为了研究Q235钢在氢氟酸中的腐蚀性,通过维氏硬度试验、拉伸试验对Q235钢进行了力学性能分析,通过光谱分析仪和金相显微镜对Q235钢进行化学成分分析和组织观察。采用室内浸泡法考察了Q235钢在不同温度和不同浓度下的氢氟酸溶液中的腐蚀性能。结果表明:Q235随着氢氟酸腐蚀溶液温度的升高腐蚀加剧。而在不同浓度下,氢氟酸浓度为30%(体积比)的腐蚀速率最低,在40%氢氟酸中腐蚀速率最高。

In order to study the corrosion of Q235 steel in hydrofluoric acid, The Q235 steel mechanical performance analysis by vickers hardness test and tensile test , and Q235 steel chemical composition analysis and microstructure observation with spectrum analyzer and metallographic microscope. Using indoor soaking method and examined the Q235 steel acid corrosion under different temperatures and concentration of hydrofluoric. The results showed that: Q235 corrosion intensified with the increase of hydrofluoric acid etching solution temperature. And under different concentrations, the corrosion rate is the lowest in Hydrofluoric acid concentration of 30%(volume ratio), and in 40% hydrofluoric acid corrosion rate is the highest.

在实验室配制不同含水率土壤介质,利用线性极化及电化学阻抗技术,测试了Q235钢在冻土环境下的线性极化曲线和交流阻抗曲线,并对测试结果进行了分析拟合,得到线性极化电阻值和电荷转移电阻值,并与常温下Q235钢的腐蚀行为进行了对比,从而确定了Q235钢在不同含水率的冻土环境中的自腐蚀电位值以及Q235钢的腐蚀情况。

The linear polarization curves and Electrochemistry plots were measured in different containing water ratio at 0℃and-5℃in laboratory. The linear polarization and Electrochemistry results were achieved through analyzing the curves and plots. They were compared with the results which were measured at 23℃and 5℃in different containing water ratio, consequently the self-corrosion potential and corrosion behavior of Q235 steel in different containing water were confirmed.

采用浸泡法和电化学实验研究了汽车用 Q255钢在不同融雪盐(NaCl)质量分数雪水溶液中的腐蚀行为。浸泡实验结果表明,含融雪盐的雪水溶液比天然雪水更具腐蚀性,Q255钢在天然雪水中腐蚀速率较小,浸泡168 h 后的腐蚀速率为0.02107 mm/a；随着雪水中 NaCl 质量分数的增加,腐蚀速率也随着增大,在质量分数为3%NaCl 雪水溶液中,Q255钢的腐蚀速率为0.03971 mm/a,比纯雪水中 Q255钢的腐蚀速率高出将近1倍。电化学实验结果表明,Cl-的存在加速了腐蚀产物 Fe2+的溶解和传质过程,减弱了腐蚀产物的附着,使腐蚀产物起不到保护作用,加快了 Q255钢的腐蚀速度。

The immersion and electrochemical methods has been used to study the corrosion behavior of automotive steel Q255 in different content of snow melting salt (NaCl)solution.Immersion test show that,the snow melting salt solution is more corrosive than the natural snow solution.The corrosion rate of Q255 steel in the natural water water is smaller than that of the snow melting salt solution,with the corrosion rate of 0.021 07 mm/a after the immersion of 1 68 h.The corrosion rate increased with the increase of NaCl concentration of the snow solution.The corrosion rate of Q255 steel could reach 0.039 71 mm/a in 3%NaCl solution,the value of which was almost double to the natural snow solution.Electrochemical experiments show that, the presence of chloride ions accelerated the dissolution and mass transfer process of Fe2+ corrosion products,subsequently reduced the adhesion of the corrosion product.Accordingly,the corrosion products would not be able to protect the steel surface,thus

利用碳在马氏体与奥氏体之间的扩散分配实现钢的组织结构与力学性能调控,是近年来钢铁材料领域的重要研究方向。基于碳的完全均匀分配,Speer提出了淬火-分配(Q-P)热处理工艺,本文总结了近年Q-P工艺碳分配机理研究和工艺实践。同时,根据碳在奥氏体和马氏体中的扩散分配过程分析,提出了碳的梯度扩散分配与控制理念,并开发出了分级-淬火-分配(S-Q-P)工艺,希望能获得低碳马氏体、残留奥氏体、高碳马氏体相间分布的组织。对35SiMn钢分别进行淬火-回火(Q-T)、Q-P及S-Q-P工艺试验,并测量力学性能及观察显微组织。结果表明,S-Q-P工艺处理后钢的强塑性积达到31.2 GPa%(1240 MPa×25%),比传统Q-T和现行Q-P工艺分别提高67%和32%,其显微组织也接近于工艺设计的理想组织,证明了利用碳的梯度扩散分配可以实现对钢的组织与性能的调控。

Microstructure and mechanical properties of steels can be controlled by manipulating the partitioning process of carbon from martensite to austenite , and it becomes an important research direction in the field of iron and steel materials in recent years .Based on the concept of full carbon partitioning , Speer developed a novel process for the heat treatment of steels , that is the quenching and partitioning (Q-P) process.According to analysis on the diffusion and distribution process of carbon in austenite and martensite , stepping-quenching and partitioning ( S-Q-P) process was developed in order to get a better combination of low-carbon martensite , retained austenite and high-carbon martensite , and to enhance the mechanical properties of steels .Mechanical properties tests and microstructure observation have been done to 35SiMn steel treated by Q-T, Q-P and S-Q-P process.The results show that compared to Q-T and Q-P process, the product of strength and ductility of 35SiMn steel i

为满足汽车工业轻量化发展要求，以Q&P（quenching&partitioning）工艺为基础的先进高强度钢受到了广泛关注，为使其在普通热连轧生产线上实现工业化并广泛应用，本文对Q&P理念在热轧工艺中的应用进行了基础研究。结果表明在传统热处理Q&P工艺中引入热变形处理后，组织细化显著，并获得了一定量的残余奥氏体。实验钢在保持较高强度的同时获得了较大的强塑积，结合目前国内热连轧生产线以超快冷系统为核心的新一代控轧控冷（TMCP）技术的应用，确定了在热连轧生产线生产热轧Q&P钢（DQ （direct quenching）&P钢）的可行性。

In order to satisfy the requirements of lightweight in the automotive industry,the development of advanced high strength steel obtained using the quenching and partitioning (Q&P)process has been paid extensive attentions. In the present work,the application of Q&P concept during hot rolling was investigated for wide use of Q&P process on the conventional hot rolling production line. It was shown that introducing thermo-mechanical treatment during the conventional Q&P process was favorable for significantly refining the microstructure and obtaining a certain amount of retained austenite,and the experimental steel possessed the higher product of strength and ductility under the condition of maintaining higher strength. The feasibility of producing the hot rolled Q&P steel(DQ(direct quenching)&P steel)was determined on the hot rolling production line by employing the new-generation thermo mechanical control process (TMCP)with ultra fast cooling at the core.