热丝脉冲TIG堆焊Inconel 625的组织及性能

采用热丝脉冲TIG工艺在AISI 4130基体表面堆焊Inconel 625合金,获得了平坦、连续、无缺陷的堆焊层。借助光学显微镜、XRD、SEM、EDS对堆焊层的微观组织、相组成、成分进行了分析。堆焊层主要由γ-Ni基体、分布在晶间不规则的Laves以及颗粒状的MC组成;晶体形态对Laves相的分布特征有着重要的影响,不同的晶体形态对应着Laves相的不同分布特征。堆焊层与基体、层间融合界面附近合金元素含量变化显著,层内部元素分布比较均匀,堆焊层表面Fe元素质量分数为1.81%。同时,采用动态极化曲线法对堆焊层与基体的耐腐蚀性能进行了研究。结果表明:其耐腐蚀性能与铸态Inconel 625基本相当,能够满足耐腐蚀要求。     

基于响应面法的Inconel625镍基合金GTAW堆焊工艺优化

堆焊层稀释率和厚度是影响电弧堆焊质量的重要因素,它们是由各焊接参数相互影响综合作用决定的。文中通过中心复合设计试验方案,基于响应面法建立了Inconel625镍基合金GTAW堆焊参数（焊接电流、焊接速度、送丝速度）与响应值稀释率、堆焊层厚度之间的数学模型,分析了各焊接参数对稀释率和堆焊层厚度的影响,并对堆焊参数进行了优化。结果表明,文中试验条件下送丝速度对堆焊层的厚度有着显著的影响,焊接速度和焊接电流对堆焊层厚度的影响较小;焊接电流对稀释率的影响最大,而焊接速度的影响最小;焊接电流和送丝速度的交互作用对稀释率有着重要的影响。     

Inconel 625堆焊接头组织与性能分析

采用焊条电弧焊在0Cr18Ni10Ti奥氏体不锈钢表面堆焊Inconel 625,并对堆焊层的金相组织、化学成分、拉伸性能、弯曲性能及断裂形貌进行了分析测试。试验结果表明:堆焊接头焊缝熔合良好,未出现焊接缺陷;焊接接头抗拉强度达到780 MPa,断裂形式为韧窝状的韧性断裂;弯曲性能能够满足要求;堆焊层显微组织为枝晶状的γ组织;化学成分检测未见异常。     

复合管管端堆焊Inconel625合金工艺及性能研究

采用福尼斯自动堆焊机及滚轮架设备、脉冲熔化极气体保护焊方法对规格为φ219.1 mm×(14.3+3) mm、材质为X65+316L的复合管管端内壁堆焊3mm厚、50mm长的Inconel625耐蚀合金层,堆焊后对堆焊层进行化学分析、金相组织观察和性能测试.结果表明,在堆焊层与基层界面处化学元素扩散不严重,未影响堆焊层的耐蚀性能;堆焊层的显微组织为树枝状奥氏体;堆焊层与基层形成致密的冶金结合,界面处没有出现气孔、裂纹及熔合不良等冶金缺陷;堆焊层的硬度高于基层;堆焊后界面结合强度平均为415MPa.     

耦合电弧热丝GTAW堆焊Inconel 625组织和耐蚀性

采用无熔滴耦合电弧热丝GTAW工艺将Inconel 625镍基合金堆焊在20钢表面,对堆焊层微观组织及稀释率对耐蚀性的影响进行了研究。结果表明,堆焊层主要由柱状树枝晶组成,无裂纹、气孔等缺陷;堆焊层与基体界面熔合良好,没有产生分离现象;该焊接工艺可有效降低堆焊稀释率;堆焊层中合金元素分布均匀,稀释率的增加使堆焊层中Fe元素含量增加,极大地降低了堆焊层的耐蚀性。     

国产镍基Inconel 625堆焊材料的力学性能与耐腐蚀性能

对国产Inconel 625型镍基材料的耐腐蚀性能进行研究,从国产镍基Inconel 625堆焊焊材的堆焊层取样,分别进行化学成分、剪切、弯曲、硬度等试验,化学成分和力学性能均满足技术要求;堆焊层进行晶间腐蚀、点腐蚀、应力腐蚀开裂(SCC)等试验,耐腐蚀试验数据较好,耐腐蚀性能优良。     

热丝脉冲TIG堆焊Inconel 625成型质量优化与耐腐蚀性能研究（英文）

基于中心复合试验设计方法,采用热丝脉冲TIG(tungsten inert gas arc welding)工艺,在AISI 4130基体上堆焊Inconel 625合金层。借助响应面法建立了焊缝几何特征与工艺参数之间的数学模型。根据优化后的工艺参数,获得了平坦、连续、无缺陷的多道两层堆焊层。堆焊层微观组织主要由柱状晶组成,在融合界面附近存在少量的平面晶与胞状晶,其顶部组织为等轴晶与转向晶。利用动态极化曲线法对基体与堆焊层的耐腐蚀性能进行了评价。结果表明:堆焊层的耐腐蚀性随着Fe含量的增加而降低,但增加堆焊层的层数可以显著提高耐腐蚀性能。而且,两层堆焊层试样与铸态Inconel 625的耐腐蚀性能基本相当。     

