热处理对T91耐热钢的组织结构及力学性能的影响

研究了T91钢经700～800℃热处理后的组织结构及力学性能特点,特别是碳化物的长大对T91钢结构与性能的影响。结果表明:供货态T91钢是由板条状铁素体F及在其晶界、晶内弥散分布的M23C6型碳化物构成的回火索氏体组织;随热处理温度的升高和时间的延长,F发生回复、再结晶和晶粒长大;同时,碳化物逐渐在F晶界聚集;经800℃×58 h热处理,碳化物长大成1～3μm的大颗粒,弥散度降低,从而导致T91钢的强度、硬度降低,而塑性、韧性提高。热处理态T91钢具韧窝聚集型断裂机制,塑性断裂特征较供货态明显。     

热处理态NiCoCrAlY涂层的抗中性盐雾腐蚀性能

通过500 h中性盐雾试验研究了在低膨胀高温合金GH907上低压等离子喷涂(LPPS)的NiCoCrAlY涂层在热处理后的抗腐蚀性能,并与热处理态的LPPS制备的NiCr涂层的抗腐蚀性能进行了对比.结果表明,盐雾腐蚀500 h后,NiCoCrAlY涂层在扫描电镜下可以看到几个无破坏性作用的腐蚀坑,涂层表面仍保持较好的完整性和光洁性,对腐蚀产物的EDS面扫描表明腐蚀产物主要为Al的氧化物,涂层的腐蚀保护等级仅下降到9级;而NiCr涂层的表面出现了较多的腐蚀斑点,涂层的完整性和均匀性均已经被破坏,涂层表面产生了腐蚀裂纹,其腐蚀等级下降到4级.EDS分析表明腐蚀产物主要为Ni、Fe、Co等的氧化物.对比结果表明,NiCoCrAlY涂层表现出比NiCr涂层更强的抗中性盐雾腐蚀性能.     

热处理对35CrMo钢耐蚀性能的影响

研究了热处理对35CrMo钢硬度、显微组织的影响,通过测定极化曲线分析其耐腐蚀性能的变化规律.结果表明:在ω(NaCl)=3.5%腐蚀环境中,淬火样由于存在较大的淬火应力导致应力腐蚀倾向很大,回火降低了淬火应力,试样耐蚀性提高.材料的组织是否均匀则影响形成微观腐蚀电池的数量,其数量越多,腐蚀电流越大,耐蚀性能就越差.     

热处理工艺对35CrMo钢耐蚀性能的影响

通过淬火、回火实验研究了不同热处理对35CrMo钢组织的影响,并利用极化曲线分析研究了35CrMo钢在不同热处理条件下的组织和性能的变化对该钢腐蚀性能的影响,结果表明:在3.5%NaCl腐蚀环境下,合金的组织对材料的耐腐蚀性能具有决定性的作用,淬火使合金存在较大的淬火应力引起材料耐腐蚀性能下降,而回火后消除了材料淬火应力,材料耐腐蚀性能得到明显提高,并且随着材料组织的粗化,合金耐腐蚀性能反而提高。     

热处理工艺对430铁素体不锈钢耐蚀性的影响

将真空感应熔炼得到的试验钢进行固溶处理和稳定化处理,通过金相、扫描电镜、能谱、显微硬度及电化学方法,研究了热处理工艺对430铁素体不锈钢组织和耐蚀性能的影响。结果表明,通过1 050℃保温1h水冷后得到的试验钢的耐蚀性最好,通过分析可以发现,通过固溶处理能得到过饱和固溶体,减少碳化铬的析出,呈现较为均匀的显微组织,从而改进试验钢的耐蚀性能。     

热处理温度对Ni-W-P镀层耐蚀性能的影响

采用失重法及电化学方法对镀态和热处理后的Ni-W-P镀层在5%硫酸溶液中的耐蚀性能进行了研究.比较了不同温度热处理后Ni-P镀层和Ni-W-P镀层的耐蚀性能,并结合X射线衍射(XRD)、扫描电镜(SEM)对镀层的耐蚀性机理进行了分析.结果表明,Ni-P镀层在400～700℃热处理后耐蚀性能下降,而Ni-W-P镀层的耐蚀...     

