Assessment Task 3 - BBQ Case & Accessories

2024 Assessment Task 3 Notification - BBQ Case Project & Portfolio

Statement of Intent

Aim

What is the project we are designing? Describe the features?
What purpose is the project trying to achieve?
Why are you making the Project?
How will you make your design unique?

Design

Discuss the functionality of your design
What are the dimensions of the project?
Describe the design
What techniques and processes you previously used might you incorporate into this project?
What machines and technology might you use to manufacture the BBQ carry case?

Design Constraints

What must the project do?

You might also discuss the following points below:

The materials that are available
Software requirements - for example, what programs will you use to design your project
Time constraints - the project has a due date.

2. Time Management

A critical aspect of project management is to manage effectively the time taken to produce the project. To do this

You need to show the marker proposed steps of production along with information detailing how long the step is intended to take and how long it took.

An industry standard tool that is used to manage the project is called a GANTT Chart

A Gantt chart, commonly used in project management, is one of the most popular and useful ways of showing activities (tasks or events) displayed against time. On the left of the chart is a list of the activities and along the top is a suitable time scale. Each activity is represented by a bar; the position and length of the bar reflects the start date, duration and end date of the activity. This allows you to see at a glance:

What the various activities are
When each activity begins and ends
How long each activity is scheduled to last
Where activities overlap with other activities, and by how much
The start and end date of the whole project

In the context of Industrial Technology - the Gantt chart that you will develop will list the various steps of production and will also have the following information:

The proposed beginning and end times of the task (usually represented by a coloured bar)
The actual beginning and end times of the task (usually represented by a different coloured bar)
A short annotation or evaluation statement if there is significant variation between the actual and proposed dates/times taken

Example time management plan from the BBQ Project

3. Research

WHAT IS STAINLESS STEEL AND HOW IS IT MADE?

Due to its excellent corrosion resistance, high strength and attractive appearance, stainless steel sees a wide range of uses across both industrial and consumer markets. But how does stainless steel go from a pile of scrap or refined ores to its final shape and application? Most stainless steel starts life in a similar manner before heading off to processing. This processing—along with the exact composition of the steel alloy—determine its many characteristics. So to understand how stainless steel is produced, we must first dive into its composition.

WHAT IS STAINLESS STEEL?

Stainless steel is an iron and chromium alloy. While stainless must contain at least 10.5% chromium, the exact components and ratios will vary based on the grade requested and the intended use of the steel.

Other common additives include:

Nickel
Carbon
Manganese
Molybdenum
Nitrogen
Sulfur
Copper
Silicon

The exact composition of an alloy is strictly measured and assessed throughout the alloying process to ensure the steel exhibits the required qualities.

The common reasons to add other metals and gasses to a stainless steel alloy include:

Increased corrosion resistance
High temperature resistance
Low temperature resistance
Improved strength
Improved weldability
Improved formability
Controlling magnetism

What’s in your stainless steel isn’t the only factor in determining its unique characteristics however…

How it’s made will further alter the steel’s properties.

HOW STAINLESS STEEL IS MADE

The exact process for a grade of stainless steel will differ in the later stages. How a grade of steel is shaped, worked and finished plays a significant role in determining how it looks and performs. Before you can create a deliverable steel product, you must first create the molten alloy. Because of this most steel grades share common starting steps.

Step 1: Melting

Manufacturing stainless steel starts with melting scrap metals and additives in an electric arc furnace (EAF). Using high-power electrodes, the EAF heats the metals over the course of many hours to create a molten, fluid mixture.

As stainless steel is 100% recyclable, many stainless orders contain as much as 60% recycled steel. This helps to not only control costs but reduce environmental impact.

Exact temperatures will vary based on the grade of steel created.

Step 2: Removing Carbon Content

Carbon helps to increase the hardness and strength of iron. However, too much carbon can create problems—such as carbide precipitation during welding

Before casting molten stainless steel, calibration and reduction of carbon content to the proper level is essential.

There are two ways foundries control carbon content.

