316L超低碳不锈钢的焊接性分析

用不同焊接方式和同一焊接方式不同焊口坡度焊接多种316L超低碳不锈钢焊接试板。通过外观观察、X射线检验、机械性能检验等方法对成品进行分析,掌握了316L材料的焊接性能。结果表明通过采取适当的工艺措施,316L奥氏体不锈钢焊接接头可以避免热裂纹、晶间腐蚀、刀状腐蚀等缺陷。同时验证了316L焊接接头良好的耐蚀性和机械性能。     

L450/316L不锈钢复合钢管对焊缝焊接接头组织性能研究

对壁厚(10+2)mm的L450/316L复合管进行了对焊试验,打底焊及过渡焊采用管内外充氩保护的GTAW焊,填充及盖面焊采用手工电弧焊,并对其焊接接头进行拉伸、刻槽锤断、弯曲、冲击、晶间腐蚀试验评价对焊焊缝的性能,采用光学、扫描电镜(SEM)及能谱分析(EDS)对焊接接头的冲击断口、显微组织及合金元素的进行扩散分析。试验结果表明:接头力学性能良好,耐晶间腐蚀性能较好;焊缝不锈钢层主要有奥氏体、铁素体组成;过渡层组织较细小,可以防止不锈钢层金属中合金元素被扩散层稀释;扩散层组织主要为马氏体、少量的残余奥氏体;合金钢层组织为先共析铁素体、针状铁素体、粒状贝氏体和及少量珠光体。     

DP-TIG焊接工艺对316L不锈钢搭接接头耐腐蚀性能的影响

本文采用DP-TIG焊接技术对316L不锈钢进行搭接试验,研究了焊接电流和焊接速度对搭接接头的金相显微组织及耐腐蚀性能的影响,并用扫描电镜分析了腐蚀后试样的表面形貌。结果表明,随着焊接电流的增大、焊接速度的降低,焊缝中残余铁素体组织减少,接头的耐腐蚀性能提高;焊接接头的极化曲线及阻抗谱结果表明,焊接电流为170A、焊接速度为280mm/min时,接头表现出较好的耐腐蚀性能,焊接电流对接头耐腐蚀性能的影响大于焊接速度对其的影响;试样腐蚀形貌扫描电镜结果显示,蚀坑主要产生于铁素体晶粒内部或晶界处,并沿着铁素体相界扩展腐蚀,随着蚀坑的长大最终引起结构失效。     

316L U.G的焊接

1　前言在川化 1.2万ｔ/ａ三聚氰胺工程中 ,使用 316ＬＵ .Ｇ管道输送熔融尿素。该管材为尿素级 316Ｌ ,国内较为少见 ,其管子、管件、焊材均由国外供货 ,焊接要求无相关的标准规范 ,只能按意大利欧技公司提供的技术附件执行。与普通 316Ｌ焊接施工不同的是 ,它的焊接检验要求焊后铁素体含量≤ 1%。为了控制焊缝铁素体含量和防止焊缝产生热裂纹 ,除了采用匹配焊材外 ,还应在焊接工艺上采取相应的措施。2　分析2 .1　母材耐蚀性分析尿素级 316Ｌ与普通 316Ｌ相比 ,化学成份相似 (见表 1)。在尿素等介质中δ -铁素体将优先腐蚀 ,造成选择性腐…     

尿素级316L材料的焊接

川化 1 .2万 t/ a三聚氰胺装置输送熔融尿素的管道采用 3 1 6 L UG管材 ,管子、管件、焊材均由国外供货 ,焊接要求按意大利欧技公司提供的技术附件执行。与普通 3 1 6 L焊接施工不同的是 ,要求焊后铁素体含量≤ 1 %。为了控制焊缝铁素体含量和防止焊缝产生热裂纹 ,除了采用匹配焊材外 ,还应在焊接工艺中采取相应的措施。1　分　析1 .1　母材分析尿素级 3 1 6 L与普通 3 1 6 L的化学成分相似(见表 1 )。尿素等介质先腐蚀管材的 δ相铁素体 ,造成选择性腐蚀。另外在高温工作条件下或多层焊时 ,δ相铁素体将转变为σ相 ,对母材的韧性及抗腐…     

LNG加气站不锈钢管道焊接质量控制

管道焊接质量对LNG加气站的安全运行起着关键作用,要从焊接工艺、焊前准备和焊后检验等方面严格控制。     

不锈钢复合材料的压力容器焊接质量控制

本文在针对不锈钢复合材料的压力容器焊接质量控制相关问题进行分析时,与实际产品进行结合,将该产品作为研究对象。在这一基础上,从焊接坡口、装配、焊接之前的准备工作等角度出发,对其进行分析,并且提出融合复合板在实际焊接过程中的具体顺序以及技术要求。在保证焊接质量得到有效控制的基础上,能够提高不锈钢复合材料的整体利用率。     

316 L奥氏体不锈钢纤维高温氧化研究

利用失重法对316 L奥氏体不锈钢纤维的高温氧化动力学进行了研究,通过对氧化动力学曲线的分析可以得出:700℃时因氧化反应动力学曲线一直呈上升趋势,直至120 h后曲线开始平缓;900～1 000 ℃时氧化到一定阶段后,因氧化物(MoO3、Cr2O3等)的挥发均呈现一个下降趋势,之后氧化达到饱和状态基本不再变化;且达到饱和的时间随温度升高而减少.扫描电镜对高温氧化后的形貌观察发现700℃时碳化物(Cr23C6)大量析出,900℃下氧化后纤维表面呈密集颗粒状,温度再升高至1 000℃后,由于颗粒周围基体的氧化和氧化物的挥发,颗粒掉落严重.     

关于316H耐热不锈钢的焊接实践

通过对316H奥氏体耐热不锈钢的焊接性分析,进行了焊接工艺评定;通过合理的焊接工艺保证了再生器的焊接质量.     

The transpassive dissolution mechanism of 316L stainless steel

The transpassive dissolution mechanism of AISI 316L stainless steel was studied using electrochemical impedance spectroscopy (EIS). A generalized model of the transpassivity is proposed. The transpassive film is modeled as a highly doped n-type semiconductor-insulator-p-type semiconductor (n-i-p) structure. Injection of negative defects at the transpassive film/solution interface results in their accumulation as a negative surface charge. It alters the non-stationary transpassive film growth rate controlled by the transport of positive defects (oxygen vacancies). The model describes the process as dissolution of Cr as Cr(VI) and Fe as Fe(III) through the transpassive film via parallel reaction paths.     

化学镀镍316不锈钢激光焊接裂纹研究

通过调整镀液中磷酸钠的质量浓度,在316不锈钢表面化学镀得到P质量分数分别为1.2％、2.3％和3.4％的镍镀层.对镀镍316不锈钢进行激光焊接实验,得到较佳的工艺参数为:激光功率50 W,脉冲宽度60 ns,焊接速率200 mm/s.当镀层中磷的质量分数为1.2％时,焊缝中无裂纹,剪切强度为242 MPa.随镀层中磷...     

Hydrogenated amorphous carbon films deposited on 316L stainless steel

Research on hydrogen amorphous carbon films (a-C:H), which possess the diamond-like characteristic, has been stimulated for many years by need to simultaneously optimizing the mechanical, optical and biological properties, and by challenges related to the deposition of a-C:H films on medical implants. In the present work, we investigate the structure, optical and mechanical properties (hardness, elastic modulus and stress) of a-C:H films deposited on 316L stainless steel substrate by the radio frequency plasma enhanced chemical vapor deposition (RF PECVD). The negative self-bias voltages significantly influence on temperature of steel substrates during the deposition process and films properties. Specifically, the high energetic deposition leads also to stabilization of the sp² content and thermally-activated relaxation in the stress of a-C:H films. Presented correlation between the obtained results and literature analysis let deem the Raman spectra as a good tool to control the properties of implants made of 316L stainless steel with a-C:H film for general use.     

Mechanical properties of P/M 316L stainless steel materials

In this work, 316L stainless steel (SS) powder was used. The composition of the powder is as follows: 0.015% C, 1.75% Mn, 0.45% Si, 17.24% Cr, 2.79% Mo, 14.65% Ni, and balance iron. Mixed powder was compressed cold using single action press under 800 MPa pressure. Compressed samples were sintered at 1200 °C, 1250 °C, and 1300 °C into the nitrogen gas atmosphere. In order to determine the mechanical properties of the produced specimens, the fatigue tests, tensile test, three-point bending test, impact test and hardness tests were applied to the specimens. Determined mechanical properties in the result of this work were compared to the properties as stated in ASTM F138-G2. Besides that to define the microstructures of the produced specimens in detail, metallographic studies were performed.     

