News 
All manufacturers are now concerned with the elimination of lead-containing steel components such as 20AP.
The widely appreciated advantages of this material include its good machinability, enabling high cutting speeds, a very good surface finish before burnishing as well as low wear on cutting tools. No wonder that 20AP has become the basic steel used in the watch industry. Some disadvantages should nevertheless be mentioned: its propensity to oxidation, the lack of homogeneity seen in batches and especially its lead content, which the RoHS directive aims to limit.
The European RoHS directive (Restriction of the use of certain Hazardous Substances) aims to limit the use of six dangerous substances, including lead, whose maximum tolerated level is restricted to 0.1%.
When MPS Watch began its mobile business in 2014, it immediately began looking for alternatives to replacing 20AP and focused its research in two directions: lead-free steels and stainless steels. The selection of alternatives is based on Finemac and LAW 100 lead steels on the one hand; and on X35ST+, 1.4305 and 1.4197 stainless steels on the other. It should be noted that MPS Watch has been using these to manufacture its ball-bearing components for more than ten years.
Many tests were necessary – relating to cutting speeds, cutting-tool development, lubrication – before mobile gears (or any other movement components) could be manufactured to meet the demanding dimensional and aesthetic criteria required by manufacturers. And all this had to be done without neglecting economic constraints.
Five years of regular practice in machining the main alternatives to 20AP steel have enabled MPS Watch to acquire solid industrial experience and to become an expert in this field.
March 28, 2019