ASTM A387 Grade 9 Class 2 Steel Plate | A387 Gr.9 Cl.2 9Cr-1Mo Vessel Plate
What is ASTM A387 Grade 9 Class 2 Steel?
ASTM A387 Grade 9 Class 2, also searched as A387 Gr.9 Cl.2, A387GR9CL2, A387GR9 CL2, A387GR.9 Class 2, A387-9 Cl.2 and SA387 Grade 9 Class 2, is the higher-strength class of Grade 9 in ASTM A387/A387M. The book is chromium-molybdenum plate for welded boilers and elevated-temperature vessels. Nominal alloy is 9.00Cr-1.00Mo. This page is not Class 1. Class 1 is 415–585 MPa. This page is not ASME SA387 Grade 91 Class 2. Grade 91 is 9Cr-1Mo-V-Nb. This page is not ASME SA387 Grade 5 Class 2. Grade 5 is 5Cr-0.5Mo. This page is not EN 10028-2 X10CrMoVNb9-1. That grade is P91.
Tensile is 75–100 ksi / 515–690 MPa. Yield is 45 ksi / 310 MPa min. Class 2 values are not used on annealed plate. Usual delivery is normalized and tempered, or accelerated cooling plus temper. Minimum temper for Grade 9 is 1250 °F / 675 °C. SHH STEEL is a global steel mill sourcing partner and steel manufacturer & exporter (mill-direct, China origin). We buy this grade from qualified Chinese mills, check the certificate against A387 / SA-387 and A20 / SA-20, and ship it to fabricators in the USA, Europe, Middle East, Southeast Asia, Africa and South America.
If a drawing says A387 Gr.9 Cl.1, we will not ship Class 2 and call stronger automatically acceptable. For ASME Code work the name on the certificate should be SA-387 Grade 9 Class 2. Related category pages: ASTM A387 and ASME SA387.
Material Specification
| Specification Element | Requirement | SHH STEEL Compliance |
|---|---|---|
| Grade / class | ASTM A387/A387M Grade 9 Class 2 | Confirmed |
| Code counterpart | ASME SA-387 Grade 9 Class 2 | Available |
| Other search names | A387 Gr.9 Cl.2, A387GR9CL2, A387GR9 CL2 | Covered |
| Steel type | Killed 9Cr-1Mo vessel plate | Confirmed |
| Usual delivery | N+T; not annealed Class 2 | Confirmed |
| Tensile | 515–690 MPa (75–100 ksi) | Confirmed |
| Yield | 310 MPa (45 ksi) min | Confirmed |
| Supply role | Global steel mill sourcing partner | SHH STEEL |
| Certification | EN 10204 3.1 or 3.2 / third-party | As ordered |
This plate sits in pressure vessel steel plates and ASTM A387. European 9Cr sisters belong on EN 10028-2.
Chemical Composition
Heat analysis and product analysis follow ASTM A387 Table 1 for Grade 9. Class 1 and Class 2 share the same chemistry.
Heat Analysis and Product Analysis — ASTM A387 Grade 9
| Element | Heat Analysis (%) | Product Analysis (%) |
|---|---|---|
| Carbon (C), max | 0.15 | 0.15 |
| Manganese (Mn) | 0.30 – 0.60 | 0.25 – 0.66 |
| Phosphorus (P), max | 0.025 | 0.025 |
| Sulfur (S), max | 0.025 | 0.025 |
| Silicon (Si) | 0.25 – 1.00 | 0.13 – 1.05 |
| Chromium (Cr) | 8.00 – 10.00 | 7.90 – 10.10 |
| Molybdenum (Mo) | 0.90 – 1.10 | 0.85 – 1.15 |
Grade 9 is not Grade 91. Grade 91 adds vanadium, niobium and nitrogen and uses a different tensile table. Do not treat ASME SA387 Grade 5 Class 2 as Grade 9. SHH STEEL prints heat analysis on every certificate and product analysis when ordered. Density is 7.85 g/cm³.
