Metal properties and processes

Hello, my name's Mrs. Taylor. I'm really pleased that you can join me today. Let's have a look at our lesson. Today we are learning about metal properties and processes, and this is part of the Product analysis, encouraging healthy lifestyles unit. The outcome for today, I can identify and justify the material and process used for a metal product. We have four keywords today. Extracting means to remove or take out. Ore is a rock containing metal. Electrolysis is a process where electricity is passed through a substance which causes a chemical change. And die casting is a method of shaping metal. Molten metal is forced into a mould under pressure. And the lesson has three parts, sourcing metals, properties, and application of a zinc alloy and die casting. Let's begin with sourcing metals. Metals are naturally occurring, materials found in the earth's crust. Some are pure and some are combined with rocks which are called ores. The ores are mined and then the raw metal is extracted from the ores. There are different methods of extracting metal from the earth. This depends on how pure the metal is, and how reactive it is. Gold is an example of an unreactive metal, which is found in pure form in the earth. Pure metals can be mined from the earth and extracted using chemicals or heat. Let's have a check for understanding. Metals are A, naturally occurring. B, found in the earth. Or C, always pure. Pause the video and have a go. Okay, well done. Let's have a look. That's right. The answer is A and B. Metals are naturally occurring and found in the earth. More reactive metals, such as aluminium, are found in ores, which are a mixture of other elements and not pure metal. Metal ores are also mined from the earth and the metal is then extracted by electrolysis. Electrolysis is a process where electricity is used to separate the metal from the other elements in the ore. And another check for understanding. how are metal ores extracted? A, mine from the earth. B, heated, or C, electrolysis. Pause the video. Great. Let's have a look. How are metal ores extracted? That's right, A, they are mined from the earth and C, the process of electrolysis is used. Metals are a natural resource and cannot be replaced. They are a finite resource. Mining can damage the earth. Extracting metals uses huge amounts of energy, which is costly both financially and environmentally. Metals can be recycled repeatedly without losing quality or degrading. Scrap metal has a financial value. And we move to task A. Number one, what are the environmental considerations when choosing to use metals in the manufacture of products? And part two, explain the advantages of recycling aluminium rather than extracting more from ores. Pause the video and have a go. Well done. Let's have a look at some of the answers you may have come up with. What are the environmental considerations when choosing to use metals in a manufacture of products? You may have said using a natural material found in the earth, which cannot be replaced. Mining damages the earth. And extracting metals uses a lot of energy for heating or electrolysis. Well done. Let's look at part two. Explain the advantages of recycling aluminium rather than extracting from ore. The advantage of recycling aluminium is that there is no mining damage to the earth and no more finite resources are used. Recycling aluminium uses less energy than extracting the raw materials and unlike some other materials such as polymers, the quality of aluminium does not degrade when recycled. Well done. We now move on to the second part of our lesson, properties and application of a zinc alloy. Combining metals and creating alloys allows for materials to be made with the desired properties. Alloys can be ferrous or non-ferrous. For example, steel rusts when exposed to water as it contains iron. When mixed with chromium the process of oxidisation of the iron, which causes rust does not occur. Alloys are a mix of two or more metals. We have some examples here. Copper plus zinc results in brass. Iron plus chromium creates stainless steel and putter is a combination of antimony tin and copper. Here we have a check for understanding. why do we combine metals to make alloys? Is it A, to change some properties. B, to save money. Or C, to make materials with the desired properties? Pause the video and have a go. Fantastic. Let's have a look. That's right. Again, we've got two correct answers, A and C. It is to change some of the properties and to make materials with the desired properties. Kirksite is a zinc based alloy. It includes aluminium, copper, and magnesium. In comparison to stainless steel, kirksite has a lower melting point, which means less time and energy is used to manufacture it. Kirksite is lighter in weight than stainless steel, which means it is less expensive to transport. It is also easier to hold and use. Kirksite and stainless steel are both corrosion resistant. Here we have a check for understanding. Kirksite is an example of. A, a ferrous metal. B, a zinc based alloy. Or C, a naturally occurring metal. Pause the video. Let's have a look. That's right. It's a zinc based