METHOD OF TREATING BUSHINGS OF CATERPILLAR TRACKS Russian patent published in 1997 - IPC

FIELD: mechanical engineering. SUBSTANCE: bushings are made from steel with lowered hardening and carbon content 0.65-0.75% which is micro-alloyed with carbonitride-forming elements and subjected to bulk and surface hardening followed by low drawing to form, on outer and inner surfaces of bushing, strengthened layer with depth constituting 0.17-0.25 thickness of wall and with drawn martensite structure and, in its core, with fine-lamellar perlite or hardening troostite structure. EFFECT: increased reliability determined by increased resistance to abrasive wear and impact loads. 3 tbl