As detailed in our previous Tech Tip, the properties of steels are controlled by their alloy content, processing and heat treatment.  Steels can be broadly classified based on i) their use (e.g. construction, heat-treatable, through hardening steels, tool steels, etc), or ii) their alloy content (unalloyed/plain carbon, low alloy, or alloy steels). Unalloyed steel –  […]

Although most people in first-world countries make extensive use of steel in their daily activities, few people, other than engineers, even think about it and most people, including a surprising number of engineers, have very little understanding of what it is.  This Technical Tip is the first in a series of Tech Tips on the […]

It has been known for many years that the corrosion resistance of stainless-steels is dependent on the alloying elements, and especially chromium content, which provides the self-healing chromium oxide layer developed on the surface of the material in the presence of oxygen.  Historically, this layer has been presented as a thin, continuous, even and impenetrable […]

While computer simulations (such as Finite Element Analysis) are valuable tools, the results of these analyses should be viewed with caution – especially when these analyses are not carried out by specialists (i.e. untrained/inexperienced engineers).  Colourful models can be convincing, but they are often sensitive to small changes including i) how, where and what loads […]

In this Technical Tip we discuss the differences between SN/miners rule and fracture mechanics-based techniques for evaluating the fatigue life of components exposed to cyclic stress and highlight the deficiencies of the SN/Miners rule approach. An SN curve, or Wolher curve, for a particular material in a specific heat treatment condition, is obtained by testing […]

As the human race has not evolved to live or work in the underwater environment, conducting operations subsea has always proved difficult. This is mainly due to the low levels of oxygen and the high pressures. One could argue that it is simpler for humans to operate in space than subsea, as one only has […]

Inspection of threaded components is vital to ensure the reliability of bolted connections. Usually such inspection would entail i) the removal of the fastener, ii) measurement of the tolerances using GO/NO-GO gauges, and iii) non-destructive testing (NDT) of the fastener, after they have been retightened a certain number of times or after a specific period […]

As detailed in our October 2024 Technical Tip, oil varnishing is primarily caused by the oxidation of the lubricant which, at high temperatures in the presence of dissolved oxygen, causes the breakdown of the hydrocarbons in the base oil. This breakdown results in a degradation of the lubricating properties and accelerates the wear of components. […]

Oils are widely used in hydraulic systems, both as lubricants to reduce friction and to increase cooling capacities. An increase in the demands on the properties of the oil, and a move to more advanced base stock, which requires new additives, has led to an increase in varnishing problems associated with oil degradation. Most of […]

Tightening bolts is relatively easy to conduct in practice, but attaining a specific preload and assessment of the preload achieved is a lot more difficult than what is typically believed. In previous tech tips, we have discussed the need for using a device that can measure preload (such as a Skidmore-Wilhelm machine) to calibrate the […]