Austenitic Ductile Iron, also known as austenitic nodular iron or austenitic spheroidal iron, is characterized by having its graphite substantially in a spheroidal form and substantially free of flake graphite. It contains some carbides and sufficient alloy content to produce an austenitic structure. ww.castingquality.com
Reference Casting Standards:
ASTM A439: Standard Specification for Austenitic Ductile Iron Castings
Austenitic Ductile Iron castings can be produced in Casting Quality Industrial:
- Sand Casting
- Shell Casting
- Lost Form Casting
- Precision Lost Wax Investment Casting
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- Sand Casting
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Sand Casting is a popular metal form method, are suitable for all materiel, such as grey iron, ductile iron, malleable iron, carbon steel, stainless steel, aluminum and bronze.
- Investment Casting
also named as precision lost wax casting, mainly suitalbe for carbon steel and stainless steel parts. We also provide grey iron and ductile iron and aluminum and bronze parts by investment casting. It can achieve the best appearance with good tolerance
- Shell Casting
Shell casting method is a good option to replace investment casting and sand casting. the quality is better than sand casting parts, suitable for bulk production.
- CNC Machining
CNC Milling, CNC turning with 5 xix CNC center, we provide precision machining for all castings based on customers design drawings.
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ASTM A439 Austenitic Ductile Iron Chemical Requirements:
| ASTM A439 | C max | Si | Mn | P ≤ | Ni | Cr | Others |
| A439 Type D-2 | 3.00 | 1.50-3.00 | 0.70-1.25 | 0.08 | 18.00-22.00 | 1.75-2.75 | |
| A439 Type D-2B | 3.00 | 1.50-3.00 | 0.70-1.25 | 0.08 | 18.00-22.00 | 2.75-4.00 | |
| A439 Type D-2C | 2.90 | 1.00-3.00 | 1.80-2.40 | 0.08 | 21.00-24.00 | 0.50 max | |
| A439 Type D-3 | 2.60 | 1.00-2.80 | 1.00 max | 0.08 | 28.00-32.00 | 2.50-3.50 | (Mo: 0.7- 1.0) |
| A439 Type D-3A | 2.60 | 1.00-2.80 | 1.00 max | 0.08 | 28.00-32.00 | 1.00-1.50 | |
| A439 Type D-4 | 2.60 | 5.00-6.00 | 1.00 max | 0.08 | 28.00-32.00 | 4.50-5.50 | |
| A439 Type D-5 | 2.40 | 1.00-2.80 | 1.00 max | 0.08 | 34.00-36.00 | 0.10 max | |
| A439 Type D-5B | 2.40 | 1.00-2.80 | 1.00 max | 0.08 | 34.00-36.00 | 2.00-3.00 | |
| A439 Type D-5S | 2.30 | 4.90-5.50 | 1.00 max | 0.08 | 24.00-37.00 | 1.75-2.25 |
ASTM A439 Austenitic Ductile Iron Heat treatment requirement: www.castingquality.com
Generally, the austenitic ductile iron castings may be stress relieved by heating to 1150 to 1200°F (621 to 650°C) for not less than 1 h nor more than 2 h per inch of thickness in the thickest section. Heating and cooling shall be uniform and shall not be more than 400°F (222°C)/h for castings less than 1 in. (25.4 mm) in maximum thickness, nor more than 400°F (222°C) divided by the maximum section thickness in inches for thicker castings. During the cooling cycle, castings may be cooled in still air after the temperature has dropped to 600°F (315°C).
Whenever dimensional changes in high-temperature service are a problem, by agreement between the manufacturer and the purchaser, the castings may be stabilized by heating at 1600°F (870°C) for 1 h per inch of section, with a minimum of 1 h. Otherwise, the austenite which is super-saturated with respect to carbon may reject carbon during service and produce dimensional changes.
If necessary, the castings with chilled edges or excessive carbides may be annealed at 1750 to 1900°F (955 to 1040°C) for 1⁄2 to 5 h followed by uniform cooling, preferably in still air.
ASTM A439 Austenitic Ductile Iron Mechanical Requirements: www.castingquality.com
| Casting Grade | Tensile Strength, min | Yield Strength, min | Elongation in 2in or 50mm, %, min | Brinell Hardness (3000kg) | ||
| ksi, | Mpa | psi | Mpa | |||
| A439 Type D-2 | 58 | 400 | 30 | 207 | 8.0 | 139-202 |
| A439 Type D-2B | 58 | 400 | 30 | 207 | 7.0 | 148-211 |
| A439 Type D-2C | 58 | 400 | 28 | 193 | 20.0 | 121-171 |
| A439 Type D-3 | 55 | 379 | 30 | 207 | 6.0 | 139-202 |
| A439 Type D-3A | 55 | 379 | 30 | 207 | 10.0 | 131-193 |
| A439 Type D-4 | 60 | 414 | – | – | – | 202-273 |
| A439 Type D-5 | 55 | 379 | 30 | 207 | 20.0 | 131-185 |
| A439 Type D-5B | 55 | 379 | 30 | 207 | 6.0 | 139-193 |
| A439 Type D-5S | 65 | 449 | 30 | 207 | 10 | 131-193 |
ASTM A439 Austenitic Ductile Iron Typical mechanical property in high temperature (for reference only): www.castingquality.com
| ASTM A439 | Short-term property | Durability | ||||
| Temperature | Tensile | Elongation | Temperature | Time | Tensile | |
| D-2 | 500°C | 250Mpa | 2.0% | 500°C | 1000h | 120Mpa |
ASTM A439 Austenitic Ductile Iron Typical Casting Application
Turbo housing, exhaust manifold, Machinery, Iron Valve, truck, railway, gearbox etc.
