Microstructure and Toughness in Weld Metal and Its Reheated Zone of High Strength Steel

高强钢焊缝金属及其再加热区的显微组织和韧性

• 批准号: 60550524
• 负责人: ARAKI Takao
• 金额: $ 1.22万
• 依托单位: Osaka University, Faculty of Engineering
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1985
• 资助国家: 日本
• 起止时间: 1985 至 1986
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-60550524/
• 关键词: 80 kgf; <mm^2> class high strength low alloy steel; Weld metal; Multipass welding Heat input; Microstructure; 靭性; 組織; 島状マルテンサイト

The multipass welding are carried out for high strength low alloy steels such as 80 kgf/ <mm^2> class steel in order to mitigate the heat affected zone (HAZ) embrittlement. In that case weld pass is reheated to various temperature by welding heats of the subsequent ones. This effect will naturally lead to the microstructural change of weld metal, and as a result, to the change of fracture toughness.The objectives of this study were to provide a detailed analysis of microstructure that can be found in 80 kgf/ <mm^2> class tensile strength weld metal as a function of heat input, chemical compositions and reheating temperature which was decided by imagining multipass welding, and then to discuss the relationship between microstructure and toughness. The major findings of this work are as follows.(1) In the weld metal of high strength steel the degradation of toughness was found at high heat input welding conditions as well as in the HAZ of base metal. (2) Such an embrittlement seemed to be caused by both the increasing in the area fraction of M-A constituent and the coarsening of microstructure. (3) In the reheated zone of weld metal the degradation of toughness was found in the peak temperature range between 750 and 950゜C at the multi-thermal cycles in spaite of welding conditions. The degradation of toughness was remarkable at high heat input welding conditions. (4) This embrittlement also seemed to be mainly caused by the increasing in the area fraction of M-A constituent. (5) Therefore, it implied that the decreasing in the area fraction of M-A constituent was effective as a method of improvement of toughness in both the weld metal and its reheated zone.

多通焊接用于高强度低合金钢，例如80 kgf/ <mm^2>类钢，以减轻热影响区域（HAZ）的互惠。在这种情况下，通过焊接随后的热量，将焊接通道加热到各种温度。这种效果自然会导致焊接金属的微观结构变化，并因此导致断裂韧性的变化。这项研究的目标是提供对微观结构的详细分析，可以在80 kgf/ <mmm^2>类的抗拉伸强度焊接金属作为热量输入，化学组成和重复的温度之间的功能中，并确定乘以乘坐量的微观结构，并在乘坐微观结构。韧性。这项工作的主要发现如下。（1）在高强度钢的焊接金属中，在高热量输入焊接条件以及碱金属的危险中发现了韧性的降解。 （2）这种封闭似乎是由于M-A构造的面积分数的增加和微观结构的粗化引起的。 （3）在焊接金属的再加热区域中，在焊接条件的Spaite的多热周期下，在750至950°C之间发现了韧性的降解。在高热输入焊接条件下，韧性的降解非常明显。 （4）这种互惠似乎也主要是由于M-A成分的面积分数的增加引起的。 （5）因此，这意味着M-A成分的面积分数的下降是有效的，作为改善焊接金属及其再加热区韧性的一种方法。

项目成果

Yoneo KIKUTA: "Relationship between Microsturucture and Toughness in Weld Metal and Its Reheated Zone of High Strength Steel" TECHNOLOGY REPORTS OF THE OSAKA UNIVERSITY. 37. 75-83 (1987)

Yoneo KIKUTA：“高强度钢焊缝金属及其再加热区的显微组织和韧性的关系”大阪大学技术报告。

Yoneo KIKUTA: TECHNOLOGY REPORTS OF THE OSAKA UNIVERSITY. 37. 75-83 (1987)

Yoneo KIKUTA：大阪大学的技术报告。