Materials Database

AR500 Steel

Type	Carbon Steel
Modulus of Elasticity	30 x 10^6 psi
Poisson's Ratio	0.29
Density	0.29 lb/in^3
Ultimate Tensile Strength	225 ksi
Tensile Yield Strength	200 ksi
Brinell Hardness	450 HB
Rockwell Hardness	C48
Elongation at Break	12%
Familiar Sellers	McMaster Carr, MakeItRingTargets, Alro Steel, SendCutSend

Material Description:

• High strength, ultra wear resistant steel used in body armor and shooting targets
• Hardened steel is difficult to machine, is typically only used for Waterjet parts
• Typically used for weapons due to it's high strength, toughness, and relatively high hardness
• Anecdotal experience from builders says that AR500 typically bends before it fractures
• Will rust over time when wet or exposed to moist air

Aluminum 6061-T6

Type	Aluminum Alloy
Modulus of Elasticity	10^7 psi
Shear Modulus	3800 ksi
Poisson's Ratio	0.33
Density	0.0984 lb/in^3
Ultimate Tensile Strength	45 ksi
Tensile Yield Strength	39 ksi
Fracture Toughness (T-L dir)	26.4 ksi-in½
Brinell Hardness	93 HB
Rockwell Hardness	B52
Elongation at Break	10%
Machinability (Vs. 1112 Steel)	270%
Familiar Sellers	McMaster Carr, Midwest Steel Supply, SendCutSend

Material Description:

• Lightweight aluminum alloy that comes already pre-heat-treated T6 temper which gives it its strength
• Beware of tempers T4 and O which are weaker than 6061-T6
• Typically used for frame rails, plates, pulleys, and armor for some bots
• Tends to fail in bending before fracturing
• Tends to "ablate" and may take gashes when hit directly by weapons
• Easy to machine and relatively cheap

Aluminum 7075-T6

Type	Aluminum Alloy
Modulus of Elasticity	10^7 psi
Shear Modulus	3800 ksi
Poisson's Ratio	0.32
Density	0.102 lb/in^3
Ultimate Tensile Strength	81 ksi
Tensile Yield Strength	69 ksi
Fracture Toughness (T-L dir)	22.8 ksi-in½
Brinell Hardness	150 HB
Rockwell Hardness	B87
Elongation at Break	7.9%
Machinability (Vs. 1112 Steel)	170%
Familiar Sellers	McMaster Carr, Midwest Steel Supply, SendCutSend

Material Description:

• Aerospace grade aluminum alloy which is much stronger and harder than 6061-T6
• Pre-heat-treated to T6 temper
• Past and anecdotal experience notes that it tends to fracture before it bends
• Some builders recommend avoiding using it as armor or for parts that take direct hits due to fracture risk
• Relatively easy to machine and is more expensive than 6061-T6

Data Sources

• AR500 Steel: SendCutSend, McMaster Carr, Steel Warehouse
• Al 6061-T6: SendCutSend, Matweb, Machining Doctor
• Al 7075-T6: SendCutSend, Matweb, Machining Doctor