The effect of the characteristics of plate mills for production of plate and U-O-£ pipe, and of continuous mills for production of strip and spiral pipe, is discussed in relation to ferrite-pearlite and two-phase steels. The influence of the cold work applied during pipemaking and expansion on the behaviour of each type of steel is considered, and the role of microalloying elements, individually and in combination, is discussed. The structure and properties achievable in normalized steel for pipe fittings are reviewed, and the effect of microalloys on weld properties is summarized. MT/985Unlike most other structures, line pipe (except when quenched and tempered in pipe form) is used in the coldworked condition and the process of cold working the steel plate during pipe forming and expansion, when this is carried out, plays a critical part in determining the properties of the pipe. In some steels it lowers the strength of the pipe compared with the plate, and in others it increases the strength; in almost all steels it reduces the steel toughness. In pipe forming, the inner layers of the plate are deformed in compression, the deformation increasing from zero at the neutral axis to a maximum at the surface, while the outer part of the plate is deformed in tension.During expansion, the inner layers of a pipe wall are deformed in tension and the outer layers receive further deformation in tension. In the flattening of a pipe section to provide testpieces, the inner layers are deformed in tension and the outer layers in compression.These deformations are summarized in Fig.I.The properties of line pipes, like all structural steels, are controlled by the microstructure which in turn is determined by:(i) the effects of the alloying elements on the kinetics of transformation and the formation of intermetallic compounds, i.e. the effects on the basic structure (ii) the effect of secondary constituents on the structure, such as inclusions, which are in turn controlled by (iii) steelmaking and casting processes and hence by the plant available for making and treating steel (iv) the properties required by the pipeline engineer.These groups of practical parameters determine the selection of steel compositions and steel treatments and, when taken together with our theoretical understanding of the relationship between metal structure and properties, can be considered the 'weft and warp' of steel development, as illustrated schematically in Fig.2. There is indeed a wide variety of steel patterns available and in use today for pipe made in mills having different characteristics and being supplied to many different markets.In this paper, we are concerned primarily with the effects of alloying elements and processing of plates in relation to our theoretical understanding and the engineer's demands, but any decisions on steel composition selection must take all selection criteria into account. There are many ways in which pipeline steels can be classified, but the most important division should be made on the basis of rolling, in as ...

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A review of the work carried out for the Steels for High Temperature committee of the British Electrical and Allied Industries Research Association between 1930 and 1952.† In this paper the achievements of the J/E committee between the years 1930 and 1952 are reported. Development of steam power plant largely depends on the physical properties of the materials. Realization of the effects of creep in metals has caused creep data to supersede Hooke's law in the determination of design methods for steam power plant. The study of the effects of creep properties in different steels led to the adoption of chromium- molybdenum, and chromium-molybdenum-silicon and, to a less extent, molybdenum-vanadium steel for the high-temperature components; superheater tubes, steam pipes, and superheater headers for plant using temperatures above 900 deg. F. From creep tests made, the stress-time relation for each component was obtained. Methods of creep testing are compared, and abnormally high creep rates are investigated. The testing of the reliability of long-time creep tests deduced from short-time creep tests is described. Relaxation tests carried out enabled a mathematical relation between relaxation time and stress to be derived. Investigations into the effects on the properties of the steel, of the presence of minor elements in the steel, and the method of manufacture, are described, and also the cause and effects of grain growth. The causes of, and means of avoiding, cracking of steel are studied. Future developments are outlined. FOREWORD C. H. Desch, D.Sc, Ph.D., F.R.S. Chairman of the Steels for High Temperature Committee of B.E.A.I.R.A. Since 1930 the Steels for High Temperature committee of the British Electrical and Allied Industries Research Association has fostered work on the properties of steels used in steam power plant. The committee was formed from the committee of the Department of Scientific and Industrial Research on the behaviour of materials at high temperatures, at a time when the importance of the phenomenon of creep in designing high-temperature steam power plant was being realized. The committee has always included in its membership representatives of leading steel makers, tube manufacturers, turbine builders, and boiler makers. The Admiralty has also been well represented and, also since their formation, the British Electricity Authority and the British Iron and Steel Research Association. The views of metallurgists and engineers concerned with the production and use of high-temperature steels have thus been combined in furthering co-operative work which has effectively contributed to advances in the design and efficiency of British steam power plant. The work of this committee has thus formed an integral part of the development of high-temperature steels which has been made by British industry over the last twenty years. The committee has throughout the work had the co-operation of the Engineering and Metallurgy Divisions of the National Physical Laboratory where most of the investigational work has been carried out. This work has been supported financially by the steel-making and the appropriate user industries. Since the inception of the committee in 1930 a number of detailed technical reports have been issued on various problems which it has investigated. The following report has been prepared to provide an overall picture of the major achievements of the committee. Although he has not been concerned with experimental work, Mr. Sage has had access to all reports and papers connected with the research. The value of the contributions of numerous investigators at the National Physical Laboratory is acknowledged, and Dr. Jenkins and Mr. Tapsell should be specially mentioned as having taken a leading part in the investigation since its inception.