Stainless steel is a term that encompasses a group of iron-based alloys containing at least 10.5% chromium by mass. Besides this, the alloy must also have a maximum of 1.2% carbon to be considered stainless. It may also contain elements in requisite amounts such as nickel, manganese, silicon, nitrogen, titanium, molybdenum, niobium, and others which ascribes valuable properties to the alloy. The addition of chromium provides the alloy with its rust-resistant quality. It forms a protective film on the surface, enabling it to prevent corrosion.
The potential uses of stainless steel are endless. It is used across a wide range of industries. Stainless steel is used extensively from the automotive industry to the architectural, medical and pharmaceutical, kitchen, food, and beverage industries. Its valuable properties such as corrosion resistance, durability, temperature resistance, high tensile strength, low maintenance, eco-friendliness, and attractive appearance contribute to its popularity.
Why Stainless Steel Has Various Grades?
In the stainless-steel smelting process, the varying alloy elements present in different quantities will contribute to the performance of this grade of steel. There are various types of stainless-steel grades based on the composition of the alloy. There are five major family groups: austenitic, martensitic, ferritic, duplex, and precipitation hardening stainless steel. Each family group is further classified by grade. 321 stainless steel tube belongs to the 300 series austenitic stainless steel, made of iron, chromium, and nickel. 321 stainless is a titanium stabilized grade that provides excellent intergranular corrosion resistance. The addition of titanium helps to stabilize it against chromium carbide formation.
Besides different grades, stainless steel also comes in varying gauges. Gauges refer to the thickness of the stainless steel metal. The higher the gauge number, the lesser will be the thickness of the material. Hence, metals with higher gauge numbers will be more-thin and vice versa. Choosing the stainless steel product of the correct gauge is crucial to a successful design. For different applications, the gauge of the metal will differ. Making the right choice is essential to ensure the durability of the material. It will also help you avoid structural problems and deformation.
The finish of stainless steel tends to vary from one product to another. Based on the intended use, selecting the right finish option is essential. In projects which emphasize design, an attractive finish is crucial for appeal. In retail products, especially kitchen appliances, stainless steel No. 4 finish is popular in the marketplace. Three more commonly used stainless steel finishing options include:
- 2B – Matte finish: It is a cold-rolled finish, which gives the surface a matte and a slightly reflective appearance. It is generally used for products in which appearance is not crucial.
- 4 – Brushed finish: It has a visible grain and slight reflection. It is suitable for use in architectural, medical, and kitchen applications.
- 8 – Mirror finish: Polishing with high abrasives results in a highly polished, mirror-like surface. It has no visible grain and is applicable in cosmetic products.
The right finish will determine the stainless steel surface’s grain, smoothness, shininess, and appearance.
Various aspects ranging from composition to gauge and surface finishes define the properties of stainless steel. Defining these aspects will help to yield a suitable product for end-use in your industry.