Abstract: This paper introduces the experimental study of fatigue fracture of 1050 type box steel 43CrNi_2MoV.A series of experiments showed that tempering temperature influences steel s fatigue properties when the temperature is about 620℃; steel 43CrNi_2MoV has a high fatigue fracture strength; high frequency surface treatment adding in shot peening and surface explosive hardening obviously enhances steel s fatigue life; and hydrochloric acid solution causes fatigue crack to engender and expand much faster.

Key words: Fracturing pump, Alloy steel, Fatigue failure, Surface Pretreatment