Welded structure excellent in brittle-cracking propagation stopping characteristics

A technology of brittle crack propagation and welding structure, which is applied in welding equipment, hull, ship construction, etc., can solve the problem of reduced fracture toughness and achieve the effect of reducing the total cost

Active Publication Date: 2009-05-27
JFE STEEL CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0008] However, in recent large container ships exceeding 6,000 TEU, the plate thickness of the steel plate exceeds 50 mm. In addition to the decrease in the fracture toughness due to the effect of the plate thickness, the welding heat input also becomes larger. Therefore, the fracture toughness of the welded part (fracture toughness) has a tendency to further decrease
[0009] Recently, tests have shown that in such thick heat input weld joints (large heat input weld joint of heavy gauge steel plate), the brittle cracks generated from the

Method used

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  • Welded structure excellent in brittle-cracking propagation stopping characteristics
  • Welded structure excellent in brittle-cracking propagation stopping characteristics
  • Welded structure excellent in brittle-cracking propagation stopping characteristics

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Embodiment

[0074] Using steel plates with various plate thicknesses and brittle crack propagation stopping toughness (Kca at -10°C), various unwelded portion ratios X (width n of unwelded portion to the plate thickness of web 1 The ratio of t to the sum L of the leg lengths 3 (3a, 3b) of the left and right fillet welds of the web 1) is a T-shaped fillet weld joint 9. The T-shaped fillet welded joint 9 is manufactured when the web 1 is only a steel plate base material and when the web 1 has a butt welded joint 11 . In addition, the butt weld joint 11 is welded by single-pass high-energy input (in Table 2, it is expressed as EGW (electro gas arc) or 2-electrode EGW) or multi-layer CO 2 Welding (multi-layer carbon-dioxide welding) production.

[0075] Manufactured using the obtained T-shaped fillet weld joint 9 Figure 3A , Figure 3B The cross-shaped ESSO test piece shown is for the brittle crack arrestability test (ESSO test). For the cross-shaped ESSO test piece, the web 1 and the st...

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Abstract

Provided is a welded structure suitable for a hull structure and excellent in brittle-cracking propagation stopping characteristics. The welded structure is provided with a fillet welded joint having an unwelded portion (4) left on the abutting face of a web (1) against a flange (2). A percentage (X) (= 100/L) (%) to the sum (L) of the width (n) of the unwelded portion (4) and the leg length (3 (3a and 3b)) of the left and right fillet welded joints in the joint section of the fillet welded joint, and the brittle-cracking propagation stopping toughness (Kca (N/mm3/2)) at the using temperature of the flange satisfy X (%) >= {5900 - Kca(N/mm3/2/85. The unwelded portion (4) in the fillet-welded joints is given a width of 15 to 90 % of the sum of the thickness (t) of the web (1) and the leg length (3 (3a and 3b)) of the left and right fillet welded joints. In case the web has the butt-welded joint portion of the thickness (t), the percentage (X) (%) and the brittle-cracking propagation stopping toughness (Kca)(N/mm3/2) satisfy the aforementioned formula.

Description

technical field [0001] The present invention relates to a base metal and welding of a welded structure that may occur in, for example, a mega-container carrier and a bulk carrier using a steel plate. A welded structure having excellent brittle crack arrestability (brittle crack arrestability) in which the propagation of brittle cracks on weld joints stops before large-scale failure, specifically, a fillet welded joint (fillet welded joint) A welded structure with excellent brittle crack stop characteristics that generates brittle cracks on the joined member (web) of the joint and stops the propagation of the brittle crack to the joined member (flange). Background technique [0002] The structure of the container ship and the bulk carrier which are welded structures has an enlarged upper aperture in order to increase the carrying capacity and improve the handling efficiency. Therefore, in order to secure the rigidity and longitudinal strength of the hull, it is necessary to ...

Claims

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Application Information

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IPC IPC(8): B23K9/02B23K9/00B63B3/34
CPCB23K33/00B23K33/004F16L57/02B23K9/0256B63B3/34
Inventor 半田恒久久保高宏川端文丸村冈隆二潮海弘资中岛喜之丰田昌信中西保正木治昇
Owner JFE STEEL CORP
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