You often see eight metals used in casting. These are gray iron, white iron, ductile iron, stainless steel, carbon steel, aluminum, copper-based alloys, and nickel-based alloys. Picking the right casting metals is important. Each metal has special properties. These include chemical composition, carbon content, and machinability. These things change how the metal is used in factories. The most common metals have special features. They are good for making things, handling stress, and welding. Look at the table below. It shows how these properties help in different jobs.
| Property | Impact on Industrial Applications |
|---|---|
| Chemical Composition | Changes how metals work in different industries |
| Carbon Content | Makes metals harder and stronger |
| Manganese | Helps metals last longer and not wear out |
| Fabrication Characteristics | Lets people make many shapes and designs |
| Machinability | Makes it easier to build and put together things |
| Weldability | Helps with building and fixing things |
| Stress Resistance | Good for big machines and tough places |
Key Takeaways
- Picking the right casting metal is very important. It affects how strong the product is. It also changes the cost and how well it works.
- Gray iron is used a lot because it is very strong. It is easy to shape and cut. It also helps stop vibrations.
- Ductile iron is very strong and bends without breaking. This makes it good for hard jobs.
- Stainless steel does not rust. It is great for food tools and medical tools because it stays clean.
- Carbon steel is strong and can be used in many ways. People use it in cars and planes a lot.
- Aluminum is light and strong. It is good for making parts for planes and cars.
- Copper-based alloys work well in things that use electricity. They carry electricity very well.
- Nickel-based alloys are picked for places that get very hot or have lots of chemicals. They last a long time.
Table of Contents
Casting Metals Overview
Importance of Metal Selection
Choosing metals for casting changes how strong your product is. It also affects how much it costs and how well it works. Picking the right metal helps your project succeed. It keeps your work fast and smooth. Many companies use common metals. These metals are tough, easy to shape, and not too expensive. Iron and its alloys are used a lot. You see them in cars and big machines.
Tip: Always pick the casting metal that fits the job. Sometimes, spending more on a special alloy saves money later. It can make your work faster and better.
Casting metals are different from wrought metals. Cast metals have bigger grains and more inclusions. This can make them break more easily. Wrought metals are shaped by squeezing or bending. They are usually stronger and bend better. But some cast alloys work better than wrought alloys for certain jobs.
Using the right casting method can save you money. If you need tricky shapes or big parts, casting is often cheaper. It costs less than making and joining many pieces. Making one part by casting can lower costs and make building easier.
Here is a table that shows how experts sort cast iron types. This helps you see why some types are common casting metals.
| Type of Cast Iron | Characteristics | Classification Status |
|---|---|---|
| Gray Iron | Easy to cast, shape, and lasts long. | Common Cast Iron |
| White Iron | Very hard and breaks easily, good for tough jobs. | Common Cast Iron |
| Ductile Iron | Very strong and bends well, used in cars and machines. | Common Cast Iron |
| Compacted Graphite Iron | Mixes gray and ductile iron traits, good for heat. | Special Cast Iron |
| Mottled Iron | Has traits between gray and white iron. | Common Cast Iron |
| Malleable Iron | Heated white iron, bends and holds up well. | Common Cast Iron |
| Austempered Ductile Iron | Gets stronger by special heat treatment. | Special Cast Iron |
Factors to Consider
When picking a casting metal, look at some key things. These steps help your product work well and last long.
- Material selection: Choose a metal with the right mix and strength.
- Design: Make sure your design matches the casting method.
- Casting/Manufacturing process: Control heat and cooling for best results.
- Quality control: Check parts with tests and measurements.
- Post-manufacturing treatment: Finish with shaping, heating, or surface work.
Doing these steps helps you get the best from your casting metals. Your parts will last longer and work better.
Types of Casting Metals
Gray Iron
Properties
Gray iron is one of the most used casting metals. It has high compressive strength and is easy to machine. It also stops vibrations well. The graphite flakes make it look gray and help soak up energy. You can shape gray iron into many forms. This makes it popular for casting. The chemical makeup has 2.8–3.9% carbon and 1.1–2.6% silicon. It also has small amounts of manganese, phosphorus, and sulfur. Gray iron’s tensile strength is between 170 and 345 MPa. Its hardness is 350 to 500 BHN.
