尹士科
,
王移山
,
彭云
钢铁研究学报
焊接区的微观组织是决定其力学性能的关键因素.为了改善低合金钢焊缝的冲击韧性,对500～1000 MPa级焊条的焊缝金属的化学组成、金相组织和力学性能进行了对比研究.采用金相显微镜和透射电子显微镜对不同强度级别的低合金钢焊缝组织进行了观察和电子衍射分析,并进行了焊缝金属拉伸强度和冲击韧性测试.结果表明,随着焊条强度级别的增加,焊缝组织由先共析铁素体、针状铁素体加珠光体变成粒状贝氏体,最后变成贝氏体加马氏体组织;当焊缝组织为粒状贝氏体时其韧性最低.
关键词:
焊条
,
强度
,
焊缝金属
,
组织
,
韧性
Q. Gao
,
Y.X. Zhao and L.X. Cai (Institute of Applied Mechanics
,
Southwest Jiaotong University
,
Chengdu 610031
,
China)
金属学报(英文版)
Based on the test results obtained from the single-step test and the incremental-step test at room temperature and 240℃, a probabilistic assessment of temperature effects on the cyclic stress-strum response and the fatigue life of 1Cr18Ni9Ti steel weld metal is performed. In orber to assess the temperature effect on cyclic stress amplitude where there is a scatter of the material cyclic constitution, a probabilistic assessment approach on the basis of probabilistic modified Ramberg-Osgood relations is introduced.The investigation shows that the cyclic stress amplitude and the scatter of cyclic stress amplitude data are decreased at 240℃. Similarly, from the consideration of the fatigue life scatter a probabilistic assessment of temperature effect on the fatigue life is suggested on the basis of probabilistic Langer S-N relations. The investigation shows that the crack initiation life is increased and the scatter of crack initiation life data is decreased at 240℃.
关键词:
1Cr_(18)Ni_9Ti stainless steel
,
null
,
null
,
null
,
null
王学林
,
董利明
,
杨玮玮
,
张宇
,
王学敏
,
尚成嘉
金属学报
doi:10.11900/0412.1961.2015.00453
以Mn-Ni-Mo-Ti-B为主要合金系,研制出适用于低温服役环境下的高强高韧管线钢埋弧焊丝,并应用于30.8 mm厚K65管线钢现场焊接实验.结果表明,焊缝金属屈服强度达到583～689 MPa,抗拉强度达到714～768 MPa,-40℃冲击功均在90 J以上,焊缝具有优异的强韧性匹配.焊丝直径为4.0 mm,适用于四丝双面埋弧焊,效率高,且热影响区(HAZ)低温韧性优异(-40℃冲击功＞100 J).采用OM,TEM和LePera方法对焊缝金属组织的观察表明,焊缝组织主要为精细的针状铁素体、少量的先共析晶界铁素体、侧板条铁素体和弥散分布的细小马氏体/奥氏体(M/A)岛状颗粒.焊缝金属中0.2％Mo可以有效抑制先共析晶界铁素体及侧板条铁素体的生成,晶粒细化作用显著.Mn和Ni的适量增加会促进针状铁素体的形成,显著提高焊缝金属低温韧性.但Mn,Ni配比不当而超过某个范围时将会导致马氏体或其它低温相变产物形成,削弱低温韧性.当K65焊缝金属中含(1.5％～2.0％)Mn,(0.9％～l.2％)Ni,(0.2％～0.25％)Mo时,可以使其具有高强度的同时低温冲击韧性优异,且在Mn与Ni配比含量不越过马氏体形成线(Ms线)的前提下,可以采用加Mn减Ni的方法配比其合金含量.
关键词:
K65管线钢
,
焊缝金属
,
热影响区
,
针状铁素体
,
马氏体/奥氏体组元
,
低温冲击韧性
