Ductile Iron Specifications
Ductile Iron Specifications ASTM A536 80-55-06 (Related standards – SAE J434C D5506; ISO 1083 500-7) is a nodular iron with a mostly pearlitic – and smaller amount of ferrite – microstructure. It has mechanical properties comparable to low alloy steels. Ductile iron 80-55-06 is one grade in a family of many. Chemistry requirements are not specified in the ASTM A536 standard. Chemistry and hardness listed in this spec would be typical for a Grade 80-55-06.
For more information on ductile iron, go to our ductile iron page.
Physical and Mechanical Properties
|Density lb/in3 (g/cm3)||0.256(7.1)|
|Thermal Conductivity Btu/hr·ft·F (W/m·K)||250(36) for Ferritic grades, will change with an increase in pearlite, approx. 20% less|
|Specific Heat at 70F Btu/lb·F (J/Kg·k)||0.110(461)|
|Coefficient of Thermal Expansion Ɛ/F(Ɛ/C)X106 average between 68-212F||6.4 (11.5)|
|Melting Temperature (F)||2100 F|
|Compressive Strength Ksi (MPa)||429 (2960)|
Ductile Iron impact properties are microstructure dependent.
Gray Iron Specifications
Gray Iron Specifications – ASTM A-48 Class 30
ASTM A48 Class 30 (Related Standards – DIN GG20, BS 1452 Grade 220) is a gray cast iron. Gray iron consists of graphite flakes in a metallic matrix. When fractured, it is grayish in colour – hence the name (specifically, a fracture will follow along the graphite flakes which are gray). The low cost of production and attractive properties make gray iron one of the most commonly used ferrous alloys. Gray iron class 30 is one grade in a family of many.
Physical and Mechanical Properties
|UTS (ultimate tensile strength)||30,000 psi (207MPa)|
|Hardness||174 – 210 BHN|
|Density lb/in3 (g/cm3)||0.258 (7.15)|
|Thermal Conductivity Btu/hr·ft·F (W/m·K)||30 (53) at 212°F (100°C). Will drop as temperature increases.|
|Specific Heat at 70F Btu/lb·F (J/Kg·k)||0.14 (586)|
|Coefficient of Thermal Expansion Ɛ/F(Ɛ/C)X106 average between 68-212F||5.8 (10.5)|
|Melting Temperature||2050 – 2120 F|
|Compressive Strength Ksi (MPa)||109 (752)|
Gray Iron Properties and Advantages
- Gray iron has great vibration and sound dampening properties. For this reason, it is still one of the best materials for machine bases
- Great thermal conductivity because of its network of graphite flakes
- Good strength in compression – typically 3-4 times that of its ultimate tensile strength
- Excellent machinability due to the presence of the graphite flakes
- Fluidity during pouring means that it can be cast into thin sections and complex shapes
Manhole Cover and Castings Overview
Gray Iron Iron conforming to ASTM A48, Class 35B, as noted in section 7.1.1 and 7.1.3 of AASHTO M306. Class 35B exhibits the best corrosion and wear resistance properties as well as the desirable quality of high compressive strength. Therefore it makes a good load bearing street hardware. 35,000 psi minimum tensile strength iron is furnished. Ductile Iron Iron conforming to ASTM A536. Ideal material for construction castings when standard gray iron castings do not have the load bearing capabilities.
Ductile Iron has greater strength characteristics than structural carbon steel without the corrosion characteristics of steel. It is usually used in areas subjected to loads greater then H20 loadings. Also because it has excellent compressive strength it is often recommended as a cost effective approach to mate ductile iron lids or grates with gray iron frames.
Steel Grates Material shall be hot rolled steel confirming to ASTM A36. Galvanizing is recommended for all steel frame, grates & covers, conforming to ASTM 123. Steel grates can be compatible with cast iron frames.
Light Duty These castings are suitable for a wide range of non-traffic locations. Castings labeled light duty are recommended for sidewalks, terraces, landscape applications, and very light duty vehicular traffic, such as golf carts or lawn mowers.
Heavy Duty AASHTO M306 Highway Loading According to AASHTO M306 castings must meet a minimum of 40,000 lbs proof load on a 9” x 9” load test area. After the test, the cover grating or frame is inspected for cracks or deformation. This specification allows for a safety factor of 2.5 over 16,000 lbs requirement of H20 and HS20. This load designation is appropriate for general traffic applications.
Extra Heavy Duty (Airport and Port Authority) Castings listed in this category can accommodate wheel loads of 100 psi or greater. They are considered for airports and any place where concentrated loads might be applied. These castings can also accept proof loads from 100,000 to 200,000 lbs, which meets the design loading associated with the FAA wheel loading.
Manhole Cover Dimensions
Clear Opening Clear opening is the diameter of the smallest opening located near the top of the frame. It is also known as the “C” dimension.
Cover Diameter The cover diameter is the diameter of the lid. It is also known as the “A” dimension. Cover Thickness Cover thickness is the thickness of the lid at the perimeter. It is also known as the “B” dimension.
Frame Height The frame height is the height of the frame. It is also known as the “F” dimension.
Base Flange Opening Base flange opening is the opening at the bottom of the frame. It is also known as the “D” dimension.
Frame flange diameter Frame flange diameter is the diameter of the whole frame or the length from the outermost part of the flange directly across to the other outermost side. It is also known as the “E” dimension.