Quarterly Journal of The Japan Welding Society最新文献

ラインパイプ周溶接継手の軟化HAZを考慮した引張強度予測手法考虑了生产线管道周焊接接头的软化HAZ的拉伸强度预测方法

Quarterly Journal of The Japan Welding Society Pub Date : 2023-01-01 DOI: 10.2207/qjjws.41.263

Shoma ONUKI, Masaki MITSUYA, Mitsuru OHATA

{"title":"ラインパイプ周溶接継手の軟化HAZを考慮した引張強度予測手法","authors":"Shoma ONUKI, Masaki MITSUYA, Mitsuru OHATA","doi":"10.2207/qjjws.41.263","DOIUrl":"https://doi.org/10.2207/qjjws.41.263","url":null,"abstract":"In seismic-active area, the buried pipeline is subjected to the axial tensile load exceeding the yield stress of pipe material due to the lateral flow induced by soil liquefaction. Designing a girth weld joint that does not fracture at girth weld but base metal which has high elongation capacity is feasible to ensure adequate ground displacement absorbing capacity of the girth weld joint. However, as for fine grain steel, the heat-affected zone (HAZ) is softened by welding heat input, and then, the zone of softened HAZ can be the origin of fracture under tensile load. The apparent strength of softened HAZ is affected by the plastic constraint from the surrounding weld metal and base metal during tensile loading, and the fracture location depends on the apparent strength of HAZ. This study investigates the tensile strength and fracture location of girth weld joints with softened HAZ in the static tensile test. The effect of geometric and mechanical heterogeneity of HAZ, strength overmatching of weld metal, and the width-thickness ratio of tensile test specimen on tensile strength are elucidated using parametric finite element analysis. Subsequently, an equation is proposed to predict the tensile strength and fracture location of the welded joint. Using the proposed equation, the condition of geometric and mechanical heterogeneity of the weld to confirm the girth weld joints that fracture at base metal under tensile load is clarified. The proposed equation can be used to design a girth weld joint with liquefaction earthquake resistance.","PeriodicalId":20941,"journal":{"name":"Quarterly Journal of The Japan Welding Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135611741","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Optimization of welding conditions for friction stir spot welding of A6063S-T5 with composite coated films using a triangular prism-shaped tool 利用三角棱柱形工具优化A6063S-T5复合涂层搅拌摩擦点焊条件

Quarterly Journal of The Japan Welding Society Pub Date : 2023-01-01 DOI: 10.2207/qjjws.41.273

Terumichi MURAKOSHI, Toshiya SHIBAYANAGI

引用次数: 0

A Mathematical Model of Shunting in Resistance Spot Welding 电阻点焊中分流的数学模型

Quarterly Journal of The Japan Welding Society Pub Date : 2023-01-01 DOI: 10.2207/qjjws.41.302

Manabu FUKUMOTO, Naoya TADA

{"title":"A Mathematical Model of Shunting in Resistance Spot Welding","authors":"Manabu FUKUMOTO, Naoya TADA","doi":"10.2207/qjjws.41.302","DOIUrl":"https://doi.org/10.2207/qjjws.41.302","url":null,"abstract":"In resistance spot welding, which is widely used for assembling automobile bodies, reduction of weld spacing (short-pitch welding) has been put to practical use to improve the strength and stiffness of the welded assemblies and to advance collision safety and ride comfort. In short-pitch welding, shunt current going through the previously welded points is inevitable and delays nugget formation and growth, but it is difficult to know the degree of shunting because it varies depending not only on the weld spacing but also on the sheet combination. In order to study the shunt phenomenon, several theoretical models have been proposed, but they have some critical problems in practical use, such as overestimation of the shunt resistance and many parameters to be determined from experiments. In this study, a mathematical model is established which can easily predict the ratio of effective weld current (or non-effective shunt current) to the total input current with only one experimental parameter, in the case of two-sheet stack-up with a single existing (shunting) weld. By using this model, delayed nugget growth curve of the second weld can be predicted taking the shunting effects into account, from the known nugget growth curve of the first weld. Furthermore, the efficiency of the shunt current to ease some three-sheet stack-ups welding was shown experimentally, and the optimal weld-spacing to maximize the welding current range was estimated by the proposed model.","PeriodicalId":20941,"journal":{"name":"Quarterly Journal of The Japan Welding Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135612396","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

水冷銅板及び液体窒素を用いたアーク溶接の熱効率測定と影響を与える要因の考察采用水冷铜板和液氮的电弧焊的热效率测量和影响因素的考察

Quarterly Journal of The Japan Welding Society Pub Date : 2023-01-01 DOI: 10.2207/qjjws.41.248

