1. Introduction
Hot rolling of stainless steel is a process by which mill operator achieves desired material sheet thickness, sheet size, and mechanical properties. Hot rolling of stainless steel is typically done on a reversing mill or in a tandem mill arrangement. SUS304 stainless steel is one of the most prominent and versatile grades of stainless steel in the market. The properties it offers include good corrosion resistance, formability, good weldability, and excellent strength. Thus, it makes SUS304 grade ideal for applications as diverse in nature as architectural, medical, and foodware. This paper aims to present an overview of the hot rolling process of SUS304 stainless steel.
2. Overview of the Hot Rolling Process
Hot rolling of SUS304 stainless steel is typically done in the temperature range of 1200°C to 1250°C. Above this temperature range, the material undergoes recrystallization, resulting in a significant change in the microstructure. Cold rolling, in contrast, is typically done at room temperature or at lower temperatures. The recommended hot rolling speed for SUS304 grade ranges from 10 to 20 mm/sec. Depending on the required end properties, rolling temperature, roll speed and roll gap are adjustable. The workability of SUS304 grade is improved upon hot rolling and the forming possibilities it offers can be used to produce finished parts with desired shapes and aesthetic appeal.
3. Advantages of Hot Rolling
Hot rolling of SUS304 stainless steel offers several advantages over the cold rolling process:
a) Improved Strength: Hot rolling of SUS304 stainless steel increases its strength due to improved grain size and improved microstructure. This makes the material more suitable for applications that require high strength.
b) Improved Corrosion Resistance: Hot rolling of SUS304 stainless steel improves its grain size, which makes it better resistant to corrosion. Thus, it can be used in a larger spectrum of applications.
c) Increased Ductility: Hot rolling of SUS304 stainless steel results in increased flow of the material, which makes the material more ductile. This feature makes it well suited for applications in which forming of complex shapes is necessary.
d) Improved Surface Finish: Hot rolling of SUS304 stainless steel improves its surface finish significantly. This makes it easier to apply subsequent coatings without major preparation.
4. Technological Limitations
Despite its several advantages, the hot rolling process for SUS304 stainless steel also has some limitations. The general technological concern in hot rolling of SUS304 stainless steel is that the material begins to recrystallize gradually and rapidly at temperatures above 1250°C. This behavior of SUS304 material limits the scope of hot rolling process, as the mill operator has to be careful not to overheat the material during processing. Moreover, undergoing recrystallization can alter the grain size, shape, and distribution of the material, which can drastically change the mechanical and physical properties of the material.
5. Conclusion
Hot rolling of SUS304 stainless steel offers several advantages over the cold rolling process, such as improved strength, corrosion resistance, ductility, and surface finish. Despite its advantages, recrystallization at temperatures above 1250°C is a major limitation of hot rolling process for SUS304 stainless steel. To avoid such, mill operators must be careful in controlling the temperature to ensure the finished material has desired properties.
