Page 30 - Best of 2019 English

a little more molybdenum or other alloying agents have to be added to the steel,” says Dr. Charles Stallybrass, who is responsible for the Materials Engineering Unit in the Materials Development Department. SZMF will sometimes even go into pre-development and experiment with steels that are subsequently used at the Mannesmannröhren plant in Zeithain, where they undergo industrially processing to make pipes.
Time and again, SZMF bases advice to custom- ers on simulations, such as: “You have to increase the temperatures in the rolling process in order to achieve such and such an outcome”. Customers are amazed when the simulation anticipates reality. As Dr. Mentz recalls: “Our calculations once showed that there ought to be cracks at a certain point on a forming stand. The immediate response from the plant was: “We don't have any cracks there”. But when they looked more closely, they did actually find fine cracks.”
So how can a material as complex as steel be so “predictable”? Because there are the three ways in which its properties can be influenced, and each of these can be expressed in figures: the compo- sition of the steel in terms of the quantities of ingredients, heat treatment based on temperature and time, and forming based on the forces that act on the steel during the rolling process. “In this context, we’re using increasingly finer-res- olution methods and more powerful simulation software based on material databases as well as thermodynamic databases,” says Dr. Ritterbach.
One well-known technique is the finite ele- ment method (FEM), which can be harnessed
to investigate the mechanical properties of a car body panel, for instance. In lay terms, it works like this: if the software knows what the hammer head is made of as well as the force and angle of the impact, it can calculate precisely the dent that will be made in the sheet metal and show it in 3D.
By contrast, Dr. Juliane Mentz and her team use simulation tools that primarily perform thermody- namic calculations – in other words, they inves- tigate the impact of temperature and time on the material.
Numerical simulation: this calculation looks at the impact of process parameters on the joint area in submerged arc welding
Experiment: five-wire production plant for the process-oriented investiga- tion of submerged arc welding – e.g. longitudinally welded large-diameter pipes
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