Note: Gray iron moves heat well and costs less. This makes it great for making lots of parts.
Applications
Gray iron is used in pump housings and engine blocks. It is also found in heavy machine bases. It helps protect equipment by stopping vibrations. Makers use gray iron for brake drums and tool frames. It is also used for pipes. These uses need wear resistance and easy machining.
White Iron
Properties
White iron is different from gray iron. It has cementite instead of graphite. This gives it a shiny white break and makes it harder. White iron resists wear and stays strong at high heat. But it is brittle and hard to machine. White iron is 30–50% harder than gray iron. It does not have much toughness and can crack if hit.
| Property | White Cast Iron | Gray Cast Iron |
|---|---|---|
| Hardness | Very high | Lower |
| Brittleness | High | Lower |
| Toughness | Low | Good |
| Wear Resistance | Excellent | Good |
| Machinability | Poor | Good |
| Tensile Strength | Higher | Lower |
Applications
White iron is used in crusher parts and mill liners. It is also found in grinding media and pump parts. Its hardness helps tools that get worn out fast. White iron is used for plowshares and railway brake shoes. It works well in shot blasting nozzles and other parts that face lots of wear.
Ductile Iron
Properties
Ductile iron is also called nodular cast iron. It has graphite in round shapes. This makes it stronger and more bendable than gray or white iron. Ductile iron can handle both squeezing and pulling forces. It does not wear out or break easily. This makes it good for tough jobs. Ductile iron lets you make many designs in casting.
| Advantage | Ductile Iron | Traditional Cast Iron |
|---|---|---|
| Strength | High | Lower |
| Ductility | Excellent | Poor |
| Wear Resistance | Good | Lower |
| Design Options | Versatile | Limited |
Applications
Ductile iron is used in engine blocks and gears. It is also found in crankshafts and machine parts. Car makers use it for cylinder heads and brake calipers. It is also used for suspension parts. In building, ductile iron is used for pipes and manhole covers. It is also used for supports. Ductile iron is tough and flexible. This makes it a top pick for water systems, city projects, and valves.
Stainless Steel
Properties
Stainless steel is a popular metal for casting. It does not rust easily and is very strong. Chromium in stainless steel makes a shield on the surface. This shield keeps out rust and stops chemical damage. Stainless steel lasts a long time in tough places. Its strength changes with each grade. Some types, like AISI 316L, can get brittle after some treatments. Other types, like Steel 2 and Steel 5, stay strong.
| Steel Sample | Corrosion Resistance | Mechanical Strength |
|---|---|---|
| AISI 316L | Lowest among tested | Enormously embrittled |
| Steel 2 | Best performance | Reasonably strong |
| Steel 5 | Best performance | Reasonably strong |
| Steel 1 | Weak performance | Enormously embrittled |
| Steel 4 | Weak performance | Enormously embrittled |
Stainless steel makes a shield over time. This helps slow down rust. Most types do not change much after aging, except AISI 316L.
Applications
Stainless steel castings are used in many fields. Food equipment uses 304L stainless steel. It stops germs and meets health rules. Medical tools use stainless steel because it does not react and is easy to clean. You see it in surgical tools, bolts, boat parts, and kitchen items. Its smooth surface and acid resistance make it good for clean places. Stainless steel castings are safe for food and do not react with harsh chemicals.
- Food equipment
- Medical tools and surgical tools
- Storage tanks and kitchen items
- Boat parts and bolts
Carbon Steel
Properties
Carbon steel is a common metal for casting. People pick carbon steel for its strength and many uses. Its tensile strength is between 414 and 1724 MPa. This depends on how much carbon it has and how it is treated. Hardness also changes with these things. You can change carbon steel’s properties by adding more carbon or using different casting methods. Carbon steel is easy to cut and weld. This makes it good for many shapes.
| Property | Range |
|---|---|
| Ultimate Tensile Strength | 414 to 1724 MPa |
| Hardness | Varies with treatment |
- Carbon steel strength is usually 400 MPa to 1,200 MPa.
- Heat treatment can make it harder and stronger.
