[en] The goal of this work is to construct a mathematical model to describe the strip temperature evolution at a continuous finishing hot rolling mill. the model predicts in a satisfactory way the strip temperature, with a finishing one (exit of stand 6) with a deviation of + 6,5 degree centigrade for a mean temperature drop of 150 degree centigrade at the continuous finishing hot mill and a mean error of 4.3 %. It also predicts a coiler temperature with a difference of + 9,2 degree centigrade a mean temperature drop of 240 degree centigrade in the cooling table and a mean error of 3.8%. (Author) 16 refs

[en] The laser window problem is reviewed with emphasis on failure mechanisms, absorption processes, and material evaluation. Failure by thermal fracture and by optical distortion is discussed and the material parameters needed to calculate figures of merit for these failure modes are tabulated for a variety of materials. The exponential dependence of absorption coefficient on wavenumber for intrinsic multiphonon processes is discussed and its use in discriminating extrinsic from intrinsic absorption emphasized. Laser calorimeter absorption measurements at 10.6 and 5.25 μm are described and the measured values tabulated. The use of internal reflection spectroscopy to examine the effect of various surface treatments on surface absorption is discussed. The absorption of most KCl crystals at 10.6 μm is shown to be impurity dominated

[en] In the construction of heat exchangers, particularly the steam generators of pressurized water nuclear power stations, it is necessary to make large perforated plates for securing and holding the tubes through which flows the exchange fluid carrying the heat for vaporizing the water forming the secondary fluid of the reactor. The invention concerns a device for trimming and bevelling the holes of a perforated plate which comprises a series of holes of various shapes machined during an operation leaving a raised metal edge and sharp angles around the edges of the holes, on at least one of the sides of the plate, by means of a rotating metal brush

[en] Short communication

[en] Diamond burnishing is one of the most popular surface finishing technique used to achieve an excellent surface finish. The aim of the present study is to investigate the effect of process parameters in diamond burnishing of 17-4 PH stainless steel (PH SS) under cryogenic environment. The requirement of a sustainable environment for various machining processes urged to explore the importance of cryogenic burnishing over other cooling techniques. Surface modification was achieved by the application of liquid nitrogen (LN₂) during diamond burnishing. The process parameters considered to reduce the surface roughness (Ra) and increase the surface hardness (H) are burnishing speed, burnishing feed and burnishing force. The diamond burnishing experiments were conducted based on the L₉ orthogonal array. The significant parameters and the optimal level of each parameters were determined by using analysis of variance (ANOVA) and main effect plots respectively. Multi-response optimization has been carried out for cryogenic diamond burnishing of 17-4 PH stainless steel by using Taguchi’s grey relation analysis (TGRA). From the TGRA, it was observed that at burnishing speed 73 m min⁻¹, burnishing feed 0.048 mm/rev and burnishing force 150 N, improved diamond burnishing performance characteristics were obtained. An improvement in grey relation grade (GRG) was found to be 38.47%. Cryogenic diamond burnishing has led to modifications in the microstructure and also an improvement in the subsurface hardness of the material. (paper)

[en] A cavity of an acceleration unit built up from one or more individual resonators is filled to about half way with ceramic grinding bodies and with water, and turned slowly at about 9 rpm. The rotation is maintained for about a week. The inner surface of the cavity is thus smoothed and freed of faults, so that the cavity can be used without difficulty in superconducting operation with improved properties. By this simple process, success is achieved in increasing the practically possible longitudinal field strength for acceleration by at least a factor of 2 or more, i.e. one can save at least half the acceleration units. To remove grinding wear, the cavity is also filled with an acid mixture of about 1 part of HF, 1 part of HNO₃ and 6 parts of H₃PO₄ and cleaned, and the surface is etched. (orig.)

[en] An annotated summary of 204 articles and publications on burrs, burr prevention and deburring is presented. Thirty-seven deburring processes are listed. Entries cited include English, Russian, French, Japanese and German language articles. Entries are indexed by deburring processes, author, and language. Indexes also indicate which references discuss equipment and tooling, how to use a process, economics, burr properties, and how to design to minimize burr problems. Research studies are identified as are the materials deburred

No abstract available

[en] The angular correlation curves of the annihilation photons and the probability of three-quantum annihilation in silicon single crystals with mechanically processed surfaces were measured. The narrowing of the angular correlation curves increases and the three-quantum yield decreases with the depth of the surface abrasion. This is tentatively interpreted in terms of formation of positronium states on the surface of the silicon crystals. (orig.)

[en] The mechanisms by which radioactive contamination would be bonded to a DWPF canister surface are being investigated. Tests with low pressure water and air-injected water decontamination of radioactive specimens showed that bonding of contamination increases rapidly with postoxidation temperature. Even with the least severe temperature conditions expected on the waste glass canister, bonding is so great that decontamination cannot be affected by water-only techniques. A preoxidation film increased rather than decreased bonding. This memorandum describes detailed surface analyses of coupons simulating DWPF canister surfaces. Based on this examination we conclude: contamination will be dispersed throughout the oxide film on DWPF canisters. Contamination is concentrated at the surface, decreasing farther into the oxide film; some samples contain sludge contamination at the steel/oxide interface. This was not the case for semi-volatile (Cs₂O) contamination; in samples with contamination at the steel/oxide interface, at least 80% of the contamination is usually in the oxide layer; no difference in contamination dispersion between preoxidized and non-preoxidized samples was found; and postoxidation atmosphere had no effect on the contamination dispersion within the oxide layer. 6 references, 9 figures