Stainless steel material analysis: 210, 303, 304, 316 and 430 stainless steel

210 stainless steel

Chemical composition and organizational structure

210 stainless steel belongs to the chromium-manganese-nickel-nitrogen austenitic stainless steel series. Among them, chromium (Cr) is a key alloying element in stainless steel. Its content provides stainless steel with basic corrosion resistance and can form a dense passivation film on the surface of the steel to prevent further oxidation and corrosion. The presence of manganese (Mn) helps to improve the strength and toughness of steel, giving the steel better comprehensive mechanical properties. Nickel (Ni) plays an important role in stabilizing the austenite structure and further enhances the corrosion resistance, allowing stainless steel to maintain structural stability in a variety of environments. Nitrogen (N) can strengthen the austenite phase and improve the steel's ability to resist local corrosion, such as effectively preventing corrosion in the presence of tiny gaps or surface defects.

Performance characteristics and applications

Mechanical properties

• 210 stainless steel has high strength characteristics. Its tensile strength and yield strength are relatively excellent, which makes it play a role in some occasions with certain requirements for structural strength. For example, in the manufacture of some small mechanical parts, such as simple connectors, small transmission parts, etc., it can provide sufficient strength support to ensure that the parts will not be deformed or damaged under normal working conditions. In some non-critical parts in the field of architectural decoration, such as small decorative ornaments, simple frame structures, etc., its strength characteristics can also meet the basic use requirements.

Corrosion resistance

• Compared with several other stainless steels, its corrosion resistance is slightly insufficient. In general atmospheric environment and fresh water environment, it can remain stable for a certain period of time, but in harsh environments with strong acidity, alkalinity or containing chloride ions, it is prone to corrosion. For example, in the acidic gas environment of some chemical production workshops or in the humid air with high chloride ion content near the sea, 210 stainless steel products may quickly develop rust spots, thereby affecting their service life and appearance.

Processing performance

• Due to the presence of a certain amount of manganese and other elements, it is relatively easy to produce work hardening during cutting. This means that during the processing, as the cutting progresses, the surface hardness of the steel will gradually increase, resulting in increased tool wear and increased processing difficulty. However, through the use of suitable tool materials, such as carbide tools, and reasonable adjustment of processing parameters, such as controlling cutting speed, feed rate and cutting depth, 210 stainless steel can still be effectively processed to produce parts or products that meet the requirements.

Processing cost

• Due to its work hardening characteristics, special tools and process adjustments are required, making the processing cost relatively high, but compared with some high-end stainless steels such as 316 stainless steel, its raw material cost is lower, and there is still room for application in some scenarios where cost control is more stringent and processing accuracy requirements are not extremely high.

303 stainless steel

Chemical composition and structure

303 stainless steel is a kind of free-cutting stainless steel. It adds elements such as sulfur (S) and selenium (Se) to 304 stainless steel. Sulfur forms sulfide inclusions in steel, and selenium has a similar effect. These sulfides and selenides can make the chips fragile when the steel is cut, thereby reducing the friction between the tool and the chips, reducing the wear of the tool, significantly improving the cutting efficiency, and greatly reducing the processing cost. Its matrix structure is still austenite, and the content of chromium (Cr) and nickel (Ni) is similar to that of 304 stainless steel, which ensures that it has a certain corrosion resistance and a good comprehensive mechanical performance foundation.

Performance characteristics and applications

Mechanical properties

• The strength of 303 stainless steel is similar to that of 304 stainless steel, but due to the addition of sulfur and selenium, its toughness will be slightly reduced to a certain extent. In general mild environments, such as indoor environments and ordinary atmospheric conditions, it has good corrosion resistance, can prevent rust and oxidation, and its appearance can maintain a metallic luster for a long time. However, in high-temperature and high-concentration acid and alkali environments, its corrosion resistance will decrease. For example, in the high-temperature reactor in chemical production, if there is a high concentration of acid and alkali solution, 303 stainless steel may be gradually corroded, causing equipment damage.

Machining field

• 303 stainless steel is widely used in the manufacture of parts that require a lot of machining, such as various nuts, bolts, shaft parts, etc. In the precision machining industry, its easy cutting makes it one of the preferred materials, and it can quickly and efficiently produce parts that meet precision requirements.

Processing cost

• Due to its easy cutting characteristics, the processing cost is relatively low, and it has obvious cost advantages in the large-scale production of standard mechanical parts. For example, in the watch manufacturing industry, some small shafts, gears and other parts are processed using 303 stainless steel, which can not only meet the precision requirements, but also reduce processing costs and improve production efficiency.

304 stainless steel

Chemical composition and organizational structure

304 stainless steel is a star product in the stainless steel family and is one of the most widely used stainless steels. Its main chemical composition includes about 18% chromium (Cr) and about 8% nickel (Ni). This reasonable ratio of chromium and nickel gives it excellent comprehensive performance. The passivation film formed by chromium on the surface of steel is the key to its corrosion resistance, while nickel not only helps to stabilize the austenite structure, but also further improves the stability and repair ability of the passivation film, so that 304 stainless steel can maintain good corrosion resistance in a variety of complex environments.

Performance characteristics and applications

Corrosion resistance

• 304 stainless steel exhibits good corrosion resistance in the atmosphere, fresh water, general acid and alkali solutions, and a variety of food media. It can resist general oxidation, and the passivation film formed on the surface allows it to maintain its metallic luster for a long time and is not easy to rust.

