X20CrMoWV12-1 (1.4935 / AISI 422) Open-Die Forgings
Creep resisting 12 % Cr martensitic steel to EN 10302:2008. Bars, rings, discs, hollow sections, turbine blade blanks, valve spindles and studs forged to drawing.
X20CrMoWV12-1, material number 1.4935, is a creep resisting martensitic steel in EN 10302:2008, alloyed with 11.0–12.5 % chromium plus molybdenum, tungsten and vanadium. The nearest American grade is AISI 422 / UNS S42200. It is used for steam and gas turbine blades, valve parts and high temperature bolting, with good creep resistance in continuous service to about 580 °C and scaling resistance to about 600 °C. Jiangyin Jiangnan Metal Co., Ltd., an open-die forging factory in Jiangyin, Jiangsu, China, supplies this grade as forged bars, seamless rolled rings, discs, hollow bars, turbine valve spindles and double-end studs in the +QT700 or +QT800 condition.
- Material No.
- 1.4935
- Standard
- EN 10302:2008
- Structure
- Martensitic
- Rm (+QT800)
- 800–950 MPa
- Max service
- about 580 °C
- Density
- 7.7 g/cm³
Designations and equivalent grades
Enquiries reach us for this grade under three spellings, X20CrMoWV12-1, X20CrMoWV12.1 and X20CrMoWV121. All three mean the same EN material number 1.4935.
| Region / standard | Designation |
|---|---|
| Europe, EN 10302 / EN 10088-3 | X20CrMoWV12-1, 1.4935 |
| USA, ASTM / AISI | AISI 422, AISI 616, UNS S42200 |
| Japan, JIS G 4311 | SUH 616 |
| Italy, UNI 7500 | X 22 CrMoWV 12 1 |
| Other designations in use | T502, HW Mo V 3, 56 BI, Grade 616, EW 4935 |
Equivalents are close but not identical. Tungsten is 0.40–0.60 % in EN 1.4935 against 0.75–1.25 % in AISI 422 and SUH 616, so state the governing standard on the purchase order.
Chemical composition
| C | Si | Mn | P | S | Cr | Mo | Ni | V | W |
|---|---|---|---|---|---|---|---|---|---|
| 0.17–0.24 | 0.10–0.50 | 0.30–0.80 | max 0.025 | max 0.015 | 11.0–12.5 | 0.80–1.20 | 0.30–0.80 | 0.20–0.35 | 0.40–0.60 |
Balance iron. Some stockholders publish a narrower vanadium band of 0.25–0.35 %; the figures above follow the EN 10302 table. Where a customer specification is tighter than the standard, we work to the customer specification.
Mechanical properties
EN 10302 sets two quenched and tempered delivery classes. The figures below are room temperature values on longitudinal test pieces.
| Property | +QT700 | +QT800 |
|---|---|---|
| Tensile strength Rm (MPa) | 700–850 | 800–950 |
| 0.2 % proof strength Rp0.2 (MPa) | min 500 | min 600 |
| Elongation at fracture A (%) | min 15 | min 14 |
Proof strength at temperature
| Test temp. °C | 100 | 200 | 300 | 400 | 450 | 500 | 550 |
|---|---|---|---|---|---|---|---|
| +QT700 | 460 | 430 | 390 | 360 | 330 | 290 | 250 |
| +QT800 | 560 | 530 | 480 | 420 | 380 | 335 | 280 |
Creep rupture strength runs at roughly 275 MPa for 100,000 h at 500 °C. Full creep data and impact (KV) requirements are agreed order by order and reported on the EN 10204 3.1 certificate.
Physical properties
| Property | Value |
|---|---|
| Density | 7.7 g/cm³ |
| Modulus of elasticity | 216 GPa |
| Coefficient of linear expansion | 10.5–12.5 × 10-6 m/(m·K) |
| Thermal conductivity | 24 W/(m·K) |
| Specific heat capacity | 460 J/(kg·K) |
| Electrical resistivity | 0.6 µΩ·m |
Heat treatment, machining and welding
Normal practice is austenitising and quenching from 1020–1070 °C, then tempering at 680–780 °C. Where the tempering temperature sits inside that band decides the delivery class: a higher temper gives the softer +QT700 condition, a lower temper the stronger +QT800 condition. We rough machine forgings before the final temper so the section size is representative, and every furnace cycle is run on calibrated, chart recorded equipment.
