Analysis and Discussion on the Influence of Multiple Factors of Hairline Cracks on the Fatigue Life of 45B Pin Shafts
LI Xiangcai
LIU Jinqiang
CHEN Xinyan
ZHANG Linlin
FAN Junkai
Abstract：This paper uses the finite element software and based on the general fatigue S-N curve of structural steel,simulates and studies the influence of various factors such as the length,width,and the presence or absence of internal inclusions of cracks on the fatigue of 45B pin shaft steel on different crack detection steps.The following conclusions are ultimately drawn:The detection standard of pin shaft billets using the acid immersion crack inspection result as the judgment basis is not scientific.The crack inspection should take the magnetic particle inspection result as the judgment basis;it is reasonable to use 1 mm as the starting length for crack length;when the crack width is less than 0.4 mm,its fatigue life remains basically unchanged;when the crack width is greater than 0.4 mm,the fatigue life of the crack gradually increases;for internal inclusion-type cracks,it can be considered that they have no effect on the fatigue life of the pin shaft;when the crack is greater than 4 mm,the fatigue life of the pin shaft basically approaches 0.The original standard using 5 mm length as the judgment basis is not appropriate.A unified judgment standard can set the crack limit length to 4 mm.
Keywords：finite element softwareS-N curvehairlinesteel for pin shaftmagnetic powder inspection
Publication Date：2025-08-20
Online Publishing Date：2026-05-22(First online date of this platform, not the publication date of the document)
Pages：6( 30-35 )