ASME SA-266/SA-266M Gr.2 · ASTM A266/A266M Gr.2 · UNS K03506 · formerly Class 2 (Cl.2 / Cl-2 / GR II)
ASME SA-266 Grade 2 Open-Die Forgings
Forged tube sheets, discs, shells, nozzles and rolled rings in carbon steel to ASME SA-266 Grade 2, normalised and tempered and ultrasonically examined.
ASME SA-266 Grade 2 is a carbon steel forging grade for boilers, pressure vessels and associated equipment, published in ASME Boiler and Pressure Vessel Code Section II Part A as the adoption of ASTM A266/A266M Grade 2 and catalogued as UNS K03506. The grade is specified for a tensile strength of 485–655 MPa with a minimum yield strength of 250 MPa, and is the grade most often ordered for tube sheets, hubbed flat heads and forged nozzles. Jiangyin Jiangnan Metal Co., Ltd., an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, forges SA-266 Grade 2 to customer drawings in diameters from 100 to 6000 mm and unit weights from 10 to 15 000 kg, supplied with EN 10204 3.1 or 3.2 certification.
- UNS
- K03506
- Tensile strength
- 485–655MPa · 70–95 ksi
- Yield, 0.2%, min
- 250MPa · 36 ksi
- Elongation, min
- 20 %in 50 mm
- Reduction of area, min
- 33 %ASTM A370
- Hardness
- 137–197HBW
What is ASME SA-266 Grade 2?
SA-266 covers four grades of carbon steel forgings made by a melting process and hot worked as close as practical to the finished shape. Grade 2 is the most widely ordered of the four. Its strength range keeps tube sheet thicknesses within normal design limits, its ductility suits components drilled through the full thickness, and its carbon equivalent limit keeps welding procedures straightforward.
The specification is written around three components: heat exchanger tube sheets, hubbed flat heads and forged nozzles. Shells, girth flanges, channel covers, cover flanges, sleeves, blocks and bars are also regularly ordered to this grade.
Ordering to SA-266 or to A266
They are the same steel. ASTM A266/A266M is published by ASTM International; ASME SA-266/SA-266M is the version adopted into ASME Boiler and Pressure Vessel Code Section II Part A. Order to SA-266 when the vessel carries an ASME code stamp and to A266 otherwise. Jiangyin Jiangnan Metal Co., Ltd. issues one material test certificate listing both designations.
Grade 2 and the former Class 2 designation
Drawings are still written SA-266 Cl.2, Cl-2, Class II, GR II or SA266 Gr2. These designations refer to the same material. The specification originally used classes and later renamed them grades, so former Class 1, 2, 3 and 4 are now Grade 1, 2, 3 and 4. The technical requirements were not changed by the rename.
Purchase orders written under any of these designations are accepted without re-drawing. Where the drawing revision is unclear, send it with the enquiry and the metallurgy department will confirm the grade before quoting.
SA-266 Grade 2 chemical composition
The limits below are heat analysis values. Product analysis is permitted the tolerances of ASTM A788/A788M. Every heat Jiangyin Jiangnan Metal Co., Ltd. forges is reported on the certificate as a ladle analysis; product analysis is added on request.
| Element | Grade 2 | Why it is controlled |
|---|---|---|
| Carbon (C) | 0.30 max | Sets strength; capped to keep the steel weldable without heavy preheat |
| Manganese (Mn) | 0.40 – 1.05 | Strength and hardenability; ties up sulfur as MnS |
| Silicon (Si) | 0.15 – 0.35 | Deoxidiser; the range confirms a fully killed steel |
| Phosphorus (P) | 0.025 max | Residual; promotes temper embrittlement and cold shortness |
| Sulfur (S) | 0.025 max | Residual; low sulfur protects through-thickness ductility in tube sheets |
| Nickel (Ni) | 0.25 max | Residual limit |
| Chromium (Cr) | 0.20 max | Residual limit |
| Molybdenum (Mo) | 0.08 max | Residual limit |
| Iron (Fe) | Balance | Base metal, approximately 98.3–99.4 % |
Carbon equivalent
The specification caps carbon equivalent at 0.50 for Grade 2 (0.45 for Grade 1), calculated as:
CE = C + Mn/6 + (Cr + Mo + V)/5 + (Ni + Cu)/15
Carbon equivalent governs preheat selection in the welding procedure. Jiangyin Jiangnan Metal Co., Ltd. reports the calculated value on every certificate, and can select a heat to a tighter CE ceiling where the welding procedure requires it.
