Casting alloys of aluminum-tin

These aluminum alloys, doped tin, specially developed for bearings. Quality bearings main criteria are the load-bearing capacity, fatigue and corrosion resistance in lubrication conditions in internal combustion engines. Aluminum Alloy Bearings, tin alloyed, unsurpassed among other types of bearing materials.

Aluminum tin phase diagram

Aluminum tin phase diagram

Aluminum-tin alloys contain about tin 6 %, as well as small amounts of copper and nickel to increase strength. They are used for cast bearings.. It is tin that provides very good glide in these alloys..

American aluminum-tin alloys

American Tin Aluminum Alloys 850.0, 850.1 and 852.0 can be cast as in sand, so in the chill mold. However alloys 850.0 (6,3Sn-1Cu-1Ni) and 852.0 (6,3Sn-2Cu-1,2Ni-0,8Mg) is usually poured only into permanent forms. Sand casting is used for large rolling mill bearings, which are usually made of alloy 851.0 (6,3Sn-2,5Si-1Cu-0,5Ni).

Bearing structure

The “bearing” properties of aluminum-tin alloys are highly dependent on the casting method. Finely dispersed tin distribution is essential for optimum bearing properties.. This requires a small interdendritic distance., and such a distance can only be obtained with fast cooling casting methods.

Long cure interval

In terms of the casting process, the aluminum-tin alloy system is unique. The solidification of the alloy in the mold begins at a temperature of about 650 oC, and the tin remains liquid somewhere up to the temperature 225 oC. Such a too large temperature hardening range presents difficulties for casting. High solidification rates of castings are recommended to avoid excessive macrosegregation..

A casting aluminum alloy 850.0

Alloy formula:


Chemical composition:

  • copper: 0,7-1,3 %;
  • magnesium: 0,10 Max.;
  • silicon: 0,7 % Max.;
  • iron: 0,7 % Max.
  • lead: 5,5-7,0 %;
  • nickel: 0,7-1,3 %;
  • titanium: 0,20 % Max.;
  • others: 0,30 % Max.;
  • aluminum: rest.

Influence of impurity content:

  • high iron content, manganese or magnesium reduces plasticity and increases hardness;
  • high silicon improves slip characteristics.

Typical mechanical properties in T5 condition:

  • tensile strength: 160 MPa;
  • yield point: 75 MPa;
  • relative extension: 10 %;
  • hardness: 45 NV;
  • Poisson's ratio: 0,33;
  • elastic modulus: 71,0 GPa.

Physical properties:

  • density: 2,880 g / cm3;
  • liquidus temperature: 650 ºS;
  • solidus temperature: 225 oC.

Technological properties:

  • melting point: from 650 to 730 ºS;
  • temperature spills: from 650 to 705 ºS;
  • aging temperature: 230 oC, excerpt - 8 hours.


Aluminum and Aluminum Alloys, ASM International, 1996

Aluminum Alloy Castings: Properties, Processes And Applications – J. Gilbert Kaufman, Elwin L. Rooy