The first is through Argon Oxygen Decarburization (AOD). Injecting an argon gas mixture into the molten steel reduces carbon content with minimal loss of other essential elements.

The other method used is Vacuum Oxygen Decarburization (VOD). In this method, molten steel is transferred to another chamber where oxygen is injected into the steel while heat is applied. A vacuum then removes vented gases from the chamber, further reducing carbon content.

Both methods offer precise control of carbon content to ensure a proper mixture and exact characteristics in the final stainless steel product.

Step 3: Tuning

After reducing carbon, a final balancing and homogenization of temperature and chemistry occurs. This ensures that the metal meets requirements for its intended grade and that the steel’s composition is consistent throughout the batch.

Samples are tested and analyzed. Adjustments are then made until the mixture meets the required standard.

STEP 4: Forming or Casting

With the molten steel created, the foundry must now create the primitive shape used to cool and work the steel. The exact shape and dimensions will depend on the final product.

Common shapes include:

Blooms
Billets
Slabs
Rods
Tubes

Forms are then marked with an identifier to track the batch through the various processes to follow.

From here steps will differ depending on the intended grade and final product or function. Slabs become plates, strips and sheets. Blooms and billets become bars and wires.

Depending on the grade or format ordered, a steel might go through some of these steps multiple times to create the desired appearance or characteristics.

The following steps are the most common.

Hot Rolling

Performed at temperatures higher than the recrystallization temperature of the steel, this step helps to set the rough physical dimensions of the steel. Precise temperature control throughout the process keeps the steel soft enough to work without altering the structure.

The process uses repeated passes to adjust the dimensions of the steel slowly. In most cases, this will involve rolling through multiple mills over time to achieve the desired thickness.

Cold Rolling

Often used when precision is required, cold rolling occurs below the recrystallization temperature of the steel. Multiple supported rollers are used to shape the steel. This process creates a more attractive, uniform finish.

However, it can also deform the steel’s structure and often requires heat treatment to recrystallize the steel to its original microstructure.

Annealing

After rolling, most steel undergoes an annealing process. This involves controlled heating and cooling cycles. These cycles help to soften steel and relieve internal stress.

The exact temperatures and times involved will depend on the grade of steel, with both heating and cooling rates impacting the final product.

Descaling or Pickling

As steel is worked through the various steps, it often accumulates scale on the surface.

This accumulation isn’t simply unattractive. It can also impact the stain-resistance, durability and weldability of the steel. Removing this scale is essential to creating the oxide barrier that gives stainless it’s characteristic corrosion and stain resistance.

Descaling or pickling removes this scale using either acid baths (known as acid pickling) or through controlled heating and cooling in an oxygen free environment.

Depending on the final product, the metal might return to rolling or extruding for further processing. This is followed by repeated annealing phases until achieving the desired properties.

Cutting

Once the steel is worked and ready, the batch is cut to fit order requirements.

The most common methods are mechanical methods, such as cutting with guillotine knives, circular knives, high-speed blades or punching with dies.

However, for complex shapes, flame cutting or plasma jet cutting may be used as well.

The best option will depend on both the grade of steel requested and the desired shape of the delivered product.

Finishing

Stainless steel is available in a variety of finishes from matte to mirror. Finishing is one of the last steps involved in the manufacturing process. Common techniques include acid or sand etching, sand blasting, belt grinding, belt buffing and belt polishing.

At this point, the steel is gathered in its final form and readied for shipping to the customer. Rolls and coils are common ways to both store and ship large quantities of stainless for use in other manufacturing processes. However, the final form will depend on the type of steel required and other factors specific to the order.

FINAL THOUGHTS

Understanding the proper stainless steel grades and types for specific uses and environments is an essential part of ensuring long-lasting results and optimizing costs. Whether you’re looking for something strong and corrosion-resistant for marine environments or something stunning and easy to clean for restaurant use, there’s a stainless steel alloy available to suit your needs.

Source: Unified Alloys

What Is Galvanising?

