Stainless steel is a common material in our daily life. It is widely used in building materials, industry and food industry. So, do you know the classification of stainless steel? According to different production processes, stainless steel can be divided into cold-rolled stainless steel and hot-rolled stainless steel. We have learned about cold-rolled stainless steel before (please see the previous article). Today, let's learn about hot-rolled stainless steel!
1.What Is Hot-Rolled Stainless Steel?
Hot-rolled stainless steel refers to the process of processing stainless steel billets into plates or strips through multiple rolling processes at high temperatures (usually above 900°C). Hot-rolled stainless steel has high production efficiency, relatively low cost, and a wide range of product thickness.
2.What Is The Production Process Of Hot-Rolled Stainless Steel?
The production process of hot-rolled stainless steel includes heating, hot rolling, cooling, shaping and cutting. Each step has an important impact on the final quality and performance of the product.
Heating
The stainless steel billet is heated to a certain temperature at high temperature (usually above 900°C) to make it have good plasticity. The heating process needs to be uniform, avoiding overheating or overcooling to ensure uniform internal organization and stable performance of the material.
Hot rolling
The heated stainless steel billet is subjected to multiple rolling processes to gradually reduce its thickness to form a plate or strip. The high-temperature deformation during hot rolling refines the grain of the material and makes the internal structure uniform, which improves the mechanical properties and surface quality of the product.
Cooling
The hot-rolled stainless steel is cooled to improve its hardness and strength. The cooling method can be natural cooling or controlled cooling, and the specific choice depends on the performance requirements and process conditions of the product. Controlled cooling can obtain specific metallographic structures and properties by adjusting the cooling rate and cooling medium.
Shaping and cutting
The cooled stainless steel is shaped and cut to form a product that meets the specification requirements. Shaping is to stretch and flatten the stainless steel sheet through rolling or straightening equipment to ensure uniform thickness and smooth surface. Cutting is to trim the length and width of the sheet to ensure that the dimensional accuracy meets the requirements.
3.What Is The Appearance Color Of Cold Rolled Stainless Steel?
Due to high temperature processing, hot-rolled stainless steel usually has a layer of oxide scale on the surface, which is dark gray or black. Its surface quality is relatively low, and sometimes it needs to be treated by pickling to achieve a smooth surface effect. The surface treatment methods of hot-rolled stainless steel include No.1, No.2D, No.2E and other types.
| Surface | Features | Application |
| No.1 | The No.1 surface is a rough, dark gray surface obtained by hot-rolled stainless steel after hot rolling, annealing and pickling. The No.1 surface has good corrosion resistance and mechanical properties | industrial equipment, chemical containers, pipelines |
| No.2D | The No.2D surface is a hot-rolled stainless steel that has been hot-rolled, annealed and pickled, then cold-rolled and lightly leveled, with a slightly silver-gray matte effect on the surface. The No.2D surface has good processing performance and corrosion resistance | industrial equipment, building materials |
| No.2E | The No.2E surface is a hot-rolled stainless steel that has been hot-rolled, annealed and pickled, then stretched and straightened, and has a uniform silver-gray luster on the surface. The No.2E surface has good corrosion resistance and processing performance | building materials, industrial equipment |
4.Specifications Of Hot-Rolled Stainless Steel Plates：
The thickness of hot-rolled stainless steel plates usually ranges from 3mm to 200mm, the width ranges from 1000mm to 3000mm, and the length can also be customized according to customer needs. Hot-rolled stainless steel plates are thicker and are suitable for manufacturing structural materials, heavy machinery parts, etc.
- Common specifications:
Common specifications of hot-rolled stainless steel plates include thicknesses of 4mm, 5mm, 6mm, 8mm, 10mm, 12mm, 15mm, 20mm, 25mm, 30mm and other types, and widths of 1500mm, 2000mm, 2500mm, 3000mm and other sizes. Hot-rolled stainless steel plates can also be customized to specific lengths and widths according to different application requirements.
- Surface quality requirements:
The surface quality requirements of hot-rolled stainless steel plates are relatively low, including allowing a certain amount of oxide scale, large surface roughness, slight scratches and defects, etc.
5.Applications Of Hot-Rolled Stainless Steel:
- Building structures: bridges, steel structures, building frames, etc.
- Industrial equipment: pressure vessels, chemical equipment, storage tanks, etc.
- Pipeline system: oil and gas pipelines, water pipelines, drainage systems, etc.
- Shipbuilding and marine engineering: hull structure, offshore platform, marine equipment, etc.
6.Physical Properties Of Hot-Rolled Stainless Steel：
Hot-rolled stainless steel has good plasticity and toughness due to processing at high temperature, but its hardness and strength are relatively low.
- Hardness and strength
The hardness and strength of hot-rolled stainless steel are relatively low, and its tensile strength is usually around 400MPa and its hardness is around HV150. Through appropriate heat treatment processes such as quenching and tempering, its hardness and strength can be improved to meet the needs of specific applications.
- Elongation
Hot-rolled stainless steel has a high elongation, usually above 30%, and has good formability and processing performance. Its good plasticity and toughness make it less prone to cracks and fractures during processing.
