• 한국해양공학회지
• /
• 제20권1호
• /
• pp.1-6
• /
• 2006

The effects of microstructure on the damping capacity and tensile properties of 316L stainless steel were investigated. Increasing the degree of cold working, the volume fraction of $\varepsilon-martensite$ decreased after rising to maximum value at specific level of cold working, the volume fraction of d-martensite slowly increased and then dramatically increased from the point of decreasing $\varepsilon-martensite$ volume fraction. Increasing the degree of cold working, the behnvior of damping capacity is similar to that of the $\varepsilon-martensite$. After the damping capacity showing the maximum value at about $20\%$ of cold rolling, damping capacity was decreased with the volume fraction of $\varepsilon-martensite$. Tensile strength was proportional to the volume fraction of d-martensite, and elongation steeply decreased in the range low volume fraction of a'-martensite, then slowly decreased in range the above $10\%$ volume fraction of d-martensite. The damping capacity and elongation is strongly controlled by the volume fraction of $\varepsilon$ martensite with liner relationship. However, the effect of the volume fraction of d-martensite and austenite phase on the damping capacity was not observed. Tensile strength was governed by the volume fraction of d-martensite.

• 한국주조공학회지
• /
• 제22권4호
• /
• pp.155-159
• /
• 2002

Magnesium alloys have high strength to weight ratio and are extremely attractive for applications in transport industry. Most of structural magnesium alloys are manufactured by die casting process. The tensile properties of AZ91HP magnesium alloy were investigated after die casting under various die casting conditions. After die casting by using cold chamber machine, the volume porosity of specimens was examined with density method. With the increase of the volume porosity of specimens, both the tensile strength and elongation were significantly decreased, however the 0.2% offset strength was almost independent of the amount of porosity. With the increase of crystal pressure from 500 to 900 bar during die casting, the volume porosity was decreased, which resulted in the increase of the tensile strength. The mould temperature within the range of $150{\sim}250^{\circ}C$ has not influenced the microstructure with the eutectic phase and tensile properties of specimens. The tensile strength was the highest at 90m/sec of gate speed.

• 한국압력기기공학회 논문집
• /
• 제19권1호
• /
• pp.11-19
• /
• 2023

Additive manufacturing technology, called as 3D printing, is one of fourth industrial revolution technologies that can drive innovation in the manufacturing process, and thus should be applied to nuclear industry for various purposes according to the manufacturing trend change in the future. In this paper, we performed tensile tests of 3D printed stainless steel 316L as-built specimens manufactured by two types of technology; DED (Directed Energy Deposition) and PBF (Powder Bed Fusion). Their mechanical properties (tensile strength, yield strength, elongation and reduction of area) were compared. As a result of comparison, the mechanical properties of the PBF specimens were slightly better than those of DED specimens. In the same additive type of specimens, the tensile and yield strength of specimens in the X and Y direction were higher than those in the Z direction, but the elongation and ROA were lower.

• 수산해양기술연구
• /
• 제29권2호
• /
• pp.117-123
• /
• 1993

In order to analysis the tensile properties of the high-tech fibers for fishing gear materials. tensile strength was tested on raw materials, single yarns and netting twines(plied yarns)made of nylon, kevlar 29 and techmilon respectively. The results obtained are as follows: 1. The tensile stress and tenacity of unknotted single yarns in dry and wet conditions were 3 to 3.5 times greater in the high-tech fibers than in nylon. But the elongation of the high-tech fibers was about 15% of that in nylon. 2. The tensile strength of knotted single yarns in dry and wet conditions was arranged in order of as follows : techmilon. kelver 29, and nylon. The ratio of knot strength to tensile strength, knot efficiency, was the highest in nylon. 3. The tensile strength of unknotted netting twines in dry and wet conditions was 2.3 to 2.5 times greater in the high-tech fibers than in nylon. 4. The tensile strength of knotted netting twines in dry and wet conditions was arranged in order of as follows : techmilon, kevlar 29, nylon. The knot efficiency was the highest in nylon.

• 열처리공학회지
• /
• 제36권1호
• /
• pp.7-14
• /
• 2023

We investigated the effect of multiple tempering on the microstructure and mechanical properties of AISI 4340 steel. The austenitized and quenched AISI 4340 steels were tempered at 550, 600, and 650℃ for 1, 2, and 4 h by single-tempering (ST). The multiple tempering was conducted for 4 h by double-tempering (DT, 2 h + 2 h), and quadruple-tempering (QT, 1 h + 1 h + 1 h + 1 h). As tempering temperature increases, yield strength and ultimate tensile strength decrease and elongation increases due to recovery and recrystallization of martensite and coarsening of carbides. At 550℃, as the number of tempering cycles increases, the yield strength and tensile strength decrease at the expense of fracture elongation. At 600 and 650℃, the yield strength and tensile strength increase with increasing the number of tempering cycles while fracture elongation maintains similar values. The multiple tempering at the same tempering time of 4 h improves the modulus of toughness at all tempering temperatures, which is presumed to be due to the change in carbide precipitation behavior by multiple tempering.

• 접착 및 계면
• /
• 제20권1호
• /
• pp.15-22
• /
• 2019

Polybutadiene diol (PBD)과 isophorone diisocyanate (IPDI)의 반응을 통하여 이관능 우레탄 아크릴레이트 올리고머 (PB-UAO)를 합성하고, 여기에 삼관능 아크릴레이트 모노머 (Tris(2- acryloyloxyethyl) isocyanurate (TAOEIC), 또는 Trimethylolpropane triacrylate (TMPTA) 또는 Pentaerythritol triacrylate(PETA)), 단관능 아크릴레이트 모노머 (Stearyl Acrylate) 그리고 광개시제를 혼합한 후 이형필름 위에 코팅하고 자외선 경화를 통하여 감압 점착 필름을 제조하였다. 삼관능 아크릴레이트 모노머의 구조 및 함량에 따른 감압 점착제의 박리강도, 인장강도, 신율, 열안정성 및 흡습 특성의 변화를 고찰하였다. 삼관능 아크릴레이트 모노머의 함량이 증가할수록, 그리고 분자량이 작을수록 감압 점착 필름의 박리강도, 연신율 및 흡습율은 감소하는 경향을 보였으며, 인장강도 및 열안정성은 증가하는 것을 확인하였다.

• 한국식품영양과학회지
• /
• 제30권3호
• /
• pp.494-499
• /
• 2001

어분으로부터 추출한 어분 단백질을 이용하여 가식성 및 생분해성 필름을 제조할 때, 어분 단백질의 추출 시간을 달리하여 제조된 필름의 수증기 투과도, 인장강도, 신장률 및 용해도의 변화를 측정한 결과는 다음과 같다. 어분단백칠 추출시간이 FMPI 필름의 수증기 투과도에 미치는 영향은 크지 않았다. 가소제로써 glycerol을 첨가한 필름의 수증기 투과도가 sorbitol을 첨가한 필름보다 높았다. 인장강도의 신장률은 어분 단백질의 추출시간이 증가함에 따라 증가하다가 1시간일 때 가장 높았으며 그 이상 추출시간이 증가함에 따라 감소 하였다. 총 용해물질의 함량과 수용성 단백질 함량은 어분 단백질의 추출시간이 증가함에 따라 감소하였다가 1시간일 때 가장 낮았으며, 추출시간이 1시간 이상 증가함에 따라 증가하였다. 필름의 수용성 단백질 함량과 인장강도와 신장률은 음의 상관 관계를 나타내었으며 신장률($r^{2}=0.62$)보다는 인장강도($r^{2}=0.83$)가 수용성 단백질의 함량과 밀접한 상관관계를 나타내었다.