Galvanisation or galvanising, as it is most commonly called, is a metal plating process in which an iron or steel component is coated with a thin layer of zinc. The zinc acts as a protective layer that shields the underlying surface from corrosion and extends its lifespan. The process may sometimes be driven by electricity until a sufficient thickness of the zinc layer is developed. This layer is not discrete, i.e. the zinc merges into the steel at the surface and forms a strong metallurgical bond.

Galvanising is commonly used in places where the metal needs to endure harsh environments or in structural applications where the metal needs to maintain its strength over many decades. The protective coating ensures that the base metal withstands challenging conditions without compromising its critical properties, such as tensile strength, elasticity and durability. The extensive utilisation of galvanised steel can be observed in the construction of bridges, guardrails and steel equipment in chemical plants

Why Galvanise Steel?

The primary reason for galvanising steel is to increase its lifespan. Regular steel components, if not galvanised, can succumb to corrosion attacks and deteriorate quickly.

Even when embedded in concrete, steel products can corrode due to carbonation (exposure to carbon dioxide), moisture and high chloride levels. Applying a zinc coating improves the corrosion protection of the base metal and thereby enhances its durability.

Galvanising processes also provide the toughest coatings that can resist mechanical damage during transportation, storage and installation. The cost of installation is also low because galvanised components are ready to use upon arrival. Galvanised steel does not require any surface preparation, painting or inspection prior to installation.

Once installed, it provides a lifespan of over 50 years in rural areas and a minimum of 20 to 25 years in urban and coastal areas. The protective coating offers unparalleled protection by also covering sharp corners, recesses and other inaccessible areas. This feature is hard to find in some other coating processes.

Even when the coating is lost at a certain area, it still does not lead to corrosion because zinc has a higher negative reduction potential. This causes the zinc to oxidise instead of the iron, ensuring the safety of the application. To inspect the coating, only the physical condition of the layer is assessed. A close visual inspection is sufficient. If the coating appears intact, we can be confident that no damage has occurred to the steel underneath.

Galvanised steel is generally a cost-effective alternative compared to other methods, except for some large-scale applications. In the construction sector, galvanised steel may become so expensive that builders may abandon the idea of using it altogether when the budget is restrictive. A second disadvantage is that, although the zinc layer is resistant to red rust, it can still develop white rust when continuously exposed to moisture.

Galvanising Methods

There are several galvanising processes available, each with its own advantages and limitations. Let’s take a look at some of the most common galvanisation methods in use today.

Hot-dip galvanising

Hot-dip galvanising is one of the most straightforward and economical galvanising methods. It is capable of coating a variety of complex shapes with relative ease. The surface of the material is cleaned of contaminants and any oxides before being dipped in a molten zinc bath. The bath of molten zinc applies a layer of zinc coating onto the steel component. The quality of the metallurgical bond is determined by how efficiently the surfaces were cleaned beforehand.

Electrolytic galvanising

Electrolytic galvanising, also known as electrogalvanising, is the second most widespread galvanising method. It uses electrolysis to apply a layer of zinc onto a base metal, making it a form of electroplating. In this process, the steel workpiece is placed in a zinc solution with a second electrode and then direct current is passed through it. The current ionises the zinc solution, depositing a pure zinc coating on the base metal. This process provides greater control over the rate of deposition and the layer thickness.

Sherardising

Sherardising is a type of galvanising process named after its inventor, Sherard Osborn Cowper-Coles. It uses thermal diffusion to create a zinc coating on ferrous metals. In this process, the metal to be coated is placed in a container with zinc metal dust. The temperature of the workpiece is increased to 400-450 °C in the presence of this dust. The high temperature causes the dust to diffuse into the metal, forming a zinc-iron alloy.

Pre-galvanising

Pre-galvanising can be understood as a type of hot-dip process adapted specifically for long steel sheets. In this process, the sheet is passed through a cleaning agent that prepares the material for galvanising. Once the metal sheet has been cleaned, it is quickly passed through a molten zinc bath. The rapid movement enables the formation of a thin protective zinc coating that is more uniform than the one achieved in the conventional hot-dip galvanising method. This method provides the fastest turnaround times for sheet metal.

