Stainless steel casting is a common material for casting production. Unlike other iron alloys, it has a stable passivation layer, covering it from air and moisture. In addition, its rust resistance property makes it an excellent choice for various applications, such as food service, outdoor, and high-temperature uses. This guide explains stainless steel die casting, its grades, composition, uses, properties, production, and applications.
WHAT IS STAINLESS STEEL DIE CASTING?
Stainless steel is one of the most flexible materials utilized in casting manufacturing and is aesthetically pleasing and known for its strength and corrosion resistance. The process of stainless steel die casting is widely known and used across many marine and automotive industries. It is even used to make ornamental and luxury commodities.
COMMON STAINLESS STEEL COMPOSITION
- Iron is the primary (main) component of stainless steel.
- It possesses a minimum of 11% Chromium and Nickel.
- Chromium and nickel combined with iron improve the resistance of stainless steel associated with corrosion and wearing.
- Chromium composition in stainless steel offers heat-resistant properties, making it very helpful for exhaust manifolds.
FINISHES OF STAINLESS STEEL
All the available finishes of stainless steel allow for accomplishing specifications for various industries. Some of the popular finishes include:
- Shot blasting
- Satin polishing
- Chrome plating
- Mirror polishing
- Dacromet coatings
- Zinc plating
HOW IS STAINLESS STEEL CASTING DONE?
The process of stainless steel die casting includes making a wax model and producing the part with plaster and subsequent layers until a firm shell envelops the model.
Once the wax melting is completed, and the molten stainless steel is ready, it’s poured into the mold to make an excellent representation of the simple wax pattern. Stainless steel casting offers high resolution, a smooth surface finish, refined detail, and economical undercutting. But, first, let’s understand the various types of stainless steel.
STAINLESS STEEL TYPES
Each category of stainless steel has unique proportions of chromium, iron, and carbon. Some of the elements cover molybdenum, manganese, nickel, and copper. The content of these steels makes the properties vary, making this a universal group of alloys.
Some types of Stainless Steel include:
It is vital to evaluate the benefit for the end product when picking the right type and its ahead usage.
GRADES OF STAINLESS STEEL
Grades indicate the family of particular Stainless Steel. Some familiar grades are:
1. AUSTENITIC STAINLESS: 347, 321, 304, 317, 316, 310, 303, 302,
This casting type is the most common for over 70% of production. Grade 304 is the most generally specified casting grade, with different austenitic grades such as 316 and 317.
2. FERRITIC STAINLESS: 444, 430, 409
This casting type covers a chromium stainless steel process, depending on variations between chromium content between 10.5 and 18% and lower carbon content.
3. MARTENSITIC STAINLESS: 440, 431, 420, 410, 416
It has a relatively high carbon content (0.1 – 1.2%) corresponding to other types of stainless steel casting. Some popular grades among all are 410 and 416.
4. DUPLEX STAINLESS: 2304, 2205
Duplex stainless contains moderately high chromium levels (between 18 and 28%) and increased quantities of nickel (like 4.5 and 8%).
Engineers often pick alloys from a similar family, like any two commercial grades, for example, 316 & 304 from austenitic stainless steel.
METHODS USED FOR STAINLESS STEEL CASTING
Here are the most common methods of casting stainless steel:
- Investment casting
Investment casting is a method that covers the use of mold cavities created and produced from wax or foam.
- Continuous casting
Also known as strand casting, this method is commonly used in industrial manufacturing to cast a particular length of stainless steel.
- Centrifugal casting
Centrifugal casting uses a strong centrifugal force to fill up the molds.
- Sand casting
Sand casting is another standard method that utilizes sand molds to create intricate and flawless components.
- Pressure die casting
Pressure Die Casting is a convenient and cost-effective manufacturing process for producing high-end metal castings along near-net-shape designs.
- Corner casting
It is a process that helps to create corner castings.
- Lost wax casting
As the name suggests, wax is eliminated from the method of Lost wax casting, and it involves the injection of molten stainless – steel into the models.
INDUSTRIAL USE OF STAINLESS STEEL CASTINGS
Stainless steel castings are truly versatile. Like, they can be utilized in multiple sectors in many applications.
