Austempered irons garner interest.Because of their superior properties and potential to create new iron casting markets, austempered cast irons continue to be the center of much research and development work. ADI and ductile iron Ductile iron, also called ductile cast iron or nodular cast iron, is a type of cast iron invented in 1943 by Keith Millis. While most varieties of cast iron are brittle, ductile iron is much more ductile, as the name implies. , in general, made up the lion's share of the cast iron program this year.
In his continuing work on austempering B. Kovacs, Kosmar Enterprises, studied the prediction of strength properties in austempered ductile iron through acoustical measurements. This testing method can be used to predict the strength properties of ADI, making it a useful tool for both quality and production control. Kovacs related the accoustical properties of ADI to yield strength, tensile strength tensile strength
Ratio of the maximum load a material can support without fracture when being stretched to the original area of a cross section of the material. When stresses less than the tensile strength are removed, a material completely or partially returns to its , elongation and density as a function of the austenitizing and austempering temperatures. Resonant frequency resonant frequency,
n the specific frequency at which an object vibrates. , sonic velocity and internal damping were measured in ADI samples, which were austenitized at 1550, 1650 and 1750F, and austempered at 500, 600 and 700F.
Kovacs demonstrated a close relationship between accoustical and strength properties. Understanding this relationship, he said, makes it easy to determine what grade the ADI part is after heat treatment. Also, if the chemical composition is known, strength properties can be assessed.
In other research aimed at improving the understanding of ADI, Michigan Technological University Michigan Technological University (abbr. Michigan Tech or MTU) is an American public university with a range of degree offerings. Michigan Tech's main campus is in Houghton, Michigan, in the Upper Peninsula. , researchers presented their work on the tensile and fatigue properties of relatively pure ADI. They focused on hot isostatic i·sos·ta·sy
Equilibrium in the earth's crust such that the forces tending to elevate landmasses balance the forces tending to depress landmasses. processing (HIP) as well as comparisons of relatively pure material with heavily alloyed ductile irons.
They demonstrated that HIP prior to austempering resulted in a small increase in UTS (Universal Timesharing System) Amdahl's version of Unix System V. Release 4.0 is POSIX compliant. while yield strength remained fairly constant. Ductility changed dramatically, however, with increases ranging from 21-100% from the bottom of the casting to the riser/casting interface.
The comparison of relatively pure and alloyed irons indicated properties improved with the relatively pure material. All improvements in tensile performance, however, couldn't be attributed to alloy purity due to the likely presence of bainite in the matrix of the heavily alloyed iron.
Carefully controlling the metal microstructure mi·cro·struc·ture
The structure of an organism or object as revealed through microscopic examination.
a structure on a microscopic scale, such as that of a metal or a cell is essential to achieving the benefits of continuous cast ductile iron, said Y. Lerner, Grede Foundries, Inc. He noted the microstructure and service properties of continuous cast ductile iron are influenced by several key solidification factors--primarily a magnesium treatment method that preserves the structural and mechanical properties of the metal.
His investigations revealed one factor consists of changing the ratio of cooled to noncooled portions of the graphite casting dies. This, in turn, relies on a second important factor, the regulation of the water flow rate into the cooling jacket. His presentation detailed the development of an adjustable, jacketed die to facilitate the differential cooling rate. The die design provides accelerated, but uniform, heat withdrawal to regulate solidification for large bars. This assures a homogenous homogenous - homogeneous microstructure consisting of a large number of graphite nodules/|mm.sup.2~ will form in the surface zone of the cast bars.
A woven refractory cloth insert was described by R. Hetzler, Bellville Foundry, and C. Loper lope
intr.v. loped, lop·ing, lopes
To run or ride with a steady, easy gait.
A steady, easy gait.
[Middle English lopen, to leap, from Old Norse , University of Wisconsin-Madison “University of Wisconsin” redirects here. For other uses, see University of Wisconsin (disambiguation).
A public, land-grant institution, UW-Madison offers a wide spectrum of liberal arts studies, professional programs, and student activities. , that, during shakeout, affects the breakup of large, complex gating systems and the self derisering of ductile and gray iron top risers.
The cloth inserts were tested over 50 different patterns of varying sizes and modified to accept the cloth inserts in the gating and risering systems. The inserts substantially eliminated the problem of gating system entanglement in shakeout and reduced the possibility of accidents occurring during degating and derisering.