Cracking Susceptibility Of Steel Research Articles

A Novel Approach for the Simulation of Surface Crack Formation in Continuous Casting

The present study describes the possibilities of new experimental and numerical methods to predict the crack susceptibility of steels under continuous casting (CC) conditions. The first method—the In-Situ Material Characterization by Bending (IMC-B) Experiment allows measuring the critical strain values for surface defects upon all the most important process and material parameters. The IMC-B experiment uses solidified samples obtained directly from the melt and is based on the 3-point bending test. Strains are calculated directly after the experiment has used a simulation in Abaqus. The risk of surface cracks is shown by using the new numerical tool, so-called defect indices implemented in IDS. In the framework of practical series, a crack susceptibility of the commercial Nb-microalloyed steel is investigated after the subsequent cooling to the test temperature. Samples cast at two different cooling conditions show another distribution of surface defects and critical strain value.

Mechanical properties and crack susceptibility of steel during solidification

The determination of high temperature mechanical properties is a necessity for the better understanding of defect formation during continuous casting of steel. Although a lot of studies have been performed on this topic, some aspects like the influence of cast structure on crack susceptibility are still unclear. The present paper focuses on the effect of carbon on high temperature strength and crack susceptibility. Tensile tests have been performed on steel shells with different carbon content during solidification. The results indicate an important influence of the orientation of the inhomogeneous cast structure towards main stress axis. The initial shell with a thickness of only a few millimetres is more sensitive to defect formation than commonly believed. The critical limits of straining range from about 0.15 to 0.4 %. With increasing shell thickness, the critical strain ascends up to 1.6 %. The detected segregated internal cracks form within the critical temperature range. The strength near solidus temperature is lower than in comparable hot tensile tests, which can also be attributed to the detrimental effect of the inhomogeneous structure. The strength at solidus temperature amounts to 2.5 MPa for higher carbon steels and about 1 MPa for low carbon steels.

Determination of thermal and strain dependences characterising the cold cracking susceptibility of steels in welding

Determination of thermal and strain dependences characterising the cold cracking susceptibility of steels in welding