Sweets

LOAD CAPACITIES OF NEENAH CASTINGS

CASTINGS FOR DIFFERING TRAFFIC CONDITIONS

To assist in selecting castings which meet a general load bearing requirement, we have classified our castings into separate strength categories. These references as follows:

Extra Heavy Duty: For airport and concentrated loads. These applications require special castings to accommodate uniformly distributed loads of 100 to over 225 p.s.i. When selecting castings for heavy concentrated loads, advise loading conditions: total wheel load, tire or wheel contact area, and tire pressure. We will confirm your choice as being suitable for the purpose intended.

Heavy Duty: Castings in this category are generally suitable for highway traffic or H 2O wheel loads of 16,000 lbs. Many of the castings are suitable for much heavier loading.

Light Duty: These castings are recommended for sidewalks, terraces, and very light traffic.

NOTE: Check with our Product Engineering Dept. for load capacities of castings produced in aluminum or bronze.

To know how a casting will perform in use is important to responsible engineers in the fields of consulting and public works. For years empirical formulas have been erroneously used to determine loading capacities. Now Neenah offers an accurate method of determining true load bearing capabilities.

FULL SCALE DESTRUCTIVE TESTING
The U.S. Government specifies a proof load test as the recommended method for providing load performance of castings service. You will find this testing procedure explained in Federal Specification RR-F-621 for frames, covers and gratings. The elements of the test are essentially these:

1. A specified load is applied on a 9" x 9" area.
2. The cover, grating or frame will be inspected for cracks or permanent deformation such as buckling.
3. Any crack or permanent deformation will cause the casting to be rejected.

Tests are conducted on our 200,000 lb. Baldwin Compression Testing Machine. Our procedure takes a casting beyond the RR-F-621 specification; even to destruction.

WHEEL LOAD CAPACITIES FOR NEENAH CONSTRUCTION CASTINGS
The results of our laboratory tests and other research are now documented in a manual entitled "Wheel Load Capacities for Neenah Construction Castings." The performance data lists ultimate load, deflection, energy absorption and design efficiency for many of our castings. Also included is a thorough explanation of the test methodology with definitions and interpretation of results. For a free copy of this valuable manual, please write or call: Product Engineering Department, Neenah Foundry Company, P.O. Box 729, Neenah, Wisconsin 54957. Telephone (920) 725-7000.

SPECIFICATIONS

NEENAH quality construction castings conform to the following requirements. Use this data in your specifications to insure highest quality.

SUGGESTED SPECIFICATIONS FOR CONSTRUCTION CASTINGS

General: Ferrous castings shall be as manufactured by Neenah Foundry Company or prior approved equal. They shall be of uniform quality, free from blow holes, shrinkage, distortion or other defects. They shall be smooth and well cleaned by shotblasting.

Quality: Metal used in the manufacture of castings shall conform to a minimum of ASTM A48 Class 30B or Class 35B (as specified) for Gray Iron. Ductile Iron will conform to ASTM A536 Grade 80-55-06 (55 ksi).

Finish: All castings shall be manufactured true to pattern; component parts shall fit together in a satisfactory manner.

Tolerances: As-cast dimensions may vary one-half the maximum shrinkage possessed by the metal or +/- 1/16 inch per foot.

Paint: Painting of castings does not provide significant added protection to cast iron, but merely changes the appearance with a colored coating. Castings are furnished unpainted.

Weight: All published weights are average (and approximate) values. Deviation shall not exceed published weights by +5%, but may vary by -20% as a result of design improvements.

Submittals: Manufacturer’s shop drawings shall be submitted to the engineer for approval prior to manufacture or shipping of castings to jobsite. The engineer shall retain the right to reject castings not conforming to this specification and/or approved submittal drawings.

Gray Iron - Best for Construction Castings

The use of Gray Iron offers many advantages over other materials for construction castings. Of all the common castable ferrous materials, Gray Irons exhibit the best corrosion resistance and the excellent quality of high compressive strength. These are valuable qualities for load bearing street hardware.

When to Use Ductile Iron

Ductile Iron is an ideal material for construction castings when standard Gray Iron castings do not have the load bearing capabilities or required impact resistance for a particular application.

While having the advantages of Gray Iron, Ductile Iron has greater strength characteristics than structural carbon steel, without steel’s inherent corrosion characteristics. Ductile Iron is often used in areas subjected to loads greater than H 20 loadings such as:

• Industrial facilities with forklift traffic
• Container Ports
• Airports

Freeway traffic or hard rubber forklift tires may also necessitate use of Ductile Iron due to impact loading.

Due to the excellent compressive strength of Class 35 B Gray Iron, mating Ductile Iron lids or grates with Gray Iron frames is our recommendation.

There are many factors involved in choosing a grade of Ductile Iron. When there are unusual loading conditions or locations subjected to extreme heat or cold, please consult our Product Engineering Department for recommendations.

Casting Load Bearing Capabilities

Specifiers must be certain the castings they have chosen are suitable for the intended loads. The U.S. Government prescribes a Proof Load Test Procedure under Federal Specification RR-F-621. This is the same testing method used at Neenah. For details please see page 5 of Sweet’s printed Catalog 05540/NEE.