ASTM A Standard Specification for Gray Iron Castings for Pressure- Containing Parts for Temperatures up to Degrees F. Find the most up-to-date version of ASTM A at Engineering Purchase your copy of ASTM A/AM – 01() as a PDF download or hard copy directly from the official BSI Shop. All BSI British.
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Malleable iron — In malleable iron, the graphite occurs as irregularly shaped nodules called temper carbon because it is formed in the solid state during heat treatment. Ductile Iron has steel like mechanical properties with the castability, machinability, and corrosion resistance of Gray Iron. Gray iron high carbon equivalent.
ASTM A278/A278M – 01(2015)
It is named after the gray color of the fracture it forms, which is due to the presence of graphite. Class 20 has a high carbon equivalent and a ferrite matrix. Iron used in supplying castings shall conform to the required tensile strength. Because the modulus of elasticity for gray iron is higher in compression than a2278 is in tension, the use of standard structural formulas results in a conservative design. Gray iron above class 40 requires alloying to provide solid solution strengtheningand w278 treating is used to modify the matrix.
In SAE Standard J, tensile strength is not required, but hardness and a minimum tensile strength to hardness ratio are required.
Grey iron — Flake graphite provides gray iron with unique properties such as excellent machinability at hardness levels q278 produce superior wear-resistant characteristics, the ability to resist galling and excellent vibration damping.
Tension test shall be performed on each lot and materials shall conform to the tensile requirements specified.
The different metals within this family are separated further into the following classifications: The properties of all cast metals are influenced by the manner in which they solidify and cool. The different grades of ductile iron castings are produced by controlling the matrix structure around the graphite either as cast or by heat treatment.
The test bars shall be cast in aetm siliceous sand molds maintained at approximately room temperature. The graphite astj no appreciable strength, so they can be treated as voids. A typical chemical composition to obtain a graphitic adtm is 2.
Separately cast test bars having the required dimensions shall be poured from the same lot as the castings a728. A may be alloyed with Chrome and Copper. It can be cast in a wide range of casting sizes and section thickness; however, thinner sections may require annealing to obtain high ductility. The iron is cast as a white iron of a suitable chemical composition to respond to the malleabilizing heat treatment. Ductile Iron is commonly known as Nodular Iron. Historical Version s – view previous versions of standard.
Casting Processes The properties of all cast metals z278 influenced by the manner in which they solidify and cool. This page was last edited on 16 Novemberat The class then is identified as a grade. Grey cast iron’s high thermal conductivity and specific heat capacity are often exploited to make cast iron cookware and disc brake rotors. The two specifications approach the task from different standpoints, but the concept essentially remains the same. In thin asgm, the material can be hard and difficult to machine.
There are no generally accepted standards for the surface finish, machining allowances or dimensional tolerances. ASTM does a2778 give any warranty express or implied or make any representation that the contents of this abstract are accurate, complete or up to date.
As its name implies, it has zstm high degree of ductility. Gray iron is a common engineering alloy because of its relatively low cost and good machinabilitywhich results from the graphite lubricating the cut and breaking up the chips.
The silicon promotes good corrosion resistance and increased fluidity when casting. Gray Iron is commonly referred to as Cast Iron.
ASTM A – Standard for Gray Iron Castings for Pressure Containing Parts
Types of Specifications When mechanical properties are important, the most common procedure to qualify gray or ductile iron castings is to use a standard test bar poured separately with the specified lot of general engineered castings. The individual design of a casting the molding process, the way the molten metal is introduced into the cavity and the pouring temperature determines the rate of cooling in the various parts of an iron casting.
There is an insignificant amount of graphite present in Abrasion Resistant Irons. Subscribe to Premium Services Searches: Data sheets for overmetals, plastics, ceramics, and composites. This abstract is a brief summary of the referenced standard. Combining values from the two systems may result in non-conformance with the asmt. Ductile iron has the ability to be used as-cast and without heat treatments or other further refining.