Cu-P-Cr钢及其焊接接头的周期腐蚀性能

通过中试轧制、电渣压力焊制备了Cu-P-Cr钢及其焊接接头,利用光学显微镜研究了电渣压力焊接接头的组织晶粒度,利用干湿交替实验机、SEM、EPMA、XRD研究了Cu-P-Cr钢及其焊接接头在1.0×10-2mol/L的Na HSO3溶液中的耐腐蚀性能、锈层元素分布及组成,分析了母材与焊接接头的耐腐蚀机理及其影响因素。研究结果表明:焊接接头与母材的腐蚀速率相比碳钢分别为64.6%与61.5%。焊接接头锈层中Cu、Cr元素的大量富集、α-Fe OOH相的转变是腐蚀性能优异的主要原因,而焊缝及熔合区形态各异的铁素体+珠光体+魏氏组织和晶粒尺寸不均等导致了锈层中Cu、Cr富集程度低于母材、腐蚀性能稍弱于母材。     

A quantitative alternative to the Vickers hardness test based on a correlation between thermal diffusivity and hardness—applications to laser-hardened carburized steel

A quantitative non-destructive test technique for characterizing heat treated steel based on a theoretical model was developed and verified by experiments using the optical beam deflection technique at metallic samples, heated by a Gaussian beam. The analytic solution of the heat equation with appropriate approximations provides a theoretical expression of the surface temperature, which is an important guide to optimize the experimental process. Measurements have been focused on determining both, mechanical parameters and thermal local properties, in order to find correlations. The theoretically described thermal diffusivity was experimentally measured by using the new developed photo-thermal deflexion inversion procedure. A simple correlation between the micro-hardness according to Vickers and the thermal diffusivity was found for laser-hardened specimens depending on their microstructure and individual chemical composition.