Stainless steel comes in many different grades. Each grade brings its own unique chemical composition, tensile strength, and other characteristics. Let's take a look at two of the most popular grades of stainless steel - 430 and 304.
1.What is stainless steel?
Like other forms of steel, stainless steel is an alloy of iron and carbon. What distinguishes stainless steel is the addition of chromium. To be considered stainless steel, the alloy must contain at least 10% chromium by weight. The chromium gives stainless steel its non-corrosive characteristics, which help lengthen the metal's lifespan.
Carbon steel typically gets used for infrastructure, automobiles, and weapons. Stainless steel, by contrast, generally forms medical tools and food or beverage equipment. It tends to be brighter and more attractive than carbon steel.
2.What do the different grades of steel signify?
The steel industry classifies metals by grades in order to ensure the consistency and quality that precise steel processing requires. A steel's grade is determined by all the factors that make that steel unique.
Steel standards organizations determine how to classify each grade of steel. Because there are several standards organizations around the world, the same grade of steel may be classified differently across national boundaries. Grades 304 and 430 are American Iron and Steel Institute (AISI) standards.
3.What is 430 stainless steel?
Type 430 stainless steel is a mild, corrosion-resistant metal that can be easily bent, stretched, or drawn.
It features the following chemical composition:
Iron = Balance
Carbon < 0.12%
Chromium = 16-18%
Nickel < 0.75%
Manganese < 1.0%
Silicon < 1.0%
Phosphorus < 0.040%
Sulfur < 0.30%
Its relatively high carbon content and lack of stabilizing elements make this grade difficult to weld.
Type 430 stainless steel has a minimum yield strength of 30 ksi and a minimum tensile strength of 65 ksi. Most commonly, type 430 stainless steel is used in cosmetic applications that require more aesthetic appeal than strength. It is available in 430 stainless steel sheet.
4.What is 304 stainless steel?
Type 304 stainless steel is the most widely used of all stainless steel grades. It generally appears in kitchen equipment and industrial applications.
This grade of stainless steel features the following chemical composition:
Iron = Balance
Carbon = 0.0 – 0.07%
Chromium = 17.50 – 19.50%
Manganese = 0.0 – 2.0%
Silicon = 0.0 – 1.0%
Phosphorous = 0.0 – 0.05%
Sulphur = 0.0 – 0.03%
Nickel = 8.0 – 10.5%
Nitrogen = 0.0 – 0.11%
Type 304 can be welded to plain carbon steel using TIG or MIG welding. This grade of stainless steel has a minimum yield strength of 30 ksi and a minimum tensile strength of 75 ksi.
This stainless steel grade is routinely stocked in various formats, including: 304 stainless steel sheet, 304 stainless steel plate, 304 stainless steel tube, and 304 stainless steel bar.