SA-266 Grade 2 mechanical properties
Values are the specification requirements for the annealed, normalised, or normalised and tempered condition, taken on specimens located per the specification and tested to ASTM A370.
| Property | Metric | Imperial | Basis |
|---|---|---|---|
| Tensile strength | 485 – 655 MPa | 70 – 95 ksi | ASME SA-266 / ASTM A266, Grade 2 |
| Yield strength, 0.2% offset, min | 250 MPa | 36 ksi | ASME SA-266 / ASTM A266, Grade 2 |
| Elongation in 50 mm (2 in), min | 20 % | 20 % | Tension test to ASTM A370 |
| Elongation in 62.5 mm, min | 18 % | 18 % | Tension test to ASTM A370 |
| Reduction of area, min | 33 % | 33 % | Tension test to ASTM A370 |
| Brinell hardness | 137 – 197 HBW | 137 – 197 HBW | ASTM A370 / ASTM E10 |
| Austenitic grain size | 1 – 5 | 1 – 5 | ASTM E112 |
Comparison with Grades 1, 3 and 4
The four grades differ mainly in manganese content and strength range.
| Requirement | Grade 1 | Grade 2 | Grade 3 | Grade 4 |
|---|---|---|---|---|
| Carbon, max % | 0.30 | 0.30 | 0.35 | 0.30 |
| Manganese, % | 0.40–1.05 | 0.40–1.05 | 0.80–1.35 | 0.80–1.35 |
| Tensile, MPa | 415–585 | 485–655 | 515–690 | 485–655 |
| Yield min, MPa | 205 | 250 | 260 | 250 |
| Elongation min, % | 23 | 20 | 19 | 20 |
| Reduction of area min, % | 38 | 33 | 30 | 33 |
| Hardness, HBW | 121–170 | 137–197 | 156–207 | 137–197 |
| Carbon equivalent, max | 0.45 | 0.50 | — | 0.50 |
| UNS | K03506 | K03506 | K05001 | K03017 |
Heat treatment of SA-266 Grade 2 forgings
After forging and before reheating for heat treatment, forgings are cooled in a manner that prevents injury and completes transformation. The specification then allows four routes: annealing, normalising, normalising and tempering, or liquid quenching and tempering. Where tempering is applied it must be subcritical, and not below 595 °C (1100 °F).
Jiangyin Jiangnan Metal Co., Ltd. supplies Grade 2 normalised and tempered as standard. This condition gives uniform hardness across thick tube sheet sections and consistent machining behaviour during hole drilling.
Tempering temperature in works practice
The 595 °C figure is a specification minimum. Tempering at 640–660 °C places hardness within the 137–197 HBW band with less scatter, raises impact energy at sub-zero test temperatures, and reduces the residual stress that causes distortion during drilling. Project specifications stating a tempering minimum of 640 °C are met by this standard cycle.
Stress relief after final machining is a separate operation, carried out below the tempering temperature so that the tempered structure is not altered. It is normally applied to thick tube sheets and channel covers, where heavy metal removal releases residual stress.
Testing, examination and quality requirements
Weld repair of SA-266 forgings is not permitted. Volumetric examination is therefore carried out before final machining and covers the complete mass of the forging.
