共查询到20条相似文献,搜索用时 15 毫秒
1.
Heterogeneous microstructure-induced mechanical responses in EH420 shipbuilding steel welded joint by electro-gas welding processed have been systematically studied by scanning electron microscopy,electron backscatter diffraction and mechanical testing.Comparing with the coarse-grained heat-affected zone (CGHAZ),the weld metal presents higher toughness (129.3 J vs.37.3 J) as it contains a large number of acicular ferrites with high-angle grain boundaries (frequency 79.2%) and special grain boundary Σ3 (frequency 55.3%).Moreover,coarse austenite grains in CGHAZ and slender martensite-austenite constituents between bainite laths may likely facilitate crack propagation.Polygonal ferrites and tempered pearlites formed at the junction of the fine-grained heat-affected zone and the intercritical heat-affected zone induced a softened zone with an average hardness of 185 HV0.5,which is the main reason for the occurrence of tensile fracture. 相似文献
2.
大线能量焊接用钢模拟热影响区的组织与性能 总被引:8,自引:4,他引:8
研究了一种低碳低合金600MPa级耐大线能量焊接用钢模拟大线能量输入焊接粗晶热影响区(简称CGHAZ)的微观组织及力学性能。结果表明,大线能量模拟CGHAZ具有优良的强韧性配合(σs≥490MPa,σb≥610MPa,-20℃时AKV≥47J)。模拟热循环过程中CGHAZ中的高温稳定的复合夹杂物促使针状铁素体的形成,针状铁素体的数量与输入线能量有关。奥氏体和铁素体晶粒大小及针状铁素体数量显著影响焊接粗晶热影响区的力学性能。 相似文献
3.
通过常规力学性能测试设备、光学显微镜和扫描电镜研究了不同回火温度对一种大线能量焊接用钢性能和组织的影响。结果表明:试验钢在TMCP状态下的组织为铁素体+贝氏体+少量马氏体;高温回火后的组织主要为铁素体+回火索氏体,且析出了部分碳化物。断口呈韧窝特征,夹杂物一般为Al2O3、MnS和TiO2的两种或多种复合型夹杂物。随着回火温度升高,铁素体基体上的碳化物聚集长大。经过回火处理后,试样抗拉强度急剧下降,而冲击韧性得到大幅改善,延伸率逐渐升高,其最佳回火温度范围是600~630℃。 相似文献
4.
5.
6.
7.
研制的高强高韧性管线钢用埋弧焊丝与SJ10 1和SJ10 2焊剂匹配后的熔敷金属不仅具有很高的强度 (σs≥ 5 4 0MPa) ,而且还具有优良的低温韧性 (AKv - 1 0℃ ≥ 12 0J)。该焊丝的研制满足了屈服强度超过 5 0 0MPa以上管线钢对焊缝熔敷金属性能的要求。研究结果表明 ,要保证熔敷金属具有较佳的强韧性匹配 ,熔敷金属中的合金元素总量必须满足Ceq≥ 0 .38,Pcm≥ 0 .17,才能保证熔敷金属的强度 ,以及具有以针状铁素体为主焊缝组织 ;在文中的合金系统下 ,随着熔敷金属中C、Mn元素含量的增加 ,熔敷金属的针状铁素体组织的含量增加 ,韧性得到提高。随着焊剂碱度值的增加 ,熔敷金属中的氧含量降低 ,C、Mn元素增加 ,使得熔敷金属中的合金元素更趋向于最佳的配比 ,从而提高了韧性。 相似文献
8.
9.
10.
Microstructural characteristics of different sub-regions of heat affected zone (HAZ) of low welding crack susceptibility steel weldment were investigated by using optical microscopy and scanning electron microscopy equipped with electron backscattered diffraction system. And the focus was put on the correlation between microstructural characteristics and HAZ toughness of the weldment. The results reveal that the toughness of fusion line zone (FLZ) specimens is much lower than that of fine grained HAZ (FGHAZ) specimens. The coarse inclusions in the weld metal and the large martensite-austenite constituents in the coarse grained HAZ (CGHAZ) have an obvious negative effect on the crack initiation energy of FLZ. Meanwhile, the coarse granular bainite with large effective grain decreases the crack propagation energy seriously. By contrast, fine crystallographic grains in the FGHAZ play a key role in increasing toughness, especially in improving crack propagation energy. 相似文献
11.
以EH36高强度船板钢为研究对象,通过拉伸和冲击分析试验手段,对EH36船板钢不同热输入埋弧焊接头进行了力学性能测试,同时采用扫描电镜对冲击试样断口形貌进行分析.结果表明,所有断裂均发生在拉伸试样的母材区,EH36船板钢在大焊接热输入条件下,焊缝和焊接热影响区的强度好于母材,并没有出现热影响区软化现象;随着焊接热输入增加焊缝的冲击韧性降低,从焊缝和熔合区断口形貌来看,断裂类型为韧性断裂和准解理断裂的混合断裂.随着远离熔合线距离的增加,冲击吸收功有增加的趋势,在距离熔合线4 mm处的冲击吸收功跟母材接近,说明该位置处韧性基本不受焊接热循环的影响. 相似文献
12.
13.
14.
15.
16.
17.
焊接区表面高频淬火后钢的超塑焊接 总被引:4,自引:2,他引:4
探讨了结构钢与工具钢待焊接区表面高频淬火后超塑焊接的可行性及影响因素。试验表明,焊接区局部高频淬火后的结构钢与工具钢在其超塑变形温度及应变速率范围内,经短时超塑压接即可实现接头抗拉强度达到母材强度的固相焊接。 相似文献
18.
G. Magudeeswaran V. Balasubramanian G. Madhusudhan Reddy 《Journal of Materials Engineering and Performance》2009,18(1):49-56
Quenched and Tempered (Q&T) steels are widely used in the construction of military vehicles due to their high strength-to-weight
ratio and high hardness. These steels are prone to hydrogen-induced cracking in the heat affected zone (HAZ) after welding.
The use of austenitic stainless steel consumables to weld the above steel was the only remedy because of higher solubility
for hydrogen in austenitic phase. Recent studies proved that high nickel steel and low hydrogen ferritic steel consumables
can be used to weld Q&T steels, which can give very low hydrogen levels in the weld deposits. In this investigation an attempt
has been made to study the effect of welding consumables on high cycle fatigue properties of high strength, Q&T steel joints.
Three different consumables namely (i) austenitic stainless steel, (ii) low hydrogen ferritic steel, and (iii) high nickel
steel have been used to fabricate the joints by shielded metal arc (SMAW) welding process. The joints fabricated using low
hydrogen ferritic steel electrodes showed superior fatigue properties than other joints. 相似文献
19.
线能量对TC4钛合金激光焊接残余应力和变形的影响 总被引:1,自引:0,他引:1
利用有限元分析和实验测试,研究了TC4钛合金平板激光焊接线能量对变形和残余应力的影响规律,并通过焊缝金相实验分析了线能量与焊接残余应力和变形的内在关系。结果表明:钛合金激光焊接产生的纵向残余拉伸应力约700MPa~850MPa,而横向残余拉伸应力只有50MPa~80MPa。激光焊接线能量增加时,纵向残余应力拉伸区域变宽,峰值应力降低,而横向残余应力随线能量的增加而升高。在临界焊透规范以上焊接时,角变形随线能量的增大而减小,但横向收缩变形增大。试件被完全穿透焊接时,线能量对角变形的影响作用降低。 相似文献