Designing steel to resist hydrogen embrittlement Part 2–precipitate characterisation

A novel, low-alloy steel has been designed for use in the oil and gas industry. Its high strength and hydrogen trapping potential are derived from a martensitic microstructure containing a dispersion of fine vanadium–molybdenum alloy carbides that evolve during tempering. In this second paper, the effect of quench rate from austenitisation and tempering conditions are investigated with respect to the microstructure. The alloy loses its tempering resistance following slow-cooling from austenitisation as a result of MC precipitation, leading to vanadium depletion and significant M(Formula presented.)C coarsening. This is predicted using computer simulation and confirmed by high energy X-ray diffraction, combined with electron microscopy.BP-ICA

Designing steel to resist hydrogen embrittlement: Part 1–trapping capacity

A novel steel has been designed for use in the oil and gas industry, displaying properties comparable with the currently available F22 grade and possessing the additional quality of excellent hydrogen trapping capacity. Its high strength is derived from a martensitic microstructure containing a dispersion of fine vanadium-molybdenum carbides that evolve during thermal treatments. If the tempering cycle is controlled such that the precipitates maintain a degree of coherency with the matrix, then they act as hydrogen trapping sites, due to the associated strain fields, thus mitigating the problem of diffusible hydrogen. Using material modelling programmes and small-scale sample alloys this work describes the process of the new steel design and demonstrates its superior trapping capacity through thermal desorption analysis.BP-ICA

Strength in numbers: collaborative procurement and competitiveness of craft breweries

Purpose: This article aims to investigate collaborative procurement as a sourcing strategy amongst competing small enterprises in an effort to reduce their material supply costs through increased efficiencies, bargaining power and economies of scale. Design/methodology/approach: A case study approach is applied to a network of breweries that are regionally clustered. Interview data from producers, suppliers and industry experts is inductively interpreted to understand the viability, organisational impact and benefits/limitations of joint procurement activities. Findings: The craft brewing industry follows a market place strategy of differentiation to achieve competitive advantage. This has supply chain implications that promote raw material diversity, which is in conflict with standardisation – a necessary factor for collective buying. Competition impacts information sharing and governance mechanism, while the structural factors of size asymmetry along and across the supply chain influence returns. These issues impact the potential economic benefits of collaborative procurement. Research limitations/implications: The research propositions have been developed in a specific industry but are generalisable to other companies with a differentiation strategy, especially in the consumer packaged goods sector. Practical implications: Enabling conditions and constraints are captured in a framework and capability matrix, which can be used by practitioners to assess industry and product feasibility for collaborative procurement. Originality/value: Previous studies of collaborative procurement have been in the public sector amongst large organisations. This work focusses on coopetition in the context of small businesses to identify the viability and cost-benefit of this strategy.</p

Research data supporting "Surface residual stresses in multipass welds produced using low transformation temperature filler alloys"

Tensile residual stresses at the surface of welded components are known to compromise fatigue resistance through the accelerated initiation of microcracks, especially at the weld toe. Inducement of compression in these regions is a common technique employed to enhance fatigue performance. Transformation plasticity has been established as a viable method to generate such compressive residual stresses in steel welds and exploits the phase transformation in welding filler alloys, that transform at low temperature to compensate for accumulated thermal contraction strains. Neutron and X-ray diffraction have been used to determine the stress profiles that exist across the surface of plates welded with low transformation temperature welding alloys, with a particular focus on the stress at the weld toe. For the first time, near-surface neutron diffraction data have shown the extent of local stress variation at the critical, fusion boundary location. Compression was evident for the three measurement orientations at the fusion boundaries. Compressive longitudinal residual stresses and tensile trans- verse stresses were measured in the weld metal

Surface residual stresses in multipass welds produced using low transformation temperature filler alloys

Tensile residual stresses at the surface of welded components are known to compromise fatigue resistance through the accelerated initiation of microcracks, especially at the weld toe. Inducement of compression in these regions is a common technique employed to enhance fatigue performance. Transformation plasticity has been established as a viable method to generate such compressive residual stresses in steel welds and exploits the phase transformation in welding filler alloys that transform at low temperature to compensate for accumulated thermal contraction strains. Neutron and X-ray diffraction have been used to determine the stress profiles that exist across the surface of plates welded with low transformation temperature welding alloys, with a particular focus on the stress at the weld toe. For the first time, near surface neutron diffraction data have shown the extent of local stress variation at the critical, fusion boundary location. Compression was evident for the three measurement orientations at the fusion boundaries. Compressive longitudinal residual stresses and tensile transverse stresses were measured in the weld metal