| Test | Standard | Scope and acceptance |
|---|---|---|
| Heat analysis | ASTM A751 | Ladle chemistry reported for every heat |
| Product analysis | ASTM A788/A788M | On request; permitted tolerances applied |
| Carbon equivalent | SA-266 formula | Calculated and reported; 0.50 max for Grade 2 |
| Tensile test | ASTM A370 | Tensile, yield, elongation, reduction of area |
| Hardness survey | ASTM A370 / E10 | 137–197 HBW; multi-point survey on large tube sheets |
| Grain size | ASTM E112 | Austenitic grain size 1–5 |
| Charpy V-notch impact | SA-266 S13 | Supplementary; energy and temperature stated on the order |
| Ultrasonic examination | ASTM A388 / SA-388 | Complete mass of the forging, before final machining |
| Magnetic particle examination | ASTM A275 / SA-275 | All exposed surfaces after final machining |
| Liquid penetrant examination | ASTM E165 | On request, typically on sealing faces |
| Macro-etch test | ASTM E381 | On request; confirms sound centre and grain flow |
| Dimensional inspection | Customer drawing | Full dimensional measurement record issued |
| Third-party inspection | EN 10204 3.2 | Lloyd's Register, TÜV, Bureau Veritas or customer inspector |
Supplementary requirements for tube sheets and hubbed flanges
For hubbed flanges and tube sheets ordered for ASME Boiler and Pressure Vessel Code application, Supplementary Requirement S12 of A788/A788M must be specified in addition to Supplementary Requirement S8 of A266. S8 governs specimen location on forged hubs. Hubs to be butt welded to shells must be forged so that the hub itself carries the full minimum tensile properties, and the test specimen must be taken from that location, so that the certified values apply to the section that will be welded.
Low-temperature impact testing
A common project requirement is Charpy V-notch testing at −50 °C, with a minimum average of 20 J across three specimens and no single specimen below 16 J. Grade 2 can meet these values, but the result depends on a fine-grain-practice heat with restricted carbon and sulfur and on a controlled normalise-and-temper cycle. State the test temperature and energy values on the enquiry so that the heat can be selected before forging.
Documents issued during supply
- Heat treatment chart, time and temperature, for every cycle
- Mechanical and chemical test reports, including calculated carbon equivalent
- Ultrasonic examination report to ASTM A388 / SA-388
- Magnetic particle examination report to ASTM A275 / SA-275
- Dimensional measurement record against the drawing
- EN 10204 3.1 inspection certificate, or 3.2 with third-party endorsement
What SA-266 Grade 2 forgings does Jiangyin Jiangnan Metal produce?
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China. Most SA-266 Grade 2 components are one-off or small-batch pressure-retaining parts made to drawing, for which closed-die tooling is not economic.
| Forged product | Also called | Typical use |
|---|---|---|
| Tube sheets | Tube plates, tubesheets | Shell-and-tube heat exchangers, reactors, condensers |
| Discs | Disks, blanks, blind heads | Hubbed flat heads, covers, valve bodies |
| Blocks | Rectangular forgings, slabs | Machined bodies, manifolds, die blocks |
| Round bars | Forged bar, hollow bars | Studs, pins, machined components, sleeves |
| Seamless rolled rings | Rolled rings, forged rings | Girth flanges, shell courses, ring sections |
| Sleeves and bushings | Bushes, bushing, spacers | Wear surfaces, nozzle reinforcement |
| Shells and cylinders | Barrels, casings, cases | Forged vessel courses, pump and valve casings |
| Hubs and housings | Hubbed sections | Butt-welded hubs to shells, per S8 |
| Girth flanges | Shell flanges, body flanges | Exchanger and column bolted joints |
| Channel covers | Cover flanges, blind covers | Exchanger channel ends |
| Long weld neck nozzles | LWN, nozzle necks | Vessel and exchanger nozzles |
| Self-reinforced nozzles | FVC type, integrally reinforced | High-pressure nozzle connections |
| Shafts | Forged shafts, spindles | Agitators, pumps, rotating equipment |
| Pipe and tube forgings | Piping, tubing, forged pipe | Heavy-wall forged pipe sections |
Forging capability and size range
These are the published figures for the open-die works as a whole. For SA-266 Grade 2 the practical envelope is set by the forging ratio needed to break down the cast structure through the full section, so the achievable size for a given part is confirmed per enquiry.
| Parameter | Range | Note |
|---|---|---|
| Diameter | 100 – 6000 mm | Across all grades worked at the plant |
| Length | 100 – 12 000 mm | Shafts and drawn sections |
| Unit weight | 10 – 15 000 kg | Single-piece forging weight |
| Hydraulic press | 4500 t | Main open-die press |
| Forging hammers | 1 t / 3 t / 6 t / 9 t | Four hammers for smaller sections |
| Ring rolling mills | 3 m and 6 m | Seamless rolled rings |
| Heat treatment | In-house | Annealing, normalising, tempering, quench and temper, stress relief |
| Machining | In-house | Rough or finish machining; tube sheet drilling to drawing |
| Workforce | ≈ 460 | Including 9 senior and 32 intermediate engineers |
| Quality system | ISO 9001:2015 | EN 10204 3.1 / 3.2 certification |
How an SA-266 Grade 2 forging is produced
The stages run in this order because each one depends on the last.
- Billet sourcing and verificationFully killed, fine-grain-practice carbon steel billet is received with its mill certificate and verified by positive material identification before release to the forge.
- Preheat and soakThe billet is through-heated to forging temperature and held until core and surface equalise. Heavy tube sheet blanks require extended soak time, since an unequalised core deforms unevenly and can produce ultrasonic indications later in the route.
- Upsetting and drawingThe billet is upset and drawn under the 4500 t press to break down the cast dendritic structure. A forging ratio of at least 3:1 is targeted so that grain refinement reaches the centre of the section, which is the region subsequently drilled in a tube sheet.
- Punching, expanding or ring rollingRings and sleeves are punched and expanded over a saddle mandrel, or rolled on the 3 m or 6 m ring mill. Tube sheets and discs are forged flat and cooled to complete transformation.
- Normalising and temperingNormalised at 880–920 °C and air cooled, then tempered subcritically at 640–660 °C. Furnace charts are recorded and issued with the certificate.
- Rough machining and ultrasonic examinationThe forging is rough machined to a testable surface, then examined ultrasonically to ASTM A388 / SA-388 over the complete mass against the acceptance class on the order. Weld repair is not permitted, so acceptance is decided at this stage.
- Finish machining and drillingFinish machining to drawing, including tube sheet hole drilling and grooving where specified. Stress relief at 580–620 °C follows heavy metal removal when the specification calls for it.
- Final NDE, testing and certificationMagnetic particle examination of all exposed surfaces, hardness survey, dimensional record, and issue of the EN 10204 3.1 or 3.2 certificate with all supporting reports.
Which standards apply to SA-266 Grade 2 forgings?
| Standard | Scope | ASME equivalent |
|---|---|---|
| ASTM A266/A266M | Carbon steel forgings for pressure vessel components; the primary specification | SA-266/SA-266M |
| ASTM A788/A788M | Common requirements for steel forgings, including S12 for BPVC tube sheets and hubbed flanges | SA-788 |
| ASTM A370 | Mechanical testing methods and definitions | SA-370 |
| ASTM A388/A388M | Ultrasonic examination of heavy steel forgings | SA-388 |
| ASTM A275/A275M | Magnetic particle examination of steel forgings | SA-275 |
| ASTM A751 | Chemical analysis of steel products | SA-751 |
| ASTM E112 | Determining average grain size | — |
| ASME BPVC Section II Part A | Ferrous material specifications, where SA-266 is published | — |
| ASME BPVC Section VIII Div. 1 | Allowable stresses for pressure-retaining components | — |
| EN 10204 3.1 / 3.2 | Inspection certificates with actual test results | — |
Nearest comparable grades in other standards
The table below assists identification where a drawing is written to another standard. The grades are not interchangeable: chemistry limits, test scopes and delivery conditions differ, and the specification named on the purchase order governs.
| System | Designation | Comment |
|---|---|---|
| ASTM / USA | A266 Grade 2, UNS K03506 | Identical specification |
| ASME / USA | SA-266 Grade 2 | Code adoption of the above |
| EN / Europe | EN 10222-2 P280GH (1.0426) | Similar strength class of carbon steel pressure-purpose forging |
| DIN / Germany | C22.8 (1.0460) | Comparable plain carbon forging grade |
| JIS / Japan | SFVC 2A / SFVC 2B | Carbon steel forgings for pressure vessels |
| GB / NB / China | NB/T 47008 grade 20 | Carbon steel forgings for pressure equipment |
Where are SA-266 Grade 2 forgings used?
