Delayed coker drums operate under severe cyclic operating conditions: repeated high temperatures, pressure fluctuations, thermal fatigue, and exposure to hydrogen and hydrocarbon process media. Proper material selection directly governs equipment safety, service life and long-term operational costs.
ASTM A387 Grade 22 (2.25Cr‑1Mo) alloy steel plate has become the preferred material for delayed coker drums at refineries globally, owing to its superior high-temperature mechanical properties and corrosion resistance. GNEE Steel supplies fully certified ASTM A387 Gr.22 Class 1 and Class 2 pressure vessel steel plates tailored for coker drum fabrication.
Why SA-387 Gr.22 Is Specified for Coker Drum Manufacturing?
Outstanding high-temperature creep resistance
Coker drums undergo cyclic heating and cooling up to 425–480°C. Our ASTM A387 Gr.22 steel's 2.25% chromium and 1.0% molybdenum alloy composition delivers stable creep performance under prolonged cyclic high-temperature loading, effectively preventing permanent deformation and bulging of drum shells over repeated coking cycles.
Good thermal fatigue resistance under cyclic operation
Coker drums run batch-wise with frequent temperature swings. ASTM A387 Gr.22 retains consistent toughness after repeated thermal cycling, lowering the probability of thermally initiated fatigue cracks at plate shells and weld joints - a critical factor for sustained safe operation.
Favourable weldability
Fabrication of large coker drums involves extensive longitudinal and circumferential welding. ASTM A387 Gr.22 has well-established welding procedures using matching consumables: E9018-B3 (SMAW) and ER90S-B3 (GTAW). When proper post-weld heat treatment (PWHT) is implemented, weld joints can achieve mechanical properties comparable to the base metal, satisfying international pressure vessel codes.
Grade selection: Class 1 vs Class 2 for different design criteria
ASTM A387 Gr.22 Class 2: Recommended for heavy-duty coker drums with stringent design pressure, elevated operating temperatures and extended design life. Higher minimum yield strength provides an enhanced safety margin for cyclic fatigue service.
ASTM A387 Gr.22 Class 1: Suitable for projects with moderate design parameters to optimise overall material capital expenditure.
ASTM A387 Gr.22 Coker Drum Steel Plate Specification
| Specifications | ASTM A387 / ASME SA387 |
| Standard | ASTM/ASME |
| Grade |
ASTM A387 GR.22 CL.1 ASTM A387 GR.22 CL.2 |
| Thickness | 5mm-250mm |
| Width | 1500mm-4200mm |
| Length | 3000mm-18000mm |
| Technique | Hot Rolled |
ASTM A387 Gr.22 Coker Drum Steel Plate Chemical Composition
| Element | Range (heat analysis, per ASTM A387/A387M Grade 22) |
|---|---|
| Carbon (C) | 0.05–0.15 |
| Manganese (Mn) | 0.30–0.60 |
| Silicon (Si) | 0.50 max |
| Phosphorus (P) | 0.035 max (0.025 max in recent editions) |
| Sulfur (S) | 0.035 max (0.025 max in recent editions) |
| Chromium (Cr) | 1.90–2.60 |
| Molybdenum (Mo) | 0.87–1.13 |
ASTM A387 Gr.22 Coker Drum Steel Plate Mechanical Property
| Property | Grade 22 Class 1 | Grade 22 Class 2 |
|---|---|---|
| Tensile strength | 415–585 MPa (60–85 ksi) | 515–690 MPa (75–100 ksi) |
| Minimum yield strength | 205 MPa (30 ksi) | 310 MPa (45 ksi) |
| Minimum elongation (50 mm gauge) | 18% | 18% |
Heat treatment and weldability
A387 Grade 22 plate is delivered heat treated. Normalizing is performed in the standard's austenitizing range (about 870–955 °C) followed by air cooling; tempering is at a minimum of about 677 °C (1250 °F). The N&T condition refines the hot-rolled structure and tempers the transformation products, giving a stable combination of strength and toughness in thick plate.
The grade is weldable with established procedures: preheating, low-hydrogen electrodes and mandatory post-weld heat treatment (PWHT) after welding, typically in the 690 °C ± 15 °C range with soak time set by thickness. Matching consumables such as E9018-B3 (SMAW) and ER90S-B3 (GTAW) are common choices. Because PWHT is always applied to the finished drum, plate properties must also be verified in the simulated post-weld heat treated condition - see below.
Supplementary requirements for coker drum plate
Coker drum plate orders normally carry a supplementary test package on top of the base standard. The items below are the ones most frequently seen; exact values always come from the project specification.
Temper embrittlement control (J and X factors)
2.25Cr-1Mo steel can lose toughness during long exposure in the roughly 370–565 °C range, and the embrittling elements are phosphorus, tin, antimony and arsenic. Two widely used indices keep these elements within limits on the mill certificate:
J factor: J = (Si + Mn) × (P + Sn) × 10⁴
X factor: X = (10P + 5Sb + 4Sn + As) / 100 (ppm)
Common acceptance targets in refinery practice are J ≤ 100–150 and X ≤ 15–20 ppm (per general engineering knowledge); the purchaser's specification sets the exact limit. Step-cooling tests are sometimes added to demonstrate resistance to temper embrittlement directly.
