General Product Description

Introducing the new generation of ROCKHARD Wear Resistant Plates from Jindal Steel and Power – ROCKHARD 400/450/500. These are an advanced range of higher abrasion and wear resistant plates designed as per hardness

Produced through cutting-edge Quenched or Quenched & tempered process. ROCKHARD Products possess an exceptional combination of higher hardness & toughness, optimally designed chemistry, coupled with superior dimensional tolerances which helps in ease of fabrication.

Product Applications

JSP offers ROCKHARD Wear-resistant Steel Plate products for application in Yellow Goods & Mining Equipment (Dump Body Trucks, Bulldozer Buckets, Crushers, Mixers, Loaders, Shovels) and Material Handling Equipment (Chutes, Hoppers, Body Liners). ROCKHARD Plates can be used in Yellow goods, Construction, Mining Equipment applications which are subjected to hard rocks, loading of bulk materials and explosive shocks.

Dimension Range

Thickness (in mm) 8 – 100* 8 – 100* 8 – 100*
Width (in mm) 1500 – 4800 1500 – 4800 1500 – 4800

Individual size (Thickness X Width X Length) capability can be assessed based on the actual plate dimensions. 

*Thickness > 100 mm can be serviced basis mutual discussion with customer.


Mechanical Properties

ROCKHARD Steel Plates are designed according to hardness level. The table below mentions the grade with applicable level.


Hardness 360 BHN Min (Typical 360-450 BHN) 425 BHN Min (Typical 425-500 BHN) 470 BHN Min (Typical 470-550 BHN)
Grade YS in MPa (Min)*1 UTS in MPa (Min)*1 %EL (Min) at 50mm GL 1 Impact-/toughness Min*2
ROCKHARD 400 1100 1250 12% 25J(avg), 20J(ind)J at (-40) °C
ROCKHARD 450 1150 1300 12% 25J(avg) 20J(ind)J at (-40) “C
ROCKHARD 500 1250 1600 10% 25J(avg) 20J(ind)J at (-40) “C

1) Typical Tensile strength (MPa) values (YS, UTS & EL %) for up to 20 mm for reference purpose only

2) Typical CVN (Charpy V Notch) impact energy reference purpose only.

Supplementary requirements like Tensile & CVN Impact/Toughness Test shall be mutually agreed. The above are typical values for reference purposes. The orientation of tensile specimen is transverse, and impact is in longitudinal to rolling direction for above mentioned typical values.


Hardness is guaranteed and mentioned in MTC (Mill Test Certificate), the supplementary requirements can be mutually agreed upon, like YS, TS, % EL, Impact, etc. and based on agreement it can be mentioned.


Hardness Testing – Brinell hardness is guaranteed according to EN ISO 6506-1 on a milled surface 0.50 -3.00 mm below the surface. For 8 <= t <= 60 mm, typical guaranteed core hardness shall be 90% of the guaranteed minimum surface hardness.

Chemical Composition (Heat Analysis)

Grade Plate thickness range in mm %C (Max) %Mn (Max) %P (Max) %S (Max) %Si (Max) %Cr (Max) %Ni (Max) %Mo (Max) B Max (ppm) %CEV (Max)
ROCKHARD 400 8-100 0.25 1.60 0.030 0.010 0.50 0.90 0.50 0.50 50ppm 0.63
ROCKHARD 450 8-100 0.30 1.60 0.030 0.010 0.70 1.40 1.50 1.00 50ppm 0.66
ROCKHARD 500 8-100 0.30 1.60 0.030 0.010 0.70 2.00 1.50 1.00 50ppm 0.75

%CE (IIW)=C+Mn/6+ (Cr+Mo+V)/5+ (Ni+Cu)/15% CE (Carbon Equivalent). IIW (International Institute of Welding)


The steel is grained and refined. Steel may contain grain refining elements like Al, Nb, Ti, V or a combination. However, %Al-0.02 minimum with other elements like Nb+V+Ti is 0.15% max.

Typical Achievement of Carbon Equivalent

Grade %CE(8mm to 40mm thickness) %CE (>40mm to 100mm thickness)
ROCKHARD 400 0.45% -0.48% ** 0.55% -0.60%**
ROCKHARD 450 0.52% -0.60%** 0.60%~0.63%**
ROCKHARD 500 0.60% -0.63%** 0.65% -0.75%**

**Typical achievement of Carbon Equivalent based on Thickness Range mentioned above is for reference and guidance only. However, guaranteed values will be as per above table only.

Cold forming

Recommended minimum bending Radius up to 20mm thickness can be provided for reference and >20mm thickness can be discussed on case-to-case basis.

Bend Radius is dependent on the direction of bending to rolling (T=Plate Thickness).

Grade Bend transverse to rolling direction
Bend Angle Bend Radius(T=Thickness)
ROCKHARD 400 90 degree t<8: 2.5T 8st<20: 3.0T 20st<50:4.0T
ROCKHARD 450 90 degree 8st<12: 4.0T 12st<=60:6.0T
ROCKHARD 500 90 degree 8st<12: 6.OT 12st<=60:8.OT

Thickness Tolerance

Thickness Tolerances according to EN 10029 Class A for plate can be provided. Any class like Class B. C or D can be offered upon request.


Flatness Tolerances are according to EN 10029 Class N Type H. More stringent Tolerances can be offered upon request.

Ultrasonic Testing

According to EN 10160 SOEO or S1E1 or ASTM 578 Level A or B or C or ASTM A435 or as per requirements.

Width & Length Tolerance

Width & Length Tolerances according to EN 10029 can be offered or as per mutual agreement.

Surface Properties

According to EN 10163-2 Class A Subclass 1 or as per requirements.

Delivery Conditions

As Quenched, Quenched & Tempered. Trimmed, or thermally cut edges. Plates can be delivered in Shot-blasted, and Primer coated surface condition, if required by the customer.

Unique Selling Proposition (USP) of ROCKHARD

Heat Treatment and Fabrication

Mechanical properties are guaranteed in ROCKHARD Plates by water-quenching/quenching followed by tempering. The properties of the processed plates cannot be retained if exposed to service or preheating temperatures in excess of 220 °C. ROCKHARD Plates are not intended for further heat treatment.

Welding Parameters Recommendations

ROCKHARD Plates are usually used in wear part and recommended to be welded with low hydrogen electrodes like E7018H4 or E8018G. Low-strength consumables can offer several benefits, such as higher toughness of the weld metal, higher resistance to hydrogen cracking and lower residual stresses in the weld joint.

During welding, the precautions to be followed are: 

Preheat  : 30mm and above thick plate to 120 °C to 170°C max.

Interpass temperature: 220° C max.

Heat input : 1.5-2 kJ/mm.

Low carbon equivalent of ROCKHARD Plates results in good weldability. All conventional welding methods like manual electric arc welding, submerged arc welding, inert gas welding can be applied.