Cast Iron & Pig Iron — Source and Properties Which of the following statements about ironmaking and cast irons is correct?

Introduction / Context:
Understanding the flow from ore to product and the microstructures of cast irons is fundamental in materials engineering. Terms such as blast furnace, pig iron, cupola, gray iron, white (chilled) iron, and graphite morphology often appear in exams and industry discussions.

Given Data / Assumptions:

• Blast furnace produces hot metal (pig iron) as primary product.
• Cupola is a remelting furnace mainly for producing cast iron from pig iron and scrap.
• Cast iron categories include gray, white (chilled), malleable, and ductile (SG) irons.

Concept / Approach:
Pig iron is the high-carbon iron from the blast furnace, typically cast into ingot molds called pigs. It is then remelted (often in a cupola or induction furnace) to make cast iron. Gray cast iron contains flake graphite and has good compressive strength but relatively low tensile strength. Chilled (white) cast iron forms when rapid cooling promotes carbide formation (cementite) instead of graphite; hence it shows no free graphite, giving a hard, brittle, wear-resistant surface.

Step-by-Step Solution:
Identify blast furnace product: pig iron (not cast iron).Identify cupola product: cast iron from remelting (not pig iron).Recall property: chilled iron solidifies as cementite networks, lacking graphite.Therefore the correct statement is that chilled cast iron has no graphite.

Verification / Alternative check:
Micrographs of white iron show ledeburite/cementite with virtually zero graphite, confirming the statement.

Why Other Options Are Wrong:
(a) Blast furnace product is pig iron, not cast iron.(b) Cupola produces cast iron; pig iron comes from blast furnace.(c) Cast iron generally has low tensile strength compared with steels; its compressive strength is higher.

Common Pitfalls:
Confusing process steps: ore → pig iron (BF) → cast iron (cupola/other) → components.

Final Answer:
The chilled cast iron has no graphite.