|
|
|
| Fracture Analysis of Firing Pin |
| HAN Jing,WANG Li-hui,LI Hui |
| Qiqihar Railway Rolling Stock Group Co.��Ltd., Qiqihaer 161002, Heilongjiang, China |
|
|
|
|
Abstract During empty gun firing experiment of shotgun produced by a company, fracture of some firing pins occurred. Chemical analysis, metallography, scanning electron microscopy and other methods were carried out to analyze the reasons for the formation of fracture. The experimental results show that the fracture mechanism of firing pins is fatigue fracture, chemical composition and microstructure of firing pin are normal. But the surface decarburization of firing pin led firing pin surface weakened, making surface hardness and strength of firing pin significantly lower than the base, accelerating the formation of fatigue source. The firing pins withstand greater alternating stress, which accelerated fatigue source extensions. Comprehensive analysis indicated that the firing pin breakage is due to the carbon layer which causes early fatigue fracture.
|
|
Received: 23 September 2013
Published: 24 February 2014
|
|
|
|
|
|
|
2014, Vol. 32 