The grade is hard to weld. It is classed in welding group 7.2 of ISO/TR 20172, and fabrication welding normally needs preheat, matching 12 % Cr consumables and post-weld heat treatment. Machining is best done in the tempered condition with rigid set-ups and positive rake carbide tooling, since the hardened martensitic matrix work hardens quickly.
Typical applications
X20CrMoWV12-1 was developed for thermal power plant parts that must carry load for tens of thousands of hours at temperature. The main uses are steam and gas turbine blades and buckets, turbine valve spindles and stems, high temperature bolting and double-end studs, and other steam path and hot gas path hardware. It also serves in chemical and reactor equipment, steam boiler construction and vessels where both creep strength and scaling resistance near 600 °C are needed.
X20CrMoWV12-1 forgings we make
We are an open-die forging shop, so each item below is forged to the customer drawing rather than cut from a fixed stock list.
- Bars and blade stock: round bars, rods, square, rectangular and flat bars, turbine blade blanks.
- Hollow forgings: hollow bars, sleeves, bushes and bushings, pipes, tubes, barrels, casings, shells, cylinders, hubs and housings.
- Rings: forged rings and seamless rolled rings.
- Solid sections: blocks, discs and plates.
- Finished shape parts: gas and steam turbine valve spindles, stems and rods, plus double-headed and double-end studs, fasteners and bolts.
- Other forged parts to print, including shafts, flanges and special profiles.
Standard scope of supply covers forging, heat treatment to +QT700 or +QT800, rough or finish machining, ultrasonic testing, mechanical testing and an EN 10204 3.1 mill certificate. Third party inspection by TUV, SGS, BV or Lloyd's can be arranged on request.
Common questions
What is X20CrMoWV12-1 steel?
A creep resisting 12 % chromium martensitic steel, material number 1.4935, listed in EN 10302:2008. Molybdenum, tungsten and vanadium raise its creep rupture strength, which is why it goes into turbine blades, valve components and high temperature bolting.
What is the American equivalent of 1.4935?
AISI 422, also known as UNS S42200 and AISI 616. SUH 616 to JIS G 4311 is the Japanese counterpart and X 22 CrMoWV 12 1 to UNI 7500 the Italian one. The composition windows are not identical, tungsten above all, so name the standard you are buying to.
What is the maximum service temperature?
Good creep resistance for continuous operation to about 580 °C, with scaling resistance to about 600 °C.
How is the grade heat treated?
Quench from 1020–1070 °C, then temper at 680–780 °C to land in either the +QT700 class, Rm 700–850 MPa, or the +QT800 class, Rm 800–950 MPa.
Is it weldable?
It is hard to weld and sits in welding group 7.2 of ISO/TR 20172. Preheat, matching consumables and post-weld heat treatment are normally required.
What sizes and quantities can you forge?
Size depends on the part geometry and finished weight. Send a drawing or a dimensioned sketch with the delivery condition you need, +QT700 or +QT800, and the quantity, and we will confirm feasibility, weight and lead time. One-off pieces and small batches are accepted alongside production orders.
Ask for a price on X20CrMoWV12-1 forgings
Send your drawing, specification and quantity. We reply with weight, price and lead time, normally within one working day.
Jiangyin Jiangnan Metal Co., Ltd., Open-Die Forging Factory
No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China
Tel 0086-189-2135-9659 | sales@steelforgepieces.com
Standards referenced: EN 10302:2008 (creep resisting steels, nickel and cobalt alloys), EN 10088-3:2014, JIS G 4311, UNI 7500, ISO/TR 20172 (welding groups), EN 10204 (inspection documents).
Published by Jiangyin Jiangnan Metal Co., Ltd., open-die forging factory, Jiangyin, Jiangsu, China. The data is given for guidance and does not replace the governing standard or a project specification. Write to sales@steelforgepieces.com to confirm values for a specific order. Page last reviewed .
Related grades and forgings
- Heat and corrosion resisting stainless: X12CrNiTi18-9, 17-4PH, 17-7PH, PH13-8Mo
- High temperature nickel alloys: Inconel X-750, Inconel 617, Inconel 690, Incoloy 800H, Incoloy 800HT, Incoloy 825
- Product types: forged shafts, forged pipes