Seamless steel pipes for petroleum cracking: seamless steel pipes for pressure pipes such as furnace pipes for petroleum and chemical industries, refining units, cracking units, hydrogen units, heat exchangers, etc. (working pressure is generally not more than 5.88Mpa, working temperature is below 450℃) heating surface steel pipes; the manufacturing method is the same as that of seamless pipes, but there are strict requirements on the steel types used to manufacture steel pipes. Seamless steel pipes for petroleum cracking are often used under high temperatures and high-pressure conditions. Under the action of high temperature flue gas and water vapor, the steel pipes will oxidize and corrode. The steel pipes are required to have high lasting strength, high anti-oxidation and corrosion performance, and good organizational stability.
The general production standards for petroleum cracking seamless steel pipes are national standard GB/9948, American standard ASTM A335, ASTM A213, etc.
The commonly used national standard materials for petroleum cracking seamless steel pipes are No. 10, No. 20, 12Cr5MoI, 12Cr5MoNT, 12Cr9MoI, 12Cr9MoNT,
American standard materials for petroleum-cracking seamless steel pipes are P11, P22, P5, P9, T11, T22, T5, T9, etc.
Due to long-term operation under high temperatures and high-pressure conditions, the material of petroleum-cracking seamless steel pipes will creep, plasticity and toughness will decrease, the original structure will change, and corrosion will occur. Steel pipes used for boilers should have:
(1) Sufficient endurance strength;
(2) Sufficient plastic deformation capacity;
(3) Minimum aging tendency and hot brittleness;
(4) High resistance to oxidation, coal ash, natural gas corrosion at high temperature, steam, and stress corrosion;
(5) Good structural stability and good process performance. Appearance quality: There shall be no cracks, folds, rolling folds, scars, delamination, or hairline on the inner and outer surfaces of seamless steel pipes. These defects shall be completely removed. The removal depth shall not exceed the negative deviation of the nominal wall thickness, and the actual wall thickness at the cleaned area shall not be less than the minimum value allowed by the wall thickness.
Post time: Oct-21-2024