The Complete Ultimate Guide: Stainless Steel Investment Casting Parts

Stainless steel investment casting parts are a popular material for many safety-critical applications that require toughness, reliability, and integrity. Investment casting has been used for many years in a variety of industries, including aerospace, automotive, and medical. So, each is suited to different applications. 

Hengke Metal is one of the world’s largest investment casting companies for stainless steel. It is located in China. However, we have exported thousands of cast parts made from stainless steel to many overseas companies.

This guide is intended to provide a comprehensive introduction to the stainless steel investment casting process. So, it will help you understand the process.

If you want to learn more about the principles and characteristics of investment casting.

Historical Background of Stainless Steel Investment Casting Parts

Stainless Steel Investment Casting parts were discovered around 5,000 years ago. During this time, archeologists have also discovered a variety of interesting artifacts, like jewelry, idols, and artworks.

People experimented with different metal casting techniques as mankind gained more knowledge about metals. So,  its use in the manufacture of dental crowns gave it an increase at the end of the 19th century.

World War II was the event that brought this method to the forefront of public attention. The technique of investment casting was refined during those years.

What is a Stainless Steel Investment Casting Parts?

Stainless Steel Investment Casting parts is a method of metalworking that produces custom stainless steel components. The process involves pouring Melton stainless into molds to solidify. This produces a stainless steel component that is solid and in the desired form.

Compared to other processes, the stainless steel casting process can produce complex components with good detail and dimensional accuracy. It is also an excellent alternative to welding fabrication since several stainless steel components can be cast as one piece. It saves money and time by avoiding additional welding or assembly. Stainless steel, along with other cast alloys, is used in the production of castings.

Different types of investment casting materials

One of the main advantages is that it can be used with ferrous and non-ferrous metals. The final part may have a variety of mechanical properties.

• Steel: Investment casting is a great choice for mild steels, steels with high carbon content and special alloys. Investment cast steel components are used by a wide range of industries, including aerospace, shipbuilding and the military.
• Stainless Steel: Stainless steel is strong, has a good finish, and resists corrosion. Pump housings, gears, bushings, and valve parts are all common.
• Alloys made of aluminum: These alloys are lightweight, corrosion-resistant and have a high strength-to-weight ratio. Aluminum is used primarily in aircraft and auto parts.
• Nickel alloys: Nickel is a superior metal with excellent strength, corrosion resistance and thermal stability. These alloys can be used in environments with high temperatures.
• Cobalt alloys: It have a high resistance to corrosion, wear and chemical reactions. These alloys are also resistant to extreme temperatures. These metals have high performance and are used in heavy machinery, medical equipment, food processing and the pharmaceutical industry.
• Cast iron: Cast Iron is durable and strong. Cast iron can be used for electrical components, pipe fittings, and tool hardware.
• Alloys of copper: It is just like bronze and brass, are medium in tensile strength. They also have good ductility. These alloys also have an attractive appearance. These alloys can be used for heat sinks and exchangers.

How to Process: Stainless Steel Investment casting parts

There are several methods of casting stainless steel but lost wax is the most important one. Particularly for structural products that are irregular or complex. Stainless steel investment casting is therefore, almost as good as stainless steel precision casting. There are several classification of investment casting. 

There are several steps to the stainless steel casting process .

Step 1: Making a Mold

Wax patterns were created in ancient times from beeswax. They were often made by hand, and only one was made at a given time. Today, foundries in stainless steel create a metal mould to directly inject wax patterns, improving production efficiency. Aluminum is the material used for the mold. Because a pair of molds will create wax patterns over and over again. The mold is permanent and only needs to be replaced when it becomes damaged or the design changes.

Step 2: Wax model making and inspection

Inject wax into the cavity of the mold after it is prepared. After cooling, remove the wax model. Check and fix some defects on wax models, such as holes, wax injection nozzles, or flow patterns.

Step 3: Shell Building

The assembled trees will then be successively dipped into refractory slurries and then coated with sand. This creates a ceramic shell that surrounds the wax.

It is important to apply the first investment coat in order to achieve a superior finish. This is a major advantage of the stainless steel casting process. After submerging the wax trees in a vat of zircon slurry that is well mixed and similar in consistency to latex paint, the first coat of slurry will be applied. The assembly is covered with zircon-based sand and allowed to dry. The assembly is then dipped into additional slurries and coated with fused silica powders that are becoming coarser. This helps to strengthen the mold. A shell is then built outside the wax assembly.

Step 4: Assembly

Weld the wax models to the casting system, one by one. This step looks like a forest, so it is called tree assembly.

Step 5: Dewaxing

Place the shelling in the oven at a high temperature. Heating melts the wax in the shell. Then drain out. Lastly, we have a cavity into which the resin can be poured. Dewaxing is the name of this process.

Step 6: Pouring

The shell becomes hollow after dewaxing and is ready to be poured. The stainless steel must be melted into a liquid before being poured. It is important to test the composition of the stainless steel at this stage to make sure it falls within the range. Pour the liquid stainless steel into the shell using gravity until the entire cavity is filled. At room temperature, the metal in the moulds begins to solidify. The cooling time also depends on the thickness and alloy of the mold. So, pouring is done by gravity and usually manually.

However, other methods like vacuum or pressure can be used.

Step 7: Cutting and Grinding

Remove the sprue gate by grinding the machine. A grinding machine is used to remove the sprue gate.

