Engineered for use in elevated temperature service, is a chrome molybdenum carbon alloy steel for use in weldable pressure vessels and industrial boilers.
The material benefits from added chromium which provides excellent corrosion and oxidation resistance making it ideal for sour service applications in the oil and gas industry.
Steel type: A387 Grade 12 is a chromium-molybdenum alloy steel (nominally 1% Cr – 0.5% Mo), not a carbon steel. A387 covers alloy-steel plate for welded boilers and pressure vessels in elevated-temperature service.
Sour service: Chromium-molybdenum steels resist oxidation, high-temperature sulfidation and hydrogen attack at elevated temperature. Wet H2S (sour) service is controlled by hardness limits and PWHT under NACE MR0103 / ISO 17945 or NACE MR0175 / ISO 15156, not by chromium content, so state any sour-service requirement on the order.
ASTM A387 GRADE 12 Class 1: Purchasing Specification
| Requirement | What to specify |
|---|---|
| Grade and specification | ASTM A387 Grade 12 Class 1 ; state the edition, and dual certification to ASME SA-387 if the plate is for ASME code construction. |
| Heat treatment | Annealed, or normalized and tempered, as A387 allows. State any simulated PWHT of test coupons. |
| Dimensions | Thickness × width × length in mm or inches, and the number of plates or cut pieces. Sizes are confirmed at quotation. |
| Tolerances | A20 thickness and flatness tolerances, or tighter project limits. |
| Supplementary tests | A20 supplementary requirements as needed: simulated PWHT of test coupons, Charpy impact tests, ultrasonic testing. |
| Documents | Mill test certificate (EN 10204 3.1 or 3.2), marking and any third-party inspection. |
Dimensions, Cutting and Tolerances
Specify thickness × width × length and the number of plates, or send a dimensioned drawing for cut pieces and profiles with the revision, finished-part tolerances and machining allowance. Plates for shells and heads may also need edge preparation for welding.
Equivalents
| BS | EN | ASTM/ASME | DIN |
|---|---|---|---|
| 620 B | 13 CRMO 45 | A387-12-1 | 13 CRMO 44 |
Comparable, not equal: BS 1501 620B is a withdrawn British grade. 13 CrMo 44 is the former DIN 17155 designation, replaced by EN 10028-2 13CrMo4-5 (1.7335); see 13CRMO45 Plates. Grades in other standards have different chemistry, strength and test requirements, so substitution needs the purchaser’s approval.
Specifications for ASTM A387 Grade 12 Alloy Steel Plates
Chromium & Molybdenum content (according to the ASME specification)
| Designation | Nominal Chromium Content (%) |
Nominal Molybdenum Content (%) |
|---|---|---|
| A387 Grade 12 | 1.00% | 0.50% |
ASME or ASTM: The original line refers to the ASME specification. ASTM A387 and ASME SA-387 give the same chromium and molybdenum ranges for the edition ASME adopts.
Tensile Requirements for ASTM A387 Grade 12 Alloy Steel Plates Class 1 Plates
| Designation: | Requirement: | Grade 12 |
|---|---|---|
| A387 Grade 12 | Tensile strength, ksi [MPA] | 65 to 85 [450 to 585] |
| Yield strength, min, ksi [MPa]/(0.2% offset) | 40 [275] | |
| Elongation in 8 in. [200mm], min % | 19 | |
| Elongation in 2 in. [50mm], min, % | 22 | |
| Reduction of area, min % | ––– |
Class 1 values: The figures in this table are the A387 Class 2 requirements. For Grade 12 Class 1, A387 requires a tensile strength of 55–80 ksi [380–550 MPa] and a minimum yield strength of 33 ksi [230 MPa]. Class 2 requires 65–85 ksi [450–585 MPa] and 40 ksi [275 MPa]. Check the values on the mill certificate against the edition you order.
