柱塞泵弹簧座失效原因及解决办法

对某工厂废水处理用液压柱塞泵的弹簧座进行了受力分析、强度计算和金相检验,找出了弹簧座内表面产生晶间腐蚀的原因和解决的方法.     

换热器防腐蚀方法介绍

文章对换热器的不同保护方法进行了介绍 ,重点讨论了渗铝、渗锌两种方法。在室温～ 80℃自来水和 3.5 %NaCl水溶液中 ,与碳钢基体相比 ,渗铝层的电位发生了反转 ,因而在针孔部位会形成大阴极小阳极的局面 ,易发生点蚀 ;而在相同条件下渗锌层不出现上述点蚀现象 ,更适宜在换热器的应用     

催化裂化再生系统设备应力腐蚀开裂成因分析及解决对策

通过对催化裂化装置再生系统设备裂纹断口分析 ,以及对再生烟气的组分、冷凝水酸度及露点等的分析及对设备焊接残余应力测试 ,阐明了设备应力腐蚀开裂发生的原因 ,指出了富氧操作、高露点温度和高应力水平对再生系统设备应力腐蚀的影响作用 ,并重点提出了解决和防止应力腐蚀开裂的一系列有效措施和部分应用情况     

合理选用过剩空气系数的重要性分析

通过分析过剩空气系数过大或过小时加热炉多方面的影响,强调了合理选用过剩空气系数的重要性,并提出了控制措施。     

空分设备的酸性腐蚀及预防

以切换式换热器空分设备为例 ,分析了空分设备酸性腐蚀的原因、可能造成的危害 ,提出了预防措施。     

新型哈氏合金G—30的耐蚀性能与工业应用

文章叙述了新型镍基耐蚀哈氏合金G-30在不同介质中的耐蚀性能以及工业应用,综合分析了该合金应用的经济性及前景。     

Pit to crack transition in stress corrosion cracking of a steam turbine disc steel

Long term exposure tests have been carried out on a 3 NiCrMoV steam turbine disc steel in the form of cylindrical tensile test specimens self-loaded to 90% of σ_0.2 and exposed to three environmental conditions, viz. deaerated pure water, aerated pure water, and aerated water containing 1.5 ppm of chloride ion. Pitting occurred in all environments but the density and depth of pits in the chloride-containing medium was markedly greater. No cracking was observed in deaerated pure water but cracks initiated in aerated water between 13 and 19 months and in less than 7 months in aerated 1.5 ppm Cl⁻ solution. The probability of a crack initiating from a pit of specific depth in aerated solution could be described well by a Weibull function. Profiling of pits and cracks in the disc steel tested in aerated 1.5 ppm Cl⁻ solution showed that there while there were many cracks with a depth greater than that of the corresponding pit the depth of some cracks was smaller than that of the corresponding pit, suggesting that cracks do not necessarily initiate from the bottom of the pits. The growth rate of short cracks emerging from pits appeared greater than that of long cracks in fracture mechanics specimens.     

Thermodynamic and kinetic consideration on the corrosion of Fe, Ni and Cr beneath a molten KCl-ZnCl2 mixture

Thermogravimetric (TG) experiments have been carried out to study the kinetics of hot corrosion of Fe, Cr and Ni, covered by a molten KCl-ZnCl₂ mixture of a composition close to the eutectic (50 mol% KCl-50 mol% ZnCl₂). Furthermore binary and ternary phase diagrams were calculated in order to describe the corrosion process. The tests were conducted at a temperature of 320 °C in an atmosphere consisting of argon and oxygen. For iron different stages are observed in a TG curve. They can be attributed to the different reaction steps of iron chloride formation (incubation phase), oxide precipitation (linear stage) and scale formation (parabolic or logarithmic stage). Based on these observations a model, described by Spiegel [A. Spiegel, Molten Salt Forum 7 (2003) 253], is confirmed. For Cr and Ni these stages are not observed. At 8 vol% O₂ only slight oxidation of Cr and Ni was observed accompanied by evaporation of the salt deposit. At 16 vol% O₂ the rate of oxidation increases and the experiments yield a curve that is either parabolic or logarithmic for both Ni and Cr. As a result it is shown that the solubility of iron chloride in the KCl-ZnCl₂ melt is higher than the solubility of nickel chloride and chromium (III) chloride in the KCl-ZnCl₂ melt. This enables a higher diffusibility of iron chloride to the upper region of the melt where a higher oxygen partial pressure (p(O₂)) is present leading to a higher oxidation rate of iron.     

胜利油田污水储罐腐蚀防护方法评价

对胜利油田纯粱采油厂A3钢制生产污水（水温约60℃）储罐使用寿命过低的原因进行了实验考察。水质分析数据表明氯离子浓度高（45-48gm）是污水腐蚀性强的主要因素。A3钢在60℃污水中的腐蚀速率，由极化曲线数据计算的值大大高于失重法测定值，敞开系统中失重法测定值又高于密闭系统中测定值，挂片上出现蚀孔，说明储罐中A3钢发生了氧存在下氟离子引起的局部腐蚀（孔蚀）。元素分析结果表明．储罐阴极保护所用的牺牲阳极铝材含铁等元素量超标。牺牲阳极密封不良，在实验污水中7天后电流效率仅为2．92％，失去阴极保护能力。处于实验污水环境中的有涂层保护的A3钢．14天后出现腐蚀极化电流，表明涂层已失去完整性。要提高该采油厂及胜利油田其他采油厂污水储罐的使用寿命，必须改用合格的牺牲阳极和保护涂层材料。图3表2参7。     

含腐蚀凹坑尿素合成塔的安全评定与分析

对尿素合成塔上封头腐蚀凹坑采用中国SAPV-95和美国API579规范分别进行安全评定，给出安全裕度，简略分析安全评定的结果。