Effect of Heat Treatment on Mechanical Properties and Corrosion Performance of Cold-Sprayed Tantalum Coatings

The cold-spray technique is of significant interest to deposit refractory metals with relatively high melting point for a variety of demanding applications. In the present study, mechanical properties of cold-sprayed tantalum coatings heat treated at different temperatures were investigated using microtensile testing, scratch testing, and nanoindentation. The corrosion performance of heat-treated coatings was also evaluated in 1 M KOH solution, and potentiodynamic polarization as well as impedance spectroscopy studies were carried out. Assessment of structure–property correlations was attempted based on microstructure, porosity, and intersplat bonding state, together with mechanical and corrosion properties of the heat-treated cold-sprayed tantalum coatings. Coatings annealed at 1500 °C, which is very close to the recrystallization temperature of tantalum, were found to perform almost as bulk tantalum, with exciting implications for various applications.     

水韧处理工艺对合金高锰钢组织和性能的影响

研究了水韧处理工艺对Cr、V、Mo合金高锰钢金相组织和力学性能的影响.试验结果表明,水韧处理工艺对合金高锰钢金相组织和力学性能有显著影响,适宜的水韧处理工艺(加热至1100℃,保温4h)可以改善高锰钢金相组织和力学性能,使σb=780MPa、δ5 30%、αK=150J/cm2、HBS=258,使用寿命达到1800h以上.     

高速钢刀具热处理腐蚀原因和预防措施

高速钢刀具在盐浴热处理过程中,往往会由于盐中含有杂质、潮湿空气、热处理操作等原因而发生腐蚀。严格按标准控制原盐的纯净度,定时对淬火加热盐浴进行脱氧和捞渣,取消酸洗或控制酸洗时间,对淬火后的刀具严格清洗和及时回火,缩短热处理生产周期等,能有效防止高速钢刀具在热处理过程中发生腐蚀。     

高强度高韧性钢的热处理与力学性能

研究了真空冶炼低碳Ｎｉ１０Ｃｏ１４Ｃｒ２Ｍｏｌ钢的碳含量，时效温度与力学性能的关系，初步探索了钢中加入稀土，镁元素的作用，试验结果表明，钢中含碳量为０．１６％时，经５１０℃时效，可获得高强度和高韧性：σｂ＝１５８５ＭＰａ，σ０．２＝１４７０ＭＰａ，Ｖ型缺口冲击韧度为５６Ｊ／ｃｍ＾２，平面断裂韧性ＫＩＣ＝１０５ＭＰａｍ＾１／２，钢中添加过量稀土，韧性显著降低，镁对性能影响不大。     

Processing and Development of Corrosion Resistance Surface-Active Thin Film Nanocellulose Composite Coatings for Mild Steel Protection

Protection of Metals and Physical Chemistry of Surfaces - Mild steels are applied in the construction of oil platforms and pipelines due to their ease of formability, machinability, good mechanical...     

热处理对高碳低合金磨球钢的组织和性能的影响

研究了热处理工艺对高碳低合金磨球钢的显微组织、硬度、冲击韧度和耐磨性的影响，并分析了钢的耐磨性与力学性能的关系。研究结果表明，该钢具有高淬透性，在水、油中冷却的临界淬透直径均大于１００ｍｍ，回火稳定性较高。该钢经８５０￣９００℃淬火及２００℃回火后，可获得具有高硬度和一定韧性的回火马氏体组织，并具有较高的耐磨性。     

热处理工艺对弹簧钢力学性能的影响

采用二次加热和余热处理对60Si2CrVAT钢进行淬火处理,研究了不同处理工艺下弹簧钢力学性能。结果表明,提高试验钢回火硬度可增加其屈服强度和抗拉强度,但随着加热速率的增加,钢的屈服强度和抗拉强度下降。在相同硬度下,经二次热处理的试验钢比余热处理时屈服和抗拉强度大,伸长率和断面收缩率高;经相同回火温度处理后,采用二次加热淬火处理的试验钢屈服强度和抗拉强度跟余热处理相差不大,但伸长率和断面收缩率均高于余热淬火。     

Effect of Pyrrole and N-Methylpyrrole Coatings on Corrosion Resistance of Mild Steel

