Accurate finishing treatments, which eliminate every possible microcracks sources, and the application of an external compressive stress (“residual stress”), are the key factors for fatigue resistance maximization.
To obtain the maximum performance from valves, precise and standardized tumbling processes are needed, with custom-made receipts, carefully studied to satisfy the requirements of each customer.
That’s why our R&D Department has been working for some years with the best Italian University Centers studying the residual stress level achievable on flapper valves and the optimization of the relevant production processes.
Through the tumbling we are able to obtain up to 100 MPa increase with respect to the starting material properties.
We continually deepen our technical knowhow to make the relationship with our customers more and more effective.
To punctually measure residual stress we purchased a highly valuable instrument, a diffractometer manufactured by the German company Bruker.
The instrument works by emitting X-rays beams, that is a spectrum of electromagnetic radiation capable of penetrating bodies that are opaque to ordinary light: these rays allow to investigate the internal features of the steel, its microstructure and inter-crystalline distance.
After the tumbling, the steel that makes up the valves is hardened, that is, is made more resistant.