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

fazovaya-diagramma-alyuminiy-olovo
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) и 852.0 (6,3Sn-2Cu-1,2Ni-0,8Mg)обычно льют только в постоянные формы. 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

Формула сплава:

6,2Sn-1Cu-1Ni

Химический состав:

  • copper: 0,7-1,3 %;
  • magnesium: 0,10 макс.;
  • кремний: 0,7 % макс.;
  • iron: 0,7 % Max.
  • lead: 5,5-7,0 %;
  • nickel: 0,7-1,3 %;
  • titanium: 0,20 % макс.;
  • другие: 0,30 % макс.;
  • алюминий: остальное.

Влияние содержания примесей:

  • high iron content, марганца или магния снижает пластичность и повышает твердость;
  • high silicon improves slip characteristics.

Типичные механические свойства в состоянии Т5:

  • прочность на растяжение: 160 MPa;
  • предел текучести: 75 MPa;
  • относительное удлинение: 10 %;
  • твердость: 45 NV;
  • коэффициент Пуассона: 0,33;
  • модуль упругости: 71,0 GPa.

Физические свойства:

  • плотность: 2,880 g / cm3;
  • температура ликвидус: 650 ºS;
  • температура солидус: 225 oC.

Технологические свойства:

  • температура плавления: от 650 by 730 ºS;
  • температура разливки: от 650 by 705 ºS;
  • температура старения: 230 oC, excerpt - 8 hours.

Источник: Aluminum and Aluminum Alloys, ASM International, 1996