ASTM A387 Grade 12 Class 2 Steel Plate | A387 Gr.12 Cl.2 1Cr-0.5Mo Vessel Plate
What is ASTM A387 Grade 12 Class 2 Steel ?
ASTM A387 Grade 12 Class 2, also searched as A387 Gr.12 Cl.2, A387GR12CL2, A387GR12 CL2, A387GR.12 Class 2, A387-12 Cl.2 and SA387 Grade 12 Class 2, is the higher-strength class of Grade 12 in ASTM A387/A387M. The book is chromium-molybdenum plate for welded boilers and elevated-temperature vessels. Nominal alloy is 1.00Cr-0.50Mo. This page is not Class 1. Class 1 is 380–550 MPa. This page is not ASME SA387 Grade 2 Class 2. Grade 2 is 0.5Cr-0.5Mo. This page is not ASME SA387 Grade 11 Class 2. Grade 11 is 1.25Cr-0.5Mo. This page is not ASME SA204 Grade B. SA-204 is Mo-only plate.
Tensile is 65–85 ksi / 450–585 MPa. Yield is 40 ksi / 275 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 12 is 1150 °F / 620 °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.12 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 12 Class 2. Related category pages: ASTM A387 and ASME SA387.
Material Specification
| Specification Element | Requirement | SHH STEEL Compliance |
|---|---|---|
| Grade / class | ASTM A387/A387M Grade 12 Class 2 | Confirmed |
| Code counterpart | ASME SA-387 Grade 12 Class 2 | Available |
| Other search names | A387 Gr.12 Cl.2, A387GR12CL2, A387GR12 CL2 | Covered |
| Steel type | Killed 1Cr-0.5Mo vessel plate | Confirmed |
| Usual delivery | N+T; not annealed Class 2 | Confirmed |
| Tensile | 450–585 MPa (65–85 ksi) | Confirmed |
| Yield | 275 MPa (40 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 Cr-Mo sisters belong on EN 10028-2. Chinese Cr-Mo sisters belong on GB/T 713.
Chemical Composition
Heat analysis and product analysis follow ASTM A387 Table 1 for Grade 12. Class 1 and Class 2 share the same chemistry.
Heat Analysis and Product Analysis — ASTM A387 Grade 12
| Element | Heat Analysis (%) | Product Analysis (%) |
|---|---|---|
| Carbon (C) | 0.05 – 0.17 | 0.04 – 0.17 |
| Manganese (Mn) | 0.40 – 0.65 | 0.35 – 0.73 |
| Phosphorus (P), max | 0.025 | 0.025 |
| Sulfur (S), max | 0.025 | 0.025 |
| Silicon (Si) | 0.15 – 0.40 | 0.13 – 0.45 |
| Chromium (Cr) | 0.80 – 1.15 | 0.74 – 1.21 |
| Molybdenum (Mo) | 0.45 – 0.60 | 0.40 – 0.65 |
Grade 12 chromium is higher than Grade 2 and lower than Grade 11. Do not treat a Grade 2 heat as Grade 12. Do not treat EN 10028-2 16Mo3 as Grade 12. 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.12 Cl.2 mechanical properties, A387GR12CL2 yield and A387 Grade 12 Class 2 tensile.
Tensile and Yield — ASTM A387 Grade 12 Class 2
| Item | Requirement |
|---|---|
| Tensile strength | 65–85 ksi / 450–585 MPa |
| Yield strength, min | 40 ksi / 275 MPa |
| Elongation in 8 in. [200 mm], min | 19% |
| Elongation in 2 in. [50 mm], min | 22% |
| Density | 7.85 g/cm³ |
Class 1 on the same grade is 55–80 ksi / 380–550 MPa with 33 ksi / 230 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 12 Class 1 | A387 | A387 Gr.12 Cl.1 / A387GR12CL1 | No |
| ASTM A387 Grade 12 Class 2 | A387 | A387 Gr.12 Cl.2 / A387GR12CL2 | This page |
| ASME SA387 Grade 12 Class 2 | SA-387 | SA387 Gr.12 Cl.2 | Code name |
| ASME SA387 Grade 2 Class 2 | SA-387 | SA387 Gr.2 Cl.2 | No |
| ASME SA387 Grade 11 Class 2 | SA-387 | SA387 Gr.11 Cl.2 | No |
| EN 10028-2 13CrMo4-5 | EN 10028-2 | 13CrMo4-5 | No auto swap |
| GB/T 713 15CrMoR | GB/T 713 | 15CrMoR | No auto swap |
| ASME SA204 Grade B | SA-204 | SA204 Gr.B | No |
Equivalent Material Grades
There is no official one-to-one worldwide swap for A387 Gr.12 Cl.2. What buyers compare is the 1Cr-0.5Mo idea in other books, not an automatic substitute.
