Development of micro rotary swaging tools of graded tool steel via co-spray forming Chengsong Cui, Alwin Schulz, Matthias Steinbacher, Eric Moumi, Bernd Kuhfuss, Florian Böhmermann and Oltmann Riemer Manufacturing Rev., 2 (2015) 22 Published online: 17 November 2015 DOI: 10.1051/mfreview/2015024