What is NACE MR0175 / ISO 15156?
NACE MR0175, published jointly as ISO 15156, sets the materials requirements for equipment used in oil and gas production environments containing hydrogen sulphide, where sulphide stress cracking is a risk.
Key Takeaways
- NACE MR0175 / ISO 15156 scope: Permitted materials, hardness limits, heat treatment conditions and manufacturing restrictions for carbon, low-alloy, stainless, duplex and nickel alloy components in sour service.
- Size range: Applies to any size; the constraint is metallurgical rather than dimensional.
- Ratings: Applies alongside the dimensional standard and pressure class.
- Material grades: Carbon and low-alloy steels within hardness limits, plus qualifying austenitic, duplex and nickel alloy grades.
- Kalp Alloys manufactures to NACE MR0175 / ISO 15156 in Ahmedabad, India, with EN 10204 3.1 and 3.2 certification issued in its own name.
- Third-party inspection by SGS, BV, TUV or Lloyds can be witnessed at our plant before dispatch.
What NACE MR0175 / ISO 15156 governs
NACE MR0175, published jointly as ISO 15156, sets the materials requirements for equipment used in oil and gas production environments containing hydrogen sulphide, where sulphide stress cracking is a risk.
Permitted materials, hardness limits, heat treatment conditions and manufacturing restrictions for carbon, low-alloy, stainless, duplex and nickel alloy components in sour service.
Scope, sizes and ratings at a glance
The envelope below is the practical reference: what to state on a purchase order so the item that arrives is the item the line needs.
| Parameter | Detail |
|---|---|
| Size range | Applies to any size; the constraint is metallurgical rather than dimensional |
| Ratings | Applies alongside the dimensional standard and pressure class |
| Material grades | Carbon and low-alloy steels within hardness limits, plus qualifying austenitic, duplex and nickel alloy grades |
| Also published as | ISO 15156 |
| Governs | Sulphide stress cracking risk in H2S-bearing service |
| Typical carbon steel hardness limit | 22 HRC maximum |
| Applies to | Parent material, weld metal and heat-affected zone |
| Companion standard | NACE MR0103 for refinery sour service |
| Documentation expected | Compliance statement plus hardness survey results |
| Common qualifying grades | A105 within hardness limits, F51, F53, F55, Inconel 625, Incoloy 825 |
The point buyers most often get wrong
The practical requirement is hardness control, and it is where most non-conformances arise. Carbon and low-alloy steel components for sour service are generally limited to 22 HRC, and that limit applies to the finished part including any weld and heat-affected zone, not only to the parent material at the billet stage. A compliance statement without supporting hardness survey results is not evidence of anything, which is why our sour-service document pack includes the hardness readings and the locations they were taken from.
What Kalp Alloys manufactures to NACE MR0175 / ISO 15156
Kalp Alloys is a manufacturer, not a stockist. Production runs at our own facility at 5, Jay Vijay Industrial Estate, B/h. Akash Vikas Estate, Keval Kanta Road, Rakhial, Ahmedabad, which means the heat number stamped on the part traces to our own melt record and the mill test certificate is issued in the name of Kalp Alloys.
That matters on standard-led purchasing more than anywhere else, because an approved-vendor submission or a code-governed line has to show who made the part. A certificate passed down a trading chain names a mill the buyer has no relationship with and cannot query.
Grades supplied against NACE MR0175 / ISO 15156 cover Carbon and low-alloy steels within hardness limits, plus qualifying austenitic, duplex and nickel alloy grades. Non-standard bores, thicknesses, drilling patterns and facing finishes are produced to customer drawing.
Ordering against NACE MR0175 / ISO 15156
State the dimensional standard, the size or NPS range, the rating or schedule, the facing where applicable, the material specification and grade, the quantity, and the certification level required. A quotation is typically returned within 24 hours.
Drawings for non-standard items can be sent by email or on WhatsApp at +91 81608 73937 and are reviewed by the technical team. Stock sizes dispatch in three to seven days; made-to-drawing items carry a firm lead time quoted at order confirmation. There is no minimum order on stock sizes and trial quantities are accepted.
Frequently Asked Questions
NACE MR0175, published jointly as ISO 15156, sets the materials requirements for equipment used in oil and gas production environments containing hydrogen sulphide, where sulphide stress cracking is a risk.
Applies to any size; the constraint is metallurgical rather than dimensional. Ratings covered are Applies alongside the dimensional standard and pressure class.
Carbon and low-alloy steels within hardness limits, plus qualifying austenitic, duplex and nickel alloy grades.
MR0175 with ISO 15156 covers upstream oil and gas production environments. MR0103 covers refinery and downstream process environments where wet hydrogen sulphide is present. Projects specify one or the other, and occasionally both.
A compliance statement referencing the applicable clause, supported by hardness survey results taken on the finished component including weld and heat-affected zone where relevant, together with the heat treatment condition on the mill test certificate.
Yes. Kalp Alloys manufactures to NACE MR0175 / ISO 15156 at its own facility at 5, Jay Vijay Industrial Estate, B/h. Akash Vikas Estate, Keval Kanta Road, Rakhial, Ahmedabad, and issues the EN 10204 3.1 or 3.2 mill test certificate in its own name rather than passing through a third-party mill certificate.
An EN 10204 3.1 mill test certificate as standard, stating the ordered standard, grade and heat number, with chemical and mechanical results and a dimensional inspection report. EN 10204 3.2 with third-party inspection by SGS, BV, TUV or Lloyds is arranged where the project requires it.