Welded structure with excellent brittle crack propagation stop characteristics

A technology of brittle crack propagation and stop characteristics, which is applied in welding equipment, welding equipment, auxiliary welding equipment, etc., can solve the problem of high safety assurance, and achieve the effect of ensuring safety and excellent brittle crack propagation stop characteristics

Active Publication Date: 2021-03-26
JFE STEEL CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Therefore, in the hull structure to which thick-walled high-strength steel plates with a plate thickness of 50 mm or more are applied, ensuring safety becomes a major issue.

Method used

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  • Welded structure with excellent brittle crack propagation stop characteristics
  • Welded structure with excellent brittle crack propagation stop characteristics
  • Welded structure with excellent brittle crack propagation stop characteristics

Examples

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Embodiment

[0097] Hereinafter, the present invention will be described in detail based on examples.

[0098] Using thick steel plates with the plate thicknesses shown in Table 1-1 and Table 1-2 as joining members (webs), doubling members and members to be joined (flanges), manufactured Figure 4 (a), (b), (c) and Figure 5 Large welded structural joints of actual structural dimensions in shapes shown in (a), (b), and (c). Figure 4 (a), (b), and (c) are diagrams assuming the occurrence / propagation of brittle cracks from the member to be joined (flange), Figure 5 (a), (b), and (c) are diagrams assuming a case where a brittle crack occurs / propagates from a joint member (web). It should be noted that, in the manufactured fillet joint, the ratio Y of the unwelded portion (=(width B of the unwelded portion / plate width of the doubled member Wd)) changes and exists figure 1 (a) Unwelded portion 4 as shown. It should be noted that no unwelded portion remained on the butt surface of the joi...

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Abstract

A welded structure in which a doubling member whose plate thickness td to a plate width Wd ratio td / Wd is less than 2 is overlapped on the surface of a member to be joined with a plate thickness of 50 mm or more and joined by fillet welding, and then the fillet welded doubling member The surfaces join the joining members with welding to form a welded structure. On the overlapping surface of the surface of the double member and the surface of the member to be joined, there is formed an unwelded portion which is 95% or more of the plate width Wd of the double member in the cross section of the joint. Also, adjust the fillet welding conditions so that the critical fracture transition temperature vTrs (°C) of the fillet weld metal corresponds to the fillet length L and in the relationship with the plate thickness tf of the members to be joined, in the case of L ≥ 20mm Adjust fillet welding by satisfying vTrs≤‑5L+65‑1.5(tf‑75)‥‥(1b), and satisfying vTrs≤‑35‑1.5(tf‑75)‥‥(1c) in the case of L<20mm toughness of seam metal. Accordingly, it is possible to provide a welded structure which can prevent the propagation of brittle cracks generated from the joined member or the joined member by the fillet weld metal portion and is suitable as a ship hull structure and has excellent brittle crack propagation stop characteristics.

Description

technical field [0001] The present invention relates to a welded steel structure, such as a large container ship or a bulk carrier, that is constructed by welding using a thick steel plate, and particularly relates to a structure that can prevent the propagation of a brittle crack generated from a thick steel plate base material or a welded joint before reaching the structure. A welded structure that stops before large-scale failure and has excellent brittle crack propagation stop characteristics. Background technique [0002] A container ship or a bulk carrier has a structure in which there are few partition walls in the hold and a large opening in the upper part of the ship, unlike an oil tanker, for example, in order to improve loading capacity or loading and unloading efficiency. Therefore, in a container ship or a bulk carrier, it is necessary to increase the strength or thicken the hull plating especially. [0003] In addition, container ships have increased in size i...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B23K37/00B23K37/02
CPCB23K9/00B23K9/02B23K31/00B63B73/43B23K9/0026B23K9/0206
Inventor 半田恒久伊木聪大井健次丰田昌信木治升
Owner JFE STEEL CORP
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