ASM Failure Analysis Case Histories: Automobiles and Trucks
An Example of Incidence of Non-Metallic Inclusions in an Alloy Steel
There was a large incidence of surface defects on the crank pins and journals and other areas of crank shafts of a high power automotive engine. The steel used was a Cr-Mo type of nitriding steel. Metallographic observations conclusively proved that the defective areas were entrapment of foreign bodies, resulting from steel making/deoxidizing/teeming stages. The occasionally globular nature of the foreign particles suggested these were formed at the liquid condition of the steel. The ratio of Mn-Si as seen on electron probe microanalysis also suggested the globules high in Mn content might have resulted in deoxidizing stage. Particularly the absence of Fe in some areas in the inclusion was indicative of precipitation deoxidation by ferromanganese/ferrosilicon. The defects apparently did not have time to coalesce and rise up to the top.
P. K. Chatterjee, An Example of Incidence of Non-Metallic Inclusions in an Alloy Steel, ASM Failure Analysis Case Histories: Automobiles and Trucks, ASM International, 2019, https://doi.org/10.31399/asm.fach.auto.c9001256
Download citation file:
New Handbook: Volume 11B
Now available in the Digital Library! Volume 11B serves as a reference and guide to help engineers determine the causes of failure in plastic components and make corrective adjustments through design and manufacturing modifications.