Manufacturing and forming: Wrought iron (a very low-carbon, slag-fiber–containing iron) is shaped using several plastic-deformation and joining processes. Which of the following is a method by which wrought iron is never shaped due to its material characteristics?

Introduction / Context:
Wrought iron is tough, fibrous, and very low in carbon, traditionally produced by puddling or similar processes. Its physical characteristics make it suitable for deformation-based shaping, but unsuitable for others. Recognizing the incompatible process helps distinguish wrought iron from cast iron and modern steels in historical and practical contexts.

Given Data / Assumptions:

• Wrought iron contains slag stringers that confer a fibrous structure.
• Carbon content is very low; melting behavior is different from cast irons.
• Processes considered: casting, cold working, forging, welding.

Concept / Approach:
Casting requires a fluid molten metal that fills a mold cavity. Wrought iron is not produced or shaped by pouring from a fully molten, highly fluid state into molds; that is the domain of cast iron and cast steels. Instead, wrought iron is shaped by plastic deformation (forging, rolling, cold working) and can be forge-welded because of its ductility and low carbon. Thus, “casting” is the method it is never shaped by.

Step-by-Step Solution:

Verification / Alternative check:
Historical blacksmithing and structural applications (gates, rivets, tie rods) were made by forging and welding wrought iron, not by casting components from it.

Why Other Options Are Wrong:

• Cold working: Possible for ductile wrought products (within limits).
• Forging: Primary historical method.
• Welding: Forge welding of wrought iron is well established.

Common Pitfalls:
Confusing “wrought” with “cast” iron; they are fundamentally different products with distinct processing routes and properties.

Final Answer:
casting