The influence of columnar dendirtes on the mechanical properties of Al-1% Cu alloys as unifirectionalloy solidified under the conditions of controlled crystal growth rate (R) and temperature gradient (G) was investigated. And the change of metallography and mechanical properties when unifirectionalloy solidified alloys and cast alloys were cold-rolled from 10% to 90% in reduction ratio was studied. The results are as follows: 1. The elongation and yield strength of unifirectionalloy solidified alloy are higher then those of cast alloy, but there is a little decrease in ultimate tensile strength. 2. The metallography and mechanical properties are changeable with the primary arm spacings when the unidirectionalloy solidified alloys were cold-rolled from 10% to 90% in reduction ratio. An alloy with larger primary arm spacings was easily changeable in metallography and mechanical properties when it was cold-rolled. 3. The tensile strength of transversely cold-rolled to 90% in reduction ratio was higher then that of longitudionalloy cold-rolled to 90% in reduction ratio. In the case, the fractorgraphs of fractured surface showed that the cast alloy and the unifirectionalloy solidified alloy was ductile-fractured, but the surface of transversely cold-rolled to 90% reduction of unidirection alloy solidified was slip plane qracture.

In order to determine the feeding distance of aluminiun alloys (Alsi7Mg and AlCu4Ti) bar castings in the sand mold, the distance of the sound castings has been observed by radiograph for various risers, melt treatment, and casting design. Variation of porosity and hardness with the distance from the riser were also measured in order to determine the casting soundness. The results obained were as follows; 1) The modulus of riser should be 1.4 times of the casting`s 2) The maximum distance which can be made sound is greatly dependent on chemical composition and ingate location, and follows the rules given by the formula; a) When the melt flows into the casting first, and the riser afterward, D = 37.7 ${\sqrt{T}}$ for AlSi7Mg D = 31.2 ${\sqrt{T}}$ for pure aluminium D ${\ge}$ 54.8 ${\sqrt{T}}$ for AlCu4Ti Where T = casting thickness in mm Of this maximum distance, $aa{\sqrt{T}}$ for AlSi7Mg and 7.5 ${\sqrt{T}}$ for pure aluminium is made sound by the chilling effect of the casting edge. b) When the melt flows into the casting passing through the riser, $30{\times}30{\times}600mm$ bars can be made sound in all cases 3) Percentage of porosity is higer in AlCu4Ti than AlSi7Mg. And it is increased gradually by moving closer to the riser in case of $30{\times}30{\times}600mm$ bars, but for the $30{\times}30{\times}600mm$ bars it is increased gradually by moving closer to the center of bars. 4) Hardness variation is similar to the tendency of porosity. And it decreased gradually with approaching to the center in case of $30{\times}30{\times}600mm$ bars.

In this paper, the cupola heat balance has been carried out by using programmable calculator with BASIC language. Computers tend to be used in almost every fields but for many people, computers are not handy yet because of its high equipment cost and its difficult language system. In view of this fact, a desk-top or a hand-held programmable calculator is the pertinent device in its calculation speed, accuracy, and easy programming language (BASIC), let alone its low cost. There have been some attempts to apply them to the foundry,${^{1),2)}}$ but they are little in number. This paper is the first attempt to apply the programmable calculator to the calculation of the cupola heat balance. After several applications in some practicalcases, the program has resulted in very satisfactory results such as saving of time and accuracy.

본 실험에서는 고정수압하에서 응고한 Al-l0% Mg합금의 조직 및 기계적 성질에 미치는 가압력의 영향을 조사하기 위하여 압력을 $0㎏f/cm^2$, 500$kgf/cm^2$, $1500㎏f/cm^2$ 및 $2000㎏f/cm^2$로 변화시키면서 냉각곡선, 조직검사, 기계적시험 및 비중 측정을 하여 얻은 결론은 다음과 같다. 1. 가압력이 증가할수록 합금의 냉각속도는 증가하였다. 2. 기공 및 수축공의 발생은 가압에 의해 억제되었다. 3. 가압력이 증가할수록 dendrite arm spacing은 감소하였다. 4. 기계적 성질 및 비중은 가압력이 증가함에 따라 증가하였다.