1.4923 forgings: X22CrMoV12-1 bars, rings, discs and turbine components

The 12% chrome-moly-vanadium steels are a series of martensitic stainless steels designed for use at moderately high temperatures. 1.4923 is a typical grade in that series, and its dominant application is steam power generating plant.

Approximate composition is 12% Cr, 0.5% Ni, 1.0% Mo, 0.30% V and 0.20% C. Adding nickel, molybdenum and vanadium to a basic 12% Cr grade improves strength, especially at temperature. The key property is creep strength, that is, resistance to continued deformation under sustained stress. For steels, creep needs to be accounted for above roughly 450 °C. Steam temperatures in power generation sit around 550 °C, which explains why these grades are used so heavily in that sector.

Characteristics of the grade:

• Moderate strength: about 800 MPa UTS and 600 MPa 0.2% PS at room temperature
• Moderate high-temperature strength: about 280 MPa 0.2% PS at 550 °C
• Good creep strength: about 137 MPa rupture stress at 550 °C for 100,000 hours
• Moderate toughness: typically around 50 J at room temperature
• Basic corrosion resistance, adequate for steam
• Weldable with care, requiring pre-weld and post-weld heat treatment

The family was developed further with additions of tungsten, cobalt, niobium and nitrogen. Those variants are often known by brand names such as FV 448, FV 535 and Jethete M152.

1.4923 is supplied quenched and tempered. The standard route is austenitising, quenching in oil or air, then tempering to the specified strength band.

1. Austenitise at approximately 1020 to 1070 °C, soaked for section thickness.
2. Quench in oil, or in air for smaller sections.
3. Temper at approximately 680 to 780 °C, then cool in air. The tempering temperature sets the final strength and hardness, and it has to stay above the intended service temperature.

The steel air-hardens, so sections need to be handled to avoid quench cracking. Welded assemblies need preheat and a post-weld temper below the original tempering temperature. Machining is normally done in the tempered condition at 265 to 315 HBW.

• Steam turbines: blades, rotor shafts, discs, wheels, gland seal rings and guide rings
• Power plant bolting: bolts, studs and nuts for flanges and casings at elevated temperature
• Valves: bodies, bonnets, stems, spindles, seats and discs for high-temperature steam service
• Compressors: blades and impellers
• General high-temperature machinery running continuously in the 450 to 550 °C range where creep governs the design

Every 1.4923 forging is supplied with an EN 10204 3.1 mill test certificate as standard, showing heat number, ladle analysis, heat-treatment record, mechanical test results and hardness.

Available on request:

• EN 10204 3.2 certification with third-party inspection
• Ultrasonic testing to SEP 1921, ASTM A388 or your acceptance class
• Magnetic particle inspection to ASTM E709
• Elevated-temperature tensile testing and stress-rupture testing
• Grain size, macro-etch and non-metallic inclusion rating
• Charpy V-notch impact testing at specified temperature
• Witnessed heat treatment with charted furnace records

1. Send your drawing or dimensions to sales@steelforgepieces.com, with quantity, delivery condition and any testing requirements.
2. We confirm feasibility and quote, normally within one working day, with weight, tolerance and lead time.
3. We forge, heat treat and test the parts, then send the certificate for approval before shipment.
4. We ship worldwide by sea or air from Shanghai, with export packing and documentation.