Simulated post-weld heat treatment (SPWHT)
Because the finished drum receives a long PWHT, mechanical test coupons are given a simulated post-weld heat treatment (commonly about 690 °C for a soak time that depends on plate thickness, per the project specification) before tensile and impact testing. This verifies that the delivered plate still meets strength and toughness after the thermal history it will actually see in fabrication. SPWHT conditions must be stated in the enquiry; they are not part of the base ASTM A387 text.
Low-temperature impact testing
Charpy V-notch impact testing at −30 °C is a common acceptance for coker drum plate (some specifications use −20 °C or −40 °C; the code and the project spec decide). Because low-temperature toughness is a sensitive indicator of embrittlement, the test is usually performed in the SPWHT condition and on both surface and through-thickness locations.
Ultrasonic examination
Thick shell plate is normally examined ultrasonically, often 100% of the surface per ASME SA-578 or an equivalent agreed procedure, to confirm freedom from harmful internal discontinuities. Dimensional, flatness and surface checks are routine additions.
Primary Applications of ASTM A387 Gr.22 Plate in Coke Drums
Shell
The main body of the vessel; it is subjected to sustained high temperatures (425–480°C), high pressure, and erosion from hydrocarbons and coke, requiring excellent resistance to hydrogen embrittlement and creep.
Heads
Includes the top and bottom elliptical or dished heads; as primary pressure-retaining components, they require heat and corrosion resistance equivalent to that of the shell.
Large Nozzles & Flanges
Thick-walled components at critical connection points-such as inlets and outlets-requiring structural integrity of the welded joints under high-temperature conditions.
Key Applications of ASTM A387 Gr.22 Steel Plate
In addition to coke drums, ASTM A387 Gr.22 is used in the following applications:
Core equipment for petroleum refining: hydroprocessing reactors, hot high-pressure separators, reforming reactors, and high-temperature oil-gas separators.
Energy and coal chemical equipment: steam drums for supercritical/ultra-supercritical boilers, high-temperature headers, ammonia synthesis reactors, coal gasifier shells, and Fischer-Tropsch synthesis reactors.
Why Choose GNEE Steel?
Fully traceable certified material supply All SA-387 Gr.22 plates are sourced from qualified domestic steelworks. Each shipment is accompanied by official original MTC covering chemical analysis, heat treatment records and full mechanical test results, accepted for third-party inspection and pressure vessel registration.
Custom cutting and pre-processing services We provide flame cutting, plasma cutting and rough machining according to customer coker drum fabrication drawings. Supply of pre-cut plates reduces your in-house processing workload, lowers material losses and shortens equipment manufacturing lead times.
Flexible stock availability and lead time coordination We maintain regular stock of SA-387 Gr.22 N&T plates in common thicknesses. For non-standard thicknesses or bulk orders, we coordinate mill production schedules to align with your project timeline and avoid production downtime caused by material shortages.
Export-standard packaging and global logistics arrangement Plates are coated with anti-corrosive primer and secured with steel or wooden framing. We prepare the complete set of export documentation, including commercial invoice, packing list, MTC and certificate of origin, and arrange sea freight to ports worldwide.
Rigorous pre-shipment inspection Prior to despatch, we welcome customer or third-party witnessed inspections, covering dimensional verification, surface visual check, random mechanical sampling and ultrasonic scanning, to prevent quality disputes upon arrival.
If you have ongoing coker drum fabrication projects requiring SA-387 Gr.22 steel plates, please send your required thicknesses, quantity, class specification (Class 1 / Class 2), drawings and inspection requirements. GNEE Steel will provide competitive quotations and reliable material solutions for your pressure vessel manufacturing.
FAQ
Q: What is the equivalent of ASTM A387 Gr.22?
A: The international equivalent for ASTM A387 Grade 22 is the European EN 10028-2 Grade 10CrMo9-10 (often designated as 1.7380). Other prominent equivalents include BS 1501 Grade 622-515B (British Standard) and the ASME equivalent ASME SA387 Grade 22.
Q: Is ASTM A387 Gr.22 easy to weld?
A: ASTM A387 Gr. 22 (a 2.25% Cr - 1% Mo alloy) has good weldability, but it is not easy to weld compared to standard carbon steel. It is highly susceptible to hydrogen-induced cracking and temper embrittlement, requiring strict adherence to strict preheating, interpass temperature controls, and post-weld heat treatment (PWHT).
Q: What are the differences between ASTM A387 Gr.22 and Gr.11?
A: ASTM A387 Gr. 11 and Gr. 22 are both chrome-moly alloy steel plates designed for elevated temperatures and welded pressure vessels. The primary differences are that Gr. 22 contains roughly double the chromium and molybdenum, offering superior high-temperature strength, creep resistance, and tensile capacity.
