Fatigue behaviour of G20Mn5QT cast steel and butt welds with Q345B steel

Abstract

A total number of 44 fatigue tests were conducted under total stain control, 26 for G20Mn5QT cast steel and 18 for butt welds between G20Mn5QT cast steel and Q345B steel. Based on the test results, cyclic stress response, plastic strain energy, strainlife curves and Coffin-Manson equations were presented. Comparing with hot rolled steels widely used in steel construction, the fatigue behaviour of G20Mn5QT cast steel is poor, the reason for which was imputed to the defects caused by the casting process. The welds between G20Mn5QT cast steel and Q345B steel exhibited similar fatigue performance as G20Mn5QT cast steel. Fatigue crack tends to initiate in the heat affected zone (HAZ) at the cast steel. Microstructure observations using optical and scanning electron microscope showed that casting defects are the common fatigue source for both G20Mn5QT cast steel and the butt welds between G20Mn5QT cast steel and Q345B steel.

A new frequency domain method for random fatigue life estimation in a wide‐band stationary Gaussian random process

“…For the material of cast steel G20Mn5QT (conditioning), from the article, 39 the P-S-N curve with 50% survival probability is given as follows: Through the use of different frequency domain methods, the fatigue life of the structure can be obtained, in which the fatigue life estimation of the rain flow counting method (RF) is used as the control. The result of fatigue life by different methods is shown in Table 6.…”

The microstructure, mechanical, and fatigue behaviours of MAG welded G20Mn5 cast steel

“…Cast steel material has been extensively adopted into manufacturing industries because of its low cost, excellent machinability, and corrosion resistance . In the locomotive industry, cast steel has also become the preferred material to build up the railway vehicle bogie frames, longitudinal stop blocks, and brake shoe seats .…”

“…Recently, welded cast metals have gained increasing interests into scientific and engineering communities. In order to effectively join large‐sized structures such as these, various welding methods have been developed during the past several decades . However, the welding process can subject materials to nonuniform thermal cycles, which, in turn, can induce significant changes in microstructures and mechanical strength as well as the fatigue behaviours of final components …”

“…In order to effectively join large-sized structures such as these, various welding methods have been developed during the past several decades. 3,[8][9][10][11] However, the welding process can subject materials to nonuniform thermal cycles, which, in turn, can induce significant changes in microstructures and mechanical strength as well as the fatigue behaviours of final components. [12][13][14][15] With the increased popularity of China high-speed railway in the past few years, the operating conditions of railway vehicles have become more stringent.…”

Corrosion fatigue behaviour and microstructural characterisation of G20Mn5QT cast steel in 3.5‐wt% NaCl solution

“…As for G20Mn5QT cast steel, the heat treatment process greatly affects the microstructure of cast steel, the welding behaviour, and the corrosion and corrosion fatigue performance in a corrosion solution . At present, Han et al analysed the fatigue performance of G20Mn5QT cast steel in laboratory air at the strain ratios of −1 and 0.1. Microstructure observations using optical microscopy (OM) and SEM indicated that casting defects would induce the fatigue crack initiation in both G20Mn5QT cast steel and butt welds.…”