高強度鉄筋の溶接性に関する調査研究（その２）：熱影響部破断による評価

• 矢部 喜堂

  (公社)日本鉄筋継手協会

• 成原 弘之

  大成建設(株)技術センター都市基盤技術研究部

• 中込 忠男

  信州大学

書誌事項

タイトル別名

• A STUDY ON WELDABILITY OF HIGH STRENGTH REINFORCING BARS (PART 2): EVALUATION BY HEAT-AFFECTED ZONE FRACTURE
• コウキョウド テッキン ノ ヨウセツセイ ニ カンスル チョウサ ケンキュウ(ソノ 2)ネツ エイキョウブハダン ニ ヨル ヒョウカ

抄録

 In the previous paper (Part 1) of this study, the weldability of high-strength reinforcing bars was evaluated from the viewpoint of the occurrence of weld cracks, and the effect of changes in the chemical compositions on weld cracks was experimentally investigated. As a result, it was found that when each index of chemical compositions such as carbon content (C), carbon equivalent (Ceq⁽¹⁾, Ceq⁽²⁾) and weld crack susceptibility composition (Pcm) was high, hot cracking (liquation cracking) occurred in the heat-affected zone near the bond.  In this paper (Part 2), we evaluated the weldability of high-strength reinforcing bars from the viewpoint of the occurrence of the fracture in the heat-affected zone, which is one of the important factors related to joint performance (toughness). The effect of changes of the chemical compositions on the fracture in heat-affected zone was investigated.  In the experiment in this report, the tensile tests of welded joint specimens were performed using several types of high-strength reinforcing bars having different chemical compositions to evaluate the occurrence of heat-affected zone fracture of the welded joints. At this time, a comparison was also made with the joints welded in a state of receiving the restraint stress.  Prior to the tensile tests of the welded joint, the hardness of the weld which may affect the fracture in the heat-affected zone was confirmed. In addition, the effect of the presence or absence of restraint stress during welding on the occurrence of weld cracking, which is considered to be one of the causes of the fracture in the heat-affected zone of the joint, was also confirmed.  Welding of the reinforcing bar joints in this experiment was performed so that the joint positions of the reinforcing bars were aligned with the groove of the rebar and the finish weld layer had a gentle shape in order to minimize the effect of stress concentration at welds.  As a result, the following became clear within the range of welding procedure conditions of this experiment.  1) Weld cracks (micro cracks) in the heat-affected zone near the bond can be evaluated by C and Pcm. When C becomes 0.32% or more and Pcm becomes 0.43% or more, they tend to occur.  2) There was no effect on the occurrence of welding cracks due to the presence or absence of the restraint stress of the reinforcing bar during welding.  3) The maximum hardness of the weld can be evaluated in terms of C and Pcm. When C exceeds 0.32% and Pcm exceeds 0.43%, the maximum hardness exceeds 350HV.  4) Heat-affected zone fracture of welded joints tends to occur rapidly when C is about 0.32% or more, Ceq⁽²⁾ is 0.57% or more, and Pcm is 0.43% or more.

収録刊行物

• 日本建築学会構造系論文集

  日本建築学会構造系論文集 85 (776), 1245-1253, 2020

  日本建築学会

キーワード

• 高強度鉄筋
• 溶接継手
• 溶接性
• 熱影響部破断

詳細情報

• CRID: 1390567901488292608
• NII論文ID: 130007931479
• NII書誌ID: AN10438559
• DOI: 10.3130/aijs.85.1245
• ISSN: 18818153
• ISSN: 13404202
• NDL書誌ID: 030686185
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I030686185
• Web Site: https://www.jstage.jst.go.jp/article/aijs/85/776/85_1245/_pdf
• 本文言語コード: ja
• データソース種別:
  • JaLC
  • NDL
  • Crossref
  • CiNii Articles
• 抄録ライセンスフラグ: 使用不可