Design & Technology (9-1) - 0979 CIE

Metals

Bayani Gaba-gaba

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.

Manufura

  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.

Takardar Darasi

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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Nazarin Darasi

Barka da kammala darasi akan Metals. Yanzu da kuka bincika mahimman raayoyi da raayoyi, lokaci yayi da zaku gwada ilimin ku. Wannan sashe yana ba da ayyuka iri-iri Tambayoyin da aka tsara don ƙarfafa fahimtar ku da kuma taimaka muku auna fahimtar ku game da kayan.

Za ka gamu da haɗe-haɗen nau'ikan tambayoyi, ciki har da tambayoyin zaɓi da yawa, tambayoyin gajeren amsa, da tambayoyin rubutu. Kowace tambaya an ƙirƙira ta da kyau don auna fannoni daban-daban na iliminka da ƙwarewar tunani mai zurfi.

Yi wannan ɓangaren na kimantawa a matsayin wata dama don ƙarfafa fahimtarka kan batun kuma don gano duk wani yanki da kake buƙatar ƙarin karatu. Kada ka yanke ƙauna da duk wani ƙalubale da ka fuskanta; maimakon haka, ka kallesu a matsayin damar haɓaka da ingantawa.

  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

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Akwai a Android, Windows, macOS, da Linux

Akwai a cikin manhajar Green Bridge

Zazzage manhajar Green Bridge CBT a wayar ka ko kwamfyuta ka don samun cikakkiyar bayanan darasi, tambayoyin aiki, da ƙari.

Cikakkiyar bayanan darasi tare da zane-zane
Mataimakiyar koyo da AI
Yi karatu ba tare da intanet ba, a kowane lokaci, a ko'ina
Akwai a Android, Windows, macOS, da Linux

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