A
plunger for use in manufacturing glass containers comprises a first portion configured for contact with a gob of
molten glass, and a second portion. At least the first portion has a
metal coating of a self-fluxing Fe-based
alloy and with a microhardness between 300 HV0.3 and 900 HV0.3. The Fe-based
alloy comprises in wt. %): C, 0.5-2.5; Si, 1.0-4.0; B, 1.5-6.0; Cr, 15.0-30.0; Ni, 0-5.0; Co, 15.0-40.0; W, 1.2-5.0; Mo, 0-5.0; Cu, 0-5.0; P, 0-3.0; and N, 0-1.0. The Fe-based
alloy may further comprise metals selected from Al, Mn, Nb, S, Ti, V, Zn And Zr each in an individual amount that ranges from 0.01 wt. % to about 2 wt. %, with the overall content of the additional metals less than 10 wt. %.