OPen Die Forging

1. High Strength and Superior Mechanical Properties:

Refines the metal's grain structure through forging, enhancing fatigue resistance, toughness, and load-bearing capacity.

2. Production Flexibility:

No complex molds required, making it suitable for small batches, customized parts, or large-scale workpieces.

3. Cost-Effectiveness:

Saves on mold costs, especially for single-piece or low-volume production.

4. High Material Utilization:

Reduces the need for subsequent machining and minimizes overall material waste.

5. Broad Size Adaptability:

Capable of producing ultra-large components weighing hundreds of tons (e.g., marine crankshafts).

Open die forging involves shaping heated metal using repeated hammering or pressing between flat or contoured dies.

1. Key technical parameters include:

Press Capacity: Ranges from 10 MN to 80 MN (e.g., 80 MN hydraulic press used for heavy forgings up to 80,000 kg)

Workpiece Dimensions:

Weight: From a few pounds to 440,000 lbs (200,000 kg)

Length/Diameter: Up to 22 meters in length and 2.4 meters in diameter

Temperature: 850–1300°C for hot forging

Material Utilization: High efficiency with minimal waste due to controlled deformation

Tolerance & Precision: Achieves tight tolerances (e.g., ±1–3 mm for large components) with pre-stressed frame structures and advanced control systems

2. Commonly Used Steel Grades in Open Die Forging

Carbon and Alloy Steels:

ASTM Standards:

AISI 4140, 4340 (high-strength alloy steels for shafts and gears)

AISI 1020, 1045 (general-purpose carbon steels)

ASTM A182 (e.g., F11, F22, F91 for high-temperature applications)

European Standards:

34CrMo4, 42CrMo4 (DIN standards for structural components)

30CrNiMo8 (high-toughness steel for heavy machinery)

X20CrMoV12.1 (heat-resistant steel for power generation)

Stainless Steels & Nickel Alloys:

Austenitic Stainless Steels: AISI 304, 316 (ASTM A182-F304, F316)

Super Alloys: Inconel 625, 718 (for aerospace and petrochemical industries)

Duplex Stainless Steels: UNS S31803 (ASTM A182-F51)

3. Reference Standards for Open Die Forgings

ASTM (American Standards):

ASTM A668: Specifies requirements for carbon and alloy steel forgings for general industrial use.

STM A182: Covers forged or rolled alloy and stainless steel piping components

ASTM A694: Standard for high-yield-strength carbon steel forgings for pipeline fittings

European Standards (EN/DIN):

EN 10222: For steel forgings under pressure (e.g., P280GH, P355NH)

DIN 17100: General structural steel grades (e.g., St52-3)

EN 10083: Quenched and tempered steels (e.g., 34CrMo4)

Industry-Specific Standards:

API 6A: For oil and gas valve components

ASME Boiler and Pressure Vessel Code: Governs forgings for power generation systems

4. Key Applications & Material Selection

Open die forgings are critical in industries requiring high strength and reliability:

Energy: Wind turbine shafts (34CrMo4), nuclear reactor vessels (AISI 4130)

Aerospace: Turbine discs (Inconel 718), landing gear (AISI 4340)

Heavy Machinery: Mining equipment shafts (30CrNiMo8), rolling mill rolls (42CrMo4)