STUDIES ABOUT PROLONGING SERVICE LIFE OF PIERCING PLUG

Analyzed in the paper are the inactivation mechanism and the improvement of the matetial of the piercing plug. The said inactivation mechanism involves nose-flattening, steel pickup and cracking. Experimental research of rare earth aluminium alloying was conducted with the H13 Steel piercing plug. The experiment result shows that rare earth aluminium alloying can provides the plug such advantages as considerably improved castibility, elimination of the central porosity, fine grains and carbides as well as reduction of contents of S and P. Trial piercing operation has proven- that service life of the said H13 St. rare earth aluminium alloyed piercing plug is 40% longer than that of the H13 St. piercing plug.