What is the Difference Between RHA and HHA Plates? – Understanding Armor Steel Types for Ballistic and Blast Protection

When selecting armor steel plates for defense, vehicle, or infrastructure protection, one of the most common buyer questions is:
“What is the difference between RHA and HHA plates?”

At Hindustan Steel Corporation, we help buyers make the right choice between Rolled Homogeneous Armor (RHA) and High Hardness Armor (HHA), depending on ballistic threat levels, weight requirements, and application zones.

Meaning of RHA (Rolled Homogeneous Armor) vs HHA (High Hardness Armor)

Term	Full Form	Hardness Range	Common Usage
RHA	Rolled Homogeneous Armor	250–300 BHN	Blast protection, structural reinforcement, general vehicle armor
HHA	High Hardness Armor	470–540 BHN	Multi-hit rifle and armor-piercing bullet protection, ballistic doors, vehicle sidewalls

Applications Where RHA and HHA are Used Differently

RHA Plates Are Used For:

Mechanical Property Comparison: RHA vs HHA

Property	RHA	HHA
Hardness	250–300 BHN	470–540 BHN
Yield Strength	Lower	Higher
Tensile Strength	Lower	Higher
Elongation	Higher (more ductile)	Lower (more brittle)
Impact Toughness	High	Moderate
Ballistic Rating	Low (Blast/Low Threat)	High (Rifle/AP Protection)

Standards to Fabrication (H5 to H10)

International Standards for RHA and HHA Plates

RHA Plates Are Typically Supplied As Per:

• MIL-DTL-12560 (Class 1 and 2)
• Indian Defense Grade Equivalents

HHA Plates Are Typically Supplied As Per:

• MIL-DTL-46100
• STANAG 4569 Level 2/3 Zones
• EN 1522 FB6 / FB7 (Material Level Equivalents)
• HIND ARMOR 500 and HSC 500T (Hindustan Steel Corporation Proprietary Grades)

Thickness Range and Available Sizes for Both Types

Type	Thickness Range
RHA	6 mm to 50 mm
HHA	6 mm to 50 mm

Size Options:
Width: Up to 2500 mm
Length: Up to 12000 mm
Custom Cut-to-Size: ✅ Yes
CNC Drilling / Profiling: ✅ Yes

Heat Treatment and Toughness Differences

RHA Plates:

• Typically supplied in annealed or normalized condition
• Focused on ductility and blast energy absorption

HHA Plates:

• Supplied in quenched and tempered condition
• Focused on surface hardness and ballistic stopping power

Impact Toughness:
RHA offers better toughness
HHA offers better hardness and bullet resistance

Fabrication and Welding Considerations

Fabrication Step	RHA	HHA
Cutting	Easier	Needs careful heat control
Drilling	Easier	Requires carbide tools and coolant
Welding	Standard practices	Needs preheat and low hydrogen electrodes
Forming/Bending	Easier	Limited (especially for thicker plates)

For multi-threat applications, buyers often use a combination of RHA and HHA layers.

Why Buy RHA and HHA Plates from Hindustan Steel Corporation?

• One-stop source for both RHA and HHA grades
• Made-in-India alternatives to imported defense armor steel
• ustom size, drilling, and CNC profiling
• Ballistic test support for OEMs and defense projects
• Export-ready packaging with full documentation
• Competitive pricing and fast dispatch

We supply both Indian defense contractors and global OEM armor fabricators.

Related Grades / Buyer Alternatives

If you’re comparing RHA and HHA, you may also want to explore:

• HIND ARMOR 500 Plates
• HSC 500T Tactical Armor Plates
• MIL-DTL-12560 Class 1 / 2 RHA Plates
• MIL-DTL-46100 HHA Plates
• STANAG 4569 Level Armor Steel

Our technical team can help with grade selection for your project.

Export Destinations and Packaging

We export RHA and HHA plates to:

• UAE, Saudi Arabia, South Africa, Germany, Nigeria, Kenya, and more.

Packaging Includes:

• Seaworthy pallets/crates
• VCI anti-corrosion wrapping
• Labeling by grade, thickness, and heat number
• Export documents: MTC, Packing List, Commercial Invoice, Ballistic Test Reports (on request)

How to Choose Between RHA and HHA Plates?

Choose RHA for:

• Blast zones, structural parts, and low-velocity threat protection

Choose HHA for:

• Direct bullet resistance, rifle threats, and armor-piercing protection

For multi-threat applications, consider layered designs using both RHA and HHA.

Discuss your project details with our technical team for exact recommendations.

Certifications, Testing, and Quality Control

For every order, we provide:

• Mill Test Certificates (MTC)
• Hardness Test Reports
• Ballistic Test Reports (chargeable, on request)
• Third-Party Inspection Certificates (SGS, BV, Lloyds, etc.)
• Ballistic Compliance Declaration

FAQs: RHA vs HHA Plates