Inconel 625堆焊管板退火过程中的组织和耐蚀性变化

对Inconel 625堆焊管板试样在690 ℃进行不同时间的退火处理,采用X射线衍射、扫描电子显微、能谱面扫描分析等方法考察退火过程中堆焊管板试样的组织结构和耐蚀性变化。结果表明,不同时间退火的堆焊管板基材12Cr2Mo1R均具有典型的回火粒状贝氏体组织;不同时间退火的堆焊层组织形态均为柱状树枝晶;随着退火时间的增加,堆焊层内在γ-Ni柱状树枝晶的晶界及其附近会不断析出MC型碳化物、Laves相和γˊ相,致使堆焊层腐蚀速率单调增加,耐蚀性随之降低。     

30CrMo合金表面堆焊Inconel625镍基合金的耐腐蚀性能

为了解决石油、天然气井口装置在高含硫介质中的强腐蚀问题,以30CrMo钢作采油树的阀体或阀盖材料,在其表面堆焊两层Inconel625镍基合金。采用全浸式均匀腐蚀试验测定堆焊层的腐蚀速率。结果表明,Inconel625镍基合金堆焊层的腐蚀速率约为30CrMo钢的腐蚀速率的1／8,Inconel625镍基合金具有良好的抗...     

Inconel 625合金堆焊金属开裂机理研究

针对Inconel 625合金焊接热裂纹问题,文中基于大厚度堆焊裂纹敏感性评价方法对采用GTAW工艺、ERNiCrMo-3焊丝堆焊的金属进行了开裂机理研究.结果表明,堆焊金属的微观组织主要由柱状树枝晶组成,堆焊金属组织中析出相主要有Laves(Ni,Fe,Cr)₂(Nb,Ti,Mo)相、MC型碳化物和针状δ(Ni₃Nb)相.大厚度堆焊金属组织局部存在位于一次枝晶间、沿柱状晶方向的结晶裂纹.在裂纹附近的组织及断口发现存在大量密集分布的δ相,裂纹的形成主要与结晶终了阶段形成的共晶δ(Ni₃Nb)有关.Inconel 625合金堆焊金属存在以共晶Laves、共晶δ分别为终凝析出相的(1)、(2)两种凝固模式.相比较而言,结晶终了阶段发生L→γ+δ共晶反应的模式(2)热裂纹敏感性较大,从而造成Inconel 625合金开裂.创新点：(1)研究了625合金堆焊金属开裂的机理.(2)提出了625合金堆焊金属存在以共晶Laves、共晶δ分别为终凝析出相的两种凝固模式.     

Formation mechanism and wear behavior of gradient nanostructured Inconel 625 alloy

The formation mechanism and wear behavior of a gradient nanostructured (GNS) Inconel 625 alloy were investigated using SEM, TEM and ball-on-disc sliding wear tester. The results show that surface mechanical grinding treatment (SMGT) induced an approximately 800 μm-deep gradient microstructure, consisting of surface nano-grained, nano-laminated, nano-twined, and severely deformed layers, which resulted in a reduced gradient in micro-hardness from 6.95 GPa (topmost surface) to 2.77 GPa (coarse-grained matrix). The nano-grained layer resulted from the formation of high-density nano-twins and subsequent interaction between nano-twins and dislocations. The width and depth of the wear scar, wear loss volume, and wear rate of the SMGT-treated sample were smaller than those of untreated coarse-grained sample. Moreover, the wear mechanisms for both samples were mainly abrasive wear and adhesive wear, accompanied with mild oxidation wear. The notable wear resistance enhancement of the GNS Inconel 625 alloy was attributed to the high micro-hardness, high residual compressive stress, and high strain capacity of the GNS surface layer.     

