Lesson video

Hi there everybody, my name is Mr. Butt and welcome to your design and technology lesson for today.

It's brilliant that you could join me.

Today's lesson is all about metal properties, sources and stock forms. So we are gonna be taking a look at the properties of metals, the sources of where we get metals from, and also how we process them into stock forms so we can use them for our products.

This lesson is part of the materials testing unit.

Today's outcome, I want you to be able to describe where different materials come from, and identify their common stock forms with a focus on metals.

We have three keywords today, the first is metal: a shiny solid material.

We're gonna keep it as simple as that for now.

We then have properties: the characteristics of a material that determine how it looks, feels and behaves when used.

And then, we have stock form: the standard shapes and sizes in which materials like metals are supplied.

Two learning cycles today, the first is about sourcing and processing materials, so let's take a look.

A source is where a material originally comes from.

Metals occur naturally and are mined from the earth.

Metal raw material types are ores containing metals, metal compounds, such as iron ore and ores are mined.

And here you can see an iron ore mine in the image.

We also have what we call native metals, those that do not require any extraction, such as gold.

You might have heard a term called panning for gold, where people find gold in rivers.

The metal must be extracted from the ore and processed.

And here we have a few common ores.

The first is iron ore, which is known as haematite.

We have copper ore, that is malachite and tin ore, cassiterite.

So all these ores occur naturally in the ground, but we've gotta extract those metals out of them.

There are several processes for extracting metals.

For copper and silver, it's a chemical reaction.

For zinc, iron and tin, it's a carbon reduction.

And for aluminum, sodium and magnesium, electrolysis is used.

Now, the chemical reaction is quite easy to extract.

And as we get down towards electrolysis, that is far more difficult to extract and it also uses lots of energy.

Quick check for understanding, where do ores come from? Is it A, they are made in factories from melted metals; B, they are naturally found in rocks underground; or C, they are formed when plants decompose in soil.

Have a go at this, pause the video now and come back to me when you've completed it.

It is of course, B, they are naturally found in rocks on the ground.

After metals are extracted and refined, they are melted and cast into what we call ingots.

Now these are large solid blocks of metal as you can see in that image.

These ingots can then be reheated and they can be processed into what we call blooms, slabs and billets before then being made into their final stock form before they're made into products.

Let's have a closer look at that process then.

So we have our ingots, we then can then make 'em into a bloom, a slab or a billet, and then they can be manufactured into stock forms. And here we have three examples, the first is an I shaped, cross-section beam.

We have sheets or coils, and then also bars, rods, and wires.

So you can see the process from ingots all the way through to a stock form there.

Metals can be categorized as ferrous, non-ferrous and alloys.

Now from all the images in this picture, can you identify any examples of each from this collection? Why don't you pause the video now, have a look and see how many of the metals you can identify and see if you can categorize them into ferrous, non-ferrous and alloy.

Pause the video now, have a go at that and come back to me when you've done it.

So how did you get on? Well, I can certainly see materials like stainless steel in there.

I think I can see aluminum, maybe pewter, iron, copper, and maybe brass as well.

Let's have a look at what else you might have been able to see.

Now ferrous, that's a mined metal containing iron.

Most are magnetic and they rust apart from the alloy stainless steel and wrought iron.

So here we have cast iron and this is an engineer's vice.

We also have stainless steel, which is an alloy, with chromium, magnesium and nickel.

And that's also what all our cutlery is made of.

We also have non ferrous, now this is a mined metal, which does not contain iron.

It's not magnetic and has a higher resistance to rust and corrosion.

Examples of this include aluminum and of course, copper in our wires.

Alloys are manufactured by mixing metals or combining with another element to make them stronger, harder, lighter in weight or better in some other way to improve those or enhance those properties.

Brass, that is of course, an alloy of copper and zinc.

And we have solder and in this case, it's lead and tin, that's just one combination, there are many combinations of solder alloy.

Metals can be heat treated to modify their properties as well.