| Industry | Equipment | Forged components |
|---|---|---|
| Oil refining & petrochemical | Shell-and-tube exchangers, columns, reactors | Tube sheets, channel covers, girth flanges, LWN nozzles |
| Power generation | Feedwater heaters, condensers, boiler drums | Tube sheets, hubbed flat heads, shell courses, nozzle necks |
| Chemical processing | Reactors, mixing vessels, condensers | Discs, blind covers, rolled rings, sleeves |
| Fertiliser & ammonia | Heat exchangers, waste heat boilers | Thick tube sheets, forged shells, self-reinforced nozzles |
| LNG & gas processing | Cold boxes, exchangers with low-temperature duty | Impact-tested tube sheets and flanges to S13 |
| Desalination | Multi-stage flash and MED evaporators | Tube sheets, tube plates, nozzle forgings |
| Pulp & paper | Digesters, evaporators | Rolled rings, flanges, shafts, blocks |
What to include in an SA-266 Grade 2 enquiry
Quotations can be prepared from a sketch. A complete enquiry allows a firmer price and a confirmed lead time.
| Item | Why it changes the price or the process |
|---|---|
| Drawing or rough dimensions | Determines input billet weight and the achievable forging ratio |
| Grade and governing specification | SA-266 Gr.2 alone and SA-266 Gr.2 plus a client spec impose different test scopes |
| Supplementary requirements | S8, S12 and S13 each add operations; S13 may decide which heat is used |
| Impact test temperature and energy | Sub-zero requirements must be known before the heat is selected |
| Ultrasonic acceptance class | Sets the rough machining stage and the rejection threshold |
| Supply condition | As-forged, rough machined with allowance, or finish machined and drilled |
| Certification level | EN 10204 3.1, or 3.2 with a named third-party inspector |
| Quantity and delivery date | Batching heats and furnace loads changes both cost and lead time |
Frequently asked questions about ASME SA-266 Grade 2
What is ASME SA-266 Grade 2?
ASME SA-266 Grade 2 is a carbon steel forging grade for boilers, pressure vessels and associated equipment, published in ASME Boiler and Pressure Vessel Code Section II Part A as the adoption of ASTM A266/A266M Grade 2, and catalogued as UNS K03506. Typical products are heat exchanger tube sheets, hubbed flat heads and forged nozzles. Jiangyin Jiangnan Metal Co., Ltd. forges the grade at its open-die works in Jiangyin, Jiangsu, China.
What is the difference between ASME SA-266 and ASTM A266?
The technical content is the same. ASTM A266/A266M is the ASTM International specification; ASME SA-266/SA-266M is the version adopted into ASME BPVC Section II Part A for code-stamped construction. Order to SA-266 when the vessel is built to the ASME code, and to A266 otherwise. Jiangyin Jiangnan Metal Co., Ltd. certifies against either designation on the same material test certificate.
Is SA-266 Grade 2 the same as SA-266 Class 2?
Yes. The specification renamed its classes as grades, so former Class 1, 2, 3 and 4 are now Grade 1, 2, 3 and 4. Drawings written SA-266 Cl.2, Cl-2, Class II or GR II all refer to what is now Grade 2, and purchase orders under any of these designations are accepted.
What is the chemical composition of SA-266 Grade 2?
On heat analysis: carbon 0.30 % max, manganese 0.40–1.05 %, silicon 0.15–0.35 %, phosphorus 0.025 % max, sulfur 0.025 % max. Residuals are limited to 0.25 % nickel, 0.20 % chromium and 0.08 % molybdenum, and the carbon equivalent must not exceed 0.50. Iron is the balance, roughly 98.3–99.4 %.
What are the mechanical properties of SA-266 Grade 2?
Tensile strength 485–655 MPa (70–95 ksi), minimum 0.2 % offset yield 250 MPa (36 ksi), minimum elongation 20 % in 50 mm, minimum reduction of area 33 %, Brinell hardness 137–197 HBW, austenitic grain size 1–5. Tensile strength is specified as a range, so material above 655 MPa is also outside specification.
What heat treatment is applied to SA-266 Grade 2 forgings?
