A handheld alloy analyser that reads 9% chromium cannot tell P92 from P91, because the difference lies in tungsten and boron rather than chromium, and a mixed header can pass a quick PMI check on the rack. Read the tungsten. ASTM A335 P92 pipe adds roughly 1.75% tungsten and a trace of boron to the Grade 91 recipe, lifting minimum yield to 440 MPa for the hottest steam service. It is specified on supercritical and advanced combined cycle plants in the GCC. Neighbouring grades are on the alloy and chrome-moly pipes and tubes hub.
Where A335 P92 Pipe Is Used
- Main steam and hot reheat piping in supercritical and ultra-supercritical plants
- High-temperature headers where P91 walls would still be heavy
- Advanced HRSG steam systems
- Retrofits and replacement sections in plants designed in Grade 92
For most high-temperature steam duty, ASTM A335 P91 remains the more widely available choice.
P91 vs P92: What the Tungsten Buys
|
Property |
P91 |
P92 |
|---|---|---|
|
Chromium |
8.00 to 9.50% |
8.50 to 9.50% |
|
Molybdenum |
0.85 to 1.05% |
0.30 to 0.60% |
|
Tungsten |
Not specified |
1.50 to 2.00% |
|
Boron |
Not specified |
0.001 to 0.006% |
|
Minimum tensile strength |
585 MPa |
620 MPa |
|
Minimum yield strength |
415 MPa |
440 MPa |
|
ASME Section IX |
P-No. 15E |
P-No. 15E |
Tungsten and boron slow the coarsening of the fine precipitates that give these steels their creep strength, so P92 holds strength longer at the highest steam temperatures and allows thinner walls than P91 in the same duty. Both grades share the same fabrication discipline: correct normalising and tempering, preheat, controlled interpass temperature, PWHT and hardness checks. Because both sit in P-No. 15E, welding procedures must still be qualified for the specific grade, and filler metal must match.
P92 and Service Environments
P92 is a high-temperature steam grade rather than a sour service material. If H2S exposure is possible, NACE MR0175 / ISO 15156-2 hardness limits apply and material selection should be reviewed with the operator. State any such requirements in the RFQ; they are confirmed at quotation.
P92 Pipe Price Factors
Alloy pipe prices follow chromium, molybdenum and steel markets, so P92 is quoted per enquiry. The main drivers:
- Size, schedule and length
- Order quantity against mill minimums
- Stock or mill order
- Supplementary requirements such as PMI, hardness surveys or ultrasonic testing
- Limited mill availability and long lead times compared with P91
- EN 10204 3.1 or 3.2 certification and third-party witness
- Incoterm and port of delivery
Quotations are available in USD, OMR, AED, SAR, QAR, KWD and BHD, on EXW, FOB, CFR or CIF terms.
What to send for a quotation:
grade, NPS, schedule or minimum wall, length, quantity, end finish, supplementary tests, hardness range and PMI scope including tungsten, certification, inspection, destination port and required date.
Mill Certificates, PMI and Inspection
Material is supplied with EN 10204 3.1 certificates as standard, and EN 10204 3.2 certificates on request. Inspection by the buyer's nominated third-party agency can be arranged; state your requirement in the RFQ. For P92, the certificate should record the heat treatment route and tempering temperature, the chemistry, including tungsten and boron and the tensile and pressure test results. Positive material identification on delivery is the simplest guard against a mixed grade. See the MTC and EN 10204 certification guide.
Delivery and Storage in Gulf Conditions
Lead time is confirmed at quotation. Pipe is capped or bevel-protected, varnished where specified and marked with the grade along its length. Keep P92 segregated from carbon steel and other chrome-moly grades on the laydown yard, since they look alike, and store it off the ground with ends capped against sand and coastal humidity.
Fittings and Flanges for P92 Pipe
Complete the line in the same grade: ASTM A234 WP92 buttweld fittings and ASTM A182 F92 flanges and forged fittings.
- Alloy steel fittings and flanges hub
- ASTM A213 T92 tubes, the tube form of the same alloy
- Alloy steel seamless pipes and tubes
P92 is used mainly in power generation plants.
ASTM A335 P92 FAQ
What is the difference between P91 and P92?
P92 contains 1.50 to 2.00% tungsten and a small boron addition, with less molybdenum. It has higher strength (440 MPa yield against 415 MPa) and better long-term creep strength.
Can PMI distinguish P92 from P91?
Only if the analyser reads tungsten. Chromium alone is not enough, since both grades are 9Cr steels.
What heat treatment does P92 need?
Normalising and tempering to the temperatures set in A335, with PWHT after welding and hardness verification.
What is the EN equivalent of P92?
EN 10216-2 X10CrWMoVNb9-2 (1.4901).
Where is P92 used?
Mainly in supercritical and ultra-supercritical steam piping and advanced HRSG systems.
What should I send for a P92 quotation?
Send the NPS, schedule or wall, length, quantity, hardness and PMI requirements, certification, inspection, destination port and required date.
Request a Quote for ASTM A335 P92 Pipes
Send the NPS, schedule and quantity, with the steam piping specification attached. Every enquiry is checked against ASTM A335 before the offer is prepared, so grade verification and lead time are addressed at the start.