alloy. Well done. Here we have task B. Part one, stating the properties. Explain why kirksite alloy is suitable for the citrus fruit juicer shown here in the picture. Pause the video and have a go. Wonderful, let's have a look at some of the answers you may have come up with. Zinc alloy is suitable for the citrus fruit juicer because it is a non-ferrous alloy, which means it does not rust when washed. It is also corrosion resistant to acidic fruit juice. The alloy can be shaped easily into the two complex parts required for the citrus fruit juicer. Well done. We now move on to the third part of our lesson, which is die casting. Casting is a reforming process. It is where a material is heated until molten and then poured or forced into a mould. The material cools and solidifies in the shape of the mould. Metals are well suited to casting. There are different types of casting. Sand casting and die casting are two which are used for metals. Sand casting involves a shape being made in sand and molten metal being poured into the sand mould. This can be a curved shape. Here we have a check for understanding. What type of manufacturing process is casting? A, wasting B, deforming, C reforming, or D fabrication. Pause the video and have a go. Wonderful. Let's have a look. That's right. It's reforming. The definition of reforming is to change the shape and the state. Casting involves changing the state from a solid to a liquid and back to a solid. And therefore casting is a reforming manufacturing process. Well done. Die casting is where metal is forced into a mould under pressure. We can see in this table some of the advantages and disadvantages. The advantages of die casting include, it is suitable for high volume production. It is also suitable for complex shapes. It is a quick process and it is easy to repeat and replicate using the same mould. The disadvantages include, mould making is a specialist job, which takes time, and mould making is expensive, so it is not a suitable process for low volume production. Here we have a check for understanding. What makes die casting expensive? A, the speed at which it can be repeated. B, the time it takes to make moulds. Or C, the specialist skill of mould making. Pause the video and have a go. Great. Let's have a look. That's right. It's B and C. The time it takes to make the moulds and the specialist skill of mould making. Well done. Here we have a picture showing the die casting process. This is a cold chamber die casting process. The first part of the process is the mould is made from two parts. This allows for complex shapes. The second part of the process is that the molten metal is heated in a furnace. And a ladle of molten metal is then poured into the shot chamber. The fourth part of the process is that a hydraulic ram forces the molten metal into the mould. And the fifth part of the process is that the metal is left to cool and solidify. Sometimes this process is sped up by cooling it with water. Part six, the two part mould is opened and the cast item is ejected using the ejector pins. We now move on to task C. The first part is to add the following labels to the die casting diagram. Hydraulic ram, shot chamber, ladle of molten metal, mould and ejector pins. The second part of task C is to fill in the blanks using the words here to describe the process of die casting. And the third part of task C is to explain why this citrus fruit juicer has been manufactured using the die casting process. Pause the video and have a go. Fantastic. Let's have a look at some of the answers you may have come up with the mould. A ladle of molten metal, the shot chamber, hydraulic ram and ejector pins. Did you get them all right? Part two, the description of the die casting process. A, a two part mould is made. This is complex and expensive. B, the metal is heated in a furnace. C, the molten metal is poured into the shot chamber. D, the ram forces the molten metal along the shot chamber into the two part mould cavity. E, the metal is left to cool and solidify. And F, the two part mould is opened and the ejector pins push the die cast part out. Well done. And part three was to explain why this citrus fruit juicer has been manufactured using the die casting process. Your answers could include, this citrus fruit juice squeezer has been manufactured using the die casting process because it is a complex shape which can be reliably made using this method. The product is manufactured in high volume, which die casting is suitable for. As can accurately repeat the process. The mould is very specialist and expensive to manufacture, so only suitable for high volume production runs. Well done. We have here the summary of today's lesson. Metals are not a sustainable material as we cannot replace the ores found naturally in the earth. Metals can however be recycled without degrading the quality. This uses a lot of energy. Zinc based alloys can be used for kitchenware due to not corroding when used with liquids. They use less energy and time to process than steel based metals. Die casting is a suitable manufacturing process for complex shapes. Thank you for joining me today. See you next time.