Chemical Requirements for ASTM A387 Grade 12 Alloy Steel Plates
| Element | Chemical Composition (%) | |
|---|---|---|
| ASTM A387 Grade 12 | ||
| Carbon: | Heat Analysis: | 0.05 - 0.17 |
| Product Analysis: | 0.04 - 0.17 | |
| Manganese: | Heat Analysis: | 0.40 - 0.65 |
| Product Analysis: | 0.35 - 0.73 | |
| Phosphorus: | Heat Analysis: | 0.035 |
| Product Analysis: | 0.035 | |
| Sulphur (max): | Heat Analysis: | 0.035 |
| Product Analysis: | 0.035 | |
| Silicon: | Heat Analysis: | 0.15 - 0.40 |
| Product Analysis: | 0.13 - 0.45 | |
| Chromium: | Heat Analysis: | 0.80 - 1.15 |
| Product Analysis: | 0.74 - 1.21 | |
| Molybdenum: | Heat Analysis: | 0.45 - 0.60 |
| Product Analysis: | 0.40 - 0.65 |
Reading the chemistry: Single values for phosphorus and sulfur are maximums. “Heat analysis” is the ladle analysis; “product analysis” is a check analysis on the finished plate. Later editions of A387 have lowered some phosphorus and sulfur limits, so the certificate must meet the edition stated on the order.
Class 1 or Class 2: Choosing A387 Grade 12
A387 sets two strength levels for each of Grades 5, 9, 11, 12 and 22. Class 1 has the lower tensile and yield requirements; Class 2 has the higher. The class sets the allowable stresses used in the design (ASME Section II Part D), so order the class your design calculations use. Class 1 is specified where the design is based on the lower allowable stresses.
| Class | Tensile strength | Yield strength, min | Product page |
|---|---|---|---|
| Class 1 | 55–80 ksi [380–550 MPa] | 33 ksi [230 MPa] | This page |
| Class 2 | 65–85 ksi [450–585 MPa] | 40 ksi [275 MPa] | ASTM A387 GRADE 12 Class 2 |
Comparing A387 Grades
| Grade | Nominal alloying | Typical reason to choose |
|---|---|---|
| Grade 5 | 5% Cr – 0.5% Mo | More chromium than Grades 11, 12 and 22, for hot, sulfur-bearing refinery service |
| Grade 9 | 9% Cr – 1% Mo | Higher chromium for oxidation and sulfidation resistance at higher temperatures |
| Grade 11 | 1.25% Cr – 0.5% Mo | A widely used 1¼Cr–½Mo grade for refinery and power-plant vessels |
| Grade 12 (this page) | 1% Cr – 0.5% Mo | The lowest-alloy chrome moly grade in the range, for moderately elevated temperature |
| Grade 22 | 2.25% Cr – 1% Mo | Higher temperature capability than Grades 11 and 12, and common for hydrogen service |
| Grade 91 | 9% Cr – 1% Mo – V – Nb | Vanadium and niobium additions give much higher creep strength than plain 9Cr–1Mo |
These grades are not interchangeable; use the grade and class approved in your design.
Applications for A387 Grade 12 Plate
Boilers, pressure vessels and heat exchangers at moderately elevated temperature. Selection depends on design temperature, pressure, process media, hydrogen partial pressure and design life, so give these with your enquiry.
| Component or duty | Information for selection |
|---|---|
| Pressure-vessel shells and heads | Design code and edition, design temperature and pressure, thickness and PWHT. |
| Reactors and hydrogen service | Hydrogen partial pressure, temperature, toughness and step-cooling requirements. |
| Boiler and heat-exchanger parts | Steam or process temperature, media and corrosion allowance. |
Cutting, Fabrication and Welding
Champak Industries describes full and part plate/profile supply and a plasma-cutting service. Send drawings, piece quantities, tolerances, edge preparation and machining allowances for your Grade 12 requirement.
Welding
Use matching chromium-molybdenum consumables, for example AWS A5.5 E8018-B2 (1¼Cr–½Mo) type, with a procedure qualified to ASME Section IX. Preheat thicker sections and apply PWHT as the construction code requires for the thickness.
