NACE MR0175ISO 15156-01 and MR 0103

CNQ PREMIUM VALUE | DEFINED GROWTH | INDEPENDENT Slide 2

NACE MR0175/ISO 15156-01 and MR 0103Materials Requirements for Sour Services

• The consequences of sudden failures of metallic oil and gas field components ,associated with their exposure to H2S-containing production fluids lead to the preparation of the first edition of NACE MR0175 which was published in 1975 by the National Association of Corrosion Engineers.

• In 2003 ,NACE MR0175 merged with ISO 15156 and it supersedes all previous version of MR0175.



• The NACE Standard MR-0103 establishes material requirement for resistance to sulfide stress cracking (SSC) in sour refinery process environments.

• The NACE Standards MR-0175/ISO-15156 establishes materials for use in H2S-containing environments in oil and gas production.

• High concentration of CO2 and Chloride are present in this environments as well.



• NACE MR-0175/ISO-15156 Standard is comprised on the following three parts:

Part 1: General Principles for Selection of Cracking-Resistant Materials.

Part 2: Cracking Resistant Carbon and Low –Alloy Steels, and the Use of Cast Irons

Part 3: Cracking-Resistance CRAs(Corrosion-Resistance Alloys) and Others Alloys.


Part 1: General Principles for Selection of Cracking-Resistant Materials.

Part 1 describes general principles and gives requirements and recommendation for the selection of materials for service in equipment used in oil and gas production in H2S –containing environments ,where the failure could pose a risk to the health and safety of the public and personnel.


Part 1: General Principles for Selection of Cracking-Resistant Materials.• Part 1 addresses seven mechanisms of cracking that can occur in

oil and gas production environments containing H2S:

1. Sulfide Stress Cracking (SSC)2. Stress Corrosion Cracking (SCC)3. Hydrogen-induced Cracking (HIC)4. Stepwise Cracking (SWC)5. Stress-Orientated Hydrogen Induced Cracking (SOHIC)6. Soft Zone Cracking (SZC)7. Galvanically Induced Hydrogen Stress Cracking (GIHSC)


Part 1: General Principles for Selection of Cracking-Resistant Materials.• WARNING• Metallic materials selected using NACE MR0175/ISO15156 are

resistant to cracking in defined H2S-containing environments in oil and gas production ,but NOT NECESSARILY IMMUNE to cracking under all service condition.

• It is the equipment user’s responsibility to select materials suitable for the intended service!

• Therefore, before selecting or qualifying materials, the user of the equipment shall defined ,evaluate and document the service condition to which materials can be exposed .


Part 1: General Principles for Selection of Cracking-Resistant Materials.• Evaluation and Service Condition:• Factors, others than material properties ,known to affect

susceptibility of materials to cracking in H2S service include:

H2S partial pressureIn situ pHPresence of elemental sulfur or other oxidantTemperatureGalvanic effectMechanical stress Time to exposure to contact with a liquid water phase.


Part 2: Cracking Resistant Carbon and Low-Alloy Steel, and the use of Cast Irons

• This part addresses the resistance of these steels to damage that can be caused by:

1. Sulfide Stress Cracking (SSC)2. Stress-Orientated Hydrogen Induced Cracking (SOHIC)3. Soft Zone Cracking (SZC)4. Hydrogen-induced Cracking (HIC)5. Stepwise Cracking (SWC)

This part is concerned only with cracking. Localized corrosion is not addressed.


Part 2: Cracking Resistant Carbon and Low-Alloy Steel, and the use of Cast Irons• The behavior of carbon and low-alloy steel in H2S environments are

affected by:

Chemical composition ,strength ,hardness , product form .Grain sizeH2S partial pressureAcidity (pH) of the water phaseExposure temperatureExposure timeTensile stress Presence of elemental sulphur


Part 2: Cracking Resistant Carbon and Low-Alloy Steel, and the use of Cast Irons• There are three main ways to qualify and selecting carbon and low-

alloy steels with resistance to SSC1. Qualification by “pre-qualified” materials2. Qualification by laboratory testing 3. Qualification by 2 years of documented field experience Within the “pre-qualified” materials choice ,there are two options:Option 1: For partial pressure H2S below 0.3KPa no specialprecaution are required

For partial pressure H2S equal to or greater 0.3KPa the material shall be heat-treated and maximum hardness 22HRC.Option 2: Using diagrams based upon partial pressure of H2S and the pH of the process.


Part 2: Cracking Resistant Carbon and Low-Alloy Steel, and the use of Cast Irons• Hardness Testing Requirements for Welds

• The qualification of welding procedures for sour services shall include hardness testing using the Vickers HV10 or HV5 method in accordance with ASME E92 or Rockwell 15 N scale in accordance with ASME E18

• Figure 1 shown below the butt weld survey method for Vickers hardness measurement.

