Performance characteristics of materials Performance characteristics of papers and boards - Performance characteristics of metals — AQA A-Level Design and Technology: Product Design
Verified courseTeaching note checked against the official specification.
Performance characteristics of materials Performance characteristics of papers and boards - Performance characteristics of metals explained
In this specification, 'flat' names a stock form in which metals are supplied, not a performance characteristic such as strength or hardness.
Read the full explanation
Metals reach the workshop as flat bar or flat section: rectangular cross-section stock that is wider than it is thick, sold as strip or bar of a stated width and thickness. A designer selects flat stock when a component needs a broad, low-profile face, for example a bracket base, a reinforcing plate or a hinge leaf, and then considers the genuine performance characteristics of the chosen alloy, such as tensile strength, hardness, malleability, conductivity and resistance to corrosion. Recognise that flat describes geometry and supply, so questions about how a metal performs in service are answered with material properties, while questions about what arrives from the supplier are answered with stock form.
Your focus
- State that 'flat' refers to a metal stock form, namely flat bar or flat section.
- Distinguish stock form from performance characteristics such as strength, hardness and malleability.
- Select flat stock appropriately for a component needing a broad, low-profile face and justify the choice by reference to the alloy's properties.
Performance characteristics of materials Performance characteristics of papers and boards - Performance characteristics of metals exam tips
Marking Points
- Identifies 'flat' as a form of metal supply (flat bar or flat section) rather than a performance characteristic.
- Describes flat stock as rectangular cross-section material that is wider than it is thick.
- Distinguishes stock form from genuine performance characteristics such as tensile strength, hardness, malleability, conductivity or corrosion resistance.
- Links the choice of flat stock to a suitable product context, such as a bracket base, plate or hinge leaf needing a broad low-profile face.
- Recognises that the performance of a flat component still depends on the alloy selected, not on its being flat.
Examiner Tips
- 💡Read the question stem to see whether it asks about supply form or material performance before choosing an answer.
- 💡When a term names a stock form, reject options that describe mechanical or physical properties.
- 💡Justify your choice by naming the actual property or stock form involved, for example flat bar versus tensile strength.
Common Mistakes
- Treating 'flat' as a measure of flatness or surface quality of sheet metal; correct this by identifying it as a stock form supplied as flat bar or flat section.
- Assuming flat stock is a performance characteristic such as strength; correct this by separating supply form from material properties like tensile strength and hardness.
- Confusing flat bar with sheet or plate; correct this by noting that flat bar has a rectangular cross-section with a defined width and thickness rather than a thin, wide sheet format.