does not include any fatigue load model for anti-fatigue design. So it is imperative to develop the model. This p...

This paper evaluates the effects of microbiologically influenced corrosion (MIC) on fatigue-crack growth of candidate materials useful in expanding bio-ethanol usage, including a storage-tank steel (ASTM A36) and two pipeline steels (API 5L X52 and X70). The microbiological species sampled and cultivated from an ethanol fuel production stream are responsible for both acetic acid and hydrogen su...

Alloy ASTM A710 (HSLA-80) is a co-precipitation hardened steel with a desirable combination of mechanical properties and weldability, making it an excellent candidate for use in structural applications such as bridges, shipbuilding, and pipelines. There have been extensive studies of the strengthening mechanisms, effect of heat treatment and continuous cooling, and kinetics of the precipitation...

The interior defect-induced fracture of surface-hardened metallic materials in the long life region has become a key issue on engineering design. In the present study, the axial loading test with fully reversed condition was performed to examine the fatigue property of a surface-carburized low alloy gear steel in the long life region. Results show that this steel represents the duplex S-N (stre...