【摘要】：利用光學(xué)顯微鏡、掃描電鏡分析了某廠生產(chǎn)的X90鋼管線鋼焊接接頭的顯微組織,通過硬度試驗(yàn)和沖擊試驗(yàn)測試了其硬度和韌性變化規(guī)律。試驗(yàn)結(jié)果顯示,其焊縫為針狀鐵素體和粒狀貝氏體組織,熔合區(qū)和粗晶區(qū)為粗大粒狀貝氏體組織,細(xì)晶區(qū)為多邊形鐵素體、珠光體和MA組織,混晶區(qū)為粒狀貝氏體、多邊形鐵素體、珠光體和MA的混合組織;熱影響區(qū)有局部硬化和軟化現(xiàn)象,且內(nèi)焊縫硬度高于外焊縫;試驗(yàn)溫度高于-20℃時(shí),熱影響區(qū)的沖擊吸收能量和剪切斷面率高于焊縫,低于-40~-20℃區(qū)間某個(gè)值后,沖擊性能將降低至焊縫性能以下;熱影響區(qū)的韌脆轉(zhuǎn)變溫度約在-50℃附近,而焊縫的韌脆轉(zhuǎn)變溫度約在-70℃附近。
[Abstract]:The microstructure of the welded joints of X90 steel tube made in a factory was analyzed by optical microscope and scanning electron microscope. The hardness and toughness of the welded joints were tested by hardness test and impact test. The results show that the weld is acicular ferrite and granular bainite structure, the fusion zone and coarse grain zone are coarse granular bainite structure, the fine grain zone is polygonal ferrite, pearlite and MA structure, and the mixed crystal zone is granular bainite. Polygonal ferrite, pearlite and MA mixed structure; The heat affected zone has the phenomenon of local hardening and softening, and the hardness of the inner weld is higher than that of the outer weld. When the test temperature is higher than -20 鈩，

本文編號(hào)：2387953