What are the tensile strength and yield strength of P22 steel pipe?
Tensile strength ≥415 MPa, yield strength ≥205 MPa (ASTM A335). The actual value can be adjusted by heat treatment, such as increasing tempering temperature will reduce strength. Strength will gradually decrease at high temperature, and creep rupture data should be referred to. These indicators ensure its safe use in high-pressure pipelines. The test should be carried out according to ASTM E8 standard.
How to test the impact toughness of P22 steel pipe?
The Charpy V-notch impact test (ASTM A370) is adopted, and ≥27J is required at room temperature. Low-temperature applications require additional testing of -30°C performance. The specimens are taken in the transverse or longitudinal direction, and the results may be significantly different. High toughness prevents brittle fracture of the pipeline under impact load. The heat treatment process has a great influence on toughness.
What international standards are applicable to P22 steel pipes?
ASTM A335 (seamless pipe), A213 (boiler pipe), and A182 (flange material) are the core standards. ASME B16.34 covers dimensional requirements in valve applications. The European equivalent is EN 10216-2. Different standards have slightly different emphasis on composition and testing. It is necessary to clarify the standard version when purchasing to avoid disputes.
How to determine the allowable stress of P22 steel pipe at high temperature?
Refer to the stress table of ASME BPVC Section II-D, based on creep and rupture data. For example, the allowable stress is about 60 MPa at 500°C. A safety factor (usually 1.5) needs to be added during design. Stress relaxation needs to be evaluated after long-term use. Regularly check the thickness change to correct the remaining life.
What is the elongation requirement for P22 steel pipe? Why is it important?
The standard requires an elongation of ≥30% (gauge length 50mm), which reflects the plasticity of the material. High elongation means better deformation ability and reduced risk of sudden fracture. This performance needs to be relied on when installing elbows or expansion joints. The elongation may decrease in low temperature environments, so special attention should be paid. The fracture location and necking phenomenon should be recorded during testing.