In the United States the Code name is ASME SA-387 Grade 12 Class 2. That is the same chemistry and the same Class 2 tensile table. ASTM A387 Grade 12 Class 1 is the same chemistry at the lower strength class. ASME SA387 Grade 2 Class 2 is 0.5Cr-0.5Mo. ASME SA387 Grade 11 Class 2 is 1.25Cr-0.5Mo.
In Europe the nearest comparison is EN 10028-2 13CrMo4-5 (about 1.25Cr-0.5Mo). EN 10028-2 16Mo3 is 0.3Mo only. Both sit on EN 10028-2.
In China the usual vessel comparison is GB/T 713 15CrMoR. See 15CrMoR.
In Japan JIS G3103 SB450M / SB480M are 0.5Mo boiler plates without the Grade 12 chromium window. See SB480M.
| Designation | Country / region | Standard | Notes |
|---|---|---|---|
| ASTM A387 Gr.12 Cl.2 / A387GR12CL2 | USA | ASTM A387 | Name on this page |
| ASME SA-387 Grade 12 Class 2 | USA | SA-387 | Code counterpart |
| ASTM A387 Grade 12 Class 1 | USA | A387 | Same chemistry, lower class |
| ASME SA387 Grade 11 Class 2 | USA | SA-387 | 1.25Cr-0.5Mo sister |
| EN 10028-2 13CrMo4-5 | Europe | EN 10028-2 | 1.25Cr-0.5Mo comparison |
| EN 10028-2 16Mo3 | Europe | EN 10028-2 | 0.3Mo only |
| GB/T 713 15CrMoR | China | GB/T 713 | 1Cr-0.5Mo vessel |
| JIS G3103 SB480M | Japan | JIS G3103 | 0.5Mo boiler |
Dual marking is possible only when both books are fully met.
1Cr-0.5Mo Elevated-Temperature Service
Buyers pick A387 Gr.12 Cl.2 when a file wants 1Cr-0.5Mo at the Class 2 strength band. Search phrases such as A387GR12CL2, A387 Grade 12 Class 2 and SA387 Grade 12 Class 2 all point here.
It is not a substitute for ASME SA387 Grade 11 Class 2. That grade is 1.25Cr. It is not a substitute for ASME SA387 Grade 22 Class 2. That grade is 2.25Cr-1Mo. Dual marking with SA-387 Grade 12 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 12 Class 2 is killed 1Cr-0.5Mo vessel plate at 450–585 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 1Cr-0.5Mo family. A procedure written for ASME SA516 Grade 70 is the wrong alloy. A procedure written for ASME SA387 Grade 22 Class 2 is too rich in Cr and Mo. A procedure written for EN 10028-2 13CrMo4-5 is the usual European comparison. Preheat, interpass and PWHT must stay inside the qualified WPS. Minimum temper on the plate is 620 °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.12 Cl.2 is normalized and tempered, or accelerated cooling plus temper. Minimum tempering temperature for Grade 12 is 1150 °F / 620 °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 Cr-Mo 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 12 Class 2 and, when ordered, ASME SA-387 Grade 12 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.12 Cl.2 1Cr-0.5Mo 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. 1.25Cr plate belongs on ASME SA387 Grade 11 Class 2. 2.25Cr-1Mo plate belongs on ASME SA387 Grade 22 Class 2.
Tolerances
Dimensional limits for ASTM A387 Grade 12 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.12 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 A387GR12CL2 unless the order says so.
