Austempered Ductile Iron (ADI) is a ductile iron which is processed by heat treatment of austempering. ADI have very high mechanical property and hardness, but it’s cheaper much than hardened steel www.castingquality.com
Reference Casting Standards: www.castingquality.com
ASTM A897/897M: Standard Specification for Austempered Ductile Iron Castings
ADI castings can be produced in Casting Quality Industrial:
- Sand Casting
- Shell Casting
- Lost Form Casting
gear 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.
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Mould design and production will be served for metal casting ad plastic injection industry. Based on our more than 10 years experience, we supply professional molds for our customers in Europe and North American.
Austempered Ductile iron standard grades in ASTM A897
| Casting Grade Inch-pound units | Tensile Strength, min | Yield Strength, min | Elongation, min | Impact energy | Typical Hardness |
| Ksi | Ksi | % | Ft-lb | HWB | |
| A897 Gr. 110/70/11 | 110 | 70 | 11 | 80 | 241-302 |
| A897 Gr. 130/90/09 | 130 | 90 | 9 | 75 | 269-341 |
| A897 Gr. 150/110/07 | 150 | 110 | 7 | 60 | 302-375 |
| A897 Gr. 175/125/04 | 175 | 125 | 4 | 45 | 341-444 |
| A897 Gr. 200/155/02 | 200 | 155 | 2 | 25 | 388-477 |
| A897 Gr. 230/185/01 | 230 | 185 | 1 | 15 | 402-512 |
| Casting Grade SI units | Tensile Strength, min | Yield Strength, min | Elongation in 50mm, min | Impact energy | Typical Hardness |
| MPa | MPa | % | J | HWB | |
| A897 Gr. 750/500/11 | 750 | 500 | 11 | 110 | 241-302 |
| A897 Gr. 900/650/09 | 900 | 650 | 9 | 100 | 269-341 |
| A897 Gr. 1050/750/07 | 1050 | 750 | 7 | 80 | 302-375 |
| A897 Gr. 1200/850/04 | 1200 | 850 | 4 | 60 | 341-444 |
| A897 Gr. 1400/1100/02 | 1400 | 1100 | 2 | 35 | 388-477 |
| A897 Gr. 1600/1300/01 | 1600 | 1300 | 1 | 20 | 402-512 |
ASMT A897 Ductile Iron Heat treatment requirement: www.castingquality.com
all castings should be heat treated by an austempering process consisting of heating the castings to a fully austenitic, homogeneous condition or an austenite/ferrite condition for Grade 110/70/11 [750/500/11], cooling (at a rate usually sufficient to avoid the formation of pearlite) to a temperature above the martensite start temperature, and isothermally transforming the matrix structure for a time sufficient to produce the desired properties. This process shall produce a microstructure that is substantially ausferrite or ausferrite/proeutectoid ferrite for Grade 110/70/11[750/500/11].
Microstructure requirement in ASTM A897: www.castingquality.com
- The graphite component of the microstructure shall consist of a minimum 80% spheroidal graphite conforming to type I and II per ASTM A247
- The matrix microstructure shall ssubstantially consist of ausferrite (acicular ferrite and high carbon, stable austenite). Proeutectoid ferrite will also be present in grade 110/70/11 (750/500/11)
- Martensite may be present in minor amounts in the microstructure of Grade 200/155/02 (140/1100/02) and 230/185/01 (1600/1300/01). Acceptable quantities of martensite maybe agreed again.
- The microsturcture shall be substantially free of underirable microconstituents.
Chemical Composition in ASTM A897: www.castingquality.com
Chemical requirements may be agreed upon between manufacture, heat treater, and the purchaser. But to achieve the required mechanical property in castings or test coupons, the standard also has some suggestion as below:
- Carbon Equivalent (CE) can be approximated by the relationship: CE=%C+1/3(%Si)
| Suggested Carbon Equivalent Ranges for various Section Sizes | |
| Section Size | CE Range |
| 0 to 1/2 in. (0 to 13 mm) | 4.4 – 4.6 |
| 1/2 to 2 in. (13 to 51 mm) | 4.3-4.6 |
| Over 2 in. (51mm) | 4.3-4.5 |
- Allying elements such as Molybdenum, Copper, Nickel and additional Manganese above the base metal level should be added only when additional hardenability is required for heavy section:
| Suggested Targets and Control Ranges for Intentionally Added Elements | |
| Element | Recommended Range |
| Carbon (C) | 3.60% ± 0.20% |
| Silicon (Si) | 2.50% ± 0.20% |
| Magnesium (Mg) | (%S X 0.76) + 0.025% ± 0.005% |
| Copper (Cu) | 0.80% max, only as needed ± 0.05% |
| Nickel (Ni) | 2.0% max, only as needed ± 0.10% |
| Molybdenum (Mo) | 0.20% max, only as needed ± 0.03% |
| Suggested Targets and Control Ranges for Trace or Tramp Elements | ||
| Trace or Tramp elements | Suggested Target (or maximum) | Typical Contral Range |
| Tin (Sn) | 0.02%, max | ± 0.003% |
| Antimony (Sb) | 0.002%, max | ±0.0003% |
| Phosphorus (P) | 0.04%, max | – |
| Sulfur (S) | 0.02%, max | – |
| Oxygen (O) | 50 ppm, max | – |
| Chromium (Cr) | 0.10%, max | – |
| Titanium (Ti) | 0.04%, max | – |
| Vanadium (V) | 0.10%, max | – |
| Aluminum (Al) | 0.05%, max | – |
| Arsenic (As) | 0.02%, max | – |
| Bismuth (Bi) | 0.002% max | – |
| Boron (B) | 0.0004%, max | – |
| Cadmium (Cd) | 0.005%, max | – |
| Lead (Pb) | 0.002%, max | – |
| Selenium (Se) | 0.030%, max | – |
| Tellurium (Te) | 0.003%, max | – |
Austempered Ductile Iron Castings Application: www.castingquality.com
ADI have high strength and excellent wear resistance property. It’s popular used in
Gear, crankshafts, axles, guide rollers, railway brake shoes, abrasive liners, bearing/bushing sleeves, camshafts, chain sprockets, pulleys, pump impellers, shredder knives and etc.
