GX Gray Iron

GX is a pearlitic gray iron offered in a variety of small and large rounds and rectangles for non-typical size applications. GX benefits include wear resistance, noise and vibration damping, and can be heat treated using conventional methods. Download the GX Gray Iron Product Brief, or X Products for all X grades.

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Dura-Bar Gray Iron G2


The core microstructure will consist of Type A graphite flake, per ASTM A247, with a matrix containing a minimum of 90% pearlite. The edge or rim will have a combination of Type D and Type E graphite flake and a matrix with a mixture of ferrite and pearlite. The rim will contain as much as 5% carbides.

Center Area

100x, etched in 5% Nital

Edge Area

100x, etched in 5% Nital

Heat Treat Response

GX can be heat treated by conventional methods. Hardening can be accomplished by heating and quenching the material from 1600° F resulting in Rockwell C hardness up to 50 HRC. Induction and flame hardening can be performed but may require an additional pre-heat treatment to reach the desired hardness and microstructure.

Stock Sizes


Size Range: 1.250" to 26.560"

As-cast round bars are made to clean up at the nominal size. Additional stock is added to allow for out-of-round and normal imperfections in the as-cast surface. Stock allowance is a function of the bar diameter - see Stock Allowances for details. Other finishes available are Centerless Grinding and Centerless Turning, for demanding tolerance applications.


Size Range Rectangles: 0.750" x 1.500" to 17.000" x 30.000"

Size Range Squares: 1.500" x 1.500" to 21.000 x 21.000"

As-cast rectangles and squares are made to the actual size with no allowance for machine stock added. Rectangles and squares are cast to actual dimension, with clean up stock dependent on the height and width ratio. See Stock Allowances for details. Rectangles and squares can be milled to achieve close tolerance benefits - see Services/Milling for details.

Technical Specifications

Chemical Composition

Carbon2.70 - 3.45%
Silicon2.10 - 2.90%
Manganese0.50 - 0.90%
Sulfur0.04 - 0.1%
Phosphorus0.15% Max

Mechanical Properties

Hardness values listed are minimum and maximum across the bar. Hardness values for rectangles and squares are a function of the height and width ratios and will be supplied on request.

Size RangeBHN
1.000 - 28.00025 - 711183285

Tensile Strength

GX conforms to ASTM A48 Class 40 - download the GX Class 40 Tensile Table. Tensile data from the as-cast bar in conjunction with separately cast tensile data, correlates to a Class 40 Gray Iron.

Typical Applications



Fluid Power:

Cylinder blocks, Glands, Manifolds, Pistons, Rotors, Spools, Valves


Bushings, Gears, Gibs, Housings, Pulleys, Rams, Sheaves, Side Frames, Slides, Spindles, Ways


Aluminum Molds Plates, Cams, Chain Sheaves, Core Boxes, Dies, Pattern Plates, Wheels

Oil and Gas:

Bridge Plugs, Cement Plugs, Cones, Mandrels, Retainers, Slips

Power Transmission:

Gears, Pulleys

Pump and Compressor:

Gears, Housings, Liners, Pistons, Rollers, Rotors, Seals

Steel Mill/Foundry:

Continuous Caster Rolls, Pattern Plates, Core Box Patterns, Foot Rolls, Table Rolls, Torch Rolls


Brake Rotors, Cylinder Liners, Gears, Lash Adjusters, Pulleys, Shock Absorber Pistons, Valve Guides, Valve Seat Inserts