Project Description
616 (UNS S42200 / 1.4935 / X20CrMoWV12-1 / SUH616 / 15X12BHMФ / 22Cr12NiWMoV) is a creep-resistant martensitic stainless steel bar engineered for sustained high-temperature service up to 580–650°C. With roughly 12% chromium plus deliberate additions of molybdenum, tungsten, and vanadium, it delivers hot strength, temper resistance, and oxidation resistance unmatched by standard 410-type grades. SHUNFU METAL supplies this high-performance alloy as a core product for the global oil and gas sector, leveraging ISO 9001 and API Q1 certified manufacturing with electroslag remelting (ESR) to ensure cleanliness and structural integrity for critical rotating and pressure-retaining components.
616 Stainless Steel — Creep-Resistant Martensitic Grade
616 stainless steel (also designated AISI 422) belongs to the creep-resistant martensitic stainless family — alloys hardened through quenching and tempering, then stabilized by molybdenum, tungsten, and vanadium carbide precipitation for prolonged elevated-temperature exposure. Unlike basic 410 or 420 grades that soften rapidly above 500°C, 616 retains meaningful tensile and creep-rupture strength through 580°C continuous operation and tolerates intermittent excursions to 650°C in exhaust and turbine service. SHUNFU METAL produces this grade via AOD refining followed by ESR, achieving inclusion ratings meeting AMS 5655 and GE B50A951 cleanliness requirements. Every heat undergoes full spectrometric verification, ultrasonic testing per ASTM E2375 / EN 10228-3, and hardness mapping, with complete traceability under the ISO 9001 quality framework.
The strategic advantage of 616 over common stainless grades lies in its creep-rupture performance: at 500°C under 100,000-hour design life, it delivers a creep-rupture strength exceeding 275 MPa, roughly double that of standard 12Cr martensitics. This allows thinner sections, reduced rotating mass in turbine and compressor rotors, and extended service intervals in high-temperature oil and gas applications. SHUNFU METAL supplies 616 bars in the quenched-and-double-tempered condition (+QT700 or +QT800 per EN 10302, or GE B50A951 Classes A1–A4), cut to customer specification and protected for transit.
Equivalent Grades of 616 Across International Standards
| Standard / Specification | Designation |
|---|---|
| ASTM A565 | Grade 616 (UNS S42200) |
| ASTM A437 | Grade B4B (turbine bolting) |
| AMS 5655 | 422 / 616 |
| EN 10088-3 / EN 10302 | X20CrMoWV12-1 (1.4935) |
| DIN | X20CrMoWV12-1; X23CrMoWMnNiV12-1-1 |
| JIS G4311 | SUH 616 |
| GOST 5632 | 15Х12ВНМФ (15X12BHMФ) |
| GB/T 8732 | 22Cr12NiWMoV (S47220); 2Cr12NiWMoV |
| GE B50A951 | 422 Class A1, A2, A3, A4 |
| GE B50A125 / B50A249 | 422 / B50A249 S12 |
| Siemens PDS | 10705BU / 10705BL/M / 10705BR |
| BS 970 | 442S19 |
Oil & Gas Industry Applications
616 stainless steel bars serve across upstream and downstream oil and gas operations where components must simultaneously resist high temperature, oxidation, and mechanical load over extended service campaigns. Typical deployment spans refinery combined-cycle power blocks, gas processing plant turbine-driven compressor trains, LNG liquefaction turbo-machinery, and high-temperature pressure-boundary fasteners. SHUNFU METAL supplies 616 bars to OEM workshops and machining houses producing finished parts under API, ASME, and GE/Siemens quality requirements, with ISO 9001 and API Q1 certification covering every shipment.
Steam Turbine Blades
LP-stage blades and buckets in refinery cogeneration and waste-heat recovery turbines.
Gas Turbine Compressor Blades
Axial compressor blades and stator vanes in pipeline booster and LNG liquefaction gas turbines.
High-Temperature Bolting
ASTM A437 Grade B4B studs and tensioning bolts for flanged casings and pressure-retaining joints.
Valve Stems & Trim
Stems, seats, and discs in high-pressure steam and process valves at operating temperatures up to 580°C.
Compressor Shafts & Rotors
Through-hardened shafts and rotor forgings for centrifugal gas compressors in process and pipeline duty.
Boiler Feed Pump Shafts
High-temperature multi-stage pump shafts in refinery boiler feed and heat-recovery steam generator circuits.
Turbine Exhaust Components
Exhaust diffuser struts, rings, and support structures in gas turbine hot sections.
Heat Exchanger Fasteners
Tie-rods, tube-sheet bolting, and flange studs for shell-and-tube exchangers in high-temperature hydrocarbon service.
Actuator & Governor Spindles
Precision-ground spindles for pneumatic and hydraulic actuators, turbine speed governors, and control linkages.