Supplementary Requirements
ASTM A387 Grade 12 Class 2 already defines chemistry, Class 2 tensile and the 620 °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 12 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, 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.12 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 12 Class 2 / A387 Gr.12 Cl.2, SA-387 Grade 12 Class 2 when ordered, thickness and mill logo on each plate.
Applications
| Industry | Typical components |
|---|---|
| 1Cr-0.5Mo boilers | A387 Gr.12 Cl.2 / A387GR12CL2 shells |
| Elevated-temp vessels | A387 Grade 12 Class 2 courses from SHH STEEL |
| ASME Code dual-name | A387 Gr.12 Cl.2 / SA-387 Grade 12 Class 2 |
| Comparison vs 1.25Cr plate | A387GR12CL2 next to ASME SA387 Grade 11 Class 2 |
A387 Grade 12 Class 2 is the plate for a file that wants 1Cr-0.5Mo at the higher strength class. It is the wrong plate for 2.25Cr-1Mo hydrogen service. That work is ASME SA387 Grade 22 Class 2. It is the wrong plate for 9Cr-1Mo-V. That work is ASME SA387 Grade 91 Class 2.
Supply Capability SHH STEEL
SHH STEEL sources ASTM A387 Grade 12 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 12 away from Grade 2 and Grade 11, 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.12 Cl.2 from first-line mills, reports 1Cr-0.5Mo chemistry, records N+T delivery, and issues 3.1 as standard or 3.2 when specified.
We keep the grade on the order. A387GR12CL2 is not A387 Gr.12 Cl.1. A387 Grade 12 Class 2 is not ASME SA387 Grade 11 Class 2. A387 Gr.12 Cl.2 is not ASME SA204 Grade B. If the drawing says Class 1, we will not ship Class 2 and call stronger automatically acceptable.
FAQ
- What is A387 Grade 12 Class 2 steel plate?
- ASTM A387 Grade 12 Class 2, also searched as A387 Gr.12 Cl.2, A387GR12CL2 and SA387 Grade 12 Class 2, is 1Cr-0.5Mo pressure-vessel plate. Tensile is 450–585 MPa and yield is 275 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.12 Cl.2?
- The Code counterpart is SA-387 Grade 12 Class 2. Related comparisons are 13CrMo4-5 in Europe and 15CrMoR in China. Dual marking is possible only when both books are fully met.
- How is Class 2 different from Class 1 on Grade 12?
- Class 2 is 450–585 MPa with 275 MPa yield. Class 1 is 380–550 MPa with 230 MPa yield. Chemistry is the same. Annealed plate cannot be Class 2.
- How is A387GR12CL2 different from Grade 11 Class 2?
- Grade 12 is 1.00Cr-0.50Mo. Grade 11 is 1.25Cr-0.50Mo. Do not swap chromium.
- Can SHH STEEL issue EN 10204 3.2 for A387GR12CL2?
- Yes. EN 10204 3.1 is standard. EN 10204 3.2 is arranged with SGS, TÜV, BV, ABS, CCS, DNV or the inspector named on the order.
Conclusion
ASTM A387 Grade 12 Class 2 Steel Plate is 1Cr-0.5Mo pressure-vessel plate at 450–585 MPa tensile and 275 MPa yield. Whether the inquiry says ASTM A387 Grade 12 Class 2, A387 Gr.12 Cl.2, A387GR12CL2, A387GR12 CL2 or SA387 Grade 12 Class 2, SHH STEEL as a global steel mill sourcing partner and steel manufacturer & exporter (mill-direct, China origin) supplies plate with Grade 12 chemistry, Class 2 tensile, recorded N+T delivery, and EN 10204 3.1 or 3.2 certification.
SHH STEEL supplies ASTM A387 Grade 12 Class 2 / A387 Gr.12 Cl.2 1Cr-0.5Mo 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 12 Class 2 Steel Plate, A387 Gr.12 Cl.2, A387GR12CL2, 1Cr-0.5Mo vessel plate, A387 Gr.12 Cl.2 supplier, SHH STEEL








