The effect of neutral red on the corrosion inhibition of cold rolled steel in 1.0 M hydrochloric acid

The corrosion inhibition of neutral red on the corrosion of cold rolled steel in 1.0 M hydrochloric acid (HCl) was studied using weight loss method and potentiodynamic polarization method. Results obtained revealed that neutral red is an effective inhibitor. It was found that the adsorption of neutral red could prevent steel from weight loss and the adsorption accorded with the Langmuir adsorption isotherm. Potentiodynamic polarization studies showed that neutral red mainly acted as a mixed-type inhibitor for steel in 1.0 M hydrochloric acid. Thermodynamic parameters such as adsorption heat, adsorption entropy and adsorption free energy were obtained from experimental data of the temperature studies of the inhibition process at four temperatures ranging from 30 to 45 °C. The most suitable range of inhibitor concentration was discussed. The kinetic data such as apparent activation energies and pre-exponential factors at different concentrations of the inhibitor were calculated, the effect of the apparent activation energies and pre-exponential factors on the corrosion rates of cold rolled steel was discussed. The inhibitive action was satisfactorily explained by using both thermodynamic and kinetic models. Synergism between chloride ion and neutral red was proposed. The results obtained from weight loss and potentiodynamic polarization were in good agreement.     

热力管线中不锈钢波纹管破裂原因分析

采用金相显微镜和扫描电镜分析了热力管线中不锈钢 波纹管破裂原因.该波纹管破裂特征与一般环向开裂不同，裂纹沿轴向扩展.分析认为，破裂 属穿晶应力腐蚀.引起应力腐蚀的介质是土壤中的氯化物，而应力则来自环向工作应力和冷 加工残余应力，而环向工作应力起主导作用。     

钢种、轨型及生产工艺对钢轨矫后残余应力的影响

研究了不同钢种（U74、U71Mn、BnbRE）、不同轨型（50kg/m、60kg/m、75kg/m）及在不同生产工艺下，钢轨矫后残余应力值的变化。结果表明，不同钢种生产的同轨型钢轨，矫后钢轨轨底中心部位残余应力值随着钢轨强度级别的增加而增加，同钢种、不同轨型的钢轨矫后轨底中心残余应值随着钢轨单位长度质量的增加而增加，同钢种、同轨型的钢轨随着矫直力的增加，钢轨矫后轨底中心残余应力值也增加。而钢轨终轧温度的高低，矫前原始弯曲度的大小（Y轴方向）在现有生产工艺条件下，对钢轨矫后轨底中心残余应力值无明显影响。     

不锈钢过钝化－二次钝化的研究

通过对３０４不锈钢在较高电位下过钝化和二次钝化的稳态过程和电化学交流阻抗（ＥＩＳ）的分析，认为不锈钢过钝化和二次钝化现象与膜／溶液（ｆ／ｓ）界面上的电化学反应有密切关系，并通过理论模型分析，解释了过钝化和二次过钝化膜在高电位下溶解速度高，而在开路自腐蚀电位下反而有较好的稳定性这一现象．     

易切削钢冲击断口分维的随机分形分析

建立横向冲击时易切削钢裂纹扩展的随机分形模型，计算了冲击断口的随机分形维数Ｄ，比较和分析了Ｄ、非随机分形维数与实测分形维数。结果表明随机分形断裂模型与实验数据完全吻合。     

Φ100mm自动轧管机组穿孔方头缺陷的产生及消除方法

对Φ１００ｍｍ自动轧管机组穿孔方头缺陷产生的原因进行了分析。方头的形成是由顶杆位置过后，轧辊径向颤动及穿孔变形时椭圆度系数过大等原因造成的。同时提出了相应的解决方法。     

High Temperature Oxidation of Steels in Air and CO2–O2 Atmosphere

Three kinds of hot rolled steel slabs, viz. high strength steel, bake hardened steel and low carbon steel, were oxidized isothermally between 1100 and 1250 °C for up to 2 hr in 1 atm of air and an 85%N₂–10%CO₂–5%O₂ gas mixture. The steels were oxidized in a similar fashion in both the atmospheres. The oxidation process followed an initial linear rate law, which then gradually transformed to a nearly parabolic rate law. Thick, porous and nonadherent scales formed rapidly, due to the high oxidation temperature. The scales formed consisted of Fe₂O₃,(Fe₂O₃+Fe₃O₄), (Fe₃O₄+Fe₂O₃ +FeO) and (FeO+Fe₃O₄) from the outer surface. The presence of supersaturated oxygen beneath the scale resulted in grain boundary oxidation and the formation of internal oxide precipitates.     

Resistance of Mo-bearing stainless steels and Mo-bearing stainless-steel coating to naphthenic acid corrosion and erosion-corrosion

Naphthenic acid corrosion (NAC) and erosion-corrosion (NAEC) behavior of Mo-bearing (0-7.0 wt.%) stainless steels have been investigated in laboratory to evaluate the essential role of Mo on their NAC and NAEC resistance. The NAC and NAEC resistance of a high-velocity-oxygen-fuel (HVOF) thermal sprayed Mo-bearing stainless-steel coating was also investigated in both laboratory and an oil refinery. It was found that increasing the Mo content remarkably enhanced the NAC and NAEC resistance of stainless steels. The Mo-rich areas or phases in the steels played an importance role in resisting the NAEC. The HVOF coating showed excellent NAC and NAEC resistance in laboratory tests. The 700-day field test in an oil refinery revealed that the coating can effectively prevent the carbon-steel substrate from erosion-corrosion during long-term exposure in oil-refining environment. The corresponding NAC and NAEC mechanisms of the stainless steels and the beneficial role of Mo were discussed by taking account of inherent susceptibility of metal elements to corrosion, possible effects of Mo on surface films, and Mo-induced change in microstructure and microhardness.     

热处理对1Cr18Ni9Ti钢焊接接头性能的影响

试验研究了固溶＋稳定化处理、固溶处理和去应力退火处理对1Cr18Ni9Ti钢焊接接头力学性能的影响。结果表明：固溶＋稳定化处理试样的屈服强度、伸长率、抗拉强度均最高。扫描电镜观察结果表明：所有的断口均为韧窝型断裂。     

焊接工艺参数对奥氏体不锈钢焊接接头腐蚀行为的影响

通过草酸腐蚀和硫酸-硫酸铁腐蚀实验，研究了奥氏体不锈钢焊接接头腐蚀与焊接热输入的关系。结果表明，随着焊接线能量的增加，其焊接接头腐蚀越严重。随着焊接线能量的增大，腐蚀率增大且有加速趋势。