For example, annealing to soften and improve malleability, the ability of a metal to be shaped.

Quick check for understanding.

Which of the following best describes an alloy? We have A, a pure metal found naturally in the earth; B, metal that has been reshaped; C, mixing metals or combining with other elements; or D, metal that has been coated in plastic for protection.

Have a go at this, pause the video now and come back to me when you completed it.

It is of course C, mixing metals or combining with other elements, well done.

Stock form is a standard shape and size in which a material is supplied.

Standardizing means that the shape and size of the materials are made to specific dimensions.

Now stock forms are really useful.

They allow designers and manufacturers to know which form a material is available in.

This information is required when designing a product and planning its manufacture.

Now common metal stock forms include round bar, tube and wire.

Now round bar might be used for things like rails or support rods.

Tube is often used for bike frames, plumbing or possibly, scaffolding.

And then, of course, we have wire used for electrical wires and often in jewelry.

We also have T sections, RSJs and channels.

So a T section is often used for load-bearing structures, or construction and supports.

We have an RSJ used in building frameworks often in bridges.

And then, of course, a channel used in construction or even vehicle chassis.

Other stock forms of metals include sheet, square bar and flat bar.

So sheet is often used for car body panels, or possibly even in signage.

Square bar is used in frames and brackets, flat bar for braces and supports.

We have angle, box section and hexagon.

Now angle is often used for things like shelving, box section used for gates, again, support structures.

And the hexagon is used for fasteners, but also things like tool handles.

Now there are many benefits to materials being available in a range of stock forms. Let's have a look at some of those benefits.

So first of all, handling, it's easier to store and transport if they are in standardized stock forms. The cost, well, bulk production of standardized size is actually lowest cost overall, so it makes our materials cheaper.

Waste, we only need to buy what we want because we can measure it very precisely 'cause we know what form it's gonna come in.

And of course, efficiency, consistent sizes are much easier to work with.

So we're now onto your first task.

First of all, I want you to describe the process of sourcing metals.

Use the three stages of extract, refine, and process into stock forms in your answer.

I then want you to identify the common stock forms here and give one use.

There are your stock forms. Pause the video now, have a go at this task and come back to me when you've completed it.

So how did you get on? Well, let's have a look at some sample answers.

So I wanted you to describe the process of sourcing metals.

Use three, the three stages of extract, refine, and process into stock form in your answer.

Well, first of all, we have extract.

Ores containing metals or metal compounds such as iron ore and they're mined.

We then refine them.

After metals are extracted and refined, they are melted and cast into ingots, the big ingots, if you remember those.

These ingots can then be reheated and made to blooms, slabs and billets.

The blooms, slabs and billets are then processed into stock forms. So stock form is a standard shape and size in which material is supplied, well done.

I then want you to identify the common stock forms and give one use.

Well, here we have round bar for support rods, tube for bike frames, T section for load-bearing structures, angle for shelving and box section for gates.

You probably got something very similar.

Well done with that task.

So we're now onto the second learning cycle, metal properties.

Material properties describe how a material looks, feels and behaves.

They're important because they help the designer choose the right material for a product.

It's what makes one material different from another.

For example, why metal is hard and shiny, while rubber is stretchy.

Let's have a closer look at some common metal properties.

First of all, they have a high melting point.

They don't melt easily.

They are ductile, they can be stretched or drawn out into wires.

They're hard, they resist being scratched or indented.

They're malleable, they can be hammered or rolled into sheets or other shapes without breaking.

They're shiny, they have a shiny surface when polished.

They're strong, they won't break easily when a force is applied.

And they are good conductors of both heat and electricity.

Quick check for understanding.

Which of the following are properties of metals? We have A, ductile; B, malleable; C, strong; and D, elastic.

Pause the video now, select all the properties of metals and come back to me when you've done that.

So you should have got ductile, malleable and strong, well done.

When metals are grouped into ferrous, non-ferrous and alloy metals, their properties are different.

