MIL 12560 Class 4a (420-460HB)
Bozhong Metal Group always focuses on Medium Hard Armor- Mars 220 quality who devotes itself to improve its study , develop and manufacturing
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  • Description
  • Parameter
Bozhong 220: Medium hardness steel (440 HB) for blast protection

Bozhong  220 armour steel is dedicated to modern vehicles structures for protection against mines.

Bozhong  220 grade has the aimed mechanical properties hardness, thoughness, ductility for protection against mines explosions, while keeping an excellent workablilty, particulary bending and welding for realization of specific complex designs defined for blast protection.

Standard
Bozhong  220
Bozhong  220 satisfies requirements of following specifications:
• France : NF A 36-800 THD1
• Germany : TL 2350 Quality O
• U.K. : DEF STAN 95-24 Class 3A (420-480HB)
• USA : MIL 12560 Class 4a (420-460HB)

Chemical Analysis
C S P Si Mn Ni Cr Mo B
4 to 50 mm (.16″ to 2″) ≤ .22 ≤ .005 ≤ .015 ≤ .5 ≤ 1.5 ≤ 2.0 ≤ 1 ≤ .6 ≤ 0.005
>50 to 80 mm (2″ to 3.15″) ≤ .24 ≤ .005 ≤ .015 ≤ .5 ≤ 1.5 ≤ 5 ≤ 1 ≤ .6 ≤ 0.005

Mechanical Properties
As supplied Hardness Yield Strength UTS Elongation Charpy V
-40°Transversal to rolling direction
HB MPa ksi MPa ksi 5d(%) J ft.lbs
4 to 50 mm
(.16″ to 2″)
Required by spécifications 400 – 480 ≥1100 ≥ 160 ≥ 1250 ≥ 182 ≥ 10 ≥ 27 ≥ 20
Typical values 440 1150 165 1450 210 13 48 35
>50 to 80 mm
(2″ to 3.15″)
Minimal Values ≥400 ≥800 ≥115 ≥1300 ≥188 ≥9 ≥20 ≥15
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