Alloy МЛ6

Designation

Name	The value
Designation GOST Cyrillic	МЛ6
Designation GOST Latin	ML6
Transliteration	ML6
By chemical elements	CuЛ6

Description

Alloy МЛ6 used: for the manufacture of castings in sand casting and gravity die casting of high — and sredneshirotnykh parts requiring higher yield strength with maximum operating temperature of +150 °C.

Note

Alloy system Mg-Al-Zn.
Most doped alloy of this group МЛ6 has the best casting properties, little is prone to hot cracks.
Compared with the alloy ML5 less plastic, but has the best elastic properties.
Aluminum and zinc increase the mechanical properties of the alloy (and the effect of aluminum effect is stronger than zinc) and manganese improves corrosion resistance. To reduce oxidation, the alloy is injected beryllium (0.002% when casting in sand molds and the mold and to 0.01% when casting under pressure).
The alloy can strengthen its positions heat treatment — quenching and aging.
The alloy has a broader crystallization range than alloys based on aluminum, therefore has a low castability. Due to the large interval of crystallization of the alloy is prone to hot cracks.

Standards

Name	Code	Standards
Non-ferrous metals, including rare, and their alloys	В51	GOST 2856-79
Thermal and thermochemical treatment of metals	В04	OST 1 90121-90

Chemical composition

Standard	Mn	Si	Ni	Fe	Cu	Al	Zn	Zr	Mg	Be
GOST 2856-79	0.1-0.5	≤0.25	≤0.01	≤0.06	≤0.1	9-10.2	0.6-1.2	≤0.002	Rest	≤0.002

Mg is the basis.
According to GOST 2856-79, the content of other impurities is ≤ 0.10%, the sum of the impurities to be determined is 0.50%.

Mechanical properties

Section, mm	s_T\|s_0,2, MPa	σ_U, MPa	d₅, %
Casting sand casting and gravity die casting without heat treatment according to GOST 2856-79
	-	≥150	≥1
Casting sand casting and gravity die casting according to GOST 2856-79. Mode T4: Homogenization + annealing in air
	≥110	≥225	≥4
Casting sand casting and gravity die casting according to GOST 2856-79. Mode Kzt61: Homogenization + annealing in water + aging
	≥140	≥230	≥1
Casting sand casting and gravity die casting according to GOST 2856-79. T6 mode: Homogenization + annealing at air + aging
	≥140	≥225	≥1

Description mechanical marks

Name	Description
s_T\|s_0,2	Yield strength or limit of proportionality with a tolerance for residual deformation of 0.2%
σ_U	Limit short-term strength
d₅	Elongation after rupture

Physical characteristics

Temperature	Е, HPa	r, kg/m³	l, W/(m · °C)	С, J/(kg · °C)
20	43	1810	789	10467

A description of the physical symbols

Name	Description
Е	The normal elasticity modulus
r	Density
l	Coefficient of thermal conductivity
R	UD. the resistivity

Technological properties

Name	The value
Features of heat treatment	According to OST 1 90121-90 for a significant increase in mechanical properties of the alloy (σв, δ, an) casting in the ground and gravity die casting, heat treatment is performed on taimu T4 Heat to 360±5 °C (2-4 h exposure), heating up to 410±5 °C (extract 20-28 hours), quenching in air. Due to the low rate of diffusion processes as the cooling medium is usually a calm air. To improve the mechanical properties of the cooled castings may be conducted by blowing of air. To improve the mechanical properties (σв, σ0,2) is also applied to heat treatment by mode T6 - Annealing in air, 410±5 °C (Step of heating to 360±5 °C (2-4 h exposure), heating up to 410±5 °C (extract 20-28 CH)) + Aging at 190±5 °C (delay of 4-8 h), air cooling. In this case the plastic properties decrease. A noticeable increase in the values of σв, σ0,2 is achieved in the hardening of the casting by blowing air. To maximize the mechanical properties of the alloy (σв, σ0,2) mode is applied Kzt61 - Quenching in warm water (80-90 °C) 410±5 °C (Step of heating to 360±5 °C (2-4 h exposure), heating up to 410±5 °C (extract 20-28 CH)) + Aging at 190±5 °C (delay of 4-8 h), air cooling.