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Hydrogen Induced Cracking of Carbon Seamless Pipe Materials
Sources: this site Click: Date: 2016-11-22 20:30:10
Carbon seamless steel pipe is mainly used for conveying high-pressure oil and gas near the wellhead. With the increasingly serious problem of hydrogen sulfide corrosion, the development of anti-sulfur seamless pipeline is imminent, and the performance of sulfur-resistant is the key. The influence of Cu and Ni on the HIC properties of the seamless pipe materials and the S content in the steel were also investigated. The effects of Cu and Ni addition on the properties of the HIC were also investigated. Hydrogen bubbling sensitivity.
1. Test method
According to the ISO3183 standard, the ingot method was used to smelt 7t 1 t ingot in the laboratory. After forging, perforation, pipe jacking and sheet reduction, the pipe was cut to 20 mm × 100 mm × 5 mm , And then immersed in the solution prepared according to the standard. After 96 h, the specimens were taken out and taken perpendicular to the cross-section. Three parameters (crack length ratio CLR, crack thickness CTR and cracking susceptibility CSR) were calculated by metallographic method. (HIC) susceptibility.
2. Factors on affecting HIC performance
1) PH. A large number of studies have shown that the sensitivity of hydrogen bubbling decreases with the increase of pH in the range of 1 ~ 6. When pH> 6, hydrogen bubbling does not occur.
2) H2S concentration. The higher hydrogen sulfide concentration, the greater the sensitivity of hydrogen bubbling.
3) Chloride ion. The presence of Cl- increases the corrosion rate and increases the sensitivity of hydrogen bubbling in the pH range of 3.5 to 4.5.
4) Temperature. 25 ℃, the maximum CLR, hydrogen bubble sensitivity of the largest. When the temperature is lower than 25 ° C, the corrosion reaction and the diffusion rate of hydrogen are accelerated, and the sensitivity of hydrogen bubbling is increased. While after 25 ℃, H2S concentration decreased, but decreased the sensitivity of hydrogen bubbling.
5) Time. 96 h was used as the contrast, and the corrosion degree became serious with the increase of the test time under normal condition.
1. Test method
According to the ISO3183 standard, the ingot method was used to smelt 7t 1 t ingot in the laboratory. After forging, perforation, pipe jacking and sheet reduction, the pipe was cut to 20 mm × 100 mm × 5 mm , And then immersed in the solution prepared according to the standard. After 96 h, the specimens were taken out and taken perpendicular to the cross-section. Three parameters (crack length ratio CLR, crack thickness CTR and cracking susceptibility CSR) were calculated by metallographic method. (HIC) susceptibility.
2. Factors on affecting HIC performance
1) PH. A large number of studies have shown that the sensitivity of hydrogen bubbling decreases with the increase of pH in the range of 1 ~ 6. When pH> 6, hydrogen bubbling does not occur.
2) H2S concentration. The higher hydrogen sulfide concentration, the greater the sensitivity of hydrogen bubbling.
3) Chloride ion. The presence of Cl- increases the corrosion rate and increases the sensitivity of hydrogen bubbling in the pH range of 3.5 to 4.5.
4) Temperature. 25 ℃, the maximum CLR, hydrogen bubble sensitivity of the largest. When the temperature is lower than 25 ° C, the corrosion reaction and the diffusion rate of hydrogen are accelerated, and the sensitivity of hydrogen bubbling is increased. While after 25 ℃, H2S concentration decreased, but decreased the sensitivity of hydrogen bubbling.
5) Time. 96 h was used as the contrast, and the corrosion degree became serious with the increase of the test time under normal condition.
