Creating a Thermal Property Database for Investment Casting Shells
A recent study developed a set of thermal properties for investment casting shells to aid in simulation modeling of solidification and shrinkage prediction.
MINGZHI XU, SIMON LEKAKH AND VON L. RICHARDS, MISSOURI UNIVERSITY OF SCIENCE AND TECHNOLOGY, ROLLA, MISSOURI, U.S. 库据数ৗ性热的גֹ造铸模熔建Ӫ
,Շ开据数ਈ性热ङד型造铸模熔й用是果成९ू项一ङ近最 。ঢ়收չ֡凝ङў铸Иד型测预拟模й助有
3/4-@./ >; 9/354 2+1'1. ո <54 2 8/).'8*9。 学ל技य里苏ؤ٠拉罗州里苏ؤ֡ষ R
eliable and realistic thermal properties data for investment casting shell molds are required to correctly simulate the metal solidification and predict the shrinkage. Investment casting shells
exhibit several phase transformations during firing and pour- ing that affect their transient thermal properties which affect solidification. Tese properties depend on time, temperature and process history. A recent study collected thermal conductivity and specific heat capacity data from seven industrially produced ceramic molds of various types using an inverse method in which pure nitrogen was poured into ceramic molds equipped with two thermocouples. Software was used to simulate virtual cooling curves that were fitted to experi- mental curves by adjusting the temperature-dependent properties of the ceramic mold. Te data were compared with measurement results from laser flash. Te analysis of the differences will serve to improve the accuracy of invest- ment casting simulation.
Finding a Better Way to Measure
In a relatively thin-walled steel casting, most of the super heat and part of the latent heat of the liquid metal are accumulated in the investment ceramic shell, where specific heat capacity plays an important role. However, excessive
Ք
正לਈ,据数验ડਈ性热ד型造铸模熔ङ靠 型造铸模熔。ঢ়收测预չ֡凝ً金拟模֪े ,Պ转ङ段阶Зә现ղ,时注浇չ烧焙֨ד
性特п这。३过֡凝ր影৲ђ,ਈ性热ہहङћѕր影 。定৲३过ਫ工չچ温、间时随
最近ङ一项ू९,ђ՟य़ঝ型陶瓷型И收集д य़工 ,И型瓷陶ङҢ电热ЗД有装ҵ注氮ষر,ד型瓷陶Џ 陶整લ过通。据数ङ容热比չ率ح热ӟ得法方է逆用采 实Њি曲却Ӓ际实ङ拟模ў软,性特ङՊ৲چ温随型瓷 д੧进果ৈӱ得法ذ照Ұ激Њ据数п这。合契बি曲验 ेӕङ拟模造铸模熔高提й助有ر析ӣङڑ差。较比 性。
法方量测的װ更找ث
֨॥ম热潜ӣ部չ热过ӣ部ם液ً金,ў钢铸א薄ث ҁङ要重व起容热比,ӑەय़这,Иדי瓷陶造铸模熔 ەय़这,热ङ量ם输Ѯ型铸过通ѫў铸型ם,৲然。用 用应ثৱД,Иф生际实。প֜ङ要П是率حѮ热,ӑ
Fig. 1. Surface topology is used to calculate the effective thicknesss of the test specimen.
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FOUNDRY-PLANET.COM | MODERN CASTING | CHINA FOUNDRY ASSOCIATION March 2016
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