Electrodeposition of copper on thermally oxidized 316 L stainless steel substrates

The effect of thermal oxidation of 316 L stainless steel cathode blanks used in copper electrodeposition was studied. Current and potential step experiments were performed to evaluate electrochemical changes caused by the oxidation treatments. SEM and AES were used to characterize the stainless steel substrates and the deposited copper films. Particular emphasis was given to the initial stages of copper nucleation and growth. The copper electrocrystallization process was strongly influenced by the temperature employed in oxidizing the stainless steel. Dense, uniform and fine copper nuclei were obtained on the stainless steel substrate oxidized in air at 200°C and 300°C for 3h. The copper nucleation density and uniformity decreased considerably on substrates treated at 500°C and 600°C. Attempts were made to identify changes in the mechanism of copper nucleation on the various oxidized stainless steel substrates using models developed by Thirsk and Harrison.     

Evaluation of 316 L porous stainless steel for SOFC support

Solid oxide fuel cells (SOFCs) supported on porous steel substrates are recently gaining much attention, because fabrication cost of SOFC might be significantly reduced. In this paper high temperature properties of porous stainless steel 316 L for application in SOFCs are evaluated. The 316 L was investigated using thermogravimetric analysis, XRD analysis and electrical measurements of scales formed on steel surface. The YSZ ceramic electrolyte was deposited on the 316 L and interaction of formed interlayer was evaluated. The results show that the 316 L is applicable only for SOFCs operated below 500 °C.     

Study of CNx films on 316L stainless steel for orthodontic application

In order to improve the friction property and corrosion resistance of 316L stainless steel (316LSS) in orthodontic application, carbon nitride (CNx) films were synthesized by using IBAD technique at a set of assisted N ion beam currents. X-ray photoelectron spectroscopy and Raman spectroscopy were used to characterize the bonding state and the microstructure of the CNx films. Results of tribological tests indicated that the 316LSS coated by CNx films exhibited lower friction coefficients than the uncoated one both in air and in artificial saliva. The electrochemical tests in artificial saliva confirmed that the corrosion resistance of 316LSS was evidently improved after coated with CNx films.     

316L不锈钢管与管板的焊接工艺

阳极保护管壳式不锈钢浓硫酸冷却器的制作,除了一般的机械性能要求外,对列管与管板间焊缝的耐腐蚀性能,特别是耐晶间腐蚀性能要求也较高。最近我公司承接了一台浓硫酸冷却器,列管和管板材料均为316L不锈钢。我们采用手工钨极氩弧焊,通过焊接工艺试验,确定了焊接控制条件。检验结果表明焊缝金属具有较高的耐腐蚀性,证明了焊接工艺的可靠性。     

Electrodeposition of bilayered polypyrrole on 316 L stainless steel for corrosion prevention

The electropolymerization of pyrrole in aqueous solutions of salicylate leads to the formation of hollow rectangular-sectioned microtubes. With the aim to develop a coating with this morphology but with better anticorrosive properties we synthesized a bilayer system by depositing a polypyrrole underlayer electropolymerized in the presence of molybdate and nitrate and a polypyrrole film formed by the microtubes as a top layer. The corrosion performance of the coatings was monitored by following the open circuit potentials, polarization curves and electrochemical impedance spectroscopy in acid and neutral chloride solutions. The bilayers have the capacity to protect the steel against uniform as well as against pitting corrosion during long exposure times. The system with the inner layer formed in alkaline solution was the most protective coating in this study. The results are discussed in terms of the galvanic interaction between the polymer and the substrate and the role played by the dopant anions.     

回用水对冷却水系统316L不锈钢的腐蚀

城市污水回用作循环冷却水系统,讨论了NH3-N、COD、Cl-、SO42-等因素对316L不锈钢耐腐蚀性的影响。极化曲线表明:当NH3-N的质量浓度超过18 mg/L时,NH3-N促进了不锈钢的点蚀;COD对316L不锈钢的点蚀并无多大的影响;Cl-促进点蚀,而SO42-的质量浓度小于300 mg/L时,SO42-对其点蚀有缓蚀作用。