Hot-Dip Galvanising Process

As mentioned previously, the hot-dip process is the most widely used method for galvanising steel components. It provides a reliable method for coating various shapes and sizes, ranging from nuts and bolts to large structural beams. The complexities can range from simple steel rods to artistic pieces with intricate shapes.

In this section, we’ll explain the general hot-dip galvanising process to understand its stages and their purpose. The process can be divided into four major stages:

Removal of hard contaminants
Chemical cleaning
Flux application
Immersion in a zinc bath

Removal of Hard Contaminants

When the surface of a workpiece contains hard contaminants, such as welding slag, heavy grease and paint, chemical cleaning is not going to cut it. These impurities must be removed beforehand by using a paint stripper or by mechanical means such as blasting, grinding, etc, as they’ll affect the final quality of the galvanised products. Once the surface is free of any hard contaminants, chemical cleaning will be sufficient to further prepare the part for immersion in a zinc bath.

Chemical Cleaning

In the chemical cleaning stage, all contaminants, such as dirt, grease, scales and oxides, will be removed from the surface of the steel.

To achieve this, several operations take place in sequence. The first step is degreasing, where the component is dipped into a caustic solution, held for a predetermined amount of time, and then rinsed.

After removing the surface grease, the part is immersed in a hydrochloric acid solution to eliminate mill scale and oxides. It is then rinsed once more. This step is also known as the acid pickling process.

Flux Application

Once out of pickling, the part’s exposure to air can lead to the formation of a very thin oxide layer on its surface. This layer can interfere with the adhesion of the zinc coating to the steel component and, therefore, needs to be removed.

To accomplish this, the component is exposed to a chemical flux (typically zinc ammonium chloride) that facilitates the dissolution of the surface oxide into it. The concentration varies from case to case. The flux usually also contains wetting agents, anti-foaming agents and viscosity adjusters. The flux is allowed to dry before being dipped into liquid zinc.

Immersion in Zinc Bath

After applying flux, the openings for venting and draining on the component are checked before the actual dipping process. The air will exit through the vent opening, while the molten zinc will enter through the drain opening.

Once they are found to be satisfactory, the part is cleared to go through the hot-dip galvanising process. The component is immersed in a bath of molten zinc at 450°C. The bath cannot be heated too much, as excessive temperature can cause the chemical flux on the component to burn away. The component is held in place until its temperature becomes equal to that of the bath.

The immersion creates layers of zinc-iron alloys with different compositions. There is no clear demarcation between the layers, and the steel component gradually transitions into a pure zinc coating on the surface.

Upon successful coating, the component is cooled down in a quench tank to prevent exposure to air.

Source: Fractory

4. Onshape Working Drawings

Stainless Steel Scraper Drawing

5. Production Process

This section of the folio requires you to monitor your production processes and progress in the workshop over terms 2 & 3. The purpose of this task is to ensure you are on target to deliver/manufacture the projects by the due date.

Instructions

Refer to your initial Time Management Plan to compare your proposed timeline to your actual time line.
As you complete this table in your folio, you need to include the following information for each process:

Name of the process/component
Equipment used
Material used
Dimensions

See the example below that shows how this task looks once it is completed. *Note: This example is only the first 4 weeks of a project. You need to do this for every week over terms 2 & 3.

Exemplar Construction Process Monitoring

6. Evaluation

Rewrite your statement of intent, but this time you are going to reflect on what you have actually completed.

What did you make? Describe with details
- What are the key features?
What materials did you use?
- Refer to the material list, list the material available
What tools and processes did you use?
- List them. Go through the construction sequence and list them out
What tools and procedures did you use for the first time?
- How did they go?
- What would you do different next time?
Did you achieve any of your personal goals during this project? Explain them...
- How will you achieve your goals?
- Whose help will you need?
Did you make any design changes? What influence these?

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