Design & Technology - 0445 CIE

Metals

Akopọ

Metals give us the strongest, most enduring everyday objects: the steel in a car body, the aluminium in a drinks can, the copper in the wiring behind your wall. What makes metals special is a combination of strength, ductility and the ability to conduct heat and electricity, plus a property that polymers and timbers lack - the structure of a metal can be changed by force or heat to make it harder, tougher or softer to suit the job.

This note covers the 0445 Materials-option metals objectives: classifying metals and their stock forms, properties, environmental impact and uses; the ferrous metals and alloys (cast iron, mild steel, stainless steel, high-speed steel and the carbon steels); the non-ferrous metals and alloys (aluminium, copper, lead, tin, zinc, brass, duralumin, pewter); and how work hardening and heat treatments change the molecular structure to alter properties.

Awọn Afojusun

  1. demonstrate knowledge of metals and understand their classification, stock forms, properties, environmental impact and uses
  2. demonstrate knowledge of ferrous metals and alloys, for example: - cast iron - mild steel - stainless steel - high-speed steel (HSS) and carbon steels
  3. demonstrate knowledge of non-ferrous metals and alloys, for example: - aluminium - copper - lead - tin - zinc - brass - duralumin - pewter
  4. understand how work hardening and heat treatments can affect the properties of metals by changing the molecular structure.

Akọ̀wé Ẹ̀kọ́

The first division of metals is whether they contain iron. Ferrous metals contain iron as their main element (the Latin ferrum means iron). Because they contain iron, most ferrous metals rust when exposed to moisture and oxygen, and most are magnetic. Non-ferrous metals contain little or no iron - aluminium, copper, zinc and so on - so they resist corrosion better and are generally not magnetic. An alloy is a mixture of two or more metals (or a metal and another element) made to combine their best properties: brass mixes copper and zinc to be harder and more corrosion-resistant than either alone, while steel is iron alloyed with carbon.

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Ìdánwò Ẹ̀kọ́

Oriire fun ipari ẹkọ lori Metals. Ni bayi ti o ti ṣawari naa awọn imọran bọtini ati awọn imọran, o to akoko lati fi imọ rẹ si idanwo. Ẹka yii nfunni ni ọpọlọpọ awọn adaṣe awọn ibeere ti a ṣe lati fun oye rẹ lokun ati ṣe iranlọwọ fun ọ lati ṣe iwọn oye ohun elo naa.

Iwọ yoo pade adalu awọn iru ibeere, pẹlu awọn ibeere olumulo pupọ, awọn ibeere idahun kukuru, ati awọn ibeere iwe kikọ. Gbogbo ibeere kọọkan ni a ṣe pẹlu iṣaro lati ṣe ayẹwo awọn ẹya oriṣiriṣi ti imọ rẹ ati awọn ogbon ironu pataki.

Lo ise abala yii gege bi anfaani lati mu oye re lori koko-ọrọ naa lagbara ati lati ṣe idanimọ eyikeyi agbegbe ti o le nilo afikun ikẹkọ. Maṣe jẹ ki awọn italaya eyikeyi ti o ba pade da ọ lójú; dipo, wo wọn gẹgẹ bi awọn anfaani fun idagbasoke ati ilọsiwaju.

  1. Which of the following is a ferrous metal? A. Copper B. Aluminium C. Mild steel D. Brass Answer: C
  2. Brass is an alloy of which two metals? A. Iron and carbon B. Copper and zinc C. Aluminium and copper D. Tin and lead Answer: B
  3. Which property makes high-speed steel (HSS) suitable for drill bits and cutting tools? A. It is the cheapest steel available B. It is non-magnetic C. It keeps its hardness even at high cutting temperatures D. It cannot rust under any conditions Answer: C
  4. What is the effect of work hardening on a metal? A. It softens the metal and makes it more ductile B. It makes the metal harder and stronger but more brittle C. It melts the metal D. It has no effect on properties Answer: B
  5. Why is high-carbon steel tempered after it has been hardened? A. To make it even harder B. To remove some brittleness and increase toughness C. To make it rust-resistant D. To increase its carbon content Answer: B

O wa lori ohun elo Green Bridge

Gba ohun elo Green Bridge CBT sori foonu tabi kọmputa rẹ lati ri awọn akọsilẹ ẹkọ ni kikun, awọn ibeere adaṣe, ati diẹ sii.

Awọn akọsilẹ ẹkọ ni kikun pẹlu awọn aworan apejuwe
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Kọ ẹkọ laisi intanẹẹti, nigbakugba, nibikibi
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O wa lori ohun elo Green Bridge

Gba ohun elo Green Bridge CBT sori foonu tabi kọmputa rẹ lati ri awọn akọsilẹ ẹkọ ni kikun, awọn ibeere adaṣe, ati diẹ sii.

Awọn akọsilẹ ẹkọ ni kikun pẹlu awọn aworan apejuwe
Oluranlọwọ ẹkọ ti AI ṣe agbara rẹ
Kọ ẹkọ laisi intanẹẹti, nigbakugba, nibikibi
O wa lori Android, Windows, macOS, ati Linux

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