Mechanical Properties
Buyers search A387 Gr.9 Cl.2 mechanical properties, A387GR9CL2 yield and A387 Grade 9 Class 2 tensile.
Tensile and Yield — ASTM A387 Grade 9 Class 2
| Item | Requirement |
|---|---|
| Tensile strength | 75–100 ksi / 515–690 MPa |
| Yield strength, min | 45 ksi / 310 MPa |
| Elongation in 2 in. [50 mm], min | 18% |
| Reduction of area, min | 40% |
| Density | 7.85 g/cm³ |
Class 1 on the same grade is 60–85 ksi / 415–585 MPa with 30 ksi / 205 MPa yield. Do not quote Class 1 numbers on a Class 2 order. Class 2 tensile is not applicable to annealed plate.
Material Comparison
| Grade | Book | What buyers search | Swap? |
|---|---|---|---|
| ASTM A387 Grade 9 Class 1 | A387 | A387 Gr.9 Cl.1 / A387GR9CL1 | No |
| ASTM A387 Grade 9 Class 2 | A387 | A387 Gr.9 Cl.2 / A387GR9CL2 | This page |
| ASME SA387 Grade 9 Class 2 | SA-387 | SA387 Gr.9 Cl.2 | Code name |
| ASME SA387 Grade 91 Class 2 | SA-387 | SA387 Gr.91 Cl.2 | No |
| ASME SA387 Grade 5 Class 2 | SA-387 | SA387 Gr.5 Cl.2 | No |
| EN 10028-2 X10CrMoVNb9-1 | EN 10028-2 | P91 / X10CrMoVNb9-1 | No |
| EN 10028-2 X12CrMo5 | EN 10028-2 | X12CrMo5 | No |
Equivalent Material Grades
There is no official one-to-one worldwide swap for A387 Gr.9 Cl.2. What buyers compare is the 9Cr-1Mo idea in other books, not an automatic substitute.
In the United States the Code name is ASME SA-387 Grade 9 Class 2. That is the same chemistry and the same Class 2 tensile table. ASTM A387 Grade 9 Class 1 is the same chemistry at the lower strength class. ASME SA387 Grade 91 Class 2 is 9Cr-1Mo-V-Nb, not Grade 9.
In Europe there is no daily 9Cr-1Mo twin without vanadium. X10CrMoVNb9-1 / P91 is the Grade 91 family. X12CrMo5 is 5Cr-0.5Mo. Both sit on EN 10028-2.
In China there is no daily GB/T 713 twin that buyers treat as Grade 9. 12Cr2Mo1R is 2.25Cr-1Mo. See 12Cr2Mo1R.
| Designation | Country / region | Standard | Notes |
|---|---|---|---|
| ASTM A387 Gr.9 Cl.2 / A387GR9CL2 | USA | ASTM A387 | Name on this page |
| ASME SA-387 Grade 9 Class 2 | USA | SA-387 | Code counterpart |
| ASTM A387 Grade 9 Class 1 | USA | A387 | Same chemistry, lower class |
| ASME SA387 Grade 91 Class 2 | USA | SA-387 | 9Cr-1Mo-V-Nb |
| ASME SA387 Grade 5 Class 2 | USA | SA-387 | 5Cr-0.5Mo sister |
| EN 10028-2 X10CrMoVNb9-1 | Europe | EN 10028-2 | P91, not Grade 9 |
| EN 10028-2 X12CrMo5 | Europe | EN 10028-2 | 5Cr-0.5Mo |
Dual marking is possible only when both books are fully met.
9Cr-1Mo Elevated-Temperature Service
Buyers pick A387 Gr.9 Cl.2 when a file wants 9Cr-1Mo at the Class 2 strength band. Search phrases such as A387GR9CL2, A387 Grade 9 Class 2 and SA387 Grade 9 Class 2 all point here.
