ISSN:0267-0844    

DOI:10.1179/sur.1992.8.1.1

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

ISSN:0267-0844    

DOI:10.1179/sur.1992.8.1.3

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

ISSN:0267-0844    

DOI:10.1179/sur.1992.8.1.6

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

ISSN:0267-0844    

DOI:10.1179/sur.1992.8.1.34

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

AbstractTitanium carbonitride and titanium nitride coatings deposited on two powder metallurgy high speed steels have been characterised with respect to their microstructure, residual stresses, thickness, and hardness. The adhesion between coatings and substrates has also been determined. Finally, the tribological performance of the coatings was studied using an erosive wear test. The results show that the Ti(C,N) coating on the ASP 60 substrate is not only the hardest and best adhering, but also the coating with the lowest erosion rate. It is concluded that in order to obtain a general characterisation of the tribological properties of a coated material a number of coating properties must be determined. The overall performance of a coated component depends on both substrate and coating materials as well as their compatibility, and in order to fully understand how the substrate material influences the coating properties, powerful analytical techniques such as analytical transmission electron microscopy must be used.

ISSN:0267-0844    

DOI:10.1179/sur.1992.8.1.39

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

AbstractA method has been developed to study the behaviour of materials under conditions of simultaneous high temperature oxidation and mechanical wear by the action of abrasive particles in a jluidised bed. The possibility of using TiN coatings to provide a barrier to such an environment has been explored. The behaviour of steels coated with TiN by PVD was compared with that of the unprotected substrate materials. It wasfound that the TiN coating survived for a longer period at lower impact velocities of the bed particles. An increase in coating wastage rate with temperature between 200 and 400°C was suggested to be primarily due to a decrease in the coating hardness. A large reduction in the survival time of the coating above 400°C was believed to be due to the increase in the oxidation rate of TiN at these temperatures. Mechanisms of material removal were identified by SEM examination of worn specimen surfaces.

ISSN:0267-0844    

DOI:10.1179/sur.1992.8.1.47

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

AbstractThis paper examines the wear characteristics of M50 and T 1 high speed steels at temperatures up to 600°C by means of pin on disc wear tests. The mechanism is found to be one of severe oxidation wear for loads of 10-50 N; wear increasing with load applied. The T 1 steel showed superior wear resistance to M50 but was not wear resistant above 400°C and showed a very high wear rate at 600°C.

ISSN:0267-0844    

DOI:10.1179/sur.1992.8.1.55

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

AbstractAn industrial advantage of laser processing is that it permits local treatment of mechanical components on those specific areas subject to high stress levels. The way in which this type of laser treatment enhances structural steel properties has been studied. The 42CD4 and X C42 steel specimens were notched to create a stress concentrationfactor identical to that observedfor gears. The work involved optimising three parameters: the laser beam itself, i.e. the beam energy-time of interaction couple; specimen preparation, i.e. selection of the best laser beam-specimen coupling medium (phosphating gave the best emissivity coefficient while avoiding specimen contamination); the metallurgical heat treatment, designed to obtain both high toughness and good ductility. Specimens tempered at various temperatures before the laser treatment were fatigue tested. The results enabled the selection of an intermediate tempering temperature resulting in the highest fatigue limit. They also showed that, in regard to fatigue behaviour, laser surface treatment compared favourably with thermochemical carbonitriding.

ISSN:0267-0844    

DOI:10.1179/sur.1992.8.1.61

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

AbstractThe simultaneous decarburising and boronising of high speed steel (HSS) gear cutting hob with 2 kW CO2laser and a four dimensional machine tool is described. First, the HSS gear cutting hob is partially decarburised at the edge, which involves the use of a special decarburising agent. The edge is then partially boronised after coating with a boride based paste. The laser beam is moved across the hob at relative scanning speed of between 400-1800 mm min-1. Under conditions where surface melting does not occur a thin boride layer (FeB and Fe2B) only 0.08 mm deep is produced, but a transformation hardened layer of 0.9 mm is also produced beneath the boride surface. Good keying of the boride layer to the substrate is ensured due to the sawtooth microstructure of the duplex compound layer. Industrial trials have demonstrated a 100% increase in tool life after this treatment.

ISSN:0267-0844    

DOI:10.1179/sur.1992.8.1.66

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor