• 대한용접접합학회:학술대회논문집
• /
• 대한용접접합학회 2006년도 춘계 학술대회 개요집
• /
• pp.89-91
• /
• 2006

• 대한용접접합학회:학술대회논문집
• /
• 대한용접접합학회 2005년도 춘계학술발표대회 개요집
• /
• pp.279-281
• /
• 2005

• 대한용접접합학회:학술대회논문집
• /
• 대한용접접합학회 2005년도 추계학술발표대회 개요집
• /
• pp.150-151
• /
• 2005

High capacity container carrier has been considered for many decades to transport the more containers at the same time. Therefore, it is required for high capacity container ship to be applied thicker plate to accomodate a mumber of containers compared to that of general container ship. To increase productivity of welding, new welding process should be considered. A representive process for increase of weld productivity is EGW(Electrode Gas Welding) process. Both sides EGW process was evaluated for thicker-plate TMCP Steel. From the test result, it is considered that this process can be applied, showing satisfaction of mechanical properties such as tensile strength and impact property.

• Corrosion Science and Technology
• /
• 제3권2호
• /
• pp.81-86
• /
• 2004

The sulfide stress corrosion cracking (SSCC) resistance of API X70 grade steel weldment has been studied using SSCC test in NACE TM-O177 method A. Also, microstructures and hardness distribution of weldment was investigated. The microstructure of SAW joint composed ferrite, pearlite and some MA constituent. Instead of hardening in CGHAZ, softening on the HAZ near base metal occurred. The low carbon TMCP type steel used for SAW showed softening behaviour in the HAZ adjacent to base metal, which was known to be closely related with the SOHIC (stress oriented hydrogen induced cracking). The SSC testing revealed that the API X70 SAW weld was suitable for sour service, satisfying the NACE requirements. By suppressing softening in the ICHAZ region, the SSCC resistance of low carbon TMCP steel welded joints could be more improved.

• 대한용접접합학회:학술대회논문집
• /
• 대한용접접합학회 2004년도 추계학술발표대회 개요집
• /
• pp.101-102
• /
• 2004

This study was investigated on the impact toughness and microstructure of welded metal and heat affected zone for B grade steel. With welding procedures, welding heat inputs applied were 30, 79 and 264 kJ/cm, Prior austenite grain size in coarse zone has increased with increasing welding heat input for B grade steel. The toughness of fusion line zone of Bgrade steel has decreased with increasing welding heat input while the toughness fusion line +3 and +5 mm zone increased contrarily.

• 한국해양공학회지
• /
• 제2권1호
• /
• pp.125-134
• /
• 1988

The feasibility for improving the cooling rates and mechanical properties of wet welding process is experimentally investigated by using new developed underwater wet electrodes and H.T. steel plates. Main results of this experimental study can be summarized as follows; 1) By shielding around weld arc surrounding, the cooling rates resulting from wet welds with developed electrodes on TMCP steel plates can be lower than of non-shielded wet welds. 2)A high quality of mechanical properties of wet welds on TMCP steel plates can be obtained with shielded weld arc surrounding.

• 대한용접접합학회:학술대회논문집
• /
• 대한용접접합학회 2005년도 춘계학술발표대회 개요집
• /
• pp.276-278
• /
• 2005

Bridge constructed recently is preferred to have a long span and a simple structure detail considering not only functions as bridge but scenic beauty, maintenance, construction term and life cycle cost, etc. Therefore, it demands a high quality steel like a thick plate steel and a high performance steel. A TMCP steel produced by theme-mechanical control process is now spotlighted due to the weldability for less carbon equivalent. It improved at strength and toughness in microstructure. Resently the SM570-TMC steel, a high strength TMCP steel whose tensile strength is 600MPa, is developed and applied to steel structures. But, for the application of this steel to steel structures, it is necessary to elucidate not only the material characteristics but also the mechanical characteristic of welded joint. In this paper, we investigated the characteristics of residual stresses generated by welding of SM570-TMC steels through an experimental study

• Journal of Welding and Joining
• /
• 제32권1호
• /
• pp.6-14
• /
• 2014

This paper has an aim to evaluate microstructure and fracture toughness of TMCP steel weldment applied for off-shore wind tower with the focus on the effect of heat input on the weldment with various welding processes; FCAW(13kJ/cm and 30kJ/cm), SAW(62kJ/cm), and EGW(177kJ/cm). Based on experimental results developed from this study, it was found that the impact toughness of top side for TMCP steel weldments with heat input up to 62 kJ/cm satisfied the required minimum value except the EGW(177kJ/cm). The heat input and microstructure are the main factors of impact toughness. The heat input of 13kJ/cm on back side with low heat input increased the amount of grain boundary ferrite which has low impact toughness, and heat input of 177kJ/cm on top side is significant enough to produce the austenite grain growth. The compositions and sizes of inclusions which are the dominant factors for the formation of acicular ferrite were analyzed by OM and EDS. As the heat input increased, the inclusions also grew and a nucleation site decreased. The size of nonmetallic inclusions and the crack width was nearly similar, therefore the inclusions were related with the crack propagation.

• 한국산학기술학회논문지
• /
• 제13권6호
• /
• pp.2465-2471
• /
• 2012

선박이나 심해저 해양플랜트와 같이 가혹한 해양환경에서 사용되는 강구조물에서 부식피로는 설계수명과 관련하여 해결을 요하는 중요한 문제이다. 본 연구에서는 전기방식중 과도한 전기방식이 부식피로균열 전파거동에 미치는 영향을 고찰하기 위하여 근래 사용이 확대되고 있는 고장력 TMCP에 대하여 합성해수중 -950mV vs. SCE의 과방식 인가전압 환경에서 부식피로균열 전파시험을 실시하고 da/dN-${\Delta}K$ 선도를 구하였다. 이 선도에서 저 ${\Delta}K$ 영역에서는 해수중 전파속도보다 빠른 균열전파속도를 나타내었으나, 고 ${\Delta}K$영역으로 갈수록 해수중 보다 늦은 균열전파속도를 나타내었다. 부식피로균열 전파속도에 영향을 미치는 인자로서 가속요인과 감속요인으로 나누고 각각 수소기체와 석회질생성물의 역할에 대하여 고찰하였다.

• 한국산업융합학회 논문집
• /
• 제26권1호
• /
• pp.87-94
• /
• 2023

TMCP(Thermo Mechanical Control Process) steel was continuously cast (CC) by varying the argon gas flow rate and vacuum time in the Ruhrstahl Heraeus (RH) refining process. Using the CC specimens, the distribution of the inclusions and the mechanical properties were evaluated. A lot of oxides and Al-O type inclusions were observed. The average Vickers hardness did not show a constant, but showed dispersion in a certain range. The shape and scale parameters of the CC specimen with an argon gas flow rate of 160Nm³ and a vacuum time of 12 minutes was the best. Mechanical properties (tensile strength, yield strength and elongation) were consistent with the Weibull probability distribution analysis results. The impact resistance was the best for CC specimens with an argon flow rate of 140 Nm³ and a vacuum time of 12 minutes. Although the inclusions and mechanical properties of the CC specimens were evaluated according to the argon gas flow rate and vacuum time, these values were no significant difference.