Stress corrosion cracking tests for low and high alloy steels in sour oilfield service

Tests performed at VTT

Kari Saarinen, Esa Hämäläinen

Research output: Book/ReportReportProfessional

Abstract

The purpose of the studies was to validate the usefulness of the proposed NACE slow strain rate testing method /1/ and compare it with the EFC document /2/. In the NACE document the testing takes place at a temperature of 177°C, the test solution contains 20 wt% NaCl, the partial pressure of H2S varies between 14 and 28 bar and the partial pressure of CO2 between 14 and 55 bar. In the NACE document the strain rate is determined as 4 . 10-6 1/s and in the EFC document 1 . 10-6 1/s. The results showed brittle behaviour for the test material in all of the test environments, and in each case the elongation was less than 5%. For comparison purposes the SSRT was conducted with the test material also in an inert environment (N2 gas), where the fracture was ductile and elongation 65%. The tests conducted with different strain rates gave the same result, which shows that the difference between EFC /2/ and NACE /1/ documents within the strain rate is not significant in the environments studied. However, since the alloy 654 SMO, which is considered to have a high resistance to corrosion, failed the SSRT test in the environments determined in the NACE document, the NACE document can be considered too severe for testing of austenitic stainless steels. Since contrary to the NACE document the EFC document does not determine levels for hydrogen sulphide and carbon dioxide, the EFC document can be considered more suitable than the NACE document for testing of austenitic stainless steels for sour service.
Original languageEnglish
Place of PublicationEspoo
PublisherVTT Technical Research Centre of Finland
Number of pages23
ISBN (Print)951-38-4889-2
Publication statusPublished - 1996
MoE publication typeNot Eligible

Publication series

NameVTT Tiedotteita - Meddelanden - Research Notes
PublisherVTT
No.1734
ISSN (Print)1235-0605
ISSN (Electronic)1455-0865

Fingerprint

Alloy steel
Stress corrosion cracking
Strain rate
Testing
Austenitic stainless steel
Partial pressure
Elongation
Ductile fracture
Hydrogen sulfide
Carbon dioxide
Corrosion
Gases
Temperature

Keywords

  • alloy steels
  • stainless steels
  • corrosion
  • stress corrosion
  • cracking (fracturing)
  • tests
  • oil fields
  • mechanical properties
  • micro structure
  • methods

Cite this

Saarinen, K., & Hämäläinen, E. (1996). Stress corrosion cracking tests for low and high alloy steels in sour oilfield service: Tests performed at VTT. Espoo: VTT Technical Research Centre of Finland. VTT Tiedotteita - Meddelanden - Research Notes, No. 1734
Saarinen, Kari ; Hämäläinen, Esa. / Stress corrosion cracking tests for low and high alloy steels in sour oilfield service : Tests performed at VTT. Espoo : VTT Technical Research Centre of Finland, 1996. 23 p. (VTT Tiedotteita - Meddelanden - Research Notes; No. 1734).
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Saarinen, K & Hämäläinen, E 1996, Stress corrosion cracking tests for low and high alloy steels in sour oilfield service: Tests performed at VTT. VTT Tiedotteita - Meddelanden - Research Notes, no. 1734, VTT Technical Research Centre of Finland, Espoo.

Stress corrosion cracking tests for low and high alloy steels in sour oilfield service : Tests performed at VTT. / Saarinen, Kari; Hämäläinen, Esa.

Espoo : VTT Technical Research Centre of Finland, 1996. 23 p. (VTT Tiedotteita - Meddelanden - Research Notes; No. 1734).

Research output: Book/ReportReportProfessional

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AU - Saarinen, Kari

AU - Hämäläinen, Esa

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N2 - The purpose of the studies was to validate the usefulness of the proposed NACE slow strain rate testing method /1/ and compare it with the EFC document /2/. In the NACE document the testing takes place at a temperature of 177°C, the test solution contains 20 wt% NaCl, the partial pressure of H2S varies between 14 and 28 bar and the partial pressure of CO2 between 14 and 55 bar. In the NACE document the strain rate is determined as 4 . 10-6 1/s and in the EFC document 1 . 10-6 1/s. The results showed brittle behaviour for the test material in all of the test environments, and in each case the elongation was less than 5%. For comparison purposes the SSRT was conducted with the test material also in an inert environment (N2 gas), where the fracture was ductile and elongation 65%. The tests conducted with different strain rates gave the same result, which shows that the difference between EFC /2/ and NACE /1/ documents within the strain rate is not significant in the environments studied. However, since the alloy 654 SMO, which is considered to have a high resistance to corrosion, failed the SSRT test in the environments determined in the NACE document, the NACE document can be considered too severe for testing of austenitic stainless steels. Since contrary to the NACE document the EFC document does not determine levels for hydrogen sulphide and carbon dioxide, the EFC document can be considered more suitable than the NACE document for testing of austenitic stainless steels for sour service.

AB - The purpose of the studies was to validate the usefulness of the proposed NACE slow strain rate testing method /1/ and compare it with the EFC document /2/. In the NACE document the testing takes place at a temperature of 177°C, the test solution contains 20 wt% NaCl, the partial pressure of H2S varies between 14 and 28 bar and the partial pressure of CO2 between 14 and 55 bar. In the NACE document the strain rate is determined as 4 . 10-6 1/s and in the EFC document 1 . 10-6 1/s. The results showed brittle behaviour for the test material in all of the test environments, and in each case the elongation was less than 5%. For comparison purposes the SSRT was conducted with the test material also in an inert environment (N2 gas), where the fracture was ductile and elongation 65%. The tests conducted with different strain rates gave the same result, which shows that the difference between EFC /2/ and NACE /1/ documents within the strain rate is not significant in the environments studied. However, since the alloy 654 SMO, which is considered to have a high resistance to corrosion, failed the SSRT test in the environments determined in the NACE document, the NACE document can be considered too severe for testing of austenitic stainless steels. Since contrary to the NACE document the EFC document does not determine levels for hydrogen sulphide and carbon dioxide, the EFC document can be considered more suitable than the NACE document for testing of austenitic stainless steels for sour service.

KW - alloy steels

KW - stainless steels

KW - corrosion

KW - stress corrosion

KW - cracking (fracturing)

KW - tests

KW - oil fields

KW - mechanical properties

KW - micro structure

KW - methods

M3 - Report

SN - 951-38-4889-2

T3 - VTT Tiedotteita - Meddelanden - Research Notes

BT - Stress corrosion cracking tests for low and high alloy steels in sour oilfield service

PB - VTT Technical Research Centre of Finland

CY - Espoo

ER -

Saarinen K, Hämäläinen E. Stress corrosion cracking tests for low and high alloy steels in sour oilfield service: Tests performed at VTT. Espoo: VTT Technical Research Centre of Finland, 1996. 23 p. (VTT Tiedotteita - Meddelanden - Research Notes; No. 1734).