Applications
Carbon steel castings are found in cars, planes, oil and gas, energy, and big machines. These fields like carbon steel because it is strong and lasts long. Car parts need to be strong but not heavy. Plane parts need to be light and strong. Oil and gas tools must not rust and must stay tough. Energy systems need to handle heat and stay strong. Big machines use carbon steel because it resists wear and holds heavy loads.
| Sector | Performance Criteria |
|---|---|
| Automotive | Durability, strength, weight |
| Aerospace | Strength-to-weight ratio, fatigue resistance |
| Oil & Gas | Corrosion resistance, toughness |
| Energy | Heat resistance, structural integrity |
| Heavy Machinery | Wear resistance, load-bearing capacity |
Aluminum
Properties
Aluminum is a light metal used for casting. It is not heavy but still strong. Aluminum does not rust and moves heat well. You can shape aluminum into many forms with new casting methods. Aluminum alloy makes it even stronger. Aluminum is easy to cut and weld. It does not attract magnets and does not spark, which is safer in some places.
- Light and strong
- Does not rust
- Moves heat well
- Easy to cut and weld
- Not magnetic and does not spark
Applications
Aluminum castings are used in planes and cars. Common uses are engine blocks, gear cases, and wheels. Planes use aluminum for frames, wings, landing gear, and engine parts. These parts must be strong and last long. Aluminum alloy castings help lower weight but keep strength. You also see aluminum in electronics, buildings, and packaging.
- Engine blocks and gear cases
- Wheels
- Frames and wings
- Landing gear and engine parts
Copper-Based Alloys
Properties
Copper-based alloys are picked when you need good electrical and heat flow. These alloys include brass, bronze, tin bronze, and phosphor bronze. Each one has its own mix of strength, bendiness, and rust resistance. You can see their mechanical properties in the table below:
| Alloy Type | Tensile Strength (MPa) | Yield Strength (MPa) | Elongation (%) | Hardness (Brinell) |
|---|---|---|---|---|
| C83600 | 207 | 97 | 20 | 60 |
| Silicon Brass | 400 | 230 | 10 | 100 |
| Tin Bronze | 300 | 180 | 13 | 88 |
| Phosphor Bronze | 350-420 | 170-190 | 5-20 | 85-120 |
C83600 is a common casting alloy. It has mostly copper with some lead, tin, and zinc. This mix makes it easy to machine and helps it last longer. Here is what is in C83600:
- Copper (Cu): 84.0% – 86.0%
- Lead (Pb): 4.0% – 6.0%
- Tin (Sn): 4.0% – 6.0%
- Zinc (Zn): 4.0% – 6.0%
- Other elements: iron, phosphorus, nickel, aluminum, sulfur, antimony, silicon (all in small amounts)
Copper-based alloys do not rust easily, even in water or weak chemicals. You can shape them with new casting methods. They carry electricity and heat well, so they are used a lot in casting.
Applications
Copper-based alloys are used in many jobs because they are strong and last long. In plumbing, you use brass and leaded bronze for:
- Faucets, valves, and fittings
- Pipe connectors and couplings
- Water meter housings
- Backflow preventers
In electrical work, copper-based alloys help make:
- Connectors and terminals
- Bus bars
- Circuit breaker and switchgear parts
- Grounding equipment
Copper alloy castings are important in electrical systems. Their high conductivity means less energy is lost, so power moves better. You also see these alloys in boat parts, pumps, and decorations. They do not rust and are easy to machine, so they are chosen for jobs that need both good performance and long life.
Nickel-Based Alloys
Properties
Nickel-based alloys are used when you need metals that can handle tough places. These alloys are picked for their heat resistance, strength, and rust protection. The table below shows their main features:
| Characteristic | Description |
|---|---|
| Heat Resistance | Withstands high temperatures without losing strength |
| Creep Resistance | Maintains shape under stress at elevated temperatures |
| Corrosion Protection | Offers strong protection in harsh, corrosive environments |
| High Strength | Alloys like Inconel 718 reach tensile strengths around 1,200 MPa |
| Fatigue Resistance | Handles repeated loading without failing |
| Ductility | Allows for significant shaping and machining before breaking |
| Microstructural Stability | Keeps structure stable under thermal and mechanical stress |
Nickel-based alloys are used to cast parts for hot or harsh places. These alloys keep their good traits even after long use. That is why they are often picked for hard jobs.
Applications
Nickel-based alloy castings are used in energy and heavy industry. Here are some common uses:
- Valves for controlling fluids under high pressure and rust.
