Different formulae have been employed to optimize the insulating and exothermic behavior. Regarding the formula, an alumino-silicate microsphere (Fig. 5) based insulating system has been employed and bound together with an exo- thermic compound via the cold box technique. Assessments are carried out using the ETNA system (a
proprietary method developed by ASK Chemicals), so that it has been possible to identify the factors controlling the insulating capacity of each mix and its exothermic behavior. After the ETNA tests (Fig. 6), pairs of ‘test parts’ are cast
modifying exclusively the exothermic capacity of the IN-EXO sleeves. Te results show that when
increasing the exothermic level, riser volume demands are reduced.
Depending on the application, three base designs have been employed as starting points. • IN-EXO sleeves: due to their specifications they require a smaller weight of metal than conventional sleeves, consid- ering the modulus is kept constant.
• Padding sleeves: an adaptation of their geometry to each application eases metallic padding removal or increases the feeding distances; in this way avoiding the use of chills.
• Well sleeves: the parts of the mold that are affected by the feeding elements are covered with IN-EXO mixes, improving the thermal response of the surrounding area. New designs and geometries have been developed in
which remarkable benefits have been identified, since the possibility of increasing the riser’s action radius area solidifi- cation range of the alloy, finding that as the range increases the feeding system works better (Fig. 7). Te behavior of different iron based materials has been studied and it has been made evident that not all of them follow the same response model. Te obtained information belongs to low and medium alloy steels, stainless steels of different nature and manganese steels. Te relationship between alloy chemistry, solidus and liq- uidus temperature, solidification range (short and long range alloys), and solid fraction has been studied. From a feeding capacity and simulation validity point of
view, the solid fraction criterion (expressed as the solid phase/ liquid phase ratio) has been related to the solidification range of the alloy, finding that as the range increases the feeding system ‘works better’ (Fig. 8). Te criteria that are managed for the definition of an
alloy’s superheating temperature are very subjective and its effect in the contraction is seldom considered. In a generic way, it can be stated that as the superheat- ing temperature is increased, the tendency to shrink also increases (Fig.9). When optimising the response of the mini-risers, the
volume increment per each 100°C of superheating has been used as reference, which corresponds to values around 1%.
Metallurgical Considerations Te productivity and cost reduction advantages that come
along with the yield optimization must be added to a com- plete set of metallurgical improvements that have showed up
一每，ӹ验ડ化Џ工੧进֨。ऋঌङਈ性ঢ়੭化ѩ定Ӳ य़/4 +>5配方都需经过测量չછѳ。通过+:4'系统 （ंо世ॠ化学开Շङ一य़Ћ有方法）进੧છѳ，ं此 经。子֜ङਈ性热Շչ力ਈ温ґ物合混य़每Ӳ控ӰજՕ ）ե，Ցલ整/4 +>5ӈՍ套Շ热性 ֣（验测'4:+过 加增平水热Շ当，ॐ显果ৈ。ȕў铸ડ测Ȕثә造铸ਈ 时，ӈՍѽ॥需求就ѫ降Ѻ。 ગ本ׂय़Ід用҅，用应ङգЉ据根型模 әѾৈ构
ઋҁО起点。 ґ数模֨，性特ङ有独ҿйं：Սӈ热Շ ș ґ温 重ً金ङ轻更要需ঊ套统Ѯ比ћ它，时定恒持 量。
ș ੭ૉӈՍ：әѾৈ构ӣӰ适应՟З单独ङ应用， Ӓ用҅Ҳ避，ख़距ঢ়੭加增或ૉ੭ً金ї替Օ 铁。
ș н式ӈՍ：铸型ङ部ӣ浇铸系统覆有ґ温Շ热混 。应ր热ङֿ区֠յ高提，物合
合混加增љՕख़距ঢ়੭Ճֿ区径半用ҁՍӈ加增йं
），已经开Շӟдѩ势明显 ֣（应Ն5>+ 物本૯ङ/4 ङ新ગઋչәѾৈ构。 料材п这现Շ，ਈ性ङ料材合זׂ铁գЉд९ू 金合Ѻਘ来息ҒङՈੂ۱。式模应Նङ样գ循遵都非并 钢չИ合金钢љՃЉգ性ਈङЉ锈钢չ锰钢ͺЭू९д 长չ३ि（֠ਸ֡凝、چ温িब液չিब֡、学化金合 ચ验拟模չ力ਈঢ়੭ђ。系Ҽङ间Ф率ब֡չ）金合३ ਸ֡凝ङ金合Њ）率比ब液 ब֡（ӕ标率ब֡，र来 ֣（效有更Эҁ工ङ统系ঢ়੭，时加增֠ਸ当，Ҽ有֠ ）。
֜，观П常非ӕ标ङ立ӫ৲چ温热过ङ金合У定О
چ温热过当，પ来ਢ一。ր影ङঢ়收ثҿਖ਼ৰص很Э৲ ）。当ѩ ֣（加增Ф随Э性ਈՕङ孔ঢ়生ф，时高升 加增每چ温热过ر，时ਈ性应ՆङՍӈ型微5>+4/化 。 约םОЇқ数֨现੮，ৰՀОҁ量增॥ѽङ℃ 冶金ৰਖ਼
ђ实验阶段ङЉգ熔化物ИՕरӱङ冶金ѩ化必须 包括չӟս率ѩ化գ时ӟ现ङ生ф率提升չ成本降Ѻѩ ：是ङ提一得қ，И势ѩ有۱ङ现Շ֨。势 防Օ，Ѻ降ङਾિ热部قवն意性惯热Ѻङ型铸 ș 止ӟ现铸造बҼङ缺陷（裂়、Ҟ析ঈ）。
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FOUNDRY-PLANET.COM | MODERN CASTING | CHINA FOUNDRY ASSOCIATION March 2016
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