What is Austempered Ductile Iron (ADI) Casting?

Apr. 20, 2022

What is Austempered Ductile Iron (ADI)?

Austempered ductile iron castings, or more commonly ADI castings, is a ductile iron casting which is processed by a special heat treatment. The austempering process, with ductile iron’s superior castability, results in a material which can be used to cast complex shapes, with a greater consistency of quality, and often at less cost.  The heat treatment requires an interrupted quench, usually into a salt bath, to cool the cast part at a planned rate and long enough to achieve the desired austempered result. The resulting material has a combination of exceptional strength and toughness, meeting and often exceeding those of alloy steels.

What is Austempered Ductile Iron (ADI) Casting?

What are some Benefits of Austempered Ductile Iron Castings?

· Up to 40% less cost than hardened steel forgings.

· Lower operating noise levels.

· 10% less weight than steel.

· Better wear than case hardened steel.

· Excellent resistance to crack propagation.

· Good impact strength to -120ºF.

· Work hardening.

What Can Austempered Ductile Iron Castings (ADI) be Used for? – Application Data

· Austempered ductile iron (ADI) is often used where high strength is needed and where excellent wear resistance and fatigue strength are required. Applications like for gears ADI has been used with great success. This tough work-hardening material has proved to be an excellent replacement for hardened steels. The use of austempered ductile iron can result in less weight, reduced number of components, and quieter running. Due to the lower modulus of ADI better face to face contact can be achieved which reduces Hertzien or contact stress on the teeth surfaces. Also austempered ductile iron will work harden which adds to the contact fatigue strength. As a result, gear face widths and diameters can be reduced which will make the gear run better axially and reduces weight, and at the same time provide better protection under overload conditions. The superior tribological properties of ADI have resulted in the elimination of bronze bearing bushings, and will allow the gears to run temporarily without lubrication. Due to the type of matrix structure, the softer grades of ADI can be shot-peened to double the root fatigue strength.

· Another common application of austempered ductile iron castings has been crankshafts and axles. The majority of sealed-for-life refrigeration units are made with austempered crankshafts. Axle applications benefit from the materials lack of notch sensitivity, good fatigue strength, and reasonable machinability.

· The railroad industry has an immense application both in retarders and rolling stock. Austempered ductile iron is very popular for retarder brake shoes, where its superior quietness and wear resistance is well received in urban semi residential communities. ADI brake beams have also been shown to outlast steel beams, and withstand the cold weather, at more than 20% less cost.

· For low speed rolling stock austempered ductile iron wheels have been very successful in Europe. It has been shown that ADI railroad wheels can take larger loads than quenched and tempered steel wheels of the same hardness. ADI will also wear better when sliding between the rail and wheel exceeds more than 10%. One caveat to ADI is that it should not be used in applications where the temperature exceeds 300ºC. (570ºF) for consistently long periods. Thus high speed train wheels are not an appropriate application, nor are wheels which are braked by peripheral blocks. will allow the gears to run temporarily without lubrication. Due to the type of matrix structure, the softer grades of ADI can be shot-peened to double the root fatigue strength.

For many years, Zen Young Foundry has been providing customized metal casting services for various industries and project types.

Six Industries Where We Can Provide Customized Services:

Pump & Valve Parts

Compressor Parts

Train & Railway Parts

Cylinder & Gear Box

Mining & Engineering Machinery Casting Parts

Auto & Aerospace Parts

If you are looking for a solution that fits your custom metal Sand casting project, Zen Young can help you produce perfect metal parts through a reliable casting process.

We always welcome special material and difficult parts and would like to help our comstomers utmost.

The Types of Casting Processes:

Sand casting

The material used to make molds for sand casting is sand, not ceramics. Due to the roughness of sand, sand casting is most commonly used for large castings, which usually require less detail precision and tolerances.

Shell mold casting

Shell mold casting is a metal casting process similar to sand casting, in that molten metal is poured into an expendable mold. However, in shell mold casting, the mold is a thin-walled shell created from applying a sand-resin mixture around a pattern. The pattern, a metal piece in the shape of the desired part, is reused to form multiple shell molds. A reusable pattern allows for higher production rates, while the disposable molds enable complex geometries to be cast. Shell mold casting requires the use of a metal pattern, oven, sand-resin mixture, dump box, and molten metal.

Investment casting

Investment casting is one of the traditional casting methods. That is, the metal is heated to the temperature of the molten liquid, and then the material is poured into a mold designed with a suitable negative space and gated to effectively completely fill the molten metal. Once the metal has cooled and solidified, the metal part can be removed from the mold for finishing. Investment casting, also known as lost wax casting, is usually used to make jewelry and metal parts with complex shapes. 

Die casting 

Die casting is a kind of metal casting process, which is characterized by forcing molten metal under high pressure into the forming cavity. The cavity is made using two hardened tool steel molds, which have been processed into a certain shape, and die casting works similarly to injection molds.

Lost foam casting

Lost foam casting is a type of evaporative pattern casting. it maintains outstanding advantages, especially in casting complicated and precise molds.Unlike traditional methods which include the pattern withdrawn process before casting and require skillfulness in the pattern removal step, with respect to the lost foam method, the pattern is evaporated when the molten metal is poured into helping to reduce these considerations.

We will choose different casting methods for processing according to the product shape, material and your working conditions. Many years of processing experience can guarantee the quality of the casting parts.