At OGC Energy we help the energy industry with finding answers to some of their most difficult questions. We have created this section hoping that you will find answers to some of the most common questions in the following areas:

  • Corrosion in offshore industry
  • Downhole corrosion
  • Materials Selection
  • ANSI/NACE MR0175 / ISO 15156
  • H2S

If you require technical support in metallurgy, corrosion, or welding; or if you need assistance meeting the requirements of ANSI/NACE MR0175/ISO 15156 then contact our team, we are here to help you.

  • 21.

    What is the NACE MR0175 heat treatment?

    What is the NACE MR0175 heat treatment? NACE MR0175 is an international standard that provides the requirements for metallic materials exposed to H2S in oil and gas production environments. These requirements include: Chemistry Heat treatment form Hardness Microstructure (in some cases) HIC resistance. NACE MR0175 has specific heat treatment requirements for carbon steel and low […]

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  • 22.

    What is sour service?

    What is sour service? Sour service is referred to exploration and production environments in oil and gas that have enough H2S that could cause cracking of metallic materials. H2S (hydrogen sulphide) H2S is a highly flammable, explosive gas, and can cause possible life-threatening situations if not properly handled. H2S is deadly even at very low […]

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  • 23.

    In NACE MR0175 Part 3 Clause A.3 are 3B materials qualified for all conditions?

    Question: Shouldn’t it have the same material restrictions of all type 3b materials, and be able to be used under the conditions stated in both entries for materials type 3b, and not only according to the first entrance? Otherwise, could you kindly explain the reason of this difference in limits, with such a similar chemical […]

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  • 24.

    4130, 4140 and low alloys. When does NACE MR0175 require SSC testing for qualification?

    NACE MR0175/ISO 15156 in part 2 / Annex A does quote 4130 grades A. Tubulars and tubular components made of Cr-Mo low-alloy steels (UNS G41XX0, formerly AISI 41XX, and modifications), if quenched and tempered in the tubular form, are acceptable if their hardness does not exceed 30 HRC and they have SMYS grades of 690 […]

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  • 25.

    For duplex and superduplex stainless steels, what is the NACE MR0175 maximum hardness for HAZ (heat affected zone)?

    This request is related to ISO 15156 / NACE MR0175 part 3, A.7.3 Welding of duplex stainless steels. “The hardness of the HAZ after welding shall not exceed the maximum hardness allowed for the base metal, and the hardness of the weld metal shall not exceed the maximum hardness limit of the respective alloy used […]

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  • 26.

    In NACE MR0175, What is a carbon-manganese steel?

    Question: ISO 15156-2 Annex A.2.1.4 differentiate between “carbon steel”, “carbon manganese steel” and “low-alloy steel”. The terms “carbon steel” and “low-alloy steel” are defined in ISO 15156-1, but not “carbon manganese steel”. What is the definition of “carbon manganese steel” in the scope of NACE MR0175? Answer: Although not directly defined in ISO 15156-1, the […]

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  • 27.

    What are the NACE MR0175 stress relief requirements for fibre deformation greater than 5%?

    Question: NACE MR0175 part 2 Annex A section A.2.1.2 refers to fibre deformation greater than 5%. Is this referring to surface strain when a residual tension stress is applied as a result of manufacturing processes? A.2.1.6 Cold deformation and thermal stress relief Carbon and low-alloy steels shall be thermally stress-relieved following any cold deforming by […]

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  • 28.

    What is the NACE MR0175 criteria for retesting HIC?

    Question 1: We have a question on interpretation of clause B.2.2.2 e) in annex B of MR0175 / ISO 15156-2:2015. Third paragraph says: Re-testing is permitted as follows. If a single specimen fails to satisfy the acceptance criteria, … two further specimens may be tested. If after HIC testing a 0.5” plate to TM0284, two […]

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  • 29.

    What happens when HIC, SOHIC or SZC fails in testing as per NACE MR0175 Part 2 Clause B.4?

    Question 1: Application of section B4 (Test procedures to evaluate the resistance of carbon and low-alloy steels to SOHIC and SZC). Our Interpretation: Section B4 applies to SOHIC/SZC only. Where SSC is required section B3 applies. Answer 1: Section B.4 applies only to the evaluation of resistance to SOHIC and SZC as indicated, but per […]

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  • 30.

    In NACE MR0175, What does”shall exhibit a threshold stress >=95% of the actual yield strength (AYS)” mean for UNS S41500?

    NACE MR0175 / ISO 15156 in part 3, clause A.6, table A.22 requires impellers manufactured with martensitic stainless steel UNS S41500 to exhibit a threshold stress ≥95 % of actual yield strength in the anticipated service environment, this may involve testing as per NACE TM0177 2016.We have helped clients to qualify UNS S41500 for sour […]

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