You are working for an automobile manufacturer making automa

You are working for an automobile manufacturer making automatic transmission housings using permanent mold casting. The alloy that you are using is A356 Aluminum, a standard casting alloy. Your boss tells you that they normally specify a T6 temper for the alloy because the material operates at slightly elevated temperatures. Since you are new to the company, he wants you to do the following: Determine the composition limits for this material. Determine the expected properties (sigma_ult, sigma_y and percent elongation for A356-T6 material. Specify the appropriate casting temperature for the material and give the reasoning behind your choice. Specify the appropriate heat treatment for the transmission housings to give the above properties. Give the references for any information that you use from other sources.

Solution

ANWER:-

Cast aluminium alloys yield cost-effective products due to the low melting point, although they generally halower tensile strengths than wrought alloys. The most important cast aluminium alloy system is Al–Si, where the high levels of silicon (4.0–13%) contribute to give good casting characteristics. Aluminium alloys are widely used in engineering structures and components where light weight or corrosion resistance is required.

Temper designatioN----

The temper designation follows the cast or wrought designation number with a dash, a letter, and potentially a one to three digit number, e.g. 6061-T6

-T6

Solution heat treated and artificially aged

Cast alloys

The Aluminum Association (AA) has adopted a nomenclature similar to that of wrought alloys.  the second two digits reveal the minimum percentage of aluminium, e.g. 150.x correspond to a minimum of 99.50% aluminium. The digit after the decimal point takes a value of 0 or 1, denoting casting and ingot respectively.^[1] The main alloying elements in the AA system are as follows:

Aluminum alloy A356.0 and 356.0 are a 7% Si, 0.3% Mg alloy with 0.2 Fe (max) and 0.10 Zn (max). The alloys have very good casting and machining characteristics. Typically they are used in the heat-treated condition of T5 and T6 hardness properties.

Corrosion resistance is excellent and it has very good weldability characteristics. Mechanical properties are rated excellent particularly if given a solution and aging treatment (T5, T6). The anodized appearance is gray in color.

Typical Mechanical Properties:-

ALLOY - 356.0

TEMPER - T6

ULTIMATE TENSILE (KSI) - 33

YIELD STRENGTH (KSI) -23

HARDNESS(KG) -70

SHEARING STRENGTH - 26

CHEMICAL COMPOSITION (%):-

ALLOY - 356.0

SI -7

MG-0.3

TYPICAL APPLICATIONS :-

ALLOY - 356.0

APPLICATION - Flywheel castings, automotive transmission cases, oil pans, pump bodies

Alloy type	Temper	Tensile strength (min) in ksi (MPa)	Yield strength (min) in ksi (MPa)	Elongation in 2 in %
ANSI	UNS