Some of the industries among all where Stainless Steel castings are utilized:
- Safety – Harnesses etc
- Food machinery (316 s/s)
- Home appliances and applications
- General engineering
- Marine (Marine Grade) – Anchors, Bow chocks, Hatches, and other hardware for the boat
- Medical Equipment
- Sub-sea (Marine Grade)
- Automotive – Decorative wing vents, Exhaust Manifolds, engine parts, transmission components, bonnet emblems
ADVANTAGES OF STAINLESS STEEL CASTING
While it has various industrial benefits, stainless steel casting benefits manufacturing differently. Here are some of the significant benefits of stainless steel casting- Due to their exceptional corrosion resistance, castings are apt for medical, military, and industrial applications. Stainless steel casting has various benefits over other alloys, like more extended service life and lower maintenance costs. As mentioned above, it is available in numerous styles and grades to fulfill needs in machinery, petrochemical, plumbing, mining, electrical, automotive, aerospace, railway, submarine, and others.
- Resistant to corrosion
- Highly enduring over time, great lifespan
- High temperatures resistant
- Completely recyclable and, therefore, friendly to the environment
- Breakable due to descending malleability associated with carbon steel
- Reasonably resistant to wearing and damage
PROPERTIES OF STAINLESS STEEL
Stainless steel is explicitly chosen due to steel and its corrosion-resistant properties. However, it has many more beneficial properties like strength, toughness, hardness, response to work hardening, heat tolerance, etc. These hidden properties make steel the most used metal in construction, engineering, and manufacturing, particularly given its cost-effectiveness.
The tensile strength of stainless steel is incomparable to materials like brass, aluminum, and mild steel. The most increased tensile strength can be seen in precipitation martensitic and hardening grades.
The flexibility can be different for different grades. High ductility grades enable the usage of severe deep drawing procedures.
The toughness of the steel is its highly desirable quality as it makes it resistant to breaking and cracking in engineering applications.
STAINLESS STEEL CASTINGS APPLICATIONS
Many industries use stainless steel for its unique physical properties, even in critical environments.
Some of the applications include –
FOOD PROCESSING MACHINERY
Due to rust prevention capability, stainless steel casting is used in almost all food processing equipment. Such pieces of equipment are generally assembled with many components. There are various processing techniques to make these components, such as forging, casting, machining from the plate, welding, etc. Besides, complex-shaped parts for food processing machinery are easy to produce due to the versatility of stainless steel casting. Coffee machine components, metal grinder components, and more are some examples of the stainless steel casting process.
VALVE & PUMP COMPONENTS
Valve and pump components are crucial for the functioning of various equipment. Hence, the design must be robust enough for severe service applications and durability. Plus, the casting can be done to produce any complicated shape; it is highly feasible for the design of valve and pump components. Some valve & pump components produced from stainless steel casting are valve disc, valve body, valve bonnet, pump body, valve gland, pump impeller, and more.
Various stainless steel alloys are used in the production of marine components. In marine applications, the method is chosen to produce strong parts due to its high heat resistance, abrasion, and corrosion properties.
PIPE FITTING SOLUTIONS
Components for pipe fittings are used in many diverse industries for connecting, altering the direction of piping, and controlling flow. Stainless steel casting is the most cost-effective approach for small-volume production. Elbow, bushing, tee, and more, are some of the fittings produced with stainless steel casting.
Medical instrument manufacturers use stainless steel casting to produce various components. They work with multiple stainless steel materials, including Stainless Steel 316(L) and more, to create custom parts that fulfill the dimensional precision and tight tolerance needed by the medical application.
Some parts for medical OEMs contain implantable components, dental & surgical tools, X-ray equipment, MRI machines, wheelchairs & similar products.
Some other applications of Stainless Steel Castings are Bathroom & Toilet fittings, Sculpture parts, Doors & Windows, etc.
Hopefully, the details will help comprehend the stainless steel die-casting process. Also, the mentioned types of stainless steel for the cast and the overall elements can help determine the most suitable casting method or grade that suits your requirements.