Influence of hydrogen sulfide partial pressures on cracking of carbon and low-alloy steels

Environmental cracking (EC) susceptibility of low-alloy steels with a specified minimum yield strength of 655 MPa (95 ksi) and 758 MPa (110 ksi) manufactured by quenching and tempering heat treatments was investigated in high H2S partial pressures (more than 1.0 MPa) using four-point bend tests in autoclaves. The H2S partial pressures and testing temperatures varied from 1.0 MPa to 10 MPa and 24°C to 150°C, respectively. Materials of grades 95 ksi and 110 ksi containing high Cr and Mo showed no macrocracking under all tested conditions. Localized corrosion occurred at several locations after exposure for 1 month under high H2S pressure and high-temperature conditions. It was concluded that the localized corrosion did not form macrocracking even after long-term (3 months) immersion tests. On the other hand, 110 ksi grade material containing low Cr and Mo suffered from sulfide stress cracking at low temperatures (below 66°C) and at an H2S pressure of 1.0 MPa. The material also showed EC at an H2S pressure of 10 MPa and temperature from 107°C to 150°C. The difference of EC susceptibility among the materials is discussed based on corrosion reactions, hydrogen absorption, and morphologies of the corrosion products on the steel surface.

Download Full-text

A Method for Improving Hydrogen Sulfide Accelerated Cracking Resistance of Low Alloy Steels

CORROSION ◽

10.5006/0010-9312-25.9.380 ◽

1969 ◽

Vol 25 (9) ◽

pp. 380-388 ◽

Cited By ~ 5

Author(s):

E. SNAPE ◽

F. W. SCHALLER ◽

R. M. FORBES JONES

Keyword(s):

Hydrogen Sulfide ◽

Low Alloy Steels ◽

Cracking Resistance ◽

Alloy Steels

Download Full-text

Low Alloy Steels in Hydrogen Sulfide Environment

CORROSION ◽

10.5006/1.3579268 ◽

1982 ◽

Vol 38 (3) ◽

pp. 156-167 ◽

Cited By ~ 9

Author(s):

Yuichi Yoshino

Keyword(s):

Hydrogen Sulfide ◽

Hydrogen Absorption ◽

Carbide Precipitation ◽

Low Alloy Steels ◽

Matrix Interface ◽

Stress Cracking ◽

Sulfide Stress ◽

Alloy Steels ◽

Carbide Matrix ◽

Sulfide Stress Cracking

Abstract The effect of chemical composition on the behavior of low alloy steels in a hydrogen sulfide environment was studied with regard to corrosion, hydrogen absorption, and sulfide stress cracking. Results were interpreted in connection with microstructure and carbide precipitation. The addition of chromium results in the promotion of hydrogen absorption presumably due to the precipitation of incoherent carbides, thereby reducing, in general, the resistance to SSC. Fine coherent carbides appear to be beneficial, or at least not detrimental, to SSC resistance; e.g., Mo2C, VC, TiC, and NbC. Microstructure seems to affect both hydrogen absorption and SSC resistance largely through the trapping behavior of hydrogen at the carbide/matrix interface.

Download Full-text

Characteristics of damage of low-alloy steels in corrosion-active hydrogen sulfide-containing media

Soviet Materials Science ◽

10.1007/bf00727233 ◽

1990 ◽

Vol 26 (2) ◽

pp. 144-149 ◽

Cited By ~ 2

Author(s):

T. V. Tetyueva ◽

L. R. Botvina ◽

S. A. Krupnin

Keyword(s):

Hydrogen Sulfide ◽

Low Alloy Steels ◽

Active Hydrogen ◽

Alloy Steels

Download Full-text

Corrosion Control in Petroleum Refineries Processing Western Canadian Crude Oils

CORROSION ◽

10.5006/0010-9312-16.6.109 ◽

1960 ◽

Vol 16 (6) ◽

pp. 275t-280t ◽

Cited By ~ 3

Author(s):

C. L. EASTON

Keyword(s):

Hydrogen Sulfide ◽

High Temperature ◽

Hydrochloric Acid ◽

Dew Point ◽

Crude Oils ◽

Low Alloy Steels ◽

Potential Hazard ◽

Film Forming ◽

Alloy Steels ◽

Petroleum Refineries

Abstract Corrosion problems encountered m petroleum refineries processing Western Canadian crude oils, and the methods used to overcome them, are outlined. Hydrogen sulfide and other sulfur compounds, together with hydrochloric acid formed from chlorides in the water associated with the crude oils, are the chief factors in the corrosion of crude distillation units. Preventive measures include desalting, use of alloy materials, neutralization of the hydrochloric acid, and the use of film forming organic inhibitors. Corrosion in catalytic cracking light ends equipment is attributed to nitrogen compounds and cyanides. Water washing to reduce cyanide concentration,, the use of film-forming inhibitors, and the use of corrosion resistant materials are used with success to reduce the severity of the attack. In catalytic reforming units, the problem of high temperature hydrogen sulfide corrosion is overcome by removing the sulfur in a feed preparation unit. Embrittlement of carbon steel by high temperature, high pressure hydrogen is a potential hazard in reforming units, but can be prevented by the use of refractory linings or low alloy steels containing chromium and molybdenum. Under certain conditions, strong acids are formed in these units creating further corrosion problems at temperatures below the dew point. 8.4.3

Download Full-text

Factors in Sulfide Corrosion Cracking of High Strength Steels

CORROSION ◽

10.5006/0010-9312-24.2.31 ◽

1968 ◽

Vol 24 (2) ◽

pp. 31-37 ◽

Cited By ~ 37

Author(s):

R. S. TRESEDER ◽

T. M. SWANSON

Keyword(s):

Environmental Factors ◽

High Strength Steels ◽

High Strength ◽

Corrosion Cracking ◽

Oil Field ◽

Low Alloy Steels ◽

Field Equipment ◽

Partial Pressures ◽

Sulfide Corrosion ◽

Alloy Steels

Abstract Results of laboratory sulfide corrosion cracking tests on commercial steel alloys are presented. Emphasis is placed on effects of environmental factors, alloy composition and metallurgical variables. Environmental factors studied include pH in the range of 2 to 5, H2S partial pressures in the range 0.001 to 1.0 atmosphere and addition of sodium chloride. Twelve percent chromium stainless steels and low alloy steels containing more than 1 percent nickel, were found to have lower resistance to cracking at the same hardness level than low alloy steels normally used for oil field equipment. Plastic deformation of low alloy steels by cold rolling decreased the resistance to cracking.

Download Full-text