Composition of 304L stainless steel

Main chemical composition Chromium (Cr): The content is between 18.00% and 20.00%. Chromium is the main alloying element in stainless steel and can significantl

Main chemical composition
Chromium (Cr): The content is between 18.00% and 20.00%. Chromium is the main alloying element in stainless steel and can significantly improve the corrosion resistance of steel.
Nickel (Ni): The content is between 8.00% and 12.00%. The addition of nickel can further enhance the corrosion resistance and toughness of stainless steel.
Carbon (C): The maximum content is 0.03%. The lower carbon content reduces the precipitation of carbides in the heat affected zone of 304L stainless steel during welding, thereby reducing the risk of intergranular corrosion.
Other elements
Silicon (Si): The maximum content is 1.00%. The addition of silicon helps to improve the casting properties of steel and can improve the corrosion resistance of steel to a certain extent.
Manganese (Mn): The maximum content is 2.00%. Manganese is a deoxidizer in steel, which can remove oxygen and sulfur in steel and improve the quality and performance of steel.
Phosphorus (P): The maximum content is 0.045% (some data show ≤0.040% or ≤0.035%). Phosphorus is generally regarded as a harmful impurity in steel, but its content will not significantly affect the performance of steel under strict control.
Sulfur (S): The maximum content is 0.030%. Sulfur is also regarded as a harmful impurity, but its content is usually low in stainless steel.
In addition, 304L stainless steel may also contain trace amounts of other elements, such as cobalt (Co), molybdenum (Mo), etc. The content of these elements is low, and their specific effects may vary depending on the steel plant and production process.

Mechanical properties
In addition to the chemical composition, 304L stainless steel also has good mechanical properties. Its tensile strength is ≥520 MPa, yield strength is ≥205 MPa, and elongation is ≥40%. These properties make 304L stainless steel perform well in a wide range of applications, especially in occasions where welding is required, and its low carbon characteristics make the welded joints have good corrosion resistance and mechanical properties.

stainless steel processing

The manufacture of stainless steel involves a series of processes. First, the steel is melted, and then it is cast into solid form. After various forming steps, the steel is heat treated and then cleaned and polished to give it the desired finish. Next, it is packaged and sent to manufacturers, who weld and join the steel to produce the desired shapes.

The raw materials that constitute a stainless steel item are placed together and melted in a giant electric furnace. Intense heat is applied rigorously for a period of 8 to 12 hours during this step. Once the melting is complete, the molten steel is cast into desired semi-finished forms. Some of the most common forms or shapes include slabs, blooms (rectangular shapes), billets (these could either be round or square), rods, and tube rounds.

In the second stage, the semi-finished steel shapes undergo a series of forming operations. For instance, the stainless steel is hot rolled (heated and passed through enormous rolls). The blooms and billets mentioned above are converted to bar and wire. The slabs on the other hand are formed into plates, strips or sheets. It is very common to turn semi-finished steel shapes into bars, as it is the most versatile stainless steel form (it comes in all grades and sizes). You have round, square, octagonal, and hexagonal bars, each suitable for a different type of application.

The various stainless steel forms undergo a thorough annealing process during this step. Annealing is another name for heat treatment where the stainless steel is heated and cooled in a controlled environment. The purpose of this heat treatment is to relieve the pent-up stress inside the stainless steel and soften the material to make it more suitable for a wide variety of applications. The people in charge of carrying out the annealing process have to be very careful about the conditions as even the slightest of changes in the temperature, pressure, duration, or cooling rate could result in a faulty product.

During the annealing process, a certain amount of scale appears on the surface of the stainless steel. This scale can be removed using a number of different processes that are collectively known as descaling. Pickling is one of the more common methods of carrying out the descaling process.

The semi-finished, heat-treated, and descaled stainless steel forms are cut into specific shapes in this step. Mechanical cutting is performed with the aid of guillotine knives, blanking, nibbling, and high-speed blades.

Finishing is applied to help the stainless steel product achieve its signature aesthetically appealing appearance. Finishes are also needed to make the stainless steel product smooth and easier to clean, which is a top requirement in sanitary applications.