• Title/Summary/Keyword: 필릿용접 강도

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Effects of Plate Thickness and Weld Size on the Strength of Fillet Welded Lap Joints (모재의 두께와 용접치수에 따른 필릿용접부의 강도)

  • Jo, Jae Byung;Jung, Kyoung Sup;Lee, Jeong Woo
    • Journal of Korean Society of Steel Construction
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    • v.18 no.3
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    • pp.331-337
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    • 2006
  • Specimens with fillet-welded lap joints were fabricated from 20 mm, 60 mm, and 82 mm thick steel plates produced by Thermo Mechanical Control Process. The designed sizes of filet welds were betwen 6 mm and 16 m. The welds' axes were parallel with or perpendicular to the direction of loading or a combination of them. Specimens were axialy loaded in tension and the strength of fillet-welded joints were measured. Test results showed that the strengths of filet-welded joints are higher than the nominal strengths calculated for all the cases tested, and also approximately on the same level regardless of plate thickness and fillet weld size. Especially, the specimens with weld size les than that required by Korean design rules showed no visible defects on welds and also no str ength reduction.

Proposal of Estimation Equation for Nominal Strength of Longitudinal Fillet Welds with Different Types of Steel (강종에 따른 종방향 필릿용접부 공칭강도 계산식의 제안)

  • Jo, Jae-Byung;Lee, Hye-Youn
    • Journal of Korean Society of Steel Construction
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    • v.24 no.5
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    • pp.503-510
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    • 2012
  • High performance, high strength steels were developed and used in steel structures recently. Since the newly developed high strength steels posses different toughness, weldability, yield strength ratio, etc. in compare with conventional structural steels, it is requred to investigate the applicability of the design strength of fillet weld specified in the existing design codes. The comparison of the design strengths of various codes from domestic and overseas shows quite a difference. Test results for fillet weld strengths were collected and statistically analysed. Each of yield strength, tensile strength of parent material and tensile strength of weld metal was selected as a main parameter for each estimation equation respectively. All the estimation equations yield almost same values for each type of steel regardless the type of main parameter selected. Considering the behaviour of fillet welded joints and for practical purposes, it is proposed that the equation with tensile strength of parent material is to be used in design codes. The comparison with the proposed nominal strengths of fillet welds shows that the existing design codes could lead to an uneconomical result for low strength steels and lie on an unsafe side for high strength steels.

A Study on Characteristics of Fatigue Failure and Fatigue Life in Full Penetrated Cruciform Fillet Weld Zone (완전 용입 십자형 필릿용접부에서 피로파괴특성과 피로수명에 관한 연구)

  • Lee, Yong-Bok
    • Journal of the Korean Institute of Gas
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    • v.16 no.4
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    • pp.16-22
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    • 2012
  • The use of welding process has been increased for manufacture of machine, bridges, ships, gas facilities and so on together with development of welding technique. Accordingly, it has been needed to develop the welding methods considering higher productivity and safety design for manufacture of their welding structures. In this study, it was studied basically on characteristics of fatigue strength and fatigue life in full penetrated cruciform fillet weld zone in relation to material thickness, welding passes, loading direction and notch radius of toe zone. Most of fatigue failure occurred in toe zone of cruciform fillet weld joint. Fatigue strength and fatigue life are under the influence of stress concentration due to notch radius and flank angle of toe zone. The metal of toe zone annealed and diffused by multi-layer welding and acicular ferrite structure formed by the result improved fatigue strength and fatigue life.

A Study on Estimation of Infinite Fatigue Life in Cruciform Fillet Welded Joint (십자형 필릿 용접부에서의 무한 피로수명 평가에 관한 연구)

  • Lee, Yong-Bok
    • Journal of the Korean Institute of Gas
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    • v.17 no.1
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    • pp.19-25
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    • 2013
  • The joining methods of steel structures of gas facilities, bridges, ships etc. by welding are composed mostly of T-type or cruciform fillet welding and full penetration or partial penetration according to the uses and the shape of the structures. In this study, it was examined the characteristics of fatigue crack according to penetration depth in relation to material thickness in the cruciform fillet welded joints. From the results, it was investigated the safe design stresses within the range of infinite life. When the LOP length is long the range of infinite life is small with root failure and when the LOP length is short the range of infinite life is large with teo failure. For the specimen of material thickness, 20mm welded by 3 pass compared with 10mm, 15mm welded by 2 pass, the fatigue strength and the range of infinite life was more improved by increasing of notch toughness from formation of micro-ferrite acicular structure.

A Study of Assessment for Fatigue Strength of EH Steels at Fillet Welded Joints using 1mm Stress Method (1mm 응력 기법을 적용한 EH 강재 필릿 용접 이음부 피로 강도 평가)

  • Xin, Wen-Jie;Oh, Dong-Jin;Kim, Young-Nam;Kim, Myung-Hyun
    • Journal of the Society of Naval Architects of Korea
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    • v.51 no.1
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    • pp.26-33
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    • 2014
  • In this study, Non-load-carrying EH Grade steels in fillet welded joints were evaluated with both the hot spot stress method and the 1mm stress method. The thickness effect criterion for fatigue strength evaluation of welded of welded steel structures recommendations of the IIW was used to evaluate the fatigue strength of EH40 and EH36 and Both EH40 and EH36 have been compared with FAT 125 curve recommended in the IIW. Furthermore, fatigue strength of the welded tow and the ground conditions for Non-load-carrying EH36 based on the 1mm stress method has been discussed.

Evaluation of Mechanical Test Characteristics of Fillet Welding (필릿 용접의 기계적 시험 특성 평가)

  • Cho, Byung-Jun;Lee, Soung-Jun;Rhim, Jong-Guk
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.2
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    • pp.535-541
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    • 2020
  • FCAW is used mainly in the welding of carbon steel and alloy steel because it can be welded in all positions and can obtain excellent quality at sites with variable working conditions. Recently, many studies in Korea have estimated the fatigue strength, residual stress, and deformation, and to develop a fillet welding process. On the other hand, there have been few studies of the mechanical properties based on the strength, macro and magnetic particle test results for fillet welding. This study shows the following results through fillet welding, macro testing and strength testing using SM490A (solid-structure rolled steel) for thick plates using SS400 (rolled steel) for the upper plate and FCAW. The hardness test, macro test and magnetic particle test were then conducted. The hardness tests showed that all result values were smaller than the KS B 0893 standard values of 350Hv. The macro-test showed that each type of welded part was in a normal organic state and that there were no internal errors, bubbles, or impurities on the front of the welded part. Therefore, there were no concerns about lamination. The magnetic particle examination showed no problems.

Fatigue Strength of Fillet Weldment under Out-of-plane Bending Load (필릿 용접부의 면외굽힘하중에 대한 피로강도)

  • 강성원;한상혁;김화수;백영민
    • Journal of the Society of Naval Architects of Korea
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    • v.40 no.1
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    • pp.28-35
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    • 2003
  • Fatigue tests of transverse fillet weldment were performed under out-of-plane bending loads. Significant increase of the fatigue strength was observed under out-of-plane bending loads, compared to the one under in-plane loads (axial loads). Applicability of the crack propagation analysis using LEFM for the surface crack of fillet weldment were investigated as well, in parallel with the fatigue tests. For the rational assessment of the fatigue strength of welded ship structures where combined stresses of the in-plane axial stress and the out-of-plane bending stress are induced simultaneously due to complexity of applied load and structural geometry, further investigation is recommended for the effect of the out-of-plane bending stress on the fatigue strength of weldment.