P91 steel is also known as modified 9Cr-1Mo (P91) steel is widely used as a structural material in the construction of power plant components. In high-Cr ferritic steels, toughness degradation in welds was caused by the presence of δ-ferrite phase in the martensite matrix. The δ-ferrite phase formation is influenced by factors such as chemical composition of welds, Creq and Nieq , heat input used during welding. As the δ-ferrite phase content increases there was reduction in toughness of welds below the specified requirement of 47 Joules as per the standard EN1557: 1997. The poor toughness of welds having δ-ferrite phase can be improved by prolonging the PWHT duration at 760°C. Flux system of consumables also influences the toughness of welds. Basic flux system produces welds having higher toughness than acidic flux system. This is due to microinclusion content of welds. The flux basicity, V and Nb content, and ferrite factor are interrelated and presented as a line diagram. The present study discusses about the role of chemical composition, and welding processes (SMAW and FCAW) on the formation of δ-ferrite phase in welds and its influence on toughness of welds.

Rare earths (RE) have been used to improve the high temperature oxidation resistance of low alloy steel containing elements like Cr, Al, V and Mo. Further, the RE can be added either to the alloy or by applying as an oxide coating to the alloy surface. In this study the high temperature oxidation resistance of rare earth (RE) oxide coated 1Cr-0.3Mo-0.25V alloy was determined. This paper presents the influence of surface additions of nano-crystalline oxides CeO2 on the isothermal oxidation behavior of 1Cr-0.3Mo-0.25V alloys at temperatures ranging from 600 °C to 900 °C. The oxidation rate of RE oxide coated1Cr-0.3Mo-0.25V was significantly lower than that of the uncoated alloy. The improvements in oxidation resistance are the reduced oxidation rates and the increased oxide scale adhesion. Scanning electron microscopy (SEM), X-ray diffractometry (XRD), and electron probe micro analyzer (EPMA) were employed for these analyses. The scale formed in the presence of RE oxides was very thin, fine grained and adherent.

Incremental forging processes like radial forging become more and more crucial in industry due to their outstanding economic performance, their high flexibility and their advantageous compressive stress states. However, nowadays a basic method to analyze forging processes, FEM simulation is still a very time consuming procedure and needs complex models to implement incremental processes. Especially long term studies with focus on tool temperature development during several hours of production cannot be performed with classical FEM models for radial forging. The main problem in modelling is the high operating frequency of the forging devices, which leads to small necessary time steps and, therefore, to inacceptable calculation time due to numerous simulations that have to be run to complete a cogging process sequence. Steady state in die temperature is often only reached after processing several workpieces. Hence, it is necessary to use a simplified FE-model of the forging process to predict the steady state temperature of the forging dies. In the present work a simplified FE-model is established to investigate the steady state temperature of the dies. This approach is verified by metallographic studies proving its accuracy.

High-manganese steels are characterized by high ductility, strength and work hardening resulting from the formation of strain induced martensite (TRIP-effect) or twins (TWIP-effect). A third type is shear band induced plasticity (SIP) in Triplex steels. The Mn-content ranges from 15 to 30 %. Mn and additions of C, Si and Al exert a strong influence on the microstructure and the deformation mechanism and can accordingly affect both strength and ductility. The max. carbon content can be around 1.2 %. The main interest is currently concentrating on TWIP steels. Production of these grades via the conventional steelmaking routes can raise problems and, therefore, modifications and/or alternative production methods have to be applied. With respect to their extreme strength levels, high-Mn steels exhibit an extraordinary forming potential. Welding involves some specific challenges. The possible occurrence of delayed fracture is discussed. High-Mn steels have to compete with other lower alloy steels and special stainless grades with the same objective targets. Referring to this, the laboratory and industrial trials are to be continued in order to fully exploit the considerable market potential of the new steels.

A process for electroless deposition of NiP films on a transparent non-conductive soda lime glass is investigated. The process requires at least two repetitive cycles of etching and activation. The annealing process of the NiP films at 400 and 600˚C has been studied and the optimal heat treatment condition has been established. Different Ni bath with different pH has been employed to assess the NiP deposition. Characterization of the deposits by optical and scanning electron microscopy has provided information on the nature of crystallites and on the surface topography.

news in steel

LKAB develops new technology for producing strategic minerals from mine waste

LKAB is now investing in pilot plant facilities and, together with environmental services company Ragn-Sells, will industrialise an innovative technology for upgrading mine waste from iron ore production. This may result in LKAB producing phosphorus and rare earth metals, which in the EU are classed as strategic minerals that are of particular importance to the industry.

All-round successful electrodes: rare earths and point grinding for orbital welding

The standards for the quality of orbital welding seams are extremely high. In order to ensure they are met, a welding head orbits the round work piece on a circular path. This arc welding technology meets the required standards.

New contract signed by UNGERER with Jiansu Yongjin, Chinese leading company in precision stainless steel strip processing

On 24th April 2018 Jiansu Yongjin Metal Technology Co. LTD. based in Nantong China, has awarded UNGERER Technology GmbH a contract to supply one set of high efficiency Stretch Bend Levelling line for processing precision stainless steel.

World's First Commercial Labware Product from a Metal 3D Printer

DWK Life Sciences will reveal a new labware product at ACHEMA 2018 made from metal particles and laser beams.