铸造用CO2硬化碱性酚醛树脂的试验研究

铸造业中广泛使用的树脂材料基本上都是一些有毒、污染环境的，因此开发出高质、高效、节能、环保的新型粘结剂是当前铸造绿色集约化发展的迫切需要.针对此粘结剂的特点，以抗压强度为主要考察目标，通过对其碱加入量、硼砂加入量和硅烷加入量进行正交试验，得出优化结果，并对树脂砂的可使用时间、发气性、溃散性和树脂加入量等工艺性能进行了试验研究.试验表明，此粘结剂制得的树脂砂具有良好的工艺性能，吹CO₂气体硬化后，可获得较高的初强度和终强度.     

X70管线钢于内蒙古苏里格大气田土壤中的腐蚀特征

利用SEM,EDS,XRD及失重法研究了X70管线钢在不同含水量的苏里格大气田土壤中的腐蚀行为.实验结果表明,随着含水量的增加,钢的腐蚀速率先增大后减小,水的质量分数为10%时腐蚀速率最大;通过对腐蚀形貌的观察发现,X70钢为不均匀腐蚀;EDS和XRD分析显示X70钢的腐蚀产物主要为铁氧化物(Fe2O3,Fe3O4).     

H2SO3对X70钢在弱酸性溶液中的腐蚀行为的影响

用静态失重法、动电位扫描法、交流阻抗法结合扫描电镜、X射线能谱分析研究了H₂SO₃对X70钢在弱酸性溶液中的腐蚀行为的影响. 结果表明，随H₂SO₃浓度的增大， X70钢在弱酸性溶液中的腐蚀深度逐渐增大，电荷转移电阻依次减小，自腐蚀电流逐渐增大，自腐蚀电位先负移后正移. 当HAc-NaAc缓冲溶液中含有H₂SO₃时，X70钢在活性溶解过程中形成了吸附性中间产物Fe(HSO₃)_ad.     

Mechanism of protective film formation during CO2 corrosion of X65 pipeline steel

Electrochemical techniques, X-ray diffraction (XRD), and scanning electron microscopy (SEM) were applied to study the corrosion behaviors of X65 steel in static solution with carbon dioxide (CO₂) at 65°C. The results show that iron carbonate (FeCO₃) deposits on the steel surface as a corrosion product scale. This iron carbonate scale acts as a barrier to CO₂ corrosion, and can reduce the general corrosion rate. The protection ability of the scale is closely related to the scale morphological characteristics.     

新疆库尔勒土壤模拟溶液中X70钢的缝隙腐蚀

以新疆库尔勒土壤模拟溶液为腐蚀介质(0.06 M Cl- 0.009 M SO2-4 0.001 7 M HCO3-),在阴极极化条件下,采用楔型缝隙模型研究了具有剥离涂层缺陷X70钢的缝隙腐蚀.楔型缝隙的一端封闭,另一开口端延伸到溶池(100 mm×100 mm×100 mm)的模拟溶液中.楔型缝隙的尺寸为深100 mm,宽45 mm,开口尺寸0.15～0.45 mm.将6条X70钢电极试样安装到缝隙中用以测定缝口不同距离处的局部电流密度、极化电位并监测试样的腐蚀状况.安装在缝隙上盖测量孔中的H 离子探头用于测量缝内的pH值.采用-0.85,-1.0和-1.15 V(相对于CSE)的阴极极化电位分别对缝口尺寸(δ)为 0.15,0.30和 0.45 mm的楔型缝隙进行阴极极化.试验结果表明,随着极化时间的延长,缝内局部电流密度和极化电位变得更为均匀,随着缝口控电位的降低以及缝口尺寸的增加,缝内的局部电流密度和pH值增加.缝口控电位相同时,从缝口到缝底的pH值先增加,然后达到一个较稳定的状态.缝口控电位越低以及缝口尺寸越大,pH值越易于达到稳定状态,且pH值开始增加的速率越小.     

X70管线钢热浸渗铝处理后盐雾腐蚀行为

利用热浸渗技术对X70管线钢表面进行了渗铝处理,通过SEM和EDS观察了X70管线钢渗铝处理前后表面微观形貌和化学元素的变化,采用XRD分析了其盐雾腐蚀前后表面物相,研究了渗铝处理对X70管线钢盐雾腐蚀的影响。试验结果表明,盐雾腐蚀后未处理试样表面点蚀较为严重,热浸渗铝处理后试样表层形成一层致密的Al2O3层,有效地阻止了腐蚀性介质Cl-离子和基体活性铁的接触;热浸渗铝后X70管线钢渗铝层组织有多种析出物,其表层黑色物质为FeAl,有效地抑制了表面点蚀的发生;未处理试样表面含铁量高,产生活性铁原子,是盐雾腐蚀发生点蚀主要因素。     

Mechanism of protective film formation during CO2 corrosion of X65 pipeline steel

Electrochemical techniques, X-ray diffraction (XRD), and scanning electron microscopy (SEM) were applied to study the corrosion behaviors of X65 steel in static solution with carbon dioxide (CO2) at 65°C. The results show that iron carbonate (FeCO3) deposits on the steel surface as a corrosion product scale. This iron carbonate scale acts as a barrier to CO2 corrosion, and can reduce the general corrosion rate. The protection ability of the scale is closely related to the scale morphological characteristics...     