- Impellers and pumps that move fluids in tough places.
- Down hole tools and parts for oil and gas work, where there is high pressure and chemicals.
- Pipeline fittings and flanges that must last in rough pipelines.
- Heat exchangers and pressure vessels that work under high heat and pressure, fighting off strong chemicals.
You also find nickel-based alloys in jet engines, turbines, and chemical plants. Their strength, rust resistance, and stability make them needed for casting jobs that must work very well.
Comparing Metals in Casting
Property Comparison Table
When you pick metals for casting, you should check their main traits. Each metal has its own mix of strength, hardness, rust resistance, and price. The table below shows how the most used metals do in these areas. This helps you find the best metal for your project.
| Metal | Corrosion Resistance | Wear Resistance | Tensile Strength | Hardness | Machinability | Price |
|---|---|---|---|---|---|---|
| Carbon Steel | Low | Medium | Medium | Medium | Medium | Low |
| Stainless Steel | High | Low | Low | Low | Low | High |
| Nickel-Based Alloys | High | Low | Medium | Medium | Low | High |
| Copper-Based Alloys | High | High | Low | Low | High | Medium |
| Gray Iron | Low | High | Medium | High | High | Low |
| White Iron | Low | High | High | High | Low | Low |
| Ductile Iron | Low | Medium | Medium | High | High | Low |
| Aluminum | Medium | Low | Low | Low | High | Medium |
Tip: Use this table to help you compare metals for casting. It lets you see which metal is best for strength, cost, or wear resistance.
Application Reference
You may want to know where each metal works best. The table below lists common uses for each metal and shows what makes them a good pick. This quick guide helps you choose the right metal for your job.
| Metal | Key Properties | Common Applications |
|---|---|---|
| Aluminum | Light, strong, does not rust | Cookware, car parts, airplane frames |
| Copper-Based Alloys | Easy to shape, carries heat and electricity | Plumbing, electrical connectors, decorations |
| Nickel-Based Alloys | Handles heat, resists rust, stays strong | Jet engines, turbines, marine valves |
| Carbon Steel | Strong, tough, not expensive | Construction, machines, car frames |
| Stainless Steel | Does not rust, easy to clean, lasts long | Food tools, medical tools, kitchen sinks |
| Gray Iron | Soaks up vibration, easy to machine | Engine blocks, machine bases, brake drums |
| White Iron | Very hard, resists wear, breaks easily | Mill liners, crusher parts, pump housings |
| Ductile Iron | Strong, bends well, resists impact | Pipes, gears, suspension parts, manhole covers |
You can see each metal is best for certain jobs because of its special features. For example, aluminum is good for planes because it is light and strong. Ductile iron is picked for water pipes because it bends and does not break. When you look at the properties and uses, you can make better choices for your casting work.
Remember: Always match the metal’s features to your project’s needs. This helps you get the best results and saves money.
If you know about metal properties, you can make better choices. This helps you pick the right metal for your project and its use. Casting lets you design many shapes and use materials well. You should check important performance signs before you decide.
| Key Performance Indicator | Definition | Importance |
|---|---|---|
| Energy Intensity (EI) | Energy used for each dollar made | Shows how efficient it is |
| Specific Energy Consumption (SEC) | Energy used for each part made | Checks energy for each unit |
| Process Efficiency | Energy lost when things slow down | Points out where to get better |
Look at the tables and property lists to help you choose. Think about price, how well it works, and what your project needs for the best outcome.
FAQ
Cast iron has more carbon and breaks more easily. You use it for heavy parts and machine bases. Wrought iron bends better and resists breaking. You see it in fences and decorative pieces.
You look at the metal’s strength, cost, and how it resists wear. You match these traits to your project’s needs. Always check the application and environment before you decide.
Most cast metals do not weld easily. You need special skills and tools. Ductile iron and some steels weld better than gray iron or white iron.
Aluminum is light and strong. You can shape it into many forms. It does not rust and works well in cars, planes, and electronics.
Nickel-based alloys handle high heat and stress. You use them in jet engines, turbines, and chemical plants. They keep their strength and resist rust.
Copper-based alloys carry electricity and heat well. You use them for connectors, terminals, and bus bars. They resist rust and last a long time.
