摘要:

AbstractFriction hardening is one of the new technologies utilising concentrated energy sources to surface harden iron based structural alloys. The process has the advantage of simplicity of the methods and devices used, and the high energy densities of frictional work attained in localised areas of a large workpiece can create surface structures having similar properties to those obtained by surface hardening with laser radiation, electron beams, or low temperature plasmas without any surface melting.

ISSN:0267-0844    

DOI:10.1179/sur.1989.5.3.226

出版商:Taylor&Francis    

年代:1989

数据来源: Taylor

摘要:

AbstractThe microstructure, composition, internal stress, and corrosion properties of white layers, typically less than 2·5μm thick, formed on EN24 steel by centreless grinding, have been investigated using microscopy, electron probe analysis, X-ray diffraction, profilometry, and simple immersion tests. No accumulation or depletion of chromium, nickel, molybdenum, phosphorus, carbon, nitrogen, or oxygen occurred over a depth of 100 j1m. The hoop and axial residual stresses at the surface were compressive and about 200 and 600 MN m-2respectively. The hoop stress changed from compressive to tensile at 2 j1m depth and reached a maximum value of about 850 MN m-2at a depth of 15μm. The white layer has an ultrafine microstructure, and the mechanism of formation is consistent with a process of intense thermomechanical plastic deformation. Localised corrosion occurs in solutions containing chloride where the white layer is thin, but as corrosion proceeds it spreads and becomes more general.

ISSN:0267-0844    

DOI:10.1179/sur.1989.5.3.229

出版商:Taylor&Francis    

年代:1989

数据来源: Taylor

摘要:

AbstractThe electrochemical behaviour of a sensitised 304 stainless steel which has subsequently undergone a fusion treatment of its surface with a continuous wave CO2laser has been studied. The area directly affected by the fusion has a fine scale microstructure of austenite; the intercellular regions are interpreted as containing ferrite. The electrochemical corrosion resistance tests show that, following the laser treatment, the steel has regained its intergranular corrosion resistance properties.

ISSN:0267-0844    

DOI:10.1179/sur.1989.5.3.235

出版商:Taylor&Francis    

年代:1989

数据来源: Taylor

摘要:

AbstractA technique that involves the holographic imaging of an ultrasound field induced on the surfaces of components and its application to flaw detection are described. Optimum test parameters deduced from tests with artificially produced flaws have been found to give good results when examining protective barrier coatings. The presence of flaws detected in plasma sprayed CoCrAIY and zirconia coatings has been confirmed by metallographic analyses. Good resolution of location, size, and (in the case of cracks) depth has been achieved. The technique should be of use for complex components such as turbine blades since the imaging process is not affected by shape.

ISSN:0267-0844    

DOI:10.1179/sur.1989.5.3.239

出版商:Taylor&Francis    

年代:1989

数据来源: Taylor