Different types of stainless steel are widely used in various industries, but not all types are created equal. Each grade possesses unique properties that affect its corrosion resistance, mechanical properties, and suitability for different environments.
Although 18/8 stainless steel is widely prized for its favorable pricing, adequate mechanical qualities, and strong corrosion resistance, it is vulnerable to corrosion in seawater. 18/10 stainless steel can withstand corrosion, which makes it useful in chemical processing and maritime environments.
The affordability and rust resistance of 18/0 stainless steel make it a favored option for everyday household items like utensils, flatware, and kitchen tools.
This article will discuss the differences between 18/8, 18/10, and 18/0 stainless steel in terms of how they are made, composition, uses, and advantages.
What Is 18/8 Stainless Steel?
18/8 stainless steel refers to a type of stainless steel within the 300 series, characterized by its composition of 18% chromium and 8% nickel. The 300 series belongs to the austenitic steel category, characterized by its austenitic microstructure. This structure allows for hardening exclusively through cold working, as it maintains the austenitic form at room temperature, preventing a transformation into martensite, which is typically essential for steel hardening. This composition gives it excellent corrosion resistance, particularly in non-marine environments. Additionally, 18/8 stainless steel is non-magnetic and can be hardened only through cold working. Its versatility and affordability make it a popular choice for various applications across industries such as wastewater treatment, medical, and transportation.
How Is 18/8 Stainless Steel Made?
To produce 18/8 stainless steel, manufacturers blend approximately 66.74% iron, 0.07% carbon, 18% chromium, and 8% nickel. The raw materials required for the formation of the stainless steel undergo melting in an electric furnace, a process lasting 8 to 12 hours. Excess carbon is eliminated through vacuum oxygen decarburization or argon oxygen decarburization. Stirring the molten steel ensures uniformity, followed by forming, heat treatment, cutting, shaping, and applying surface finishes. These steps collectively yield the desired 18/8 stainless steel composition, meeting specific mechanical and quality requirements.
What Are the Advantages of 18/8 Stainless Steel?
Here are the advantages of 18/8 Stainless Steel, also known as 304 stainless steel:
- Has good corrosion resistance in mild environments due to its 18% chromium content.
- The alloy's nickel content enhances its strength, making it durable and suitable for various applications.
- It offers a good balance between performance and cost, providing adequate strength and temperature resistance without being overly expensive.
- It has good weldability, which allows for easier fabrication and repair.
- It is safe for use in cookware and food preparation surfaces.
What Are the Disadvantages of 18/8 Stainless Steel?
The disadvantages of 18/8 stainless steel are:
- Despite its corrosion resistance, 18/8 stainless steel may tarnish over time, especially when exposed to harsh chemicals or acidic environments.
- Due to its vulnerability to chloride-induced corrosion, 18/8 stainless steel is not recommended for use in marine environments.
- It can only be hardened through cold working, which may limit its applicability in certain high-strength applications.
What Is 18/10 Stainless Steel?
18/10 stainless steel is a type of stainless steel composed of 18% chromium and 10% nickel. Its composition gives it outstanding durability and resistance to corrosion. Pots and pans, flatware, and kitchen utensils benefit greatly from their increased nickel content, which also increases their resistance to rust and other types of corrosion. 18/10 stainless steel is perfect for cooking applications since it also has outstanding heat resistance.
How Is 18/10 Stainless Steel Made?
When producing 18/10 stainless steel, scrap steel is melted in an electric arc furnace, which warms the steel to liquefaction using a current flowing between carbon electrodes. To obtain the low carbon content that characterizes stainless steel, the molten steel is subsequently transported to an Argon Oxygen Decarburization (AOD) vessel. The steel is then formed into slabs or billets after chromium and nickel have been added to achieve the appropriate compositions of 18% and 10%, respectively.
What Are the Advantages of 18/10 Stainless Steel?
The advantages of 18/10 stainless steel include:
- Even when used with acidic or corrosive foods, it maintains its integrity.
- The material has a shiny and aesthetically pleasing appearance.
- It's highly resistant to rust and staining due to its high chromium and nickel content.
- It's simple to clean and is dishwasher safe.
- It can withstand high temperatures without degrading, making it ideal for cookware.
What Are the Disadvantages of 18/10 Stainless Steel?
The disadvantages of 18/10 stainless steel include:
- It has a machinability rating of 48%, which means it’s less machinable compared to other metals like 1112 carbon steel, potentially increasing manufacturing costs and effort.
- Being non-magnetic may be a disadvantage in certain applications that require magnetic properties.
- The higher alloy content of 18/10 stainless steel contributes to its higher cost compared to other stainless.
- While highly resistant to corrosion, it can be susceptible to saltwater environments
What Is 18/0 Stainless Steel?
18/0 stainless steel is a variant of stainless steel with 0% nickel and 18% chromium. The chromium gives good oxidation resistance and some protection against corrosion though not at the same level as in the nickel-containing austenitic steels. Lacking nickel and molybdenum, it's a cost-effective alternative to nickel-bearing austenitic steels.
How Is 18/0 Stainless Steel Made?
To make 18/0 stainless steel, mix iron, carbon, and at least 10.5% chromium. These raw ingredients are melted together, cast into slabs, and hot rolled to the required thickness. Subsequently, the steel undergoes annealing to alleviate internal stresses and guarantee structural consistency. Ultimately, the steel goes through several finishing procedures like pickling, cutting, and polishing to attain the required level of surface quality.
What Are the Advantages of 18/0 Stainless Steel?
The advantages of 18/0 stainless steel are:
- This grade is more affordable than stainless steel alloys containing nickel. It is a budget-friendly option for applications that don’t require the additional corrosion resistance of austenitic stainless steel.
- Its affordability and resistance to rust make it a popular choice for everyday household items such as: utensils, flatware, and kitchen tools.
- Since no nickel is present in 18/0 stainless steel, it does not cause allergic reactions in individuals with nickel allergies. It's used in cutlery, kitchen tools, and medical devices where contact with skin is common. Its hypoallergenic nature ensures safety and comfort for sensitive users.
- t has some resistance to pitting due to its chromium resistance.
- 18/0 is magnetic, making it useful in applications where magnetism is relevant.
What Are the Disadvantages of 18/0 Stainless Steel?
The disadvantages of 18/0 stainless steel are:
- Compared to stainless steel alloys containing nickel, 18/0 stainless steel typically has lower corrosion resistance, making it more prone to corrosion damage over time.
- Welding can be challenging due to its efficient heat retention. Excess heat can cause warping or distortion during the welding process, and the high melting point of stainless steel can complicate joining with other metals.
- Has a more muted, grayish appearance compared to the brighter luster of 18/8 due to the absence of nickel.
- The nickel content in 18/8 stainless steel enhances its ductility, making it more malleable for intricate forming processes like wire drawing or deep drawing. In contrast, 18/0 stainless steel, lacking nickel, tends to be more brittle and can crack when subjected to similar forming operations.
How To Choose Between 18/8, 18/10, and 18/0 Stainless Steel?
When choosing between the stainless steel grades 18/8, 18/10, and 18/0, you need to take your unique needs into account. 18/8 stainless steel provides an ideal combination of cost-effectiveness and corrosion resistance, making it well-suited for common household items such as sinks, fasteners, and tools that require strength and protection against rust. While less expensive, 18/0 stainless steel is less resistant to corrosion and may stain easily, making it best suited for applications where cosmetic appeal is extremely important.
How Do 18/8, 18/10, and 18/0 Stainless Steels Differ in Properties?
Table 1 highlights the properties of 18/8, 18/10, and 18/0 stainless steels:
