Case Histories » Mining

Metallurgical Replication of a High Pressure—High-Temperature Steam Line

Replica micrograph of a high pressure steam line
Replica micrograph of a high pressure steam line

Environment

Steam header, exposure to elevated temperatures of 750°F and pressures of 400 psi.

Material

ASTM A-53 grade B carbon steel pipe.

Service Life

More than 60 years.

Findings

Metallurgical replication of the high-temperature, high-pressure steam header that had been exposed to over six decades of service indicated that the header had come to the end of its safe service life. The microstructure indicated a primarily soft and weak ferrite matrix with -5 percent fraction pearlite. High-temperature damage from over 60 years of elevated temperature service is shown by the presence of iron carbide particles which precipitated along grain boundaries from decomposed pearlite lamellae within the grains. Recommendations were made to have the steam header and adjacent piping replaced.