It is not a substitute for ASME SA387 Grade 91 Class 2. That grade is P91 chemistry. It is not a substitute for ASME SA387 Grade 5 Class 2. That grade is 5Cr. Dual marking with SA-387 Grade 9 Class 2 is the normal Code route.
SHH STEEL supplies this plate to fabricators in the United States, Mexico, South America, Europe, the Middle East, Africa and Asia.
Weldability
A387 Grade 9 Class 2 is killed 9Cr-1Mo vessel plate at 515–690 MPa. Treat welding as production welding, and as ASME Section VIII / PED welding when the equipment is a vessel.
Qualify to the applicable code. Consumables must match a 9Cr-1Mo family. A procedure written for ASME SA516 Grade 70 is the wrong alloy. A procedure written for ASME SA387 Grade 91 Class 2 is a P91 procedure, not Grade 9. Preheat, interpass and PWHT must stay inside the qualified WPS. Minimum temper on the plate is 675 °C. The fabricator owns the WPS. SHH STEEL can share mill heat data for that review.
Heat Treatment and Delivery Condition
Usual delivery from SHH STEEL for A387 Gr.9 Cl.2 is normalized and tempered, or accelerated cooling plus temper. Minimum tempering temperature for Grade 9 is 1250 °F / 675 °C.
Class 2 tensile values are not applicable to annealed plate. If the mill only annealed the heat, it cannot be certified Class 2.
If the vessel will see PWHT, say so. Simulated PWHT on test coupons is worth naming on 9Cr work. Extra simulation, 3.2 hold points or special NDE add time. Plan about two months when those extras are on the order.
The certificate lists ASTM A387 Grade 9 Class 2 and, when ordered, ASME SA-387 Grade 9 Class 2; heat number; heat analysis; product analysis when ordered; tensile to the Class 2 table; heat-treatment route. Certificates may be EN 10204 3.1 or EN 10204 3.2.
Dimensions
Usual supply range from SHH STEEL for A387 Gr.9 Cl.2 9Cr-1Mo vessel plate:
- Thickness: commonly 6 mm – 150 mm, thicker by mill agreement
- Width: 1500 mm – 4000 mm
- Length: 3000 mm – 12000 mm
Maximum thickness is limited by the ability of the composition to meet Class 2 tensile. P91 plate belongs on ASME SA387 Grade 91 Class 2. 5Cr plate belongs on ASME SA387 Grade 5 Class 2.
Tolerances
Dimensional limits for ASTM A387 Grade 9 Class 2 follow ASTM A20 / ASME SA-20 unless the purchase order names another table. Do not apply ASTM A36 structural tolerances to a Cr-Mo vessel plate without writing them.
Typical thickness tolerance idea for A387 Gr.9 Cl.2 (A20 / SA-20 reference)
| Nominal thickness (mm) | Usual minus (mm) | Usual plus (mm) |
|---|---|---|
| 6 – 16 | −0.3 | +0.8 |
| 16 – 25 | −0.4 | +0.9 |
| 25 – 40 | −0.5 | +1.0 |
| 40 – 80 | −0.8 | +1.2 |
| 80 – 150 | −1.0 | +1.6 |
Width on 1500–4000 mm plate is commonly held to about ±20–25 mm unless the mill quote names a tighter extra. Length on 3000–12000 mm plate is commonly held to about +50 / 0 mm or ±25 mm by mill practice. Flatness follows A20 / SA-20 unless a tighter class is written. Edge condition is mill edge or cut edge as ordered. If the vessel calculation used minimum thickness after corrosion, write the allowed minus on the RFQ. SHH STEEL will not assume a zero-minus extra on A387GR9CL2 unless the order says so.
Supplementary Requirements
ASTM A387 Grade 9 Class 2 already defines chemistry, Class 2 tensile and the 675 °C minimum temper. Extra items still have to be written on the purchase order. SHH STEEL will not assume them from the grade name alone.
Code name. Write SA-387 Grade 9 Class 2 when the equipment is ASME Code work.
