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The Basics of Ferrous Metallurgy

102 Articoli

High Strengths Steels: TRIP Steels

TRIP-aided multiphase steels are a new generation of low-alloy steels that exhibit an enhanced combination of strength and ductility, thus satisfying the requirements of automotive industry for good formable high-strength steels.
After the thermal treatment of TRIP steels, a triple-phase microstructure is obtained, consisting of ferrite, bainite and retained austenite. TRIP steels are essentially composite materials with evolving volume fractions of the individual phases.

High-Alloy White Irons

High-alloy white cast irons are an important group of materials whose production must be considered separately from that of ordinary types of cast irons. In these cast iron alloys, the alloy content is well above 4%, and consequently they cannot be produced by ladle additions to irons of otherwise standard compositions. They are usually produced in foundries specially equipped to produce highly alloyed irons.

High-strength iron

It has been shown that the structures of grey cast irons are similar to those of ordinary steels but with the addition of graphite flakes which break up the continuity of the iron. Thus with a totally pearlitic structure cast iron should approach in tensile strength and toughness the properties of a 0,95% carbon normalised steel; the limiting factor being the shape and distribution of the graphite and fineness of the pearlite.

High-Strength Structural and High-Strength Low-Alloy Steels

High-strength carbon and low-alloy steels have yield strengths greater than 275 MPa and can be more or less divided into four classes: As-rolled carbon-manganese steels, As-rolled high-strength low-alloy (HSLA) steels, Heat-treated, Heat-treated low-alloy steels.
These four types of steels have higher yield strengths than mild carbon steel in the as-hot-rolled condition. The heat-treated low-alloy steels and the as-rolled HSLA steels also provide lower ductile-to-brittle transition temperatures than do carbon steels.

Hot Work Tool Steels

Hot work tool steels are specialized alloys designed to withstand extreme conditions during the hot-forming of metallic workpieces. These steels facilitate manufacturing processes such as pressure die casting, extrusion, and drop forging at elevated temperatures. Distinguished by their ability to maintain hardness and structural integrity despite thermal cycling, hot work tool steels require specific properties including high tempering resistance, thermal shock resistance, and wear resistance.

Hydrogen in Steels

This comprehensive study examines the critical role of hydrogen control in steel manufacturing and its significant impact on product quality. Hydrogen contamination, even at concentrations of a few parts per million, can cause severe defects including flaking, embrittlement, and reduced ductility. The article explores thermodynamic principles governing hydrogen behavior in steel, analyzes various contamination sources during production, and presents