• Hardness acceptance criteria for carbon steel and low-alloy steel welds are specified in Part 2.


Survey method for Vickers hardness measurement

• Hardness impressions within heat affected zones should be located as close as possible to the fusion boundary .


Heat –Affected Zones


Part 3 Cracking-resistant CRAs (corrosion-resistant alloys) and others alloys

• This part gives requirements and recommendation for the selection and qualification of CRAs(corrosion-resistant alloys) and other alloys for service in equipment used in H2S containing environment.

• Part 3 address the resistance of these materials to damages that can be caused by:

Sulfide Stress Cracking(SSC)Stress Corrosion Cracking(SCC)Galvanically Induced Hydrogen Cracking

This part is concerned only with cracking. Localized corrosion is not address.


Part 3 Cracking-resistant CRAs (corrosion-resistant alloys) and others alloys

• Cracking-resistance CRAs and others alloys could be selected:

Using “pre-qualified “ material Annex AFollowing qualification by successful laboratory testing in

accordance to Annex BBased on satisfactory 2 years of documented field experience.

Hardness Testing Requirements for welds are the same as on Part 2


• Scope:• This standard establishes material requirements for resistance to

Sulfide Stress Cracking (SSC) in sour petroleum refining and related processing environment containing H2S either as a gas or dissolved in liquid water with or without presence of hydrocarbon.

• Applicability:• This standard applies to all components of equipment exposed to

sour refinery environments where failure by SSC would compromise the integrity of the pressure system.

NACE MR 0103 Materials Resistant to Sulfide Stress Cracking in Corrosive Petroleum Refining Environments



• SSC is defined as cracking of a metal under the combined action of tensile stress and corrosion in the presence of water and H2S.

• SSC is a form of hydrogen stress cracking resulting from absorption of atomic hydrogen that is produced by the sulfide corrosion reaction. The atoms remain dissolved in the matrix and are highly mobile.

• SSC is observed in the welds or heat affected zones where high-strength/low-ductility microstructure may be present and can be identified by high hardness.



• Factors contributing to SSC:

Chemical compositionStrength (as indicated by hardness)Heat treatmentMicrostructure of the materialThe hydrogen flux in the materialTemperatureTime



• Environmental condition known to cause SSC are those containing an aqueous phase and:

>50 ppmw total sulfide content, OR≥1 ppmw total sulfide content and PH<4, OR≥ 1ppmw total sulfide contents and ≥ 20 ppmw free cyanide and

PH>7.6, OR>0.3 kPa absolute partial pressure H2S in the gas phase

associated with the aqueous phase of a process.


CNRL Standard 00-STD-MW-0034

CNRL Standard 00-STD-MW-0034 identify three levels of “Wet H2S Service :

Category 1-Mildly corrosiveH2S concentration is 50 to 2,000 ppmwPH range is 4.5 to 7.

Category 2-Moderately corrosiveH2S concentration is 2,000 to 2,500 ppmwPH range is 4.5 to 7.6

Category 3-Severaly corrosiveH2S concentration is greater than 2,500 ppmwPH is below 4.5



Hardness is related to tensile strength, a primary factor in SSC susceptibility .As such, a maximum allowable hardness is specified as a primary requirement for materials.



g

• Alloy steel included under the ASME Sec. IX P-No shall not exceed maximum hardness level:

• Other alloy steels shall have a maximum harness of 22HRC(237HBW)

Alloy Steel Maximum HardnessP-No. 3 225 HBW

P-No. 4 225 HBW

P-No. 5A 235 HBW

P-No. 5B 235 HBW

P-No. 5C 235 HBW

P-No. 6 235 HBW

P-No. 7 235 HBW

P-No. 10A 225 HBW

P-No. 10B 225 HBW

P-No. 10C 225 HBW

P-No. 10F 225 HBW

P-No. 11 225 HBW

P-No. 15E 248 HBW


Hydrogen Bake out Temperature and Time

• 35 • • 1.400

• 30 • • 1.200

• 25 • • 1.000

• 20• 0 2 4 6 8 10 • 12 14 16 18 20• Bakeout Time (Hours)

• 0.800


NACE MR 0103 Materials Resistant to Sulfide Stress Cracking in Corrosive Petroleum Refining Environments • Conclusions:NACE MR0103 standard establishes material requirements for

resistance to Sulfide Stress Cracking (SSC) in sour petroleum refining and is applicable to us.

The selection of materials for service in equipment used in oil and gas production in H2S –containing environments is very important because the failure could pose a risk to the health and safety of the public and personnel.

Metallic materials selected using MR0103 are resistant to cracking in defined H2S-containing environments ,but NOT NECESARILY IMMUNE to cracking under all service condition.

It is the equipment user’s responsibility to select materials suitable for the intended service!!!

NACE MR0175ISO 15156-01 and MR 0103

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