Step 8: Surface Finishing

Surfaces can also be polished using different surface finishes, such as mirror polishing or electropolishing.

Step 9: Machining

If the product needs to be processed further, we will need to remachine it.

Step 10: Inspection and testing of Stainless Steel Investment Castings

Inspections are important after production. Before delivery, it is also important to conduct inspection procedures. Inspections of stainless steel castings include checking for defects, measurements, and materials. Only approved products can be delivered.

Pros and Cons: Stainless Steel Investment Casting Parts

Everyone has their own benefits and demerits. 

Pros

• Tooling at an Affordable Price: Tooling represents the first step in starting a stainless steel casting process. The final quality of casting is influenced by the accuracy of the tooling and the material used. The cost of tooling stainless steel is lower than other forming processes.
• Flexible design: Investment casting allows for the production of stainless steel parts in various sizes and weights. Cast stainless steel parts are very flexible in design. Casting stainless steel parts is possible with a minimum thickness of 3mm and weights between 0.05 kg and 80 kg. Castings of stainless steel with complex shapes are also possible.
• Close tolerance: The dimensional precision of the stainless steel investment cast can meet ISO 8062 level CT5-CT6. This close tolerance allows for stainless steel castings to be produced with little or no machining.
• Smooth Surface: Even after shot-blasting, the surface is smooth and bright. People will no longer have to worry about their stainless steel castings rusting over time.
• High production efficiency: The stainless steel casting process is also fast and repeatable, which means that the production efficiency can be high.

Cons

• Longer Time: Investment casting takes longer to set up than other casting processes.
• High investment capital: Investment casting is a more expensive method of casting than other methods.
• Geometry limitation: An investment casting disadvantage is that the part’s geometry is restricted by the geometry in the mold.
• High operating temperatures: The investment casting process requires high temperatures for casting, so the facility must be designed to meet these requirements.

What are the most common applications of stainless steel investment casting parts?

Stainless steel investment castings are used in a variety of applications because of their corrosion resistance, strength, and low maintenance. 

• Food processing: Stainless steel investment castings, with their corrosion resistance, are widely used by the food processing industry. Components that are commonly used include coffee machine parts, metal grinder parts, food storage components, and components for coffee machines.
• Automotive components: It includes the grille, trim, converters, and exhaust parts.
• Medical Equipment: Medical devices often require tight tolerances, high precision, and high levels of. Stainless steel components are used in dental and surgical instruments, operating room equipment, and implantable components. They also appear on stretchers and wheelchairs, MRI machines, X-rays and MRI machinery.
• Pipe Fittings: Stainless steel investment cast elbows and bushings are common applications.

You learn about: INTRODUCING GREEN SAND CASTING: A RELIABLE METAL CASTING TECHNIQUE

Final Thoughts

Stainless steel is the ideal material for components that are exposed to the environment and are subjected to continuous stress. They are unique because of their corrosion-resistant qualities. In a nutshell, the process of investing in stainless steel is complex. The process has many benefits. This includes customization, flexibility, and durability.

Casting stainless steel is a crucial yet complex process that relies on cutting-edge technology and innovative alloys to produce high-quality output. So, computer-aided design, manufacturing, robotic automation and real-time monitoring systems are key advancements.

However, it is essential to understand the intricacies and complexities of stainless steel cast products for many industries that rely on them. So, the complexities and potentials of stainless steel casting will become increasingly apparent as we move forward, reinforcing the pivotal role it plays in our world.

China’s Top Stainless Steel Investment Casting Parts

Hengke Metal is one of China’s largest casting and machining firms. Our own CNC center and foundry are available. However, every size of stainless steel investment casting part is available. Raw materials are also available in all grades of stainless steel.

Why choose Hengke Metal Castings?

The most popular shop for stainless steel casting parts is Hengke Metal. We offer stainless steel castings at competitive prices, and we provide full service. Our products are exported all over the globe. So, contact us if you have any questions about stainless steel casting. So,  we will respond as quickly as possible.

Most Asked Questions about Stainless Steel Investment Casting Parts

Here is the most interesting information about this part of the article. However, people have confusion about this product. That’s why I mention this one. 

Q1: Why is precision investment so expensive?

Ans: The time required to dip and dry the ceramic slurry is a major factor in the high tooling and labor costs. If you require complex geometries or excellent surface finishes for your parts, investment casting can provide you with what you are looking for without the need to spend time and money on post-casting finishing. However, many manufacturing professionals are aware of the advantages that stainless steel investment casts offer.

Q2: Are there different grades of stainless steel investment casting parts to be produced?

Ans: Yes, castings made of stainless steel can be produced in different grades. Each grade is also suited for a specific application. The choice of grade is also based on factors like the intended use. So, the environment in which it will be used and the desired mechanical properties.

Q3: What is the effect of heat treatment on stainless steel investment casting parts?

Ans: Stainless steel can be significantly improved by heat treatment. Heat treatment can improve hardness, strength, and resistance to corrosion and wear. The specific effects will depend on the grade and type of stainless steel you use, as well as the heat treatment method. It is important to use the right heat treatment process in order to prevent adversely impacting the material’s characteristics.

Q4: Does investment casting have a positive impact on the environment?

Ans: Yes. Investment casting is regularly recycled to reuse wax and metal for subsequent casting operations. So, this reduces waste. It does produce fumes and energy that can be harmful to the environment. However, with proper waste management and fume disposal, these effects are also minimized.