Effect of plasma electrolytic oxidation coating on joining metal to plastic

Abstract

Joining of magnesium alloy to polyethylene without adhesive using a newly developed friction lap welding technology was investigated. The polyethylene and magnesium alloy were hard to be joined together without surface premodification due to the lack of polar groups on polyethylene surfaces. Strong hybrid joints were achieved after the polyethylene was treated by corona discharge, and the magnesium alloy was subjected to plasma electrolytic oxidation treatment. Scanning electron microscope and high resolution transmission electron microscope observations demonstrated that the high joining strength was attributed to the development of both chemical bonds at the interface and micromechanical interlocking.     

Expert system shell for welding preheating: Technical and economic problems,as well as its impact on the physical environment (Part 2)

Summary

This article, published in three parts, is based on a doctoral thesis undertaken at the Department of Applied Mechanics and Engine Construction of Genoa University in collaboration with the Italian Institute of Welding. The aim of this article is to study the thermological, metallurgical, economic and safety problems of preheating which arise in fusion welding of steels and to acquire a basic knowledge of these phenomena as fully and logically as possible. On this basis, a simple, flexible and expandable tool, illustrated by experiments, has been devised for use by expert welding engineers.

For this purpose, state‐of‐the‐art research, national and international standards were studied and experimental tests conducted to correlate available data.

An expert system was thus produced, using artificial intelligence techniques, in order to determine preheating temperature, evaluate costs, and make health and safety recommendations to the user. This second section considers the issues of economics, safety and the environment.     

Expert system shell for welding preheating: Technical and economic problems,as well as its impact on the physical environment ‐ part 3

Summary

This article, published in three parts, is based on a doctoral thesis undertaken at the Department of Applied Mechanics and Engine Construction of Genoa University, in collaboration with the Italian Welding Institute. The aim of this article is to study the thermological, metallurgical, economic and safety problems of preheating which arise in fusion welding of steels and to acquire a basic knowledge of these phenomena, as fully and logically as possible. On this basis, a simple, flexible and expandable tool, illustrated by experiments, has been devised for use by expert welding engineers.

For this purpose, state‐of‐the‐art research, national and international standards were studied, and experimental tests conducted to correlate available data.

An expert system (ES) was thus produced, using artificial intelligence techniques, in order to determine preheat temperature, evaluate costs, and make health and safety recommendations to the user.

In this third part, the development of the expert shell is described, as well as a brief software user's guide.     

Effect of weld form in electron beam welding on the properties of the welded joint in low carbon steels in different sections

Abstract

Twenty coupons of 100mm thickness SA 508 C13 and Fe 56.2 steels were electron beam (EB) welded to encourage industrial applications and to verify the advantages and drawbacks of the welding process. Various non-destructive tests and mechanical tests (hardness, tensile, bend, Charpy V and Pellini) were then carried out in different joint positions.

The results are more than satisfactory for the SA 508 C13 steel, whereas a reduction in toughness was observed for the Fe 56.2. Useful information concerning the qualification of the EB welding process was obtained.

This work has been carried out in co-operation between ENEA and TERNI, with the financial support of the ENEA-TIB, under a programme for the publicising of new technologies. The welds were performed by The Welding Institute, UK (TWI), whilst for some aspects concerning the characterisation of joints, useful advice was provided by the Italian Institute of Welding.     

Utilising friction spot joining for dissimilar joint between aluminium alloy (A5052) and polyethylene terephthalate

Abstract

The weld strength of thermoplastics with aluminium alloy, such as high density polyethylene and polypropylene sheets, is influenced by friction stir welding parameters. This paper focuses on the preliminary investigation of joining parameter at various levels as well as the mechanical properties of friction spot joining (FSJ) of aluminium alloy (A5052) to polyethylene terephthalate (PET). A number of FSJ experiments were carried out to obtain optimum mechanical properties by adjusting the plunge speed and plunge depth in the ranges of 5–40 mm min^?1 and 0·4–0·7 mm respectively, while spindle speed remains constant at 3000 rev min^?1. The results indicated that A5052 and PET successfully joined with the aid of frictional heat energy originated from the friction spot welding process. The effect of plunge speed on the joined area and the effect of formation of bubbles at the interface of joints on the shear strength of joint are discussed.     

The effect of additives on the pulsed electrodeposition of copper

Abstract

The pulsed electrodepostion of copper has been systematically investigated from a copper sulphate bath. Pulse duty cycles of 5–80%, at frequencies from 10 to 100 Hz with current densities ranging from 2·5 to 7·5 A dm^?2 were employed. The influences of pulsed current duty cycle, peak current density and frequency on the thickness and hardness of the copper deposit, current efficiency and throwing power of the plating process were studied. The effect of additives, polyethylene glycol and di-sodium EDTA on the properties of deposit were investigated.     

Preparation of chemical dispersion coatings with included boron nitride

Abstract

Chemical metallisation of cubic boron nitride (cBN) in solutions containing copper ions has been achieved in order to use the metallised hard material for its inclusion in composite materials. It was found to be appropriate to work with smaller fractions of cBN grains, in order to avoid an uneconomically long period of electroless copper plating. The possibility of obtaining composite materials by copper chemical plating with included dispersed particles of cubic beta- and alpha hexagonal boron nitride with a grain size range of 50–80 μm for cBN and 1–5 μm respectively for hexagonal boron nitride on flexible materials of the pressed polyethylene terephthalate textile was shown.     

Effects of tool tilt angle on tensile strength and fracture locations of friction stir welding of polyethylene

Abstract

The aim of this study was to investigate the effect of tool tilt angle on friction stir welding (FSW) of polyethylene (PE). The samples were longitudinally butt welded with double passes of rotating cylindrical shouldered tool in a milling machine for different tool tilt angles. The welding parameters had significant effects on tensile properties and fracture locations of the welds. The tensile strength decreased with increasing tool tilt angle. The thickness of the welding zone decreased with increasing tool tilt angle which affects the tensile strength. The interface line between weld passes was formed shorter for the higher welding speeds because of the less effect of the frictional heat.     

Effect of nanoclay on vibration welding of LLDPE nanocomposites in presence and absence of compatibiliser

Abstract

Welding is employed to develop bonded joints with mechanical properties that draw near the parent material. Vibration welding has been applied to join pure and nanoclay filled linear low density polyethylene (LLDPE). Ethylene maleic anhydride copolymer (PE‐g‐MA) is used as a compatibiliser in this study. High resolution transmission electron microscopic images showed the combination of exfoliation and intercalation of nanoclay platelets in LLDPE in the presence of a compatibiliser. The mechanical properties were studied for both the body part and the welded joints. The tensile strength and modulus of the body part for the nanoclay filled LLDPE in the presence of a compatibiliser were substantially improved. The welded joints of the same system showed better enhancement in the modulus. X‐ray diffraction analysis observed from the welded joints showed that the crystallite size of the nanoclay filled LLDPE composites in the presence of a compatibiliser was lower than that of nanocomposites in the absence of a compatibiliser.     

New standards for the fatigue calculation of steel structures

Abstract

The radical change in the parameters governing fatigue calculations in the latest standards on the subject are first described, illustrating at the same time the concepts of ‘stress range’, ‘load spectrum’ and ‘fatigue damage’ according to Miner.

The methods devised for the application of these concepts are then illustrated, when the stress spectrum and the Wöhler lines of the structural components are known.

Application of these methods in practice for the fatigue calculation of steel bridges for roads and railways is then described.     

Welded joints: Limits on criteria for plasticity zones located at weld toes

Summary

An approximate analytical method of estimating plastic zone size in the neighbourhood of welded joint toes is presented in this article.

Plastic zone dimensions are analysed in steel cruciform and lap joints, for which theoretical calculations and numerical results are compared. The expressions reported here enable some practical limits to be established on the criteria based on linear elastic Notch Stress Intensity Factors.

These limits are given both in terms of nominal stress range and number of cycles to failure.     

Anodic Behaviour of Zinc in Potassium Hydroxide Solution: II.* Horizontal Anodes in Electrolytes Containing Zn(II)

Abstract

Equilibrium solubility data for ZnO in KOH are reported for KOH concentraiions up to 14M.

Results of passivation time determination for horizontally orientated zinc anodes In alkaline zincate electrolytes are reported. These results are correlated in the form: (i–i₁) t_p½ = k, where k and i₁ depend on [Zn(II)], [OH_?] and temperature. Passivation occurs when the [Zn(II)] at the anode is equivalent to the [OH?] of the electrolyte.

Overpotential–current density relationships indicate that the charge-transfer reactIon is complicated.     

Carburisation and creep phenomena in high‐alloy materials for ethylene pyrolysis furnaces

Summary

This paper reviews the various factors forming a basis for selecting high‐temperature (1100 °C) alloys for ethylene pyrolysis furnaces.

We discuss in particular the phenomenon of carburisation with carbon diffusion in the metal matrix and its resistance to viscous creep, particularly the phenomenon of secondary creep.

Both of these phenomena are discussed as a contribution to judicious selection of such alloys.     

Editorial board page for “Welding International”, Volume 1, Number 8

Abstract

This is a scanned image of the original Editorial Board page(s) for this issue     

Editorial board page for “Welding International”, Volume 1, Number 10

Abstract

This is a scanned image of the original Editorial Board page(s) for this issue     

Editorial board page for “Welding International”, Volume 1, Number 5

Abstract

This is a scanned image of the original Editorial Board page(s) for this issue     

Editorial board page for “Welding International”, Volume 1, Number 12

Abstract

This is a scanned image of the original Editorial Board page(s) for this issue     

Editorial board page for “Welding International”, Volume 1, Number 4

Abstract

This is a scanned image of the original Editorial Board page(s) for this issue     

Editorial board page for “Crystallography Reviews”, Volume 3, Number 3

Abstract

This is a scanned image of the original Editorial Board page(s) for this issue.     

Editorial board page for “Crystallography Reviews”, Volume 5, Number 2

Abstract

This is a scanned image of the original Editorial Board page(s) for this issue.