• 열처리공학회지
• /
• 제24권5호
• /
• pp.271-276
• /
• 2011

The effect of grain size on the deformation induced martensite transformation and mechanical properties in austenitic stainless steel with high amount of Mn was studied. a'-martensite was formed by deformation and deformation induced martensite was formed with surface relief. With increase of grain size, volume fraction of deformation induced martensite was increased. With the increase in degree of cold rolling, hardness, and tensile strength was rapidly increased with linear relationship, while, elongation was decreased rapidly and then decreased slowly. With increase of grain size, hardness and tensile strength was rapidly increased with linear relationship, while elongation was decreased rapidly. The hardness, tensile strengths, and elongation were more strongly influenced by deformation induced martensite than the grain size.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 1994년도 박판성형기술의 진보
• /
• pp.11-23
• /
• 1994

Formability of sheet metals can be evaluated using tensile testing. Easily measured tensile properties such as yield strength, tensile strength, elongation, strain hardening exponent, strain rate sensitivity and plastic strain ratio are important parameters to evaluated the sheet formability. This paper briefly explains how these properties are related to deep drawability and stretchability. The plastic anisotropy of sheet metals is usually attributed to the crystallographic texture. However dislocation distribution may influence the anisotropy.

• 대한치과보철학회지
• /
• 제35권2호
• /
• pp.330-343
• /
• 1997

Extraoral maxillofacial prostheses are essential for restoring facial structures that are lost as a result of congenital missing, injuries from accidents, surgical treatments of head and neck cancer. Recently, silicone is the most useful material for this purpose and is more advantageous than other maxillofacial prosthetic materials. However, there are some problems for long-term usage of silicone prostheses due to tear and color change. These are major contributing environmental factors to those problems that are such as ultraviolet light, cleansing agents, changes in humidity and successive adhesion and removal. The aim of this study is to evaluate the physical properties and color changes of maxillofacial prosthetic silicone material by those environmental factors using A-2186 silicone material (Factor II, USA) and two pigments, cadmium yellow medium and cosmetic red. Aluminium molds were fabricated according to the ASTM No. D412 & D624 specifications and resulted specimens from molds were fabicated and treated as follows. Control group and experimental I group were fabricated with 0.1% wt. pigment mixing in silicone elastomer and II-1 group, II-2 group of experimental II group were fabricated with 0.2%, 0.3% wt. pigment mixing in silicone elastomer, respectively. Control group was kept in darkroom at room temperature, I-1 group was kept under natural sunlight during 1week, I-2 group was soaked in 20% soap water during 1wk. I-3 group was successively adhered and removed 200 times on inner region of arm using Daro adhesive-33. Experimental II groups were kept in darkroom at room temperature. Instron universal testing machine was used to measure the % elongation, tensile strength, tear strength of control, experimental I, II groups and reflectance spectrophotometer(COLOR EYE-3000, Macbeth, USA) was used to measure the color differences between control group and experimental I group. The results were as follows : 1. When compared with control group, natural weathering group and 20% soap-water soaking group had no significant differences in % elongation(p>0.05). 2. 200 times successive adhesion and removal group, 0.2% wt. pigment group and 0.3% wt. pigment group had significant decreases in % elongation(p<0.05). 3. Natural weathering group, 20% soap-water soaking group and 200 times successive adhesion and removal group had no significant differences in tensile strength (p>0.05). 4. 0.2%, 0.3% wt. pigment groups had significant decreases in tensile strength(p<0.05). 5. Values of all experimental groups were decreased in tear strength. and 200 times successive adhesion and removal group had significant decrease in tear strength(p<0.05). 6. Natural weathering group and 20% soap-water soaking group had significant color differences(${\Delta}E$) and it could be detectable to naked eye(p<0.05). 7. Color differences between control group and 200 times adhesion and removal group were not detectable to the naked eye (${\Delta}E<1.0$).