Cast Iron

Analysis Mechanical_Properties Applications Machineability_and_Weldability Heat_Treating Tolerances Speedy Metals items

Class 40 Gray Iron is a ferrous foundry metal that has been alloyed with carbon and silicon. Carbon is added to the base melt in amounts that exceed the solubility limits in iron and precipitates out as graphite particles. Silicon is added to the melt to nucleate the graphite which optimizes the properties of cast iron. Free machining characteristics are obtained by the graphite particles in the material. Class 40 Gray cast iron combines good strength with close-grain structure and has good machinability. Often dismissed as a cheap, dirty, brittle metal; cast iron is getting much more attention and use today because of its machinability, light weight, strength, wear resistance and damping properties.

ANALYSIS

* Carbon and Silicon targets are specified for each bar size produced in order to control size and shape of graphite flake Class 40 Gray Cast Iron conforms to ASTM A-48-64 Class 40

MECHANICAL PROPERTIES

Micro-Structure: Essentially Pearlitic Compressive Strength (Min PSI): 150,000 Deflection Strength**: 2600 **Average pounds load on 1.2 bar 18" span

APPLICATIONS

Class 40 Grey Cast Iron has a wide range of uses, including fluid power glands, manifolds, pistons, spools, valves, bushings, cams, gears, gibs, pulleys and wheels, rams, sheaves, side frames, slides and ways, cylinder liners, shock absorbing pistons, valve guards, rollers, rotors, seals, aluminum mold plates, chain sheaves, core boxes, dies, pattern plates, augers, screw conveyors, screw washers, pump components, etc

MACHINEABILITY AND WELDABILITY

Machinability of Class 40 Gray cast iron is good with average cutting speeds at 700 sfm and finishing speeds as high as 1,400 sfm.

Weldability is considered fair to poor as compared to low carbon steels.

HEAT TREATING

Normalizing

Gray iron is normalized by being heated to a temperature above the transformation range (1625°-1700°F), held at temperature for about 1 hour per inch of maximum section thickness, and cooled in still air to room temperature. Normalizing is used to enhance mechanical properties, such as hardness and tensile strength, and to restore as-cast properties that have been modified by another heat treatment, such as graphitizing and pre and post-heating associated with welding.

Heat Treatment

Gray Iron can be hardened from 1575° and oil quenched to attain 50 Rockwell C minimum surface hardness. Hardness will lessen towards the core.

TOLERANCES

Rounds are produced in an oversized condition.
Flats and squares are produced virtually on size, and will finish approximately 1/4" below produced size.

SPEEDY METALS ITEMS

7/8" OD 2-1/2" 3/4" {A} x 1-1/2" {B} Gray Cast Iron Class 4
1-1/4" SQ {A} Gray Cast Iron Class 4 1-1/4" {A} x 2-1/4" {B} Gray Cast Iron Class 4 1-1/4" {A} x 3-1/4" {B} Gray Cast Iron Class 4
1-1/4" {A} x 4-1/4" {B} Gray Cast Iron Class 4 1-1/4" {A} x 5-1/4" {B} Gray Cast Iron Class 4 1-1/4" {A} x 6-1/4" {B} Gray Cast Iron Class 4
1-1/2" SQ {A} Gray Cast Iron Class 4 1-1/2" {A} x 2-1/4" {B} Gray Cast Iron Class 4 1-1/2" {A} x 3-1/4" {B} Gray Cast Iron Class 4
1-1/2" {A} x 4-1/4" {B} Gray Cast Iron Class 4 1-1/2" {A} x 5-1/4" {B} Gray Cast Iron Class 4 1-1/2" {A} x 6-1/4" {B} Gray Cast Iron Class 4
1-5/8" SQ {A} Gray Cast Iron Class 4 1-3/4" SQ {A} Gray Cast Iron Class 4 1-3/4" {A} x 2" {B} Gray Cast Iron Class 4
1-3/4" {A} x 4-1/2" {B} Gray Cast Iron Class 4 1-3/4" {A} x 6-1/4" {B} Gray Cast Iron Class 4 2" SQ {A} Gray Cast Iron Class 4
2" {A} x 2-1/2" {B} Gray Cast Iron Class 4 2-1/4" SQ {A} Gray Cast Iron Class 4 2-1/4" {A} x 3-1/4" {B} Gray Cast Iron Class 4
2-1/4" {A} x 4-1/4" {B} Gray Cast Iron Class 4 2-1/4" {A} x 5-1/4" {B} Gray Cast Iron Class 4 2-1/4" {A} x 6-1/4" {B} Gray Cast Iron Class 4
2-1/4" {A} x 8-1/4" {B} Gray Cast Iron Class 4 2-1/2" SQ {A} Gray Cast Iron Class 4 3" SQ {A} Gray Cast Iron Class 4
3-1/4" SQ {A} Gray Cast Iron Class 4 4-1/4" SQ {A} Gray Cast Iron Class 4 6-1/4" SQ {A} Gray Cast Iron Class 4
5/8" {A} Rd Gray Cast Iron Class 4 3/4" {A} Rd Gray Cast Iron Class 4 1" {A} Rd Gray Cast Iron Class 4
1-1/4" {A} Rd Gray Cast Iron Class 4 1-1/2" {A} Rd Gray Cast Iron Class 4 1-3/4" {A} Rd Gray Cast Iron Class 4
1-7/8" {A} Rd Gray Cast Iron Class 4 2" {A} Rd Gray Cast Iron Class 4 2-1/4" {A} Rd Gray Cast Iron Class 4
2-1/2" {A} Rd Gray Cast Iron Class 4 2-3/4" {A} Rd Gray Cast Iron Class 4 3" {A} Rd Gray Cast Iron Class 4
3-1/2" {A} Rd Gray Cast Iron Class 4 3-3/4" {A} Rd Gray Cast Iron Class 4 4" {A} Rd Gray Cast Iron Class 4
4-1/2" {A} Rd Gray Cast Iron Class 4 5" {A} Rd Gray Cast Iron Class 4 6" {A} Rd Gray Cast Iron Class 4
6-1/2" {A} Rd Gray Cast Iron Class 4 7" {A} Rd Gray Cast Iron Class 4 11" {A} Rd Gray Cast Iron Class 4
12" {A} Rd Gray Cast Iron Class 4