How can you determine quality and what role do the casinos of Monte Carlo play in simulating mechanical properties? Prof. Andreas Kern, Head of Quality Assurance in the Heavy Plate Business Unit, provides an explanation.
Mr. Kern, your business unit deals with sheet metal for large, solid structures. Can you name a few?
Heavy plate is used for applications of considerable size and requiring high load-bearing capacities. For example, you find it in ships, mobile cranes, pipelines, and containers for gas and oil storage.
What are your different jobs?
My department handles quality management and quality assurance during the production process. It means we are constantly inspecting and ensuring the quality of the plate every day. In addition, we work on developing new products and improving existing ones wherever the customer’s requirements demand it.
And how do you do it?
We primarily utilize computational programs that continuously store and compile the data collected from our production operations. It makes it possible to regularly check the information and react quickly and in the appropriate places during the production process.
So much for the ongoing production. What about new developments?
We also use computer-based simulation programs here. They enable us to predictively calculate the mechanical properties of a specific type of steel and put together the right mix of steel and create the manufacturing parameters. By preparing a mathematical model of the mechanical characteristics, we can have an idea of how the new steel will behave.
How does it benefit your customers?
We can greatly reduce the number of experiments and have the new or optimized steels ready more quickly for the overall process using these methods than if we were to work with real test runs. We are able to react to customer needs and requirements quickly and we can deliver a high-quality product with a constant level of quality.
But computer-based simulations are nothing new?
You’re right. And others have also been working with them for a while, both internally with us and at our competitors. However, the Heavy Plate Business Unit uses and pursues modeling in a particularly intensive way. For 20 years now, we have delved into the details of it and passed along the knowledge gained to our in-house colleagues. There is a close exchange of ideas among the cold and hot-rolled strip specialists.
What is special about your material?
We need to design the material so it can withstand great loads on the one hand, and on the other, it needs to remain formable and not suddenly break. Steel used in heavy plate has to be both tough and easy to process. The extent to which both of these properties are present can be different and vary. It all depends on the customer’s project.
What are the criteria for the material when it is used for a gas tank, for example?
It needs to be strong, yet also exhibit a correspondingly high level of resistance to brittle fracture to prevent failure when it’s used in the construction project. It means that the material needs to hold up if it is subjected to a sudden or unusual impact. It cannot suddenly fail and ruin the particular structure.
What types of steel are we talking about here? Which ones are used for it?
I’m thinking about our high-strength, micro alloyed steels or high-nickel steels.
There is a method of modeling called the Monte Carlo method. It sounds a little pretentious or reminiscent of the casino highlife. What is it really?
The Monte Carlo method is a special statistical computational algorithm using random numbers that we use to simulate complex physical processes that cannot be described linearly. It was developed 70 years ago before people started working with computers. And where better to look for random numbers than at the roulette wheel? It constantly generates a random number, something that everyone associates with Monte Carlo.
Is it still used today?
Of course. The only difference now is that the computers generate the random numbers. But remember, the high-quality heavy plate that we manufacture at thyssenkrupp is by no means a random product. It is the result of concerted efforts to produce quality, as well as a product of our high-performance modeling tools – with and without Monte Carlo!