What temperature is the seamless steel pipe suitable for?

Seamless steel pipes are widely used today. The key is because of its heat resistance and corrosion resistance. The application temperature of seamless steel pipes is 190~860 ° C. However, in the specific application process, the application temperature of seamless steel pipes It can't reach as high as 860 ℃. Let's discuss what temperature the seamless steel pipe is suitable for practically.

First of all, seamless steel pipes for different purposes have different temperature requirements. For example, the cs seamless pipe for ships is the cs seamless pipe for the manufacture of class I pressure-resistant piping systems, class II pressure-resistant piping systems, boilers and superheaters. The working temperature of the cs seamless pipe wall does not exceed 450 °C, and the working temperature of the alloy steel seamless pipe wall exceeds 450 °C; 30ma of high-quality carbon structural steel and alloy steel seamless pipes for chemical equipment and pipelines.

Secondly, there are regulations on the temperature resistance of seamless steel pipes. For example, the steel pipe of GB/T8163 standard is suitable for the pipeline whose design temperature is less than 350℃ and the pressure is less than 10.0MPa; while the pipeline medium is oil, oil and gas, when the design temperature exceeds 350℃ or the pressure is greater than 10.0MPa, GB9948 should be selected. Or the seamless alloy steel pipe of GB6479 standard; for pipelines operating near hydrogen, or pipelines working in an environment prone to stress corrosion, GB9948 or GB6479 standards should also be used. The GB6479 standard should be adopted for the use of cs seamless pipes at low temperatures (less than -20°C), only it specifies the requirements for the low temperature impact toughness of materials.

Finally, the stainless steel plate made of 304 is generally better in acid resistance. The concentration of sodium cyanide is within 70%, and the temperature is 0-80 °C. The stainless steel plate 304 is one of the materials with good acid resistance. Most partial bases can be used in the range of 0-100℃.

In fact, the application temperature of seamless steel pipe should not be maintained at the middle of 450~860 °C. When the temperature of seamless steel pipe reaches 450 °C, a zero boundary point will appear. At this zero boundary point, the dilution liquid of stainless steel plate will be carbon. The chromium element around the element will produce carbonized chromium, and the chromium in the diluted solution will appear in a chromium-depleted area in the original existing area, and the appearance of the chromium-depleted area will change the characteristic material of the stainless steel; in addition, the temperature of 450 ℃ adds Compromising forces transform martensite to austenite.