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Zr기 비정질 합금 다이캐스팅 주조품의 부식 특성에 미치는블라스팅 처리의 영향
이병철 ( Byung Chul Lee ),김성규 ( Sung Gyoo Kim ),박봉규 ( Bong Gyu Park ),배차현 ( Cha Hurn Bae ),박홍일 ( Heung Il Park ) 한국주조공학회 2014 한국주조공학회지 Vol.34 No.2
A Zr-based amorphous alloy specimen was produced by vacuum die casting process. The salt spray test was carried out usingthe specimens in the as-cast, Al2O3 and ZrO2 particle blasted state. Using these specimens, the SEM-EDX and XRD analyses, DSCmeasurement and bending strength test were conducted. After the salt spray test, the specimens were not experienced phase changeand thermal characteristics of the alloys were remained unchanged. In the as-cast specimen, corrosion products were not observed. However, in the Al2O3 particle blasted specimen, pitting corrosion occurred and the detected corrosion products were ZrCl2 andNaZrO3. Due to the salt spray test, bending strength of the Al2O3 blasted specimens showed about 100 MPa lower strength than theother specimens. The bending fracture surface was vein pattern which was shown typically in the amorphous alloys.
급속응고된 Al-Zr 합금의 시효현상에 미치는 Si첨가의 영향
최상욱,박홍일,김명호 울산대학교 1987 연구논문집 Vol.18 No.2
본 연구에서는 급속응고된 Al-Zr 합금의 과포화 고용도에 미치는 제3첨가 원소 Si의 영향 및 급속응고된 Al-Zr-Si 합금계의 시효특성에 관하여 실험적으로 조사하였다. Twin-roller 장치에 의하여 급속응고시킨 시편의 응고속도는 10?? K/s 정도였으며, 이때 Al기지내에 Zr은 약 1 wt.% 정도만이 과포화 고용되었다. 그러나 Si의 첨가량이 증가됨에 따라 Zr의 과포화 고용도는 증대되어 Si의 첨가량이 1 wt.% 일때 Zr은 1.7 wt.% 정도 Al기지내에 완전 과포화 고용되었다. 그리고 Si의 첨가량이 증가됨에 따라 Al-Zr 합금의 미소경도는 증대되었다. Al -1.7wt.%Zr -1.0wt.%Si 합금을 시효처리하면 Si이 우선 미세한 구상석출물을 형성하며 초기 시효경화를 일으킨 후, 잇따라 Zr의 준안정 석출물이 불연속 석출되어 성장하며 최대 시효경화를 나타냄을 알 수 있었다. An experimental investigation has been made about the effects of the third alloying element silicon on the sold solubility of zirconium in the aluminium, and on the ageing phenomena of Al-Zr-Si alloys. Rapidly solidified specimens were prepared by a twin-roller quenching apparatus in the form of long, thin ribbon, whose cooling rate was estimated to be about 10?? K/s. Under such a cooling rate, the maximum solubility of zirconium in solid aluminum was extended to about 1.0wt.%. However, it was extended up to 1.7wt.% by addition of 1.0wt.% silicon. With the increase of silicon content, the microhardness of Al-Zr alloys were increased as well. Ageing of supersaturated Al-1.7wt.% Zr-1.0wt.% Si solid solution appeared to occur in three sequential stages; Ⅰ. precipitation of silicon as fine spherical particles which harden the alloys, followed by Ⅱ. discontinuous precipitation of metastable zirconium phases which produce remarkable age hardening of the alloys, and finally Ⅲ. formation of coarse equilibrium zirconium phases.
박육 스테인리스 주강에 대한 유동 및 응고해석의 실험적 고찰
배차헌,정해용,최학규,박홍일,최병강 한국주조공학회 2000 한국주조공학회지 Vol.20 No.5
In order to find out the casting conditions of the thin wall stainless steel exhaust manifold for automobile, the melt flow and solidification behavior simulated by the Z-CAST program were evaluated, and experimental casting result on the test casting and exhaust manifold of SSC13 alloy were investigated. From the results of this study, it was shown that the calculated results on fluid flow were in good agreement with practical thin wall test castings under the same casting conditions, as pouring metal is austenitic stainless steel(SSC13) and pouring temperature is 1575, 1630, and 1665℃ respectively. That calculated result with designed thin wall exhaust manifold was predicted filling up into the mold cavity, and practical casting was sound. The solidification simulation was predicted shrinkages at the bosses for original exhaust manifold, and designed it without bosses was predicted no defect. Therefore practical exhaust manifold casting was sound and in good agreement with calculated solidification results.
박육 스테인리스 주강의 유동성에 미치는 주조변수 및 합금원소의 영향
배차헌,정해용,최학규,강상규,박홍일 한국주조공학회 2000 한국주조공학회지 Vol.20 No.5
The effects of casting variables and alloying elements on the fluidity of thin wall cast stainless steels were investigated. Melts were poured into the sand molds to produce thin wall test castings. The length of it was 245㎜ and the thickness varied at the interval of 0.5 in the range of 1.6 to 2.6㎜. For the same casting condition, the fluidities of austenitic stainless steel, ferritic, precipitation hardenable and martensite ones were better in the order. The higher the pouring temperature, the shorter the pouring rate and the better the fluidity were. The fluidity was increased with the addition of Cr and decreased with W and Nb.