Mechanical properties

• It has moderate strength and good toughness, which can meet the use requirements of many structural parts. For example, stainless steel railings and handrails in the construction industry, stainless steel plates in interior decoration, etc., can provide sufficient structural support and show a beautiful and elegant appearance. In the food processing industry, 304 stainless steel is widely used in food storage containers, processing equipment, etc., because it meets food hygiene and safety standards and will not pollute food. In the chemical industry, for some medium environments that are not too corrosive, 304 stainless steel can also be competent for the manufacture of equipment such as pipes and containers. It has good processing performance, whether it is welding, bending, stamping or cutting, it can be carried out relatively smoothly, and after processing, appropriate heat treatment can be used to eliminate processing stress, further improving the quality and performance of the product. For example, in the manufacturing process of stainless steel kitchenware, 304 stainless steel can be easily stamped into pots and tableware of various shapes, welded into complex kitchen equipment frames, and can present a beautiful luster after surface treatment, which is deeply loved by consumers.

Processing cost

• Due to its wide application and mature processing technology, the raw material and processing costs of 304 stainless steel are at a medium level. It is a more commonly used choice in projects that comprehensively consider performance and cost.

316 stainless steel

Chemical composition and structure

316 stainless steel is a molybdenum-containing stainless steel. It adds molybdenum (Mo) elements on the basis of 304 stainless steel. The addition of molybdenum significantly improves the corrosion resistance of stainless steel, especially in environments containing highly corrosive media such as chloride ions. Molybdenum elements can enhance the stability of the passivation film on the surface of stainless steel in a chlorine-containing environment, effectively preventing the occurrence of pitting and crevice corrosion. Its chromium (Cr) and nickel (Ni) content is similar to that of 304 stainless steel, maintaining the stability of the austenite structure and the basic mechanical properties.

Performance characteristics and applications

Mechanical properties

• The strength of 316 stainless steel is comparable to that of 304 stainless steel, but it has a better strength retention rate in high temperature environments. This gives it unique advantages in the manufacture of some high-temperature and high-pressure chemical reaction equipment and marine ship parts. For example, in high-temperature and high-pressure reaction towers, heat exchangers and other equipment in chemical production, 316 stainless steel can maintain structural strength during long-term high-temperature operation to ensure the safe and stable operation of the equipment. In the marine environment, the hull of the ship, seawater pipelines, etc. are in contact with seawater for a long time. 316 stainless steel can effectively resist the corrosion of seawater and extend the service life of the ship. In the medical field, 316 stainless steel is also widely used in the manufacture of medical devices, such as surgical instruments, implantable medical devices, etc., because it not only has good corrosion resistance, but also has good biocompatibility with the human body, which can reduce adverse reactions to human tissues.

Processing performance

• Its processing performance is similar to that of 304 stainless steel, but due to the presence of molybdenum, the process parameters may need to be properly adjusted in some processing processes to ensure the processing quality. For example, in the welding process, more suitable welding materials and welding processes may need to be used to avoid welding defects.

Processing cost

• Due to the addition of molybdenum and its high performance requirements in special environments, the raw material cost of 316 stainless steel is relatively high, and the requirements for process and equipment during processing are relatively high, resulting in its overall processing cost. It is generally used in high-end fields with extremely high requirements for corrosion resistance and safety.

430 stainless steel

Chemical composition and organizational structure

430 stainless steel is a ferritic stainless steel. Its main chemical component is chromium (Cr), and the chromium content is generally between 16% and 18%. This stainless steel has good corrosion resistance, especially in oxidizing environments, and can form a stable passivation film. Its organizational structure is ferrite with a body-centered cubic lattice structure, which makes it different from austenitic stainless steel in some properties.

Performance characteristics and applications

Mechanical properties

• 430 stainless steel has relatively high strength and hardness, but slightly lower toughness. It has good thermal conductivity and thermal expansion coefficient, which makes it valuable in some occasions that require good thermal conductivity, such as in the field of kitchenware manufacturing, such as stainless steel pots and baking trays. Because of its good thermal conductivity, food can be heated more evenly. In terms of appearance, 430 stainless steel can obtain a bright surface through polishing and other treatments, but compared with austenitic stainless steel, its glossiness and aesthetics may decrease slightly after long-term use.

Processing performance

• 430 stainless steel is relatively easy to process, such as stamping, stretching, etc., but it is necessary to pay attention to controlling the welding process parameters during welding to prevent defects such as welding cracks. For example, in the manufacture of some parts of the automobile exhaust system, 430 stainless steel is selected for its high temperature oxidation resistance and relatively easy processing, but the welding process needs to be strictly controlled during the welding assembly process to ensure product quality.

Processing cost

• 430 stainless steel has relatively low raw material costs and is less difficult to process, especially in some simple forming processes such as stamping. The cost advantage is obvious, and it is suitable for large-scale production of some products that do not require top corrosion resistance and appearance requirements.

Conclusion

In summary, 210, 303, 304, 316 and 430 stainless steels each have their own characteristics and advantages. When actually selecting stainless steel materials, it is necessary to comprehensively consider factors such as the use environment, mechanical performance requirements, processing difficulty and cost. Whether it is the manufacturing of large equipment in industrial production or the production of small objects in daily life, the reasonable selection of stainless steel materials can ensure the performance, quality and service life of the product, thereby giving full play to the excellent characteristics of stainless steel materials and providing solid material guarantees for the development of modern society and people's lives. Different industries and fields should accurately select suitable stainless steel materials according to their specific needs to achieve the best economic benefits and use effects.