H2SO3对X70钢在弱酸性溶液中的腐蚀行为的影响

用静态失重法、动电位扫描法、交流阻抗法结合扫描电镜、x射线能谱分析研究了H2SO3对X70钢在弱酸性溶液中的腐蚀行为的影响．结果表明，随H2SO3浓度的增大，X70钢在弱酸性溶液中的腐蚀深度逐渐增大，电荷转移电阻依次减小，自腐蚀电流逐渐增大，自腐蚀电位先负移后正移．当HAc—NaAc缓冲溶液中含有H2SO3时，X70钢在活性溶解过程中形成了吸附性中间产物Fe（HSO3）ad。     

Effect of deteriorated microstructures on stress corrosion cracking of X70 pipeline steel in acidic soil environment

In order to investigate stress corrosion cracking (SCC) of X70 pipeline steel and its weld joint area in acidic soil environ-ment in China, two simulating methods were used: one was to obtain bad microstructures in heat affected zone by annealing at 1300°C for 10 min and then, quenching in water; the other was to get different simulating solutions of acidic soil in Yingtan in south-east China. The SCC susceptibilities of X70 pipeline steel before and after quenching in the simulating solutions were analyzed...     

Effect of Ca~(2+) on CO_2 corrosion properties of X65 pipeline steel

The effect of Ca~(2+) on CO_2 corrosion to X65 pipeline steel was investigated in the simulated stratum water of an oil field containing different concentrations of Ca~(2+). It is found that Ca~(2+) can enhance the corrosion rate,especially in the Ca~(2+) concentration from 256 to 512 mg/L,which can be attributed to the growing grain size and loosing structure of corrosion scales with increasing Ca~(2+) concentration. X-ray diffraction(XRD) and X-ray photoelectron spectroscopy(XPS) investigations reveal that a complex carbonate (Fe, Ca)CO_3 forms at high Ca~(2+) concentration due to the gradual replacement of Fe~(2+) in FeCO_3 by Ca~(2+).     

CO2增采环境下X70管线钢的应力腐蚀开裂行为研究

在CO₂增采（CCS?EOR）环境下,研究了X70管线钢在不同CO₂压力下的腐蚀开裂行为及其机理。 使用高压反应釜及模拟采出水溶液,对现场环境进行了模拟;通过电化学实验,研究了X70管线钢在CCS?EOR环境下的腐蚀速率与腐蚀机理;通过慢应变速率拉伸实验,研究了模拟环境下X70管线钢的腐蚀开裂行为;通过扫描电镜,分析了不同CO₂压力下X70管线钢的腐蚀开裂机理。 结果表明,X70管线钢的腐蚀速率随着CO₂压力的增加而增加;X70管线钢表面产生的腐蚀产物膜不能保护金属基体,而且加剧局部腐蚀;在腐蚀产物膜的影响下,CO₂压力的增高使X70管线钢应力腐蚀敏感性增加,X70管线钢腐蚀开裂同时受金属表面裂纹的影响。     

多相流动状态下原油对 X70钢 CO2腐蚀的影响

利用自制实验装置模拟起伏管路段塞流动条件下 X70钢 CO 2腐蚀问题,通过电子显微镜、腐蚀挂片等对挂片表面形貌、腐蚀速率情况进行分析,研究了多相流动状态下原油对 X70钢 CO 2腐蚀速率的影响。结果表明：油水反相点不能作为油水混输管线腐蚀临界点;原油对 X70钢腐蚀防护作用仅局限于均匀腐蚀,对局部腐蚀无防护作用,随着原油含量的增加,局部腐蚀速率可能升高;原油对均匀腐蚀的防护作用主要体现在：降低挂片表面润湿面积,减小挂片与腐蚀介质接触机会;增大腐蚀介质的混合黏度,降低挂片表面传质速度;高含蜡原油内的许多未知成分具有缓蚀作用。     

Hydrogen permeation behaviors of X52 pipeline steel in NACE a solution with saturated H2S/CO2

With the aid of hydrogen permeating devices, the hydrogen permeation behaviors of X52 pipeline steel in NACE A solution with saturated H2S/CO2 were studied under the conditions of different ambient temperatures and pH values, and the hydrogen permeation behaviors of X52 pipeline steel in weld seam zone were comparatively studied. The experimental results show that the hydrogen permeation coefficient value is directly proportional to the time required for reaching the saturation anode current and inversely proportional to the saturation anode current, and the hydrogen permeation coefficient is influenced by the corrosion scales; the temperature is directly proportional to the saturation anode current, and the hydrogen permeation coefficient is influenced by the temperature and corrosion scales, heat-affected zone and matrix zone in NACE A solution with saturated H2S/CO2 at normal temperature. The hydrogen permeation coefficient in weld seam zone is larger than that in heat-affected zone which is further larger than that in matrix zone.