【正文】
ing electron microscope (SEM) on different areas of the welding joint observation, mechanical property analysis. Known welding process test for the tungsten electrode argon arc welding welding method, welding current is 115 a, preheat temperature/temperature 250 ℃ , welding layer number 5, 770 ℃ heat treatment after welding temperature for an hour, for the best welding technology, welding seam can get grain fine, evenly tempered of the tissue. In view of the welding joint, testing the hardness of welded joint distribution. From the heat affected zone to the weld center anization change is very big, will produce larger fluctuations. In the center of the weld hardness less than or equal to 250 ℃ , the mechanical properties of the weld mechanical properties of the best. Key words: power station boiler。在焊縫中心 的溫度小于 等于 250℃ 時(shí),焊縫的機(jī)械性能力學(xué)性能最佳 。 針對(duì)焊接接頭,測(cè)試焊接 接頭 的硬度分布 。通過 對(duì)硬度、沖擊力學(xué)實(shí)驗(yàn)和 利用光學(xué)顯微鏡( OM)、掃描電子顯微鏡( SEM)對(duì)焊接接頭的不同區(qū)域進(jìn)行組織觀察、 力學(xué)性能 分析。 本文擬用 T91 鋼進(jìn)行討論 T91 屬于馬氏體類型的耐熱鋼,而且焊接性能較差,所以焊接工藝復(fù)雜并且要嚴(yán)格執(zhí)行,如果焊接過程中不嚴(yán)格執(zhí)行焊接工藝,焊接接頭將過早產(chǎn)生失效和破壞,鍋爐焊接工作是鍋爐制造過程中的關(guān)鍵技術(shù)難題 。因此為了達(dá)到機(jī)組的高熱效率、低煤耗、環(huán)境污染少的目的,通常采用提高機(jī)組蒸汽參數(shù)來實(shí)現(xiàn),即提高鍋爐出口蒸汽壓力和蒸汽溫度。沈陽工學(xué)院畢業(yè)論文 I 摘要 電力工業(yè)是我國國民經(jīng)濟(jì)發(fā)展的基礎(chǔ)產(chǎn)業(yè)之一。近年來隨著經(jīng)濟(jì)的快速發(fā)展,電站鍋爐向著高參數(shù)、大容量機(jī)組方向發(fā)展,逐步淘汰了低參數(shù)、小容量、效率低的機(jī)組鍋爐。蒸汽壓力的提高勢(shì)必要求使用耐高溫的高強(qiáng)度的鋼材,否則為滿足高溫工作的承壓部件要求,必然要增大部件的壁厚;蒸汽溫度的提高勢(shì)必要求鋼材具有更高的高溫持久強(qiáng)度。 本文 T91 焊接性進(jìn)行研究。 可知 焊接工藝試驗(yàn) 為采用鎢極氬弧焊焊接方法, 焊接電流 115A,預(yù)熱溫度 /層間溫度 250℃ ,焊接層數(shù) 5,焊后熱處理 770℃ 恒溫一小時(shí),為最佳焊接工藝,焊縫 可以得到晶粒細(xì)小、組織均勻的回火索氏體組織 。從熱影響區(qū)到焊縫中心組織變化很大, 顯 微硬度會(huì)產(chǎn)生較大的波 動(dòng)。 關(guān)鍵詞: 電站鍋爐; T91;焊接性能;力學(xué)性能 沈陽工學(xué)院畢業(yè)論文 II Abstract Electric power industry is one of the basic industry of national economy development in our country. In recent years, with the rapid development of economy, power plant boiler to develop in the direction of high parameter, large capacity units, phasing out the low parameter, small capacity and low efficiency of the boiler unit. So in order to achieve high efficiency of the unit, the purpose of low coal consumption, less environmental pollution, usually adopt to improve the unit steam parameters, namely, increase export of boiler steam pressure and steam temperature. Steam pressure increase will inevitably require the use of high temperature resistance of high strength steel, or to meet the high temperature pression part of job requirements, is bound to increase the part of the wall thickness。 T91。 mechanical properties 沈陽工學(xué)院畢業(yè)論文 III 目錄 摘要 ..................................................................... I Abstract.................................................................. II 目錄 ................................................................... III 第 1 章 緒論 .............................................................. 1 電站鍋爐簡(jiǎn)介 ...................................................... 1 電站鍋爐用鋼及發(fā)展趨勢(shì) ............................................ 1 電站鍋爐用鋼技術(shù)標(biāo)準(zhǔn)的演化 ................................... 1 鍋爐用鋼現(xiàn)狀 ................................................. 2 鍋爐用鋼展望 ................................................. 3 本文研究?jī)?nèi)容及意義 ................................................ 3 第 2 章實(shí)驗(yàn)材料及方法 ..................................................... 4 母材 .............................................................. 4 T91 實(shí)驗(yàn)制備及焊接工藝 ............................................ 5 顯微硬度試驗(yàn) ...................................................... 7 沖擊試驗(yàn) .......................................................... 7 金相顯微試驗(yàn) ...................................................... 8 SEM 掃描電子顯微鏡 ................................................ 9 第 3 章 焊接工藝對(duì)焊接接頭力學(xué)性能的影響 ................................ 11 工藝參數(shù)對(duì)焊縫抗彎強(qiáng)度的影響 ..................................... 11 顯微硬度試驗(yàn) ..................................................... 13 第 4 章 焊接工藝對(duì)焊接接頭組織性能的影響 ................................ 17 ..................................................... 18 焊接接頭的金相組織 ............................................... 19 沈陽工學(xué)院畢業(yè)論文 IV 顯微組織實(shí)驗(yàn)結(jié)果及分析 ........................................... 27 第 5 章結(jié)論 .....................................................