Official Answer
Answer
Installation stress cracking occurs when a ring is expanded (or contracted) beyond its material's ductility limit during assembly, causing immediate fracture or micro-cracking. It is identified by: 1) A fracture surface located $180$ degrees from the gap (the point of maximum strain); 2) Evidence of 'necking' or plastic deformation near the break; 3) The fracture occurring specifically during the assembly process. This is common if the wrong installation tool is used or if the ring is 'spiraled' onto a shaft too aggressively. For high-carbon steels, ensuring the material is properly tempered and the installation tool limits expansion to $105\%$ of the shaft diameter is critical.
