Alloy steel pipe is a type of steel pipe that is made up from alloy materials. The difference in the composition is directly linked to the different applications. There are some applications that require high heat resistance such as the aerospace industry applications, nuclear power plants, boilers and power generators. There are some other applications such as the sea water industry where high chloride ion resistance is required. In other cases like organic acid industries which require pipes of high acidic corrosion resistance. In some cases, the applications such as hydraulic systems and aerospace applications require high pressure containments. So the Alloy steel pipe standards and grading differ to address the specific needs of the application. These pipes are produced in different forms as well. They could be produced as Electric Resistant Welded or in seamless alloy steel pipe forms.
The applications include under water and sea water applications including water desalinization projects where the chloride corrosion cracking stress is very high. In applications like this the high chromium and molybdenum alloys are used. Chemical plants, food processing plants and the organic acid industries use P9, P11 and P22 grades because the oxidation resistance is needed in these applications to make sure that the pipes don’t cause any complications in the chemical composition of the materials already in used with these applications. Petro chemical industries use the P91 specifically due to its mechanical properties. A335 P91 price could differ with various conditions such as market availability, location of purchase, transportation, etc.