Because gray iron castings have many advantages, it is widely used in many industrial and mechanical fields. In this article, we have cited examples of working conditions and uses of different grades of gray cast iron.


1. Gray Cast Iron Castings by HT100 (GG10, EN-GJL-100)

Suitable Working Conditions
1) Very low load
2) Wear is not important
3) Very small deformation

Examples of Uses
Gray iron GG10 is usually used for simple, less important parts, such as: cover, outer cover, oil pan, hand wheel, handle, bracket, seat plate and so on. These castings can be used without testing, and generally do not need to be mechanically processed, or simply require simple mechanical processing.


2. Gray Cast Iron Castings by HT150 (GG15, EN-GJL-150)

Suitable Working Conditions
1) Parts with moderate load
2) The pressure per unit area between the friction surfaces is not more than 490 kPa.

Examples of Uses
1) Castings in general machinery manufacturing, such as: pillars, bases, gearboxes, tool holders, bearing seats, bearing sliding seats, worktables, unmachined gears and sprockets, etc. In addition, on agricultural tractors, some parts such as the intake pipe, exhaust pipe and hydraulic pump oil inlet pipe also use gray iron GG20.
2) Thin-walled parts with low weight, pipe fittings with low working pressure, and wear-resistant sleeves with wall thickness less than or equal to 30mm, etc.
3) Pulleys with a peripheral speed greater than 6 ~ 12 m/s and other parts that meet the above working conditions


3. Gray Cast Iron Castings by HT200 (GG20, EN-GJL-200) and HT250 (GG25, EN-GJL-250)

Suitable Working Conditions
1) Withstand larger parts
2) Parts whose unit area pressure between friction surfaces is greater than 490 kPa or parts whose surfaces need to be quenched
3) Parts that require air tightness, or require swelling resistance and toughness

Examples of Uses
1) The more important castings in general machinery manufacturing, such as: cylinders, gears, sprockets, ratchets, bushes, machine bed, flywheels, etc.
2) Cylinder blocks, cylinder heads, pistons, brake hubs, coupling discs, flywheels, gears, clutch housings, separator bodies and axle housings of automobiles and tractors
3) Hydraulic cylinders, pump bodies, valve bodies, etc. that bear medium pressure


4. Gray Cast Iron Castings by HT300 (GG30, EN-GJL-300) and HT350 (GG35, EN-GJL-350)

Suitable Working Conditions
1) Parts with high bending force and high tensile force
2) Parts whose unit area pressure between friction surfaces is greater than or equal to 1960 kPa or parts whose surfaces need to be quenched
3) Parts requiring high air tightness

Examples of Uses
1) Important castings in mechanical manufacturing, such as: shears, presses, automatic lathes and other heavy-duty machine tool beds, bases, and frames. Large and thick bushes, gears, cams. Cylinder blocks, cylinder liners, cylinder heads, etc. of large engines.
2) High-pressure hydraulic cylinders, water cylinders, pump bodies, valve bodies, etc.