For example, ferrous metals can rust when they come into contact with moisture, but non-ferrous metals do not.

This happens because ferrous metals contain iron, which reacts with water and oxygen and that forms the rust layer.

Let's have a closer look at some ferrous metals.

So first of all, we have low carbon steel.

Some of the properties of low carbon steel, it's tough, malleable, low cost than other metals and its uses are car bodies, nails and screws.

We then have cast iron.

The properties for this, it's strong under compression.

It's got a really good compressing strength, but it's brittle.

And it's often used for engine blocks and also cookware.

We then have medium carbon steel.

Properties for this, it's strong and it's got good hardness.

It's often used for tools, axes and also gears.

Let's have a look at some non-ferrous metals.

So we've got aluminum, some properties of aluminum, lightweight, strong, and a good conductor, uses aeroplane parts, drinks cans and ladders.

We then have copper.

Properties of copper, it's a very good conductor.

It's ductile and it's corrosion resistance.

And its uses, electrical wires, plumbing pipes, and often, parts of circuit boards.

And then, we have zinc.

It's got a medium strength, but it's got good corrosion resistance.

It's often used for galvanizing steel and in batteries.

We then have some alloys.

So the first alloy is brass, which is an alloy of copper and zinc.

The properties, it's strong, it's corrosion resistance and it's malleable.

Often used for musical instruments and things like door handles.

We have bronze, which is an alloy of copper and tin.

It's hard, it's tough and also, it's corrosion resistance.

It's often used in bearings, metals, and statues.

And then, we have pewter, which is an alloy of tin and copper.

It's soft, it's malleable, it resists corrosion, often used in jewelry, trophy and tableware.

Check for understanding, I want you to match the metal to the product.

So our metals are aluminum, copper, steel and brass.

And our products are musical instruments, a ladder, electrical wires, and then nails and screws.

Pause the video now, have a go at this and come back to me when you've completed it.

So how did it get on? Well, aluminum could be made into a ladder.

Copper, electrical wires 'cause of the conductivity.

Steel, nails and screws and brass, of course, musical instruments, well done.

We're now onto task B.

A pupil would like to manufacture a simple phone stand using a metal.

I would like you to identify a suitable metal and give reasons for your selection.

Pause the video now, have a go at this and come back to me when you've completed it.

So what was your selection? Well, aluminum would be a suitable for the phone stand, as it is lightweight and corrosion resistant.

It is malleable, allowing it to be easily shaped in a school workshop.

It also comes in sheet stock form, which is suitable for the template used to shape the phone stand.

Next, working with aluminum, I want you to manufacture a simple phone stand from sheet aluminum.

This will help you understand better the properties of a metal such as aluminum.

The tools and equipment you will need for this task, you'll need a scribe, a steel rule, a template, a junior hacksaw, or an abrafile, a flat file, wet and dry paper for finishing and a folding machine, but you can use an engineer's vice.

The process for carrying out this activity, you need to make a card template.

You can use my template on the previous slide if you like.

Use a scribe to mark out the phone stand, ensuring accuracy with a steel rule.

Cut out the shape using a junior hacksaw or an abrafile.

Smooth the edges with a large flat file using cross and draw filing.

Finish with wet and dry paper to remove sharp edges, and then bend the aluminum to a 45-degree angle using a folding machine or an engineer's vice.

Pause the video now, have a go at this task, I really hope you enjoy it and come back to me when you've completed it.

So how did you get on? Well your final outcome might look something like this.

And you, of course, have worked with aluminum, the malleable material, aluminum, well done.

So that brings us to the end of today's lesson.

Let's have a quick summary.

Metals are sourced from the earth as ores, which are mined, extracted and processed into usable materials.

Metals are categorized as ferrous, non-ferrous and alloys.

Processed metals are formed into standard stock forms. Metal properties such as strength, ductility, and conductivity determine the suitability for different products and applications.

You've been brilliant today, I hope you've enjoyed today's lesson.

I look forward to seeing you all next time, goodbye.