Annealing, normalising, normalising and tempering, or liquid quenching and tempering. Tempering must be subcritical and not below 595 °C (1100 °F). Jiangyin Jiangnan Metal Co., Ltd. normalises at 880–920 °C and tempers at 640–660 °C as works practice, with a stress relief at 580–620 °C after final machining when the specification requires it.
What is the difference between SA-266 Grade 1, Grade 2, Grade 3 and Grade 4?
Grade 1: 415–585 MPa tensile, manganese 0.40–1.05 %. Grade 2: 485–655 MPa, manganese 0.40–1.05 %. Grade 3: 515–690 MPa, manganese 0.80–1.35 %, carbon up to 0.35 %. Grade 4: same strength as Grade 2 but manganese 0.80–1.35 % with carbon held at 0.30 % max, which gives better low-temperature toughness. Grade 2 is the most widely specified for tube sheets.
Which supplementary requirements apply to SA-266 tube sheets and hubbed flanges?
For hubbed flanges and tube sheets ordered for ASME BPVC application, Supplementary Requirement S12 of A788/A788M must be specified in addition to Supplementary Requirement S8 of A266. S8 governs specimen location in forged hubs so the test result represents the hub that will be butt welded to the shell. Charpy impact testing is added through S13.
What non-destructive examination is carried out on SA-266 Grade 2 forgings?
Ultrasonic examination to ASTM A388 / SA-388 covering the complete mass, magnetic particle examination to ASTM A275 / SA-275 on all exposed surfaces, hardness survey, grain size determination and full dimensional inspection. Liquid penetrant examination and macro-etch testing are added on request. Because weld repair of the forging is not permitted, volumetric examination is carried out before final machining.
Can SA-266 Grade 2 forgings be impact tested at low temperature?
Yes, through Supplementary Requirement S13. A commonly specified project requirement is 20 J minimum average over three specimens with no single specimen below 16 J at −50 °C. Meeting it depends on a fine-grain-practice heat with restricted carbon and sulfur and on a controlled normalise-and-temper cycle. State the temperature and energy on the enquiry so that the heat can be selected before forging.
Is SA-266 Grade 2 weldable?
Yes. With carbon at 0.30 % max and carbon equivalent capped at 0.50, the grade welds readily by the usual arc processes. Heavier sections normally need preheat, and post-weld heat treatment is governed by the construction code and section thickness. Note that weld repair of the forging itself is not permitted by the specification.
What forged products does Jiangyin Jiangnan Metal supply in SA-266 Grade 2?
Tube sheets and tube plates, discs, blocks, round bars, hollow bars, seamless rolled rings, sleeves and bushings, shells, cylinders, barrels and casings, hubs and housings, girth flanges, channel covers, cover flanges, long weld neck nozzles, self-reinforced FVC-type nozzles, nozzle necks and shafts, in diameters from 100 to 6000 mm and unit weights from 10 to 15 000 kg.
What certification is supplied with SA-266 Grade 2 forgings?
An EN 10204 3.1 inspection certificate reporting heat and product analysis, carbon equivalent, tensile and yield strength, elongation, reduction of area, hardness, grain size, heat treatment charts, ultrasonic and magnetic particle results and dimensional records. EN 10204 3.2 witnessed by Lloyd's Register, TÜV, Bureau Veritas or the customer's own inspector is available on request.
Who manufactures ASME SA-266 Grade 2 open-die forgings in China?
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, producing SA-266 Grade 2 tube sheets, discs, shells, nozzles, flanges and rolled rings on a 4500 t hydraulic press with 3 m and 6 m ring rolling mills. Contact sales@steelforgepieces.com or +86 189 2135 9659.
What information is needed to quote an SA-266 Grade 2 forging?
The drawing or rough dimensions, the governing specification and grade, quantity and delivery date, supply condition, the required test package including ultrasonic acceptance class and any impact test temperature, and whether third-party witness inspection is needed. Complete enquiries are answered at sales@steelforgepieces.com.
Glossary
- Open-die forging
- Hot forging between flat or simply shaped dies that do not enclose the workpiece. Used for large discs, tube sheets, shafts, rings and blocks, for which closed-die tooling is not economic.