Heat-treatment route. Write normalized and tempered, or accelerated cooling plus temper. Do not accept annealed plate as Class 2.
Charpy details. Class 2 does not assume a default impact temperature. Write temperature, joules, location and orientation if impact is required.
Simulated PWHT. When the vessel will be stress-relieved, name hold temperature, hold time and cooling rate on the coupon.
Product analysis. Especially C, Cr, Mo, Si, P and S.
Through-thickness / Z-test. Name Z15, Z25 or Z35 when the plate will be welded in the thickness direction.
NDE. A20 / SA-20 ultrasonic extras, ASTM A435 or ASTM A578 as named. Write scanning extent and acceptance class.
Hardness. If the destination file caps hardness after heat treatment or after simulated PWHT, write the max HB and the test location.
HIC / SSC / NACE. Only when the equipment is sour service. A387 Gr.9 Cl.2 is not automatically NACE MR0175 / ISO 15156.
Third-party witness. EN 10204 3.2 with SGS, TÜV, BV, ABS, CCS, DNV or the inspector named. Hold points for heat treatment, chemistry, tensile and UT should be listed on the ITP.
Identification and stamping. Heat number, grade A387 Grade 9 Class 2 / A387 Gr.9 Cl.2, SA-387 Grade 9 Class 2 when ordered, thickness and mill logo on each plate.
Applications
| Industry | Typical components |
|---|---|
| 9Cr-1Mo boilers | A387 Gr.9 Cl.2 / A387GR9CL2 shells |
| Elevated-temp vessels | A387 Grade 9 Class 2 courses from SHH STEEL |
| ASME Code dual-name | A387 Gr.9 Cl.2 / SA-387 Grade 9 Class 2 |
| Comparison vs P91 | A387GR9CL2 next to ASME SA387 Grade 91 Class 2 |
A387 Grade 9 Class 2 is the plate for a file that wants 9Cr-1Mo at the higher strength class. It is the wrong plate for Class 1 tensile. That work is A387 Grade 9 Class 1. It is the wrong plate for P91. That work is ASME SA387 Grade 91 Class 2.
Supply Capability
SHH STEEL sources ASTM A387 Grade 9 Class 2 from first-line Chinese mills and ships it on worldwide terms. Partner mills include Wuyang (Wugang), Angang, Shougang, Hanye, Anyang Iron & Steel, Baosteel, Xinyu, Xingcheng, Yongjin, Tsingshan, TISCO (Taiyuan), Jiuquan (JISCO), Lianzhong, Zhangpu and Baoxin, plus other qualified mills when the size or heat-treatment route requires it.
Mill test certificates are issued to EN 10204 3.1 as standard. EN 10204 3.2 is arranged when the order names a third-party hold point.
Usual stock and rolling thickness: 8 mm, 10 mm, 12 mm, 16 mm, 20 mm, 25 mm, 30 mm, 32 mm, 36 mm, 40 mm, 50 mm, 60 mm, 80 mm, 100 mm, thicker by mill agreement.
Processing: CNC or flame cutting, bevel, flattening, UT to the named class.
Trade terms: FOB Shanghai main, CIF destination available. Payment: TT, LC, or TT + LC.
Ocean time from Shanghai: US West 14–18 days; US Gulf 28–35 days; Rotterdam / Antwerp 28–35 days; Jebel Ali 18–25 days; Singapore 7–12 days; other ports quoted.
Third-party: SGS, TÜV, BV, ABS, CCS, GL, VL, DNV, RINA, NK, KR, or the inspector named.
Global Delivery & Markets
SHH STEEL is a global steel mill sourcing partner with mill partnerships in China. We supply ASTM, ASME, EN, DIN, JIS and GB steel to buyers in the United States, Europe, the Middle East, Southeast Asia, Africa and South America. Origin is mill-direct, China origin.
SHH STEEL has supplied steel plates to the USA, Mexico, Argentina, Peru, El Salvador, Spain, Netherlands, Germany, UAE, Saudi Arabia, South Africa, India, Thailand, Singapore, Vietnam, the Philippines, Japan and Korea.
