State of the Art
A selection of Technical Sessions from this year’s AFS Metalcasting Congress illuminates the industry research trends in recent years.
A MODERN CASTING STAFF REPORT
metalcasting through scientific inquiry and analysis. Te 118th
F Metalcasting
Congress featured numerous highly rated technical presentations by re- searchers from across the industry. We’ve rounded up several leading
papers, according to experts at the American Foundry Society, Schaum- burg, Ill., and summarized them for you here. From alloys to austempering, these are some of the latest techno- logical achievements in cast metal production.
Presentation Resolving Warranty Risk Trough
Fault Tree Analysis (14-048)
Author T. J. Schorn, Enkei America, Inc.,
Columbus, Ind.
Background Tere is a set of problems for which the simple tools of corrective action and problem solving are often inade- quate to resolve. Tis class of problems shares the characteristics of complex- ity with multiple potential common causes and interactions with equip- ment and human decisions, and the inability to easily determine what spe- cific cause led to a defect. Metalcasters often get parts returned in a warranty environment where it is impossible in a subsequent forensic evaluation to determine the exact cause. Fault tree analysis can be used to handle a certain class of complex problems of this description extremely well. Te author describes how this quality tool has been used to successfully address difficult warranty problems with excel- lent results and customer acceptance.
or a process that has existed since ancient times, it is remarkable how much more can be achieved in
Conclusions This paper has illustrated that
with several simplifications, the sys- tem reliability and safety tool, called “Fault Tree Analysis (FTA),” can be utilized by a metalcasting facility or other organization to respond ef- fectively to warranty complaints and requests for corrective action. This is another example of safety tools in- forming the quality system, as noted in prior work.
The basic methods practiced in the use of a simplified FTA were de- scribed, including the analysis of the FTA via contribution analysis. This was shown to be valuable in directing improvement efforts and justifying effectiveness of improvement actions through direct measurement of the reduction in the probability of the undesired “top event.”
The use of this method was
developed as a part of an overall improvement cycle for warranty. It is recommended that metalcasters con- sider this methodology as a means of combating not only warranty claims themselves, but the ineffectiveness of superficial responses to such claims and the waste of application of standard corrective action methods to common cause variability. The
increase in customer understanding and appreciation for the investigation is a welcome side benefit.
Presentation Austemperability of Intercritically
Austempered Ductile Iron (IADI) (14-070)
Authors R. Aristizabal, University of Antio-
quia, Columbia; K. Hayrynen, Applied Process, Livonia, Mich.; R. Foley, J. Griffin and C. Monroe, University of Alabama at Birmingham, Ala.
Background
Step block castings of intercritically austempered ductile iron (IADI) were produced with thicknesses of 0.6 in. (1.6 cm), 1 in. (2.5 cm) and 2 in. (5.1 cm). A “low alloy” (Cu = 0.7 wt%) and a “high alloy” iron (Cu=0.7 wt%, Ni = 0.7 wt%) were produced. Two inter- critical austenitization temperatures were tested for each alloy. No pearlite was detected in any of the 0.6 in. (1.6 cm) thickness sections. In the 1 in. (2.5 cm) samples, no pearlite was found in the high alloy conditions while a small amount of pearlite was found in the two low alloy conditions. At a section thickness of 2 in. (5.1 cm) there was
This diagram illustrates the six possible categories of causes for a warranty (field) failure. May 2014 MODERN CASTING | 55
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