等温退火处理对Inconel 625合金箔材组织和性能的影响

采用OM、SEM和力学性能测试等方法,研究了不同温度和时间的等温退火处理对50 μm厚的Inconel 625合金箔材组织和性能的影响。结果表明,在650 ℃和700 ℃等温退火过程中,箔材发生再结晶,晶粒尺寸显著减小,同时在晶界处析出大量的富Ti和Nb的碳化物。由于再结晶导致的细晶强化和碳化物诱发的析出强化的共同作用,箔材的强度和塑性显著提升,特别是在650 ℃等温退火48 h后,抗拉强度达到了1513 MPa,相比于未退火前增加了近90%,伸长率也增加了105%。但是试验箔材经700 ℃等温退火48 h后,再结晶晶粒长大,使得力学性能显著下降。箔材的拉伸伸长率与晶粒尺寸密切相关。     

Effect of pulsed current micro plasma arc welding process parameters on fusion zone grain size and ultimate tensile strength of Inconel 625 sheets

The paper focuses on developing mathematical models to predict grain size and ultimate tensile strength of pulsed current micro plasma arc welded Inconel 625 nickel alloy. Four factors, five levels, central composite rotatable design matrix is used to optimize the number of experiments. The mathematical models have been developed by response surface method. The adequacy of the models is checked by analysis of variance technique. By using the developed mathematical models, grain size and ultimate tensile strength of the joints can be predicted with 99% confidence level. Contour plots are drawn to study the interaction effect of pulsed current micro plasma arc welding parameters on fusion zone grain size and ultimate tensile strength of Inconel 625 weld joints.     

The effects of microstructural features on the performance gap in corrosion resistance between bulk and HVOF sprayed Inconel 625

It is commonly observed that there is a performance gap between the corrosion resistance of thermally sprayed coatings and the equivalent bulk material. This is attributed to the significantly modified microstructure of the sprayed coatings. However, currently there is no detailed understanding of which aspects of microstructural modification are primarily responsible for this performance gap. In this work several deliberately microstructurally modified versions of the Ni-based superalloy Inconel 625 were produced. These were subjected to potentiodynamic electrochemical testing in 0.5 M H₂SO₄ to investigate the links between specific microstructural features and electrochemical behaviour. Samples were prepared by high-velocity oxy-fuel (HVOF) thermal spraying, laser surface remelting using a high power diode laser and conventional powder sintering. Microstructural features were examined by optical and scanning electron microscopy and X-ray diffraction. Potentiodynamic testing was carried out on the following forms of Inconel 625: wrought sheet; HVOF sprayed coatings; sintered powder compacts; laser melted wrought sheet and HVOF sprayed coatings. Using the corrosion behaviour, i.e. passive current density, of the wrought sheet as a baseline, the performance of different forms of Inconel 625 was compared. It is found that a fine dendritic structure (with associated microsegregation) produced by laser remelting wrought sheet has no significant effect on corrosion performance. Up to 12% porosity in sintered powder samples increases the passive current density by a factor of only around 2. As observed previously, the passive current density of HVOF sprayed coatings is 20-40 times greater. However, HVOF coatings subjected to laser surface remelting are found to have a passive current density close to that of wrought material. It is concluded that, whilst porosity in coatings produces some decrease in corrosion resistance, the main contributing factor is the galvanic corrosion of localised Cr-depleted regions which are associated with oxide inclusions within HVOF sprayed samples.     

热处理温度对冷变形Inconel625合金管组织及性能的影响

通过金相分析、拉伸试验、硬度试验以及硝酸腐蚀试验,研究了热处理温度对Inconel625合金管组织、力学性能和腐蚀性能的影响.结果表明:热处理后合金组织基本为等轴晶,随着温度的升高,晶粒长大速率呈先慢后快的趋势,且晶粒长大激活能为144.14 kJ/mol;Inconel625合金管的抗拉强度、硬度随着热处理温度的升高...     

激光热丝焊表面修复成形质量分析和控制

激光热丝焊可精确控制热输入和高效熔覆金属,适合用于表面修复,但缺乏对激光热丝多道修复成形质量的研究. 基于响应曲面法(RSM)设计了激光热丝多道修复试验,选取激光功率、扫描速度、送丝速度和搭接率作为变化因子,成形系数、稀释率和未熔合缺陷比率作为响应. 结果表明,成形系数、稀释率和未熔合缺陷比率与工艺参数呈二次关系,适当降低送丝速度,提高激光功率、扫描速度和搭接率,有利于获得无未熔合缺陷、稀释率小且表面平整的多道熔覆层. 利用重叠等高线图,根据指定的质量要求进行多响应约束,可以预测相应的工艺参数窗口,达到控制激光热丝焊多道修复成形质量的目的.     

采用响应面方法和中心复合旋转设计对低品位锰矿浸出过程建模与优化(英文)

采用实验设计软件对从低品位锰矿中浸出提取锰的过程进行优化。在中心复合响应面实验设计中,考察了4个主要影响浸出过程的参数,即硫酸浓度、草酸浓度、浸出时间和温度。将锰和铁的浸出率作为考察指标。采用统计分析和方差分析确定了最优条件,即最高的锰和铁浸出率、最短的浸出时间和最低的温度。结果表明,硫酸浓度是影响浸出过程的最显著的参数,在最优条件下:硫酸浓度7%,草酸浓度42.5g/L,浸出时间60min,反应温度65℃,锰和铁的浸出率可分别达到93.44%和15.72%。