Which steelmaking route produces steel that characteristically shows fissures and cavities (blistered appearance)? (Identify the process known for creating blister steel.)

Introduction:
Different historical steelmaking routes generate distinctive microstructural and surface features. The question targets recognition of the route that yields blister steel with visible fissures and cavities on the surface.

Given Data / Assumptions:

• Cementation involves carburizing wrought iron bars in a carbonaceous pack at high temperature.
• Absorbed carbon diffuses inward, creating gas evolution and surface irregularity.
• Products were historically termed “blister steel.”

Concept / Approach:
Carbon absorption and gas formation during cementation cause a blistered surface and internal fissures. Later remelting (crucible) could homogenize, producing higher quality steel (shear or cast steel), but the initial product is blistered.

Step-by-Step Solution:

Verification / Alternative check:
Metallurgical histories consistently depict blister steel as the hallmark of the cementation era before crucible and modern furnaces.

Why Other Options Are Wrong:

• Crucible: used to melt and homogenize; reduces defects.
• Bessemer: pneumatic refining, not producing blisters as a characteristic.
• Open-hearth: bath refining with controlled slag; no blister signature.

Common Pitfalls:
Confusing subsequent refining (crucible) with the initial blister-forming step; assuming any older process produces visible blisters.

Final Answer:
Cementation process