大入熱 高張力鋼 熔接部의 機械的 特性 變化에 關한 硏究

裵且憲 釜山工業大學校 1983 論文集 Vol.24 No.2

The mechanical and microstructural properties in high heat input welds of homemade SM 50 high strength steels were investigated and compared with the manual shileded metal arc welds. Also, the fracture toughnesses of the simulated weld-bonds with various thermal cycles were quantitatively examined in order to provide the basic data for furthur development of the high strength steels for high heat input welding. Main results obtained are as follows. (1) The embrittlement degree and the coarse grained region in high heat input welds appeares to be extra ordinary large compared with the manual shielded metal arc welds wwhile the difference in change of microhardness is not so large in both welds. (2) The embrittleness in high heat input weld-bond is mainly affected by the size of coarse grain rather than the microstructure. (3) The fracture toughness in high heat input weld-bond can be improved by controlling the cooling time from 800℃ to 500℃ rapidly.

高張力鋼材에 大入熱 熔接時의 熔接部의 熱Cycle 및 組織 變化

裵且憲 釜山工業大學校 1983 論文集 Vol.24 No.2

This study was carried out in order to consider quantitative the change of Microstructure and Hardness in welded zone between shielded Manual Arc Welding(SMAW) and Electro Gas Welding(EGW) of domestic HT-50 Class Steel. The results gained were as follows: 1) SMAW was showed faster cooling phenomenon than that of EGW from the thermal history curve between 800℃ and 500℃ 2) After welding of high heat input, the maximum value of hardness was showed Hv 220, this hardness value was lower than Hv350 in JIS 3) The prior austenite grain size of EGW was larget two times than that of the SMAW

高張力 鋼材의 急速入熱後 冷却速度에 따른 組織 및 硬度變化의 硏究

裵且憲,金雨烈,玉英建 釜山工業大學校 1982 論文集 Vol.23 No.2

The weld heat-affected zone of high strength steel was studied and then temperature range is from 1350℃ to 1400℃ Experiment was conducted about high strength steel, SM 58. Their structural and hardening properties were observed by rapid heating and cooling. The results obtained are as follows: 1) The structure was changed by rapid heating above 1350℃ and cooling. That is, the anisotropic structure before rapid heating became isotropic structure after cooling. 2) When the cooling temperature range was from 800℃ to 500℃ and cooling rate range was from 1.6℃/sec to 4.3℃/sec, structures changed were similar each other, but except 23℃/sec. 3) The hardness value had Hv from 190 to 230 when the heating temperature was from 800℃ to 500℃ and cooling rate was changed from 1.6℃/sec to 4.3℃/sec, but for 23℃/sec, vickers hardness had the value from 410 to 430.

Ferrite-Martensite 2相混合組織을 가진 Ni-Cr-Mo 鋼의 機械的 性質과 變形擧動에 響影을 미치는 因子에 관한 硏究

裵且憲,鄭炳琥 釜山工業大學校 1984 論文集 Vol.26 No.-

Effect of the intercritical annealing temperature(750~790℃), percent cold working on mechanical properties and the mechanical properties with change in orientation of deformation texture of Ni-Cr-Mo steels with Ferrite-Martensite mixtures were investigated. The observed mechanical properties are explained on the basis of the behaviors in microstructure. As the results, main results obtained are summerized as follows; It was found out that the lower volume fraction of martensite is and the higher up cold working ratio go, the better elongation is increased. That is due to the mean grain size decrease of martensite, the dispersion of martensite shape. As the results, the fracture surface exhibited a type of ductile fracture. Wheras in the case of specimen with deformation texture, UTS is decreased as a orientation of Ferrite-Martensite deformation texture to tensile axis is increased from 0°to 90°, in the orientation of 60 degree, it was increased somewhat but RA was remarkably smaller than that of 0°. In the orientation of 60 degree of deformation texture to tensile axis, fracture mode is a shear fracture in 45°plane, in the lower of that, fracture is a typical cup & cone, in the higher of that, fracture behavior shows transitional behavior from shear type fracture to cup & cone type fracture.

低濃度 Cr-Mo 合金鋼에 있어서 熱 cycle 處理가 粒狀化에 미치는 高溫加工燒入의 影響

鄭炳琥,裵且憲 釜山工業大學校 1985 論文集 Vol.27 No.-

Low-concentration Cr-Mo steel was treated by repeated thermal-cycling below Ac?? temperature after hot work-quenching in order to investigate the effect of hot work-quenching on spheroidization of carbide by martensite decomposition and on their mechanical properties. The changes of the microstructure comparing with working degree and thermal cycle change, hardness and tensile strength were investigated after repeated thermal cycling. The experimental results obtained were as follows; (1) When the repeated thermal cycling treated after hot work-quenching, the spheroidization of carbide and the number of fine spherical carbide were enhanced with increasing the number of thermal cycle and working degree. But the rate of increase was more noticeable in the range of 20% working and 30thermal cycle, and the decreasing effect of the hardness and tensile-strength were also good in this ranges. (2) The size and distribution of precipitated carbide were finner and more uniform in hot work-quenched specimens and the spheroidization of carbides in the steel was more rapid. (3) The spheroidization of carbides with repeated thermal cycling treatment after hot work-quenching were represented over 90% due to the effect of alloying elements Cr, and Mo which accelerated the spheroidization rate and the increasing effect of internal crystal lattice defect which accelerated the rate of spheroidization of carbides.

브레이크 캘리퍼용 고강도 구상흑연주철의 기계적 특성

배차헌 ( Cha Hurn Bae ),이우철 ( Woo Chul Lee ),박홍일 ( Heung Il Park ),정해용 ( Hae Yong Jeong ) 한국주조공학회 2008 한국주조공학회지 Vol.28 No.4

분사 (噴射) 주조한 입자강화 금속기타 복합재료의 복합화기구에 관한 연구

배차헌 ( Cha Hurn Bae ) 대한금속재료학회 1996 대한금속재료학회 학술대회 개요집 Vol.1996 No.1

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.

Ni-Cr-Mo 鑄鋼品의 熔接과 熱處理에 따른 機械的 性質 變化에 關한 硏究

裵且憲 釜山工業大學校 1979 論文集 Vol.20 No.-

Ni-Cr-Mo 계 强靭鋼 鑄鋼品에 있어서 容接이음에 의한 機械的 性質이 低下되는 것을 용접時 豫熱과 後列 , 溶接後 Annealing, Quenching 및 Tempering 에 依하여 機械的 性質의 低下를 捕腕 할 수 있다판는 것을 檢사한 것으로써 그 結果는 다음과 같다. 1) 鑄造應力을 逝去한 試片 鎔接後 annealing, quenching 및 Tempering을 한 것에 對한 機械的 性質은 거의 비숫하다. 2) Annealing 에 전衣하여 연결 부의 應力을 逝去할 수 있으며 이에 應用된 過程을 鑄鋼品의 抉부급 脯修 에도 安全하게 應用될 수 있을 것이다. Generally Ni-Cr-Mo component systems decreases the mechanical properties during welding, therefore, in this study the development of mechanical properties during heat treatment after welding was investigated, that results were as follows: 1) The differences of mechanical properties between the specimen relieved casting stress and the one annealed, quenched. and tempered after welding didn't find. 2) The stress in parts received heat could be relieved by annealing treatment, and also this could be applied in the repair of defect in castings.

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.