Forming and PWHT
Hot forming, and long or repeated PWHT, can lower the delivered strength. Give the PWHT cycle with your order so test coupons can be given simulated PWHT if your design requires it.
Testing, Inspection Documents and Traceability
Specify the inspection document, heat treatment and supplementary tests when ordering. A management-system certificate is separate from a material inspection document or project approval.
| Requirement | What to identify in the order |
|---|---|
| Mill test certificate | EN 10204 3.1 or 3.2 showing heat and product analysis, heat treatment and tensile results |
| Simulated PWHT | Temperature, holding time and cycles to apply to the test coupons |
| Impact testing | Test temperature and minimum absorbed energy, if required |
| UT and traceability | Ultrasonic testing (for example A435 or A578); heat and plate number transferred to cut pieces |
See the company’s Quality Policy for its published policy.
Source ASTM A387 GRADE 12 Class 1 from Champak Industries
Champak Industries’ company profile records its establishment in Mumbai in 1978 and its stockist, import and export activities. ASTM A387 GRADE 12 Class 1 plate can be requested together with the other ASTM A387 grades or the matching ASME SA 387 GRADE 12 Class 1 page for ASME code orders.
What Determines the Grade 12 Plate Quotation?
Thickness, plate size, quantity, heat treatment, supplementary tests, cutting, inspection and packing all affect the quotation. Include the destination, and say whether pricing is needed per kilogram, per plate or per finished piece.
Packing, Dispatch and Export Requirements
Give the delivery address, required date and unloading constraints; heavy plate may need special handling. For export orders, include the destination port, delivery terms and document list.
ASTM A387 GRADE 12 Class 1: Frequently Asked Questions
01What is ASTM A387 GRADE 12 Class 1?
It is 1% Cr – 0.5% Mo chromium-molybdenum alloy-steel plate to ASTM A387 Grade 12 at the Class 1 strength level, used for welded boilers and pressure vessels in elevated-temperature service.
02What is the difference between Grade 12 Class 1 and Class 2?
They share the same chemistry. Class 1 requires 55–80 ksi [380–550 MPa] tensile and 33 ksi [230 MPa] minimum yield; Class 2 requires 65–85 ksi [450–585 MPa] and 40 ksi [275 MPa].
03What is the chromium and molybdenum content of A387 Grade 12?
Nominally 1% Cr – 0.5% Mo. The heat analysis ranges are 0.80–1.15% chromium and 0.45–0.60% molybdenum.
04What tensile and yield strength does ASTM A387 GRADE 12 Class 1 require?
Class 1 requires a tensile strength of 55–80 ksi [380–550 MPa] and a minimum yield strength of 33 ksi [230 MPa].
05Is ASTM A387 the same as ASTM A387?
ASME SA-387 is the ASME Code adoption of ASTM A387, with the same requirements for the edition adopted. Vessels built to the ASME Code need plate certified to ASME SA-387, so specify dual certification if you need it.
06What is the EN equivalent of A387 Grade 12?
The closest EN 10028-2 plate grade is 13CrMo4-5 (1.7335). It is comparable, not identical, so substitution needs the purchaser’s approval.
07What heat-treatment condition is supplied?
Annealed, or normalized and tempered, as A387 allows. State any simulated PWHT of test coupons.
08Can A387 Grade 12 plate be welded?
Yes, with matching chromium-molybdenum consumables (for example AWS A5.5 E8018-B2 (1¼Cr–½Mo) type) and a qualified procedure. Preheat thicker sections and apply PWHT as the construction code requires for the thickness.
09Which tests and documents should I request?
A mill test certificate to EN 10204 3.1 (or 3.2 with third-party inspection) showing heat and product analysis and tensile results, plus any A20 supplementary requirements such as simulated PWHT, impact testing or ultrasonic testing.
10How do I get a price and delivery date?
Send the grade and class, thickness, plate size, quantity, cutting, tests, destination and required date through the enquiry form below, by WhatsApp or by phone.