Alloy Ak7ch (АЛ9)

Designation

Name	The value
Designation GOST Cyrillic	АК7ч
Designation GOST Latin	AK7ch
Transliteration	AK7ch
By chemical elements	-

Name	The value
Designation GOST Cyrillic	АЛ9
Designation GOST Latin	AL9
Transliteration	AL9
By chemical elements	-

Description

Alloy Ak7ch used: for the manufacture of various ingots and shaped castings by various casting methods (sand casting, investment casting, gravity die casting, pressure); casting of parts of metallurgical engineering (parts of devices, housings of pumps, carburetors, operating at temperatures above +200 °C; sredneshirotnykh thin-walled and welded parts; casting parts of valves and actuators; castings of high-and medium-load and high integrity in all ways, except for the molding.

Note

Aluminum foundry alloy of the system Al-Si-Mg. The alloy has high integrity. Alloy is a substitute of alloys AL2 and AL7.
Advantages: Good corrosion resistance, mechanical properties and casting technology properties. Satisfactory machinability.
Disadvantages: the mechanical strength is inferior to alloy grade АЛ4.
Heat-treatable alloy with good strength properties. For corrosion resistance and technological characteristics of the alloy close to alloy grade AK12.

Standards

Name	Code	Standards
Non-ferrous metals, including rare, and their alloys	В51	GOST 1583-93, OST 4.021.009-92, OST 4.021.010-92, STP М287-78
Castings, non-ferrous metals and alloys	В84	OST 26-07-1114-74, OST 1 80029-83, OST 24.916.01-71, OST 5.9397-90

Chemical composition

Standard	Mn	Si	Fe	Cu	Al	Ti	Zn	Sn	Pb	Mg	Be
GOST 1583-93	≤0.5	6-8	≤0.6	≤0.2	Rest	-	≤0.3	≤0.01	≤0.05	0.2-0.4	≤0.1
OST 24.916.01-71	≤0.5	6-8	≤0.6	≤0.2	Rest	≤0.15	≤0.3	≤0.01	≤0.05	0.2-0.4	≤0.1

Al is the base.
According to GOST 1583-93, the total content of titanium and zirconium should be ≤ 015%; The iron content is indicated for sand casting and for investment models. The content of iron during casting in the mold is ≤ 1.00%, when casting under pressure ≤ 1.50%. The amount of allowable impurities should be for casting in sand molds and for investment models ≤ 1.10%, casting in chill molds ≤ 1.50%, injection molding ≤ 2.00%.
According to OST 24.916.01-71, the iron content is specified for casting in sand molds and for investment models. The content of iron during casting in the mold is ≤ 1.00%, when casting under pressure ≤ 1.50%. The amount of allowable impurities should be for sand casting and for investment models ≤ 1.60%, die casting ≤ 1.20%, die casting ≤ 2.10%.
By STP M287-78, the total content of titanium and zirconium should not be more than 0.15%. The amount of allowable impurities should be for casting in sand molds ≤ 1.10%, casting in chill mold ≤ 1.50%. The iron content is indicated for sand casting. The content of iron during casting in chill molds is ≤ 1.00%

Mechanical properties

σ_U, MPa	d	HB, MPa
Casting (sand casting, investment casting, gravity die casting). Without heat treatment
≥157	≥2	≥50
Casting (sand casting, investment casting, gravity die casting, pressure). Mode T2: Annealing at 290-310 °C (2-4 h exposure)
≥137	≥2	≥45
Casting, including alloy, modified (m). Mode T4: Quenching in water from 530-540 °C (2-6 h exposure)
≥176	≥4	≥50
≥186	≥4	≥50
Casting, including alloy, modified (m). Mode T5: Quenching in water from 530-540 °C (extract 2-6 h) + Artificial aging at 145-155 °C (delay of 1-3 h) or two-stage heating: 180-200 °C (exposure 0.5 h) + 145-155 (exposure 2 hours)
≥196	≥2	≥60
≥206	≥2	≥60
Casting, including alloy, modified (m). T6 mode: Quenching in water from 530-540 °C (extract 2-6 h) + Complete artificial aging at 195-205 °C (extract 2-5 PM)
≥225	≥1	≥70
≥235	≥1	≥70
Casting, including alloy, modified (m). Mode T7: Quenching in water from 530-540 °C (extract 2-6 h) + stabilizing vacation at 215-235 °C (aging for 3-5 hours)
≥196	≥2	≥60
Casting, including alloy, modified (m). Mode T8: Quenching in water from 530-540 °C (extract 2-6 h) + soothing vacation at 240-260 °C (aging for 3-5 hours)
≥157	≥3	≥55

Description mechanical marks

Name	Description
σ_U	Limit short-term strength
d	Elongation after rupture
HB	Brinell hardness number

Physical characteristics

Temperature	Е, HPa	r, kg/m³	R, Mr. · m
20	70	2660	457

A description of the physical symbols

Name	Description
l	Coefficient of thermal conductivity
С	Specific heat

Technological properties

Name	The value
Weldability	Alloy welded satisfactorily.
Corrosion resistance	To improve the corrosion resistance of the casting is subjected to anodic oxidation.
Machinability	The alloy is well processed by cutting and grinding.