Typical lead time: ex-stock 5–7 days; standard rolling / N+T about 45–60 days; simulated PWHT / 3.2 about 2 months.
Why Choose SHH STEEL
Experience on this grade is simple: keep Grade 9 away from Grade 91 and Grade 5, and keep Class 2 away from annealed Class 1. SHH STEEL as a global steel mill sourcing partner and steel manufacturer & exporter (mill-direct, China origin) prices A387 Gr.9 Cl.2 from first-line mills, reports 9Cr-1Mo chemistry, records N+T delivery, and issues 3.1 as standard or 3.2 when specified.
We keep the grade on the order. A387GR9CL2 is not A387 Gr.9 Cl.1. A387 Grade 9 Class 2 is not ASME SA387 Grade 91 Class 2. A387 Gr.9 Cl.2 is not ASME SA387 Grade 5 Class 2. If the drawing says Class 1, we will not ship Class 2 and call stronger automatically acceptable.
FAQ
- What is A387 Grade 9 Class 2 steel plate?
- ASTM A387 Grade 9 Class 2, also searched as A387 Gr.9 Cl.2, A387GR9CL2 and SA387 Grade 9 Class 2, is 9Cr-1Mo pressure-vessel plate. Tensile is 515–690 MPa and yield is 310 MPa min. Delivery is normalized and tempered, not annealed. SHH STEEL supplies this plate worldwide as a global steel mill sourcing partner.
- What is the equivalent of A387 Gr.9 Cl.
- The Code counterpart is SA-387 Grade 9 Class 2. P91 / X10CrMoVNb9-1 is Grade 91, not Grade 9. Dual marking is possible only when both books are fully met.
- ow is Class 2 different from Class 1 on Grade 9?
- Class 2 is 515–690 MPa with 310 MPa yield. Class 1 is 415–585 MPa with 205 MPa yield. Chemistry is the same. Annealed plate cannot be Class 2.
- How is A387GR9CL2 different from Grade 91?
- Grade 9 is 9Cr-1Mo. Grade 91 is 9Cr-1Mo-V-Nb with a different tensile table. Do not swap them.
- Can SHH STEEL ship A387 Gr.9 Cl.2 to the USA, Europe or the Middle East?
- Yes. SHH STEEL quotes FOB Shanghai and CIF to US West, US Gulf, Rotterdam, Jebel Ali, Singapore and other major ports.
- What is the delivery time for A387 Grade 9 Class 2?
- Ex-stock about 5–7 days when plate is in yard. Standard mill rolling and N+T about 45–60 days. Simulated PWHT or 3.2 inspection about 2 months.
Conclusion
ASTM A387 Grade 9 Class 2 Steel Plate is 9Cr-1Mo pressure-vessel plate at 515–690 MPa tensile and 310 MPa yield. Whether the inquiry says ASTM A387 Grade 9 Class 2, A387 Gr.9 Cl.2, A387GR9CL2, A387GR9 CL2 or SA387 Grade 9 Class 2, SHH STEEL as a global steel mill sourcing partner and steel manufacturer & exporter (mill-direct, China origin) supplies plate with Grade 9 chemistry, Class 2 tensile, recorded N+T delivery, and EN 10204 3.1 or 3.2 certification.
SHH STEEL supplies ASTM A387 Grade 9 Class 2 / A387 Gr.9 Cl.2 9Cr-1Mo Vessel Plate to the USA, Mexico, South America, Europe, the Middle East, Africa and Asia for work that actually names this grade and class.
Contact SHH STEEL for mill rolling, stock inquiry, cutting, bevel, 3.2 inspection or a worldwide quotation.
ASTM A387 Grade 9 Class 2 Steel Plate, A387 Gr.9 Cl.2, A387GR9CL2, 9Cr-1Mo vessel plate, A387 Gr.9 Cl.2 supplier, SHH STEEL









