7175 improves the purity of 7075 alloy. It is mainly used as die forgings. It has three heat treatment states: T66, T74 and T7452. Among them, the static strength of T66 forging is higher than that of 7075 T6 forging, while fatigue, crack resistance and stress corrosion resistance are equivalent. The static strength of T74 die forging and free forging is similar to that of 7075 T6 forging, and the stress corrosion resistance balance is between 7075 T73 and 7075 T76, while the toughness and fatigue properties are comparable to or even better than 7075 T73 forging. The stress corrosion resistance of T74 state is obviously higher than that of 7075 T6 state, approaching 7075 T73 state.
 
7175 alloy is specially used to produce forgings and rolling rings. The material state is T74. The characteristics of 7175 T74 aluminium alloy forgings are that special processing and heat treatment processes are adopted to make the strength close to 7075 T6 alloy forgings and the stress corrosion resistance close to 7075 T73 forgings in the best corrosion state. The reduction of Fe and Si rolling can not only improve the forging properties of the alloy, but also significantly improve the stress corrosion resistance and fracture toughness of the forgings.



 

7175 7075 Aluminum Alloy Chemical Composition

Alloy

Si

Fe

Cu

Mn

Mg

Cr

Ni

Zn

Ti

Zr

Others

Al

Single

Total

7175

0.15

0.20

1.2~2.0

0.1

2.1~2.9

0.18~0.28

~

5.1~6.1

0.10

~

0.05

0.15

Rest

7075

0.40

0.50

1.2~2.0

0.3

2.1~2.9

0.18~0.28

~

5.1~6.1

0.20

~

0.05

0.15

Rest

 
  

Technical Indicators for 7075 T74 Aluminum Alloy Forging
Direction	Rm/MPa	Rp0.2/MPa	A5/%	KIC/(N.mm-2).m1/2	Conductivity/（MS.m-1）
portrait	490	420	9	33.0	22.6
Long transverse	483	400	5	27.5
Section transverse	469	393	4	23.1

 

Calibrated Mechanical Properties of 7175 T74 Alloy Rolled Forged Ring (YS/T 478)
Direction	Thickness/mm	Tension Strength Rm/MPa	Yield strength Rp0.2/MPa	Elongation A5/%
L	<80	≥505	≥435	≥8

 
 

Alloy	Temper	Aircraft model	Application parts and typical parts
7175	T74	A320、Z10、EC120 etc。	Front edge, window frame, fairing joint, control parts, etc.

 

Type	Alloy	Projected area（m2）Or weight（kg）	Temper	Standard
Aluminum free forging	5 series	≤3000kg	O、F 、T74	GBn223     ASTMB247
	2、6、7 series	≤3000kg	T6、T4、O、F
Aluminum die forging	5 series	≤2.5m2	O、F
	2、6、7series	≤2.5m2	T6、T4、O、F、T74