鎔接 鋼部材의 熱處理 效果에 관한 硏究 = Effects of Heat Treatment in Welded Steel Members

국문 초록 (Abstract)

鎔接部에서 殘留應力은 鎔接熱에 의한 局部加熱과 不規則的이고 比較的 急速한 冷却으로 誘發되는 熱應力과 構造物의 剛性 및 材料등에 의하여 發生되며 殘留應力의 存在는 脆)性破壞强度, 疲勞强度, 挫屈强度, 振動特性, 腐蝕抵抗등에 影響을 미치는 窮極的 要因으로 看故됨으로 本 硏究는 構造物의 强度를 低下시키고 機能에 惡影響을 끼치는 殘留應力의 機構學的 特性을 把握하기 위하여 SWS 58 鋼板을 X홈 鎔接하여 이것을 4段階 즉 350℃, 500℃, 650℃, 800℃로 熱處理하여 hole drilling method을 使用하여 殘留應力을 測定한 結果, 다음과 같은 結論을 얻었다.
殘留應力을 除去시키는 가장 效果的인 溫度는 650℃ 程度이었고 구멍의 直經이 구멍의 깊이와 一致할 때 구멍바로 근처의, ()性變形은 完全히 解放되었으며 硬度試驗을 通해 熱處理 後 熱影響部의 높은 硬度가 모두 消滅되는 것을 알수 있었으며 또한 殘留應力에 끼치는 鎔接入熱의 영향은 入熱量의 標準보다 1/4 以上, 以下인 경우 殘留應力은 鎔接入熱에 큰 影響이 없음을 알았다.

다국어 초록 (Multilingual Abstract)

Residual stresses have remained around welding areas of a steel structure member after welding operation. The major causes to occur these residual stresses are the local heat due to a welding, the heat stresses due to a irregular and rapid cooling condition, the material and rigidity of a steel structure. Ultimatly, these residual stresses have been known to decrease a brittle fracture strength, a fatigue strength, a buckling strength, dynamic properties, and the corrosion resistance of the material.
This paper deals with the residual stresses on a steel structure member through experimental studies. SWS 58 plates were welded by the method of X-groove type. These plates were layed on the heat treatment at four different temperature. These plates were layed on the heat treatment at four different temperatures; 350℃, 500℃, 650℃ and 800℃. The resulting residual stresses were measured by hole drilling method, and the following were obtained.
The residual stresses on the vicinity of a welding point were relieved most effectively at the temperature of 650℃, and these stresses relieved completly when the ratio of a hole diameter to a hole depth became unity. Hardness test shows that the higher value of hardness at the heart affected zone dropped to belower as the temperature went up from 350℃ to 800℃. The welding input heats have not influenced the magnitude of residual stresses at the input heat range between above and below one forth than standard.