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1. Introduction Hydrogen is viewed as a potential solution to the environmental issues associated with our reliance on fossil fuels for energy needs.  To this end, considerable effort is being expended in all areas of the hydrogen economy; in particular,...

1. IntroductionThe maximum allowable working pressure (MAWP) is the maximum pressure at which a flange may be operated at given temperature and is normally expressed in terms of the flange rating.  In the case of ASME B16.5 flanges, as the...

1. INTRODUCTIONThis is Part 3 of a series of articles covering the invention and development of Alloy 625.  In Part 2, I covered the solidification behaviour of Alloy 625 and how this affects the melting practices.  I discussed the metallurgy of...

1. INTRODUCTIONThis is Part 2 of a series of articles covering the invention and development of Alloy 625.  In Part 1, I discussed how the alloy was developed based on the effects of the different alloying elements on strength and creep...

1. INTRODUCTIONAlloy 625 (UNS N06625) is a nickel based alloy.  It is used extensively in the oil and gas and petrochemical industries when a material with high strength and good corrosion resistance is required, but process conditions preclude the use of...

In my earlier articles on the fundamentals of carbon steel I discussed the effect of time on the transformation process and the microstructures that result from the decomposition of austenite depending on the cooling rate. I introduced the concept of...

In my article “Fundamentals of Carbon Steel Part 1” I introduced the concept of the iron-carbon phase-diagram (Figure 1) and explained how it shows the phases that will be present at ambient temperature when steel is cooled slowly from a...

Carbon steel is fundamentally an alloy of iron and carbon.  At room temperature, carbon is virtually insoluble in iron; the maximum solubility of carbon is approximately 0.008 wt%.  Below 0.008 wt%, the structure will be made up entirely of ferrite,...

22%Cr duplex stainless steel (UNS S31803, UNS 32205) is a dual phase alloy containing approximately equal amounts of ferrite and austenite, as indicated in Figure 1.  Compared with Type 316/316L stainless steel, it has slightly improved resistance to general/pitting corrosion,...

The principal factors governing the pipe size to be used are the nature of the fluid, the flow velocity and pressure drop.  The sizing criteria are different depending on whether the pipe is carrying a single-phase liquid, a single-phase gas...