Supply Range of 616 Stainless Steel Bar
SHUNFU METAL manufactures and stocks 616 stainless steel in bar and forging form covering the full dimensional window required by turbine and compressor OEMs. Production routes include hot-rolling, open-die forging, peeling, and precision centerless grinding. Each bar undergoes ultrasonic testing, dimensional inspection, and hardness mapping prior to dispatch. The ISO 9001 and API Q1 quality management system guarantees full material traceability from melt practice (AOD + ESR) through heat treatment records and final mechanical test certification.
| Product Form | Diameter / Section Range | Length | Surface Condition |
|---|---|---|---|
| Hot-Rolled Round Bar | ⌀10 mm – ⌀300 mm | 3,000 – 6,000 mm | Peeled / Ground / QT Bright |
| Forged Round Bar | ⌀80 mm – ⌀1,200 mm | 2,000 – 8,000 mm | Rough Machined / Peeled |
| Hot-Rolled Flat Bar | 5–80 mm thick × 20–550 mm wide | 3,000 – 6,000 mm | Black / Pickled / Peeled |
| Forged Flat / Block | 50–500 mm thick × 200–1,500 mm wide | 1,000 – 5,000 mm | Rough Machined |
| Forged Ring / Disc | OD 200–1,500 mm × ID 150–1,250 mm | H 20 – 1,250 mm | Rough Machined |
Non-standard dimensions, stepped shafts, hollow bars, and custom-cut pieces available on inquiry. SHUNFU METAL also supplies 616 in open-die forging configurations (discs, rings, blocks) for clients requiring near-net shapes prior to finish machining of turbine and compressor rotating parts.
Chemical Composition of 616 (EN 10088-3 / ASTM A565)
The chemistry of 616 stainless steel is defined under European and North American standards with slight differences in alloying tolerance. SHUNFU METAL controls each heat within the tighter overlap of both specifications through AOD refining plus ESR, with spectrometric verification on every cast. GE B50A951 imposes additional restrictions on residual elements (Sn ≤ 0.02%, Al ≤ 0.025%, Ti ≤ 0.025%) for turbine-grade material, which SHUNFU METAL meets as standard when specified. API Q1 mandates retained reference samples and independent rechecks for all critical orders.
| Element | EN 10088-3 X20CrMoWV12-1 | ASTM A565 Grade 616 |
|---|---|---|
| Carbon (C) | 0.17 – 0.24 | 0.20 – 0.25 |
| Silicon (Si) | 0.10 – 0.50 | ≤ 0.50 |
| Manganese (Mn) | 0.30 – 0.80 | 0.50 – 1.00 |
| Phosphorus (P) | ≤ 0.025 | ≤ 0.025 |
| Sulfur (S) | ≤ 0.015 | ≤ 0.025 |
| Chromium (Cr) | 11.0 – 12.5 | 11.0 – 12.5 |
| Molybdenum (Mo) | 0.80 – 1.20 | 0.90 – 1.25 |
| Nickel (Ni) | 0.30 – 0.80 | 0.50 – 1.00 |
| Vanadium (V) | 0.25 – 0.35 | 0.20 – 0.30 |
| Tungsten (W) | 0.40 – 0.60 | 0.90 – 1.25 |
All values in weight percent (wt%). Cast analysis per respective standard. GE B50A951 turbine-grade specification additionally restricts Sn ≤ 0.02%, Al ≤ 0.025%, Cu ≤ 0.15%, and Ti ≤ 0.025%. SHUNFU METAL product analysis typically meets the tighter GE limits when specified.
Mechanical Properties — Quenched & Double Tempered Conditions
616 achieves its high-temperature service properties through austenitizing at 1,020–1,070°C, oil or forced-air quenching to below the martensite-finish temperature, and double tempering (first temper ≥ 593°C, second temper ≥ 620°C). This double-temper protocol, mandated by GE B50A951, stabilizes the microstructure and prevents in-service dimensional change. Two standard delivery conditions — +QT700 and +QT800 per EN 10302, corresponding broadly to GE Classes A3/A4 and A1/A2 respectively — cover the full spectrum of oil and gas turbine and fastening applications. SHUNFU METAL’s in-house heat treatment furnaces, calibrated under ISO 9001 and API Q1 protocols with chart-recorder validation on every cycle, ensure uniform through-section properties across all diameter ranges. Stress relief, when required, is performed at 28°C below the final tempering temperature to preserve mechanical properties.
| Condition | Tensile Rm (MPa) | Yield Rp0.2 (MPa) | Elong. A5 (%) | RA Z (%) | Impact KV2 (J) | Hardness (HB) |
|---|---|---|---|---|---|---|
| +A Annealed | – | – | – | – | – | ≤ 248 |
| +QT700 (EN 10302) | 700 – 850 | ≥ 500 | ≥ 15 | – | – | – |
| +QT800 (EN 10302) | 800 – 950 | ≥ 600 | ≥ 14 | – | – | – |
| GE B50A951 A1/A2/A4 | ≥ 965 | ≥ 620 | ≥ 13 | ≥ 35 | ≥ 13.6 (RT) | 285 – 331 |
| GE B50A951 A3 | ≥ 759 | ≥ 555 | ≥ 18 | ≥ 50 | ≥ 33.9 (RT) | 223 – 269 |
| HT + QT (1,022–1,050°C OQ/AC + ≥620°C temp.) | ≥ 965 | ≥ 760 | ≥ 13 | ≥ 30 | ≥ 11 | 302 – 352 |
Data per EN 10302, GE B50A951, and ASTM A565. Mechanicals measured on longitudinal specimens at room temperature. Stress-rupture per GE B50A249: 26,000 psi at 649°C for ≥ 25 hours. Creep-rupture strength per EN 10302: Rm > 275 MPa at 500°C / 100,000 h. Custom heat treatment conditions and non-standard properties available through SHUNFU METAL’s technical team.