---
title: "Cast iron versus wrought iron"
subject: "Civil Engineering Materials"
chapter: 8
key: "semester_3/civil_engineering_materials:cast-iron-vs-wrought-iron"
source: https://www.bctengineer.com/q/semester_3/civil_engineering_materials/cast-iron-vs-wrought-iron
site: BCT Engineering
---

# Cast iron versus wrought iron

Civil Engineering Materials · Chapter 8: Metals and Alloys

- Asked in: 2078 Kartik, 3 marks
- Video: [Difference Between Pig iron, Wrought iron, Cast Iron, And Steel - An Overview.](https://www.youtube.com/watch?v=rp5_Al2JXAg) — James Sword Engineering 
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_3/civil_engineering_materials/cast-iron-vs-wrought-iron
- Whole chapter: https://www.bctengineer.com/md/semester_3/civil_engineering_materials/chapter-8

## Question

Differentiate between cast iron and wrought iron.

## Short answer

Cast iron has 2-4.5% carbon, is hard and brittle, strong in compression but weak in tension, used for pipes and columns. Wrought iron has below 0.15% carbon, is soft, tough, can be forged/welded, and used for ornamental work, gates.

## Answer

| Point | Cast iron | Wrought iron |
|---|---|---|
| Carbon content | 2-4.5% | Below 0.15% (almost pure iron) |
| Production | Remelting pig iron in a cupola | Puddling pig iron in a furnace |
| Nature | Hard and brittle | Soft, tough, ductile and malleable |
| Tensile strength | Low | High |
| Compressive strength | High | Moderate |
| Forging / welding | Cannot be forged or welded easily | Can be forged and welded |
| Fusibility | Melts easily (lower melting point) | Melts at high temperature; not cast |
| Corrosion | Resists rust well | Resists rust (due to slag fibres) |
| Fracture | Granular | Fibrous |
| Use | Pipes, columns, manhole covers, brackets | Gates, railings, chains, rivets, ornamental work |

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. Carbon content of cast iron and wrought iron respectively:
   A. Below 0.15% and 2-4.5%
   B. 2-4.5% and below 0.15%
   C. Both about 1%
   D. Both above 4.5%
   Answer: B. Cast iron is high carbon; wrought iron is almost pure iron. (Key point: Carbon content)

2. Which is correct?
   A. Cast iron is ductile and forgeable
   B. Wrought iron is brittle and cannot be forged
   C. Cast iron is hard and brittle and cannot be forged or welded easily; wrought iron is tough, ductile and can be forged and welded
   D. Both can be forged
   Answer: C. Wrought iron is malleable and weldable; cast iron is not. (Key point: Nature and working)

3. Which strength statement is correct?
   A. Cast iron: low tensile, high compressive; wrought iron: high tensile
   B. Cast iron: high tensile
   C. Wrought iron: higher compressive than cast iron
   D. Both equal
   Answer: A. Cast iron is strong in compression but weak in tension. (Key point: Strength)

## Related in Civil Engineering Materials

- [Cast iron versus steel](https://www.bctengineer.com/question.md?key=semester_3%2Fcivil_engineering_materials%3Acast-iron-vs-steel) — Civil Engineering Materials, chapter 8, asked 2×
- [Compare cast iron, steel, aluminium](https://www.bctengineer.com/question.md?key=semester_3%2Fcivil_engineering_materials%3Acompare-cast-iron-steel-aluminium) — Civil Engineering Materials, chapter 8
- [Cast iron manufacture and properties](https://www.bctengineer.com/question.md?key=semester_3%2Fcivil_engineering_materials%3Acast-iron-manufacture-properties) — Civil Engineering Materials, chapter 8

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