[img=,576,142]https://ng1.17img.cn/bbsfiles/images/2015/06/201506301551_552384_2534456_3.jpg[/img]
以下是一个摩托车轴断裂收集到的信息，能否根据这些信息判断出断裂原因？请各位大师不吝赐教。
材料是40CrMo，从边缘到心部硬度为56-59RHC。
[img=,750,292]https://ng1.17img.cn/bbsfiles/images/2015/06/201506301550_552382_2534456_3.png[/img]
[img=,750,468]https://ng1.17img.cn/bbsfiles/images/2015/06/201506301550_552383_2534456_3.png[/img]
[img=,232,256]https://ng1.17img.cn/bbsfiles/images/2015/06/201506301552_552386_2534456_3.jpg[/img][img=,232,255]https://ng1.17img.cn/bbsfiles/images/2015/06/201506301552_552387_2534456_3.jpg[/img]
[img=,528,396]https://ng1.17img.cn/bbsfiles/images/2015/06/201506301553_552388_2534456_3.jpg[/img]
[img=,528,396]https://ng1.17img.cn/bbsfiles/images/2015/06/201506301553_552390_2534456_3.jpg[/img]
[img=,528,396]https://ng1.17img.cn/bbsfiles/images/2015/06/201506301553_552392_2534456_3.jpg[/img]
[img=,528,396]https://ng1.17img.cn/bbsfiles/images/2015/06/201506301553_552393_2534456_3.jpg[/img]
图片在文档中，只好以附件形式上传，请见谅。