資源描述：
《【碩士論文】超低碳貝氏體鋼焊接性能研究.pdf》由會(huì)員上傳分享，免費(fèi)在線閱讀，更多相關(guān)內(nèi)容在教育資源-天天文庫(kù)。
1、摘要摘要本文針對(duì)鞍鋼工業(yè)生產(chǎn)的HQ500DB和HQ620DB超低碳貝氏體鋼，采用裂紋敏感性指數(shù)、焊接熱影響區(qū)最高硬度試驗(yàn)和斜Y形坡口拘束焊接裂紋試驗(yàn)對(duì)其焊接冷裂紋敏感性進(jìn)行了評(píng)價(jià)；采用焊接熱模擬方法研究了模擬焊接熱影響區(qū)組織和低溫沖擊韌性隨線能量的演變規(guī)律；采用自行研制的YS800焊絲，對(duì)氣體保護(hù)焊接頭的力學(xué)性能進(jìn)行了工藝評(píng)定。模擬了焊前預(yù)熱、焊前不預(yù)熱和焊后激光熱處理等三種不同條件下激光焊接熱影響區(qū)的熱過(guò)程，對(duì)其組織和力學(xué)性能進(jìn)行了分析和測(cè)試。結(jié)果表明，超低碳貝氏體鋼焊接熱影響區(qū)具有較低的淬硬傾向和冷裂紋敏感性，當(dāng)板厚為20mnl時(shí)焊前無(wú)需預(yù)熱；該鋼種適應(yīng)于小線能量焊接工藝，其最
2、佳線能量范圍為14．25kJ·cm"1，采用線能量18kJ·em。的氣體保護(hù)焊時(shí)接頭具有優(yōu)異的拉伸、冷彎和低溫沖擊性能；隨焊接線能量增大，模擬焊接粗晶區(qū)原奧氏體晶粒尺寸增大，貝氏體鐵索體板條寬化，有效晶粒尺寸粗化，導(dǎo)致該區(qū)域的沖擊韌性下降；超低碳貝氏體鋼模擬激光焊接熱影響區(qū)的硬度遠(yuǎn)高于母材，采用焊前預(yù)熱和焊后激光回火，能顯著降低該區(qū)域的最高硬度和硬度梯度。關(guān)鍵詞超低碳貝氏體鋼：焊接熱影響區(qū)；組織；性能；激光焊接燕山人學(xué)上學(xué)碩士學(xué)位論文AbstractTheweldabilityoftwocommereialultra-lowcarbonbainiticsteel．HQ500DBan
3、dHQ620DBofferedbyAnshansteelwasevaluatedusingacombinationofcalculationofcrackingsusceptibilityindexPcm，restrainedY-groovedepositingtest，HAZmaximumhardnessevaluationtest．nemicrostructureandmechanicalpropertyexaminationsontheGleeblesimulatedcoarse—grainheat—affectedzones(CGHAZ)ofuniversalarcweld
4、ing，aswellaS，highpowerenergylaserweldingandthegaS—metal—arC—welded(MIG)jointwasalsocarriedout．Itisshownthatthesetwosteelshadalowhardenabilityandcold-crackingunderaof50。Corabovesusceptibilityduringweldingpreheatingtemperatureandalargerestraint．Whenaenergyinputaslowas14-25kJ‘cmlwasimposed，theCGH
5、AZwasmainlycomposedoffinelath—likebainiticferritepocketswithdifferentdirectionsinoccupationeachother,aconsiderableamountofretainedausteniteinterlayerandasmallamountofM—Aconstituentintheprioraustcnitegrain,whichresultedinatoughmicmstructure、vitilhi曲resistancetobrittlecrocking．Excellentmechanica
6、lpropertiescarlbeobtainedbyusingYS800wireasthefillermetaland18kJ+cm“orsoastheheatinputweldingenergy．The11ighpowerlaSerweldingissuitableforthistypeofsteelforthereasonatougherandalittleharderHAZcouldbeobtained，船wellas，themaximumhardnessandtheste印harnessdistributioncouldbesoothedbybothpreheattrea
7、tmentandlaSertemperingasanaccessorialoperation．KeywordsUltralowbainiticsteel，HAZ，microstructure，properties，laserweldingⅡ第1章緒論第1章緒論1．1選題的背景和意義現(xiàn)代超低碳貝氏體鋼(ultra-lowcarbonbainiticsteel，ULCB)是一類高強(qiáng)度、高韌性、多用途新型鋼種?。它的出現(xiàn)是近三十年來(lái)社會(huì)需求和現(xiàn)代冶金技術(shù)發(fā)展的必然結(jié)果。由于