COATING ON THE SURFACE of metals bypolymeric materials have been widely used inindustries for the protection of this materials against ofcorrosion[1-4].Electropolymerization is an effective technique forthe surface coating of various conductive materialswith wide variety of polymers with various thick nesses[5].Recently,electropolymerization of pyrrole on steelsubstrates has been investigated with the aim ofproducing uniform and strongly adherent coatings[6-9].It was found that only lim…     

环氧磷酸酯/水性环氧涂层的耐蚀性能

为研究水性环氧涂层缓蚀剂的制备及其耐蚀性能,采用化学法将磷酸接到双酚A环氧树脂上,并与N,N-二甲基乙醇胺中和制备水性环氧磷酸酯。将环氧磷酸酯添加到双组份水性环氧树脂中制备3种环氧磷酸酯/水性环氧涂层(E44,0.2%P-E44和0.5%P-E44)。采用极化曲线和交流阻抗谱技术研究了环氧磷酸酯/水性环氧树脂对Q235钢基体在3.5%NaCl溶液中的防护性能。结果表明:浸泡24h后,0.2%P-E44/碳钢体系的自腐蚀电流密度(0.431μA/cm2)低于E44/碳钢体系(0.928μA/cm2)和0.5%P-E44/碳钢体系(0.553μA/cm2);在浸泡24h内,3种涂层的涂层电容Qc逐渐增大,涂层电阻Rc和电荷转移电阻Rct逐渐较小,环氧磷酸酯可以显著提高纯水性环氧的Rc和Rct,进而提高水性环氧的耐蚀性能。当水性环氧树脂中环氧磷酸酯的含量为0.2%时,其防护性能较好。     

热处理对H13型钢的力学性能影响

对未经处理和热处理后H13钢芯棒进行扫描电镜、金相及力学性能分析,研究其在不用热处理条件下的力学性能的变化规律。结果表明,未经过热处理的芯棒表面较热处理后出现了失效现象,产生了热疲劳裂纹和机械磨损裂纹。未经热处理芯棒心部有碳化物析出,马氏体的回复引起基体硬度下降,芯棒的边缘冲击韧度较高,过早出现热裂纹及深裂纹导致芯棒失效。     

Innovation of Ultrafine Structured Alloy Coatings Having Superior Mechanical Properties and High Temperature Corrosion Resistance

High temperature protection requires full coating density, high adhesion, minor oxide inclusions, and preferably fine grains, which is not achievable in most thermal spray processes. High velocity oxygen fuel (HVOF) thermal spray process has been applied extensively for making such coatings with the highest density and adhesion strength, but the existence of not melted or partially melted particles are usually observed in the HVOF coatings because of relatively low flame temperature and short particle resident time in the process. This work has investigated the development of an innovative HVOF process using a liquid state suspension/slurry containing small alloy powders. The advantages of using small particles in a HVOF process include uniform coating, less defective microstructure, higher cohesion and adhesion, full density, lower internal stress, and higher deposition efficiency. Process investigations have proven the benefits of making alloy coatings with full density and high bond strength attributing to increased melting of the small particles and the very high kinetic energy of particles striking on the substrate. High temperature oxidation and hot corrosion tests at 800 °C have demonstrated that the alloy coatings made by novel LS-HVOF process have superior properties to conventional counterpart coatings in terms of oxidation rates and corrosion penetration depths.     

Effect of Heat Treatment on the Microstructure,Mechanical Properties and Corrosion Resistance of Selective Laser Melted 304L Stainless Steel

The influence of heat treatment holding temperatures from 600 to 1300 °C on the microstructure, mechanical properties and corrosion resistance in selective laser melted(SLMed) 304L stainless steel is investigated in this work. The results reveal that there is no remarkable microstructure change after holding at 600 °C for 2 h, while recrystallization leads to a slight decrease in grain size in the temperature range of 700–900 °C. The heat treatment at temperatures from 1000 to 1300 °C for 2 h ob...     

NaCl盐膜对珠光体耐热钢抗高温腐蚀性能的影响

测试了涂与未涂NaCl盐膜的珠光体耐热钢在700℃的氧化动力学曲线。通过氧化腐蚀产物的分析,研究了NaCl盐膜对珠光体耐热钢抗高温腐蚀性能的影响。结果表明,NaCl盐膜会促进珠光体耐热钢的高温氧化腐蚀,形成的氧化膜较厚、疏松,与基体结合性差,从而降低珠光体耐热钢抗高温腐蚀性能。