Effect of Pouring Temperature on Microstructures and Mechanical Properties of 7085 Ingot Casting by Finite Element Analysis

The microstructure and mechanical properties of the 7085 ingot casting was tested by OM, SEM and EDS, the fatigue damage was observed in the driving test process, the temperature gradient distribution was adjusted observably by using the FEM simulation analysis. By adjusting the pouring temperature, many micro shrinkage metallurgical defects were eliminated, the tensile strength, yield strength and elongation were raised to 498MPa, 362MPa and 7.4% at the T6 heat treatment state.

Failures Related to Hot Forming Processes

The primary purpose of this article is to describe general root causes of failure that are associated with wrought metals and metalworking. This includes a brief review of the discontinuities or imperfections that may be common sources of failure-inducing defects in the bulk working of wrought products. The article addresses the types of flaws or defects that can be introduced during the steel forging process itself, including defects originating in the ingot-casting process. Defects found in nonferrous forgings—titanium, aluminum, and copper and copper alloys—also are covered.

Analysis of Non-Symmetrical Heat Removal during Cast-ing of Steel Billets and Slabs

Steel is one of the essential materials in the world's civilization. It is essential to produce many products such as pipelines, mechanical elements in machines, vehicles, profiles, and beam sections for buildings in many industries. Until the '50s of the 20th century, steel products required a complex process known as ingot casting; for years, steelmakers focused on developing and simplifying this process. The result was the con-tinuous casting process (CCP); it is the most productive method to produce steel. The CCP allows producing significant volumes of steel sections without interruption and is more productive than the formal ingot casting process. The CCP begins by transferring the liquid steel from the steel-ladle to a tundish. This tundish or vessel distributes the liquid steel, by flowing through its volume, to one or more strands having wa-ter-cooled copper molds. The mold is the primary cooling system, PCS, solidifying a steel shell to withstand a liquid core and its friction forces with the mold wall. Further down the mold, the rolls drive the steel section in the SCS. Here the steel section is cooled, solidifying the remaining liquid core, by sprays placed in every cooling segment all around the billet and along the curved section of the machine. Finally, the steel strand goes towards a horizontal-straight free-spray zone, losing heat by radiation mechanism, where the billet cools down further to total solidification. A moving torch cutting-scissor splits the billet to the desired length at the end of this heat-radiant zone.

Segregations in Steels during Heat Treatment – A Consideration along the Process Chain

Segregation is an unavoidable phenomenon in continuous or ingot casting of steel for thermodynamic reasons. If costly processes that explicitly reduce segregation are not carried out, the segregations remain until the final product. Therefore, an understanding of the development and effects of segregation along the entire process chain is necessary. The focus in this publication is on the treatment of segregations in low alloy steels. First, the characterisation of segregation is presented. An overview of the formation and development of segregations during primary shaping and forming processes is given. The focus is on segregation-related effects during heat treatment with regard to inhomogeneous microstructure and negative heat treatment results such as distortion or hardening cracks. In a short outlook, the influence of segregation on the component behaviour is described. ◼

Perspective Chapter: A Personal Overview of Casting Processes

Casting processes are reviewed from the point of view of the type of defects they produce and their consequential properties of the castings they produce, particularly resistance to fracture, and therefore, their reliability in service. The ingot casting of steels is criticized for unnecessary degradation of the steel. The fundamental problems of continuous casting of aluminum alloys and steels are seen to be lying in inattention to the details of the processes. Vacuum casting, particularly vacuum arc remelting, as currently executed, is seen to be fundamentally unreliable for any safety critical purposes, particularly its history of helicopter tragedies resulting from its use in helicopter drive trains.