TYSC-3Q型数字测井仪深度自动校正

数字测井中铠装电缆和测量轮之间的配合误差随着磨损程度的不同和涨力的改变而发生变化。传统的制作记号的办法解决这一问题较为困难。本文介绍1种自动控制校准电路,可对不同需要进行自动控制深度校正,提高测井深度的精确度。     

Improving 410NiMo weld metal toughness by PWHT

Highlights of the present study is the importance of choosing suitable temperatures for two stage PWHT to achieve desirable toughness in the weld metals produced by ER 410NiMo filler wire. Weld pads prepared using this filler wire was used for extensive metallurgical characterization of the weld metal. Results indicate by choosing appropriate temperatures for the PWHT, it is possible to obtain toughness in the weld metal which is comparable to the toughness reported for the base metal of similar composition. Good toughness of the weld metal is attributed to the presence of retained austenite in the weld metal. Two stage PWHT that gave excellent toughness for the weld metal was employed for repair of cracked shrouds of a steam turbine in a nuclear power plant. The metallurgical characterization of the mock up weld pad prepared prior to actual repair confirmed that microstructure and hardness of the weld metal are similar to those obtained during the welding procedure development.     

Effect of component thickness on lifetime and oxidation rate of chromia forming ferritic steels in low and high pO2 environments

Abstract

Long term oxidation tests were carried out with a high-Cr ferritic steel at 800°C and 900°C in simulated cathode and anode gas of a solid oxide fuel cell (air and an Ar/H₂/H₂O mixture respectively). It was found that with decreasing sample thickness the life time of the steel decreases due to breakaway phenomena. This effect is caused by faster exhaustion of the chromium reservoir from the bulk alloy in the case of thinner components. During air exposure the oxidation rates increase with decreasing specimen thickness and this has to be taken into account in the calculation of the Cr-reservoir exhaustion. This thickness dependence is not found during the exposures in simulated anode gas. Hence, especially for thin walled components, the oxidation rates in anode gas are substantially smaller and thus the life times are longer than during air exposure. The differences in oxidation behaviour in the two environments are discussed on the basis of scale formation mechanisms involving microcrack formation in the surface oxide scale and depletion of major and minor alloying additions in the bulk alloy.     

Characterisation of amorphous phosphate coatings onto carbon steel surfaces

Abstract

This study continues the authors’ investigation of the newly developed product KAF-09OF and concerns the preparation and characterisation of amorphous phosphate coatings on carbon steels. KAF-09OF is a liquid concentrate of ammonium and alkaline phosphates, stabilising additives – buffers, softeners, activators (both inorganic and organic), as well as surfactants – a non-ionic and an anionic detergents. Gravimetric and polarisation methods, X-ray fluorescence analysis, transmission electron microscopy, X-ray photoelectron spectroscopy and atomic force microscopy have been used to determine the effect of pH (2–6), temperature conditions (20–80°C) and agitation rate (0–2000 rev min^?1) on the process of phosphating using this developed product. Coating thicknesses, compositions, structures and passivation characteristics in the phosphating baths with different concentrations of KAF-09OF have been analysed.     

Corrosion of furnace wall materials in waste-wood fired power plant

Abstract

Corrosion tests were performed with four different materials exposed at the furnace wall in a power boiler burning recycled wood, with the aim of evaluating coatings to reduce the corrosion. The nickel base Alloy 625 and the iron–chromium–aluminium alloy Kanthal APMT had the lowest corrosion rates followed by the stainless steel 310S. The low alloy steel 16Mo3, from which the walls are constructed, had the highest rate. Different corrosion mechanisms were found to occur according to the alloy type. Thermodynamic modelling showed that chlorine gas exists at extremely low levels under the prevailing conditions and the hydrated form is thermodynamically favoured.     

我国铁路用钢需求及发展趋势分析

随着我国铁路建设的加快和投资的增加,铁路用钢需求不断增加,并且对钢材也提出了新的要求。     

108t矿用汽车动力总成耦合故障分析

108 t电动轮自卸车动力总成是运矿车正常生产运行的动力源,是构成车辆最根本的总成设备,动力总成使用、维护、检修的好坏,直接关系到运矿汽车的经济效益,十几年来对电动轮自卸车动力总成各种故障进行了综合分析,积累了经验,通过不断的技术学习,对电动轮耦合工艺技术进行了改进,延长了动力总成的使用寿命周期,提高车辆的台年效率。     

Brazing of UNS S32101 and UNS S32304 lean duplex stainless steels and UNS S32750 super duplex with AWS A5.3 BNi-7 (Ni–Cr–P) filler metal

Summary

Weld metals solidified in the ferritic-austenitic solidification mode (FA mode) have dual phases of ferrite and austenite in their as-solidified condition, where ferrite exhibits different morphologies depending on the chemical composition and welding conditions. This paper describes an investigation of the effect of the solidification and transformation sequence on the formation of final ferrite morphologies. Austenite is formed through either a eutectic reaction or peritectic reaction at the dendrite boundaries after the primary formation of ferrite. During the eutectic formation of austenite, the <100>_δ direction of the primary ferrite and the <100>_γ direction of the eutectic austenite are parallel to each other and lie along the growth direction of the primary dendrites. However, any specific lattice plane relationship between the two phases is not identified. During cooling after solidification, the austenite extends into the primary ferrite via solid-state transformation, and the final morphology of the ferrite is vermicular without any coherent orientation relationship between the primary ferrite and eutectic austenite. During peritectic formation of austenite, the Kurdjumov-Sachs orientation relationship is established between the primary ferrite and peritectic austenite, and the <100>_γ direction of the peritectic austenite is not parallel to the growth direction of the primary dendrites. During cooling after solidification, the primary ferrite transforms into austenite, and the final morphology of the ferrite is lathy, since the primary ferrite and peritectic austenite have a favourable coherent orientation.     

High strength,high elongation steels obtained by hot deformation and quenching and partitioning

Abstract

An effective means to achieve energy savings, environmental protection and improved safety in automobiles is to explore higher strength steels having low cost and better processability and service performance. Two routes to develop advanced high strength steels combining ultrahigh strength with appropriate plasticity and characterised by low cost and good quality are proposed: hot stamping followed by quenching and partitioning (HS-Q&P) and deformation induced ferrite transformation followed by Q&P (DIFT-Q&P).     

电气化高速铁路用钢丝绳的研发与生产

介绍电气化高速铁路用钢丝绳的发展概况和技术要求。研制8×29F-PWRC平行捻密实钢丝绳,PWRC结构为(8×7-1×19W)。原料采用高碳钢盘条和304不锈钢盘条,外层股、内层股、中心股直径分别为2.63,1.43,2.42 mm,给出钢丝绳中各钢丝的直径和生产工艺。所研制的直径9.50 mm钢丝绳,抗拉强度1 960MPa,最小破断拉力达到82.5 kN,与国际通用的12×7-12×3-12×3-1×19W结构电气化高速铁路用钢丝绳进行对比,展示出所研制钢丝绳结构和性能等方面的优势。