• 제목/요약/키워드: Stainless Steels

검색결과 536건 처리시간 0.023초

음극 인가전위 하에서 type 2205과 type 316L의 수소취성 저항성 (Comparison of hydrogen embrittlement resistance between 2205 duplex stainless steels and type 316L austenitic stainless steels under the cathodic applied potential)

  • 서동일;이재봉
    • Corrosion Science and Technology
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    • 제15권5호
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    • pp.237-244
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    • 2016
  • 2205 duplex stainless steels have been used for the construction of the marine environment, because of their excellent corrosion resistance and high strength. However, the resistance to hydrogen embrittlement (HE) may be less than that of 316L austenitic stainless steel. The reason why 316L stainless steels have better resistance to HE is associated with crystal structure (FCC, face centered cubic) and the higher stacking faults energy than 2205 duplex stainless steels. Furthermore 2205 stainless steels with or without tungsten were also examined in terms of HE. 2205 stainless steels containing tungsten is less resistible to HE. It is because dislocation tangle was formed in 2205 duplex stainless steels. Slow strain-rate tensile test (SSRT) was conducted to measure the resistance to HE under the cathodic applied potential. Hydrogen embrittlement index (HEI) was used to evaluate HE resistance through the quantitative calculation.

냉간가공을 통한 중성자조사된 오스테나이트 스테인리스강의 기계적물성 모사 타당성 분석 (Feasibility Analysis of Simulation on the Mechanical Properties of Neutron Irradiated Austenitic Stainless Steels by Cold-working)

  • 김진원;김윤재
    • 한국압력기기공학회 논문집
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    • 제15권2호
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    • pp.9-18
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    • 2019
  • The objective of this study is to investigate the feasibility of simulating the mechanical properties of irradiatied austenitic stainless steels by cold-working. In this study, the tensile properties, cyclic hardening behaviors and fracture toughness of cold-worked TP316L stainless steel were compared with those of austenitic stainless steels irradiated by neutrons. It showed that cold-working can properly simulate the increase in strength and the decrease in ductility and fracture resistance of austenitic stainless steels by neutron irradiation, even though it could not perfectly simulate the microstructures of irradiated austenitic stainless steels. Also, cold-working can appropriately simulate the hardening behaviors of neutron irradiated austenitic stainless steels under monotonic and cyclic loading conditions.

Effect of Hydrogen Charging on the Mechanical Properties of 304 Stainless Steels

  • Lee, Sang-Pill;Hwang, Seung-Kuk;Lee, Jin-Kyung;Son, In-Soo;Bae, Dong-Su
    • 동력기계공학회지
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    • 제19권5호
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    • pp.73-79
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    • 2015
  • The effects of hydrogen charging on the mechanical properties of 304 stainless steels were investigated in conjunction with the detailed examinations of their fracture modes. The dependence of the absorbed impact energy and the surface hardness of the 304 stainless steels on the hydrogen charging time was characterized. The tensile properties of the 304 stainless steels by the variation of cross-head speed were also evaluated at the room temperature. The hydrogen charging was performed by an electrolysis method for all specimens of the 304 stainless steels. The mechanical properties of the 304 stainless steels exhibited the sensitivity of embrittlement due to a hydrogen charging. The correlation between mechanical properties and fracture surfaces was discussed.

배기다기관용 주강소재의 고온특성 평가 (Characterization of High Temperature Mechanical Properties of Cast Stainless Steels for Exhaust Manifold)

  • 이규동;하태권;정재영
    • 소성∙가공
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    • 제18권3호
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    • pp.217-222
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    • 2009
  • Automobile industries have been focusing their efforts on the development of exhaust manifolds using high temperature stainless steels. Exhaust manifolds fabricated with stainless steels can be categorized into tubular and cast ones. The former is usually manufactured by forming and welding process and the latter by vacuum casting process. In the present study, high temperature mechanical properties of 5 austenitic and 4 ferritic stainless steels were investigated by performing a series of high temperature tensile and low cycle fatigue tests. One of the austenitic stainless steels was vacuum cast and the others sand cast. Fatigue life of ferritic stainless steels was higher than that of austenitic ones.

Effect of Hydrogen Charging Time and Tensile Loading Speed on Tensile Properties of 304L Stainless Steels

  • Hwang, SeungKuk;Lee, Sangpill;Lee, Jinkyung;Bae, Dongsu;Lee, Moonhee;Nam, Seunghoon
    • 한국산업융합학회 논문집
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    • 제22권1호
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    • pp.11-20
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    • 2019
  • This study dealt with the tensile strength characteristics of stainless steel 304L steel by hydrogen charging. Especially, the effect of hydrogen charging time on the tensile strength and ductility of 304L stainless steels was evaluated, in conjunction with the observation of their fracture surfaces. The tensile properties of hydrogen-charged 304L stainless steels were also investigated with the variation of tensile loading speeds. The hydrogen amount of 304L stainless steels obviously increased with the increase of hydrogen charging time. The tensile properties of 304L stainless steels were clearly affected by the short term charging of hydrogen. In particular, the elongation of 304L stainless steels decreased with increasing hydrogen charging time, due to the hydrogen embrittlement. It was also found that the tensile properties of hydrogen-charged 304L stainless steels were very sensitive to the crosshead speed for tensile loading.

다층형 벨로우즈의 성능에 미치는 스테인리스강 물성의 영향 (Effect of Stainless Steel Properties on Performance of Multi-layer Bellows)

  • 서창희;오상균;정윤철;이락규;박명규;김영석
    • 소성∙가공
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    • 제18권3호
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    • pp.223-228
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    • 2009
  • Generally ferritic stainless steels are used for parts of exhaust system in commercial vehicle, because they have many advantages as low price and high corrosion resistant compared with austenitic stainless steels. Even though ferritic stainless steels have such various merits, austenitic stainless steels have been used to manufacture multi-layer bellows with complex geometry because of their high ductility. Recently, the mechanical properties of the ferritic stainless steels are getting improved and alternating austenitic stainless steel. In this paper, the possibility of mass production of multi-layer bellows made of ferritic stainless steel like MH1 and 443CT was studied. Tensile test, ridging test and corrosion test were carried out to observe material properties of STS304, MH1 and 443CT. Three types of prototype bellows were made using STS304, MH1 and 443CT stainless steels, and stiffness and fatigue tests were carried out to evaluate performance of the prototype bellows.

Development and Application of High-Cr Ferritic Stainless Steels as Building Exterior Materials

  • Kim, Yeong H.;Lee, Yong H.;Lee, Yong D.
    • Corrosion Science and Technology
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    • 제7권6호
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    • pp.324-327
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    • 2008
  • Stainless steels have been widely used as a building exterior materials in Asian countries for the last decade. It is required for the materials in this field to have an aesthetic appearance, a relatively high strength, and an excellent corrosion resistance. Other metallic materials such as copper, aluminum, and carbon steels have been also used as the exterior materials. Considering the cost of maintenance, stainless steel, having the outstanding corrosion resistance, is replacing other materials in the several parts in the building exteriors. Ferritic stainless steel has been applied as the roofing materials because its thermal expansion is much smaller than that of austenitic stainless steel. Therefore, it is suitable for the large-scale construction such as airport terminal, convention center, and football stadium. To improve the corrosion resistance of the ferritic stainless steels, the modification of alloy composition has been studied to develop new grade materials and the progress in the surface technology has been introduced. Corrosion properties of these materials were evaluated in the laboratory and in the field for longer than two years. High-Cr ferritic stainless steel showed excellent corrosion resistance to the atmospheric environments. In the region close to the sea, the corrosion resistance of high-Cr ferritic stainless steel was much superior to that of other materials, which may prove this steel to be the appropriate materials for the construction around seashore. In some of the large constructions around seashore in South Korea, high-Cr ferritic stainless steels have been used as the building exterior materials for six years.

Effect of alloying Copper on the Corrosion Resistance of Stainless Steels in Chloride Media

  • Ujiro, T.;Satoh, S.;Staehle, R.W.;Smyrl, W.H.
    • Corrosion Science and Technology
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    • 제2권3호
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    • pp.127-134
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    • 2003
  • In order to explain the effect of alloying Cu on the corrosion resistance of stainless steels in chloride media for both ferritic and austenitic stainless steels, the corrosion behavior of Cu-bearing stainless steels was investigated. Alloying Cu showed beneficial effect in an active potential range and harmful effect in a noble potential range. The beneficial effect of alloying Cu was explained by the stability of deposited Cu on an anodic surface. Difference in the effect of alloying Cu between the ferritic and austenitic steels was ascribed by the differences in their corrosion potentials and the morphology of the deposited Cu.

스테인레스강의 가스질화 후 내식특성에 미치는 열처리조건의 영향 (Effects of Heat Treatment on Corrosion Resistance Properties of Gas Nitrided Stainless Steels)

  • 김한군;김용현
    • 열처리공학회지
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    • 제22권5호
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    • pp.298-306
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    • 2009
  • Gas nitriding and post oxidation were performed on stainless steels and SACM 645 steel. With increasing gas nitriding time, the increasing rate of nitrided layer was most rapid on SACM 645 steel and the nitriding depth of nitrided layer was most narrow on STS 304 steel among three steels. Corrosion resistance was increased with post oxidation on stainless steels and with increasing time the effect of corrosion resistance was decreased to compare with relatively short gas nitriding time. An improvement effect of corrosion resistance was consisted of predominantly on austenitic stainless steel by post oxidation after gas nitriding among three steels and it was relatively less influenced on martensitic stainless steel.

Cryogenic Fracture Toughness Evaluation for Austenitic Stainless Steels by Means of Unloading Compliance Method

  • Yu, Hyo-Sun;Kwon, Il-Hyun
    • Journal of Mechanical Science and Technology
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    • 제15권1호
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    • pp.26-34
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    • 2001
  • Most research to date concerning the cryogenic toughness of austenitic stainless steels has concentrated on the base metal and weld metal in weldments. The most severe problem faced on the conventional austenitic stainless steel is the thermal aging degradation such as sensitization and carbide induced embrittlement. In this paper, we investigate the cryogenic toughness degradation which can be occurred for austenitic stainless in welding. The test materials are austenitic stainless JN1, JJ1 and JK2 steels, which are materials recently developed for use in nuclear fusion apparatus at cryogenic temperature. The small punch(SP) test was conducted to detect similar isothermally aging condition with material degradation occurred in service welding. The single-specimen unloading compliance method was used to determine toughness degradation caused by thermal aging for austenitic stainless steels. In addition, we have investigated size effect on fracture toughness by using 20% side-grooved 0.5TCT specimens.

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