Local control of microstructure and mechanical properties of high-strength steel in electric arc-based additive manufacturing

Additive manufacturing offers a significant potential for producing metallic parts with distinctly localised microstructures and mechanical properties, commonly known as functional grading. While functional grading is generally accomplished through compositional variations or in-situ thermo-mechanical treatments, variation of process...

Microstructure estimation and validation of ER110S-G steel structures produced by wire and arc additive manufacturing

Wire and Arc Additive Manufacturing (WAAM) emerged as a manufacturing process for large scale structures with extensive form and design freedom. WAAM can be fully exploited once the relation between the transient thermal history and its relation to microstructure development and resultant mechanical properties is established. This relation...

Microstructure Study of Pulsed Laser Beam Welded Oxide Dispersion-Strengthened (ODS) Eurofer Steel

Oxide dispersion-strengthened (ODS) Eurofer steel was laser welded using a short pulse duration and a designed pattern to minimise local heat accumulation. With a laser power of 2500 W and a duration of more than 3 ms, a full penetration can be obtained in a 1 mm thick plate. Material loss was observed in the fusion zone due to metal...

Characterisation of the influence of vanadium and tantalum on yttrium-based nano-oxides in ODS Eurofer steel

Oxide dispersion strengthened (ODS) steels are leading candidates for structural materials in nuclear fission and fusion power plants. Understanding the nature of nano-oxide particles in ODS steels is vital for a better control of the microstructure and mechanical properties to further their applications. In this study, electron microscopy...

Microstructure characterisation and mechanical properties of ODS Eurofer steel subject to designed heat treatments

The present work deals with oxide dispersion strengthened (ODS) Eurofer steel fabricated by powder metallurgy involving mechanical alloying and spark plasma sintering. A heat treatment route including normalising and tempering was applied to the as-produced steel, based on differential scanning calorimetry (DSC) measurement. The...

Effect of mechanical alloying and spark plasma sintering on the microstructure and mechanical properties of ODS Eurofer

Oxide dispersion strengthened (ODS)Eurofer steel was prepared via mechanical alloying (MA)and spark plasma sintering (SPS). Different combinations of MA and SPS parameters were adopted in order to optimise the fabrication process. The experimental results show that the sample milled for 30 h, sintered at 1373 K at a pressure of 60 MPa has...

Microstructure and mechanical properties of medium carbon steel deposits obtained via Wire and Arc Additive Manufacturing using metal-cored wire

Wire and arc additive manufacturing (WAAM) is a 3D metal printing technique based on the arc welding process. WAAM is considered to be suitable to produce large-scale metallic components by combining high deposition rate and low cost. WAAM uses conventional welding consumable wires as feedstock. In some applications of steel components, one-off...

Evaluation of solidification cracking susceptibility during laser welding in advanced high strength automotive steels

Solidification cracking susceptibility during laser welding was studied experimentally and numerically in advanced high strength steel sheets, namely transformation-induced plasticity (TRIP) and dual phase (DP) steel. Using the same heat input, laser bead-on-plate welding was carried out on single sided clamped specimens at various starting...

Residual stress measurements and model validation of single and double pulse resistance spot welded advanced high strength steel

Advanced high strength steels (AHSS) are increasingly used in automotive industry; thousands of resistance spot welds are applied to car body-in-white. High alloying levels of AHSS result in lower weldability. Residual stresses play an essential role on the formation of defects and the mechanical performance of the weld. An electrical-thermal...

Study of solidification cracking in advanced high strength automotive steels

Advanced high-strength steels (AHSS), which are increasingly used in the automotive industry, meet many functional requirements such as high strength and crash resistance. Some of these steels contain high amounts of alloying elements, which are required to achieve the necessary mechanical properties, but render these steels susceptible to weld...

Experimental evidence of liquid feeding during solidification of a steel

Sufficient liquid feeding under constrained solidification conditions like, those experienced in welding and casting, is vital to avoid solidification cracking. We present the results of unique in-situ experimental observations of liquid feeding in a solidifying steel melt pool. Liquid feeding was observed in the inter-cellular regions during...

Hot cracking investigation during laser welding of high-strength steels with multi-scale modelling approach

Hot cracking during laser welding of advanced high-strength steels is reported to be a serious problem by automotive manufacturers. In this work, hot cracking susceptibilities of transformation-induced plasticity (TRIP) and dual-phase (DP) steels are studied based on a multi-scale modelling approach. Transient temperatures measured from...

The microstructural evolution and elemental distribution of a 3rd generation 1 GPa advanced high strength steel during double pulse resistance spot welding

This paper presents the effects of double pulse resistance spot welding (RSW) on the microstructural evolution, elemental distribution and mechanical properties of a 3rd generation 1 GPa advanced high strength steel (AHSS). In order to investigate the effect of double pulsing, the steel was exposed to single and various double pulse RSW...

Elemental segregation during resistance spot welding of boron containing advanced high strength steels

The partitioning behaviour of carbon, phosphorous and boron during the solidification of a resistance spot weld pool was studied using experimental simulations and a phase field model. Steels with varying carbon, phosphorous and boron contents were designed and subjected to a range of resistant spot welding thermal cycles. Mechanical properties...