- Tube sheet
- The thick plate in a shell-and-tube heat exchanger that carries the tube ends and separates shell-side from tube-side fluid. It is drilled through the full thickness, so centre soundness and through-thickness ductility are as important as tensile strength.
- Hubbed flat head
- A flat closure forged with an integral hub so that it can be butt welded to the shell without a separate transition piece. Supplementary Requirement S8 fixes the test specimen location for this component.
- Normalising and tempering
- Austenitising and air cooling to refine grain, followed by a subcritical reheat to reduce hardness and residual stress. The standard delivery condition for SA-266 Grade 2.
- Subcritical
- Below the A1 transformation temperature, approximately 723 °C for plain carbon steel. Tempering above A1 re-austenitises the material and removes the structure produced by normalising.
- Carbon equivalent (CE)
- A single number combining carbon and the alloying elements that affect hardenability, used to predict weldability and set preheat. Capped at 0.50 for SA-266 Grade 2.
- Forging ratio
- The ratio of starting cross-section to finished cross-section, used as a measure of how thoroughly the cast structure has been broken down. At least 3:1 is targeted so that refinement reaches the centre of the section.
- EN 10204 3.1 / 3.2
- 3.1 is an inspection certificate issued by the manufacturer's own independent inspection department, reporting actual test results. 3.2 is the same document countersigned by a third-party inspector or the purchaser's representative.
Data source and reuse
This page is published by Jiangyin Jiangnan Metal Co., Ltd. and reviewed by its metallurgy department. Specification values are taken from ASTM A266/A266M as adopted in ASME SA-266/SA-266M; works practice values are the figures applied at the company's own plant and are identified as such. Reuse of the technical data on this page is permitted under CC BY 4.0 with attribution.
Jiangyin Jiangnan Metal Co., Ltd. (2026). "ASME SA-266 Grade 2 (ASTM A266 Gr.2, UNS K03506) Open-Die Forgings." Jiangyin, Jiangsu, China. https://www.steelforgepieces.com/Alloy-Steel/ASME-SA266-Grade-2.html Last reviewed 13 September 2026.
Summary of supply
- Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory located at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China.
- Jiangyin Jiangnan Metal Co., Ltd. produces ASME SA-266 Grade 2 (ASTM A266 Gr.2, UNS K03506) tube sheets, discs, blocks, round bars, hollow bars, seamless rolled rings, sleeves, shells, cylinders, hubs, girth flanges, channel covers, nozzle necks and shafts.
- SA-266 Grade 2 forgings from Jiangyin Jiangnan Metal Co., Ltd. meet a tensile strength of 485–655 MPa, a minimum 0.2 % yield strength of 250 MPa, minimum elongation of 20 % in 50 mm, minimum reduction of area of 33 % and a hardness of 137–197 HBW.
- SA-266 Grade 2 chemistry is limited to 0.30 % carbon maximum, 0.40–1.05 % manganese, 0.15–0.35 % silicon, 0.025 % phosphorus maximum and 0.025 % sulfur maximum, with carbon equivalent not exceeding 0.50.
- SA-266 Grade 2 forgings from Jiangyin Jiangnan Metal Co., Ltd. are normalised at 880–920 °C and tempered at 640–660 °C, then ultrasonically examined to ASTM A388 / ASME SA-388 over the complete mass.
- Forging capability covers diameters from 100 to 6000 mm, lengths to 12 000 mm and single-piece weights from 10 to 15 000 kg on a 4500-tonne hydraulic press with 3 m and 6 m ring rolling mills.
- Certification is EN 10204 3.1 as standard, or EN 10204 3.2 witnessed by Lloyd's Register, TÜV or Bureau Veritas on request, under an ISO 9001:2015 quality system.
- Enquiries reach Jiangyin Jiangnan Metal Co., Ltd. at sales@steelforgepieces.com or +86 189 2135 9659.
Request a quotation for SA-266 Grade 2 forgings
Jiangyin Jiangnan Metal Co., Ltd. quotes SA-266 Grade 2 open-die forgings from drawings, sketches or rough dimensions. Complete enquiries are answered with a price, a test package and a delivery date.