How to choose corrosion-resistant metal tube?

How to choose corrosion-resistant metal tube? The commonly used tubematerials include the following:

1. Stainless Steel tube: Stainless steel is widely used in various environments due to its excellent corrosion resistance. Stainless steel is divided into several types, including austenitic stainless steel, ferritic stainless steel, and duplex stainless steel, each suitable for different usage environments. For example, austenitic stainless steel has good corrosion resistance and toughness, making it suitable for industries such as chemicals and petroleum; ferritic stainless steel is suitable for environments with corrosion from atmospheric and saline mediums. Stainless steel pipes are easy to bend and weld, and are classified according to their manufacturing processes into welded tubes and seamless tubes, with seamlesss commonly used in pressurized lines. Common stainless steels include SUS304 and SUS316. SUS304 is an austenitic stainless steel composed of 18% chromium and 8% nickel, and 0.08% carbon, 2% manganese, along with trace amounts of silicon, phosphorus, sulfur, and nitrogen. SUS316 is composed of 16-18% chromium, 10-14% nickel, 2-3% molybdenum, and small amounts of silicon, manganese, and carbon. SUS316 stainless steel has better machinability and corrosion resistance, especially in acidic and saline environments, making it commonly used in marine and chemical industries.

2. Copper-Nickel Alloy tube: Nickel alloys are known for their high temperature, high strength, and excellent corrosion resistance, making them suitable for aerospace, petrochemical industries, and more. Copper-nickel alloy pipes are not only corrosion-resistant but also exhibit good heat resistance. For example, C70600 copper-nickel alloy pipes show excellent oxidation resistance in high-temperature environments, making them less likely to form surface oxide layers due to thermal oxidation. They perform excellently in extreme environments and can be used for extended periods in high-temperature and highly corrosive conditions. The surface of copper-nickel alloy pipes is smooth and delicate, providing good wear resistance. This feature makes them outstanding in high-speed fluid applications, effectively reducing wear and extending service life. Therefore, copper-nickel alloy pipes are especially suitable for industrial fields with high wear resistance requirements.

3. Titanium Alloy tube: Titanium alloys have high strength, low density, and excellent corrosion resistance, making them suitable for marine engineering, chemical industries, and more. Titanium alloys have great resistance to acids, bases, and chlorides, allowing them to be used stably in highly corrosive environments for long periods; however, titanium's corrosion resistance is relatively poor in reducing media such as hydrochloric acid. Titanium alloys maintain good mechanical properties even at high temperatures, capable of long-term operation at temperatures between 450 and 500°C. Moreover, certain titanium alloys exhibit increased strength at lower temperatures, making them suitable for ultra-low temperature environments. Titanium alloy pipes are also non-magnetic and have low thermal conductivity. They exhibit good stamping and cutting performance, such as bending and stamping, and the strength of welded joints can reach 90% of the base metal strength.

The selection of these materials should be determined based on the specific usage environment and requirements to ensure good performance and service life under various corrosive conditions.