摘要:

The results of an international round-robin intercomparison of burner rig testing to evaluate hot-salt corrosion resistance of gas turbine alloys and coatings are reported. The basis of the test programme consisted of evaluating operation of burner rigs using the same contaminant flux rate at two different temperatures (700 and 900°C). Four materials were tested; IN 738LC, Rene 80, IN 738LC coated with RT 22 and Rene 80 coated with ATD2B. Each material was tested in triplicate and detailed section loss measurements made by each participant. Compared with a previous intercomparison the reproducibility was improved for tests carried out at 900°C. Samples exposed at the lower temperature had greater scatter in the section loss data. Generally there was more variability on the data obtained from the coated samples.

ISSN:0960-3409    

DOI:10.1080/09603409.1995.11689508

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

摘要:

Carbide reactions in 1.5Cr—1.0Mo—0.3V steel are investigated at various thermal treatments at 550–650°C. The cooling rate control was carried out by cooling the environment. Metal tempering was conducted in the range 650–720°C for up to 100 h. It is shown that the rate of preliminary cooling from the austenitic region has the principal effect on the carbide reaction nature. At rapid cooling (martensite structure) the major carbide reaction during tempering and ageing is M3C→M7C3whereas for cooling rate decreasing the reaction M3C→M23C6prevails. Tempering and ageing change the quantitative characteristics of the carbide state without having an effect on the major mechanism of transformation. The carbide reaction character is compared with metal properties under the same time—temperature conditions and the correlation between the structural state and metal service properties is examined.

ISSN:0960-3409    

DOI:10.1080/09603409.1995.11689509

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

摘要:

Results of the investigation of thermocyclic strength of flat corset-type specimens (hour-glass-shape) (Getsov, L. B.et al., Industr. Lab., 1982, 7, 44)* from nine heat resistant alloys on a nickel base with protective coatings: electron-beam, i.e. single-layer system M—Cr—Al—Y, multilayer, dual-layer, diffusion, slurry and plasma spray coatings are represented. It is shown that the service life of electron-beam coatings is considerably higher than that of the pack cementation and slurry alumosilicide coatings. Dual-layer overlay coatings with an external ceramic layer have the optimum characteristics. Regularities are established for microcrack initiation and propagation in coatings and high-temperature alloys, depending upon the technology of the coating's deposition and test conditions.

ISSN:0960-3409    

DOI:10.1080/09603409.1995.11689510

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

摘要:

Impression creep tests have been performed on a 316-stainless steel at 600°C, for which conventional uniaxial creep test data are available. It is shown that the technique, based on the reference stress approach, for converting impression creep test data to equivalent uniaxial creep data, is accurate. The results show that the impression creep technique can be used for obtaining creep properties for materials which have high creep resistance at high temperature and test pressure conditions. The difficulties and limitations associated with such situations are described and methods of dealing with them are outlined.

ISSN:0960-3409    

DOI:10.1080/09603409.1995.11689511

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

摘要:

A laboratory erosion—corrosion test rig to simulate the simultaneous, synergistic interaction between solid particle erosion and corrosion at elevated temperatures is presented. The test rig is based on a propane-fired erosion system where the erosive particles are fed by a rotary vane feeder to a combined nozzle and burner. The particle system is pressurized with air and the particles are accelerated through a steel nozzle.In the present work, the performance of this test rig has been evaluated by studying the wastage characteristics of a low-alloyed carbon steel and an austenitic stainless steel. The work focuses on erosion and corrosion which are relevant to some aspects of FBC wastage problems. The tests were performed using 180–360μm angular alumina particles at 60°angle of impingement, at low particle velocities 2.6–8.2m/s and in the temperature interval 20–600°C. The steels were tested both in a blank polished condition as well as in a preoxidized condition.The erosion—corrosion rates of the steels were found to increase with increasing particle velocity. In contrast, the wastage rates were relatively independent of temperature in the temperature range investigated, the only exception being specimens of the low-alloyed steel exposed to the lowest particle velocity (2.6 m/s) which exhibited a drastic increase in wastage due to extensive spalling at the very highest temperature, i.e. 600°C. Specimens of the low-alloyed steel preoxidized at 700°C exhibited a somewhat higher erosion rate compared with non-preoxidized specimens and specimens preoxidized at 500°C.

ISSN:0960-3409    

DOI:10.1080/09603409.1995.11689512

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

摘要:

Ontario Hydro has developed several essentially non-destructive metallurgical methods for assessing the remaining life of high-temperature components in fossil-fuelled electricity generating units. For super-heater and reheater tubing, a life-prediction model has been developed and subsequently refined. For headers, piping and associated welds, surface replication has been adopted for the detection and assessment of creep cavitation damage. The scope of replication has recently been broadened significantly to include metal temperature estimation; and also detection of creep strain concentration, both being vital inputs to component life management.

ISSN:0960-3409    

DOI:10.1080/09603409.1995.11689513

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor