1. What is the hardness difference between common and high-specification carbon steel seamless pipes?
Answer: Common carbon steel pipes (10#, 20#) have a Brinell hardness (HB) of 137-170, which is relatively soft and easy to process; high-specification pipes such as 45# have a HB of 197-241, and 16Mn/Q345 has a HB of 159-197, which are harder and more wear-resistant.
2. Can common carbon steel seamless pipes be used in high-temperature environments?
Answer: Generally, common carbon steel seamless pipes can be used in environments below 350℃. When the temperature exceeds 350℃, their strength will decrease significantly, and high-specification materials (such as 20MnG) with better high-temperature performance are recommended.
3. Can high-specification carbon steel seamless pipes resist low temperature?
Answer: Yes. High-specification materials such as 16Mn/Q345 have good low-temperature toughness, and can be used in environments as low as -40℃ (after appropriate heat treatment), while common carbon steel pipes are prone to brittle fracture at low temperatures below -20℃.
4. What is the corrosion resistance of carbon steel seamless pipes?
Answer: Both common and high-specification carbon steel seamless pipes have poor natural corrosion resistance and are easy to rust in humid air or corrosive media. They usually need anti-corrosion treatment (such as galvanizing, painting, anti-corrosion coating) to extend their service life.
5. Is there any difference in corrosion resistance between common and high-specification carbon steel seamless pipes?
Answer: The corrosion resistance is basically the same, because both are mainly composed of carbon and iron. The difference lies in the strength and toughness; high-specification pipes do not have better corrosion resistance unless they are specially treated (such as adding corrosion-resistant alloy elements).
