Skip to Main Content

Abstract

The 1040 steel crankshaft in a reciprocating engine cracked within one year of operation. The journals of the main and crankpin bearings were inspected by the magnetic-particle method. Three to six indications of 1.5 to 9.5 mm long discontinuities were observed in at least four of the main-bearing journals. A crack along the fillet, almost entirely through the web, was observed in one of the main-bearing journals. Numerous coarse segregates, identified as sulfide inclusions, were identified by macroetching the surface during metallographic examination of a section taken through the main-bearing journal at the primary crack. Fatigue cracking with low-stress high-cycle characteristics was disclosed during macroscopic examination of the crack surface. Sulfide inclusions, which acted as stress raisers, were found to be present in the region where cracking originated. As a corrective measure, ultrasonic inspection was used in addition to magnetic-particle inspection to detect discontinuities.

You do not currently have access to this chapter.
Don't already have an account? Register

2019. "Fatigue Cracking of a 1040 Steel Crankshaft Because of Excessive Segregation of Nonmetallic Inclusions", ASM Failure Analysis Case Histories: Automobiles and Trucks

Download citation file:


Close
Close Modal
This Feature Is Available To Subscribers Only

Sign In or Create an Account

Close Modal
Close Modal