Surface Hardening rau Springs: Puas Yog Rau Koj Daim Ntawv Thov?
Nthuav cov springs uas poob nro sai heev? Deg hardening tsim hnav-resistant nto uas ua rau kom ntev lub caij nplooj ntoos hlav lub neej raws li xav tau tej yam kev mob. Surface hardening increases the