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The role of Mo content in austenitic stainless steel

Stainless steel is very important in our production and life. It can be used as a corrosion-resistant material, reducing corrosion losses, increasing equipment service life, improving economic efficiency, and maintaining equipment cleanliness, improving hygiene conditions, and increasing aesthetics, thanks to its alloy elements.

Corrosion resistance: Stainless steel has extremely strong corrosion resistance and can resist the erosion of various corrosive substances, ensuring the stability and safety of pipeline systems. For example, in food and beverage production, stainless steel joints can effectively resist the erosion of acidic juices and alkaline cleaning agents, ensuring the stability of the production process and product quality.

Easy to clean: The stainless steel surface is smooth and flat, not prone to dirt and impurities, and easy to clean and disinfect. This characteristic makes stainless steel widely used in industries such as food processing, catering, and brewing, as it can reduce cleaning costs and time, while reducing the risk of product contamination.

Aesthetics and durability: Stainless steel has good aesthetics and durability, and is commonly used in home decoration, building facades, railings, doors and windows, etc. Its weather resistance and aesthetics make it widely used in the construction industry.

Wide application areas: Stainless steel has important applications in multiple fields. In the field of architecture, stainless steel is used for building facades, doors and windows, and interior decoration; In mechanical manufacturing, it is used for key components such as bearings, valves, and hydroelectric equipment; In food processing, used for storage tanks, processing equipment, and tableware; In the medical industry, used for surgical and dental instruments; In chemical and petrochemical industries, used for pipelines and valves; In the fields of energy and environmental protection, it is used for water treatment equipment and pipelines.

Environmental characteristics: With the increasing awareness of environmental protection, stainless steel is regarded as an environmentally friendly material due to its sustainability, and is widely used in water treatment, solar energy equipment, and recycling systems

1. Let's first understand the benefits of increasing Mo content on stainless steel

Improve corrosion resistance

• Enhance resistance to pitting and crevice corrosion: Molybdenum can significantly improve the resistance of stainless steel to pitting and crevice corrosion. In corrosive media containing chloride ions, the passivation film on the surface of stainless steel may have defects or weak points, leading to pitting or crevice corrosion. The addition of molybdenum can enhance the performance of the passivation film, making it denser and more stable, thereby effectively suppressing the initiation and propagation of corrosion.

• Improve chloride corrosion resistance: Molybdenum containing stainless steel exhibits excellent corrosion resistance in marine environments, chemical equipment, and other environments containing a large amount of chloride, effectively resisting the corrosion of chloride on materials Improving high-temperature corrosion resistance: Molybdenum can also enhance the corrosion resistance of stainless steel in high-temperature environments, allowing it to maintain good mechanical properties even in high temperature, high pressure, and strong corrosive environments.

Enhance strength and hardness

• Improve high-temperature strength: With the increase of molybdenum content, the high-temperature strength of stainless steel is significantly improved, such as durability strength, creep strength, and other properties. Therefore, molybdenum containing stainless steel is often used in high-temperature environments.

• Enhance room temperature strength and hardness: The addition of molybdenum can also improve the room temperature strength and hardness of stainless steel, enabling it to have higher tensile strength and yield strength while maintaining good toughness. Improving high-temperature performance and enhancing oxidation resistance: Molybdenum can improve the oxidation resistance of stainless steel at high temperatures, reduce its oxidation rate in high-temperature environments, and thus extend the service life of the material.

• Enhance thermal stability:

The addition of molybdenum can improve the thermal stability of stainless steel at high temperatures, enabling it to maintain good mechanical properties and corrosion resistance in high-temperature environments.

2. Let's first take a look at the range of Mo content in different grades of stainless steel in the "Materials and Welding Specification" (2024):

summary:

The increase of Mo content can not only improve the corrosion resistance of stainless steel, but also increase the strength, hardness, and high-temperature performance of the material; In most 2G chemical tankers nowadays, due to the variety of goods loaded, there are generally requirements for the Mo content. Pipelines and valve accessories related to liquid cargo also have certain requirements for the Mo content,