Shoji FUJIYAMA, Yuki ASAI, Hisaya KOMEN, Manabu TANAKA

{"title":"水冷銅板及び液体窒素を用いたアーク溶接の熱効率測定と影響を与える要因の考察","authors":"Shoji FUJIYAMA, Yuki ASAI, Hisaya KOMEN, Manabu TANAKA","doi":"10.2207/qjjws.41.248","DOIUrl":"https://doi.org/10.2207/qjjws.41.248","url":null,"abstract":"Arc efficiencies of gas tungsten arc welding (GTAW) were measured using two different methods, liquid nitrogen calorimetry and water-cooled copper anode calorimetry, across a range of welding currents from 98 A to 302 A. Arc efficiencies determined with water-cooled copper anode calorimetry remained constant throughout the entire current range, while those measured with liquid nitrogen calorimetry exhibited a concave curve. A hypothesis was proposed to explain the changes in arc efficiency with varying welding currents. Accordingly, a decrease in arc efficiency at 149 A welding current was caused by reduced Joule heating due to increased electrical conduction from iron-vapor contamination in an arc. For welding currents above 227 A, a decrease in arc efficiency was attributed to increased penetration depth, leading to more uniform heating in the base metal beneath the arc column, thereby preventing heat conduction within the metal. Thereafter, the relationship between penetration depth and arc efficiency was experimentally confirmed. Comparing with the arc efficiency of gas metal arc welding (GMAW), it was found that the mechanism in which arc efficiency changes with welding current in GTAW was different from that in GMAW.","PeriodicalId":20941,"journal":{"name":"Quarterly Journal of The Japan Welding Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135800429","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Trial Manufacture and Performance Evaluation of Fatigue Crack Growth Restraining Sheets Using a High Water Content Gel 高含水量凝胶抑制疲劳裂纹扩展片的试制及性能评价

Quarterly Journal of The Japan Welding Society Pub Date : 2023-01-01 DOI: 10.2207/qjjws.41.289

Ichihiko TAKAHASHI

{"title":"Trial Manufacture and Performance Evaluation of Fatigue Crack Growth Restraining Sheets Using a High Water Content Gel","authors":"Ichihiko TAKAHASHI","doi":"10.2207/qjjws.41.289","DOIUrl":"https://doi.org/10.2207/qjjws.41.289","url":null,"abstract":"A simple technique of restraining fatigue crack growth utilizing wedge effects of corrosion products was newly proposed and experimentally tested. Crack growth restraining sheets with a high water content gel were manufactured by way of trial and applied to notched plate specimens of steel, and the efficacy of the sheets to restrain crack growth was evaluated by fatigue tests. In the fatigue tests, the crack growth restraining sheet was renewed at proper timing to maximize its performance. In order to find a local humid (or wet) corrosive environment, which is most suitable for the crack growth restraint by wedge effects of corrosion products on the crack surfaces, water components absorbed in the gel and effects of a cathode layer as promoting factors of the corrosive reaction were comparatively examined. As a result, it was found that all the proposed crack growth restraining sheets were effective and extend the failure life in the range of 2.1 ~ 9.6 times as compared with the bare base metal specimen. Especially, the efficacy of the gel sheets with 3% salt water and synthetic sea water was remarkable (4.1~9.6 times extension in failure life), and the cathode layer (copper-leaf tape) produced certain additional positive effects in those gel sheets. From fracture mechanical analyses with FE analyses, it was found that the crack restraining effect of the gel sheet greatly varies depending on the water gel content and the existence of cathode layer. In situ observations around the growing cracks and macro- and microscopic observations of the fracture surfaces were also performed for a comparative study between the different types of crack growth restraining sheets.","PeriodicalId":20941,"journal":{"name":"Quarterly Journal of The Japan Welding Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135611737","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

レーザクラッディングによるZr基金属ガラスのCu表面改質とはんだぬれ性の改善通过激光熔覆改善Zr基金玻璃的铜表面改性和焊锡湿性

Quarterly Journal of The Japan Welding Society Pub Date : 2023-01-01 DOI: 10.2207/qjjws.41.257

Takeshi TERAJIMA, Kazuki SHINSHI

引用次数: 0

Quality Assurance and Quality Management 质量保证和质量管理

Quarterly Journal of The Japan Welding Society Pub Date : 2012-01-01 DOI: 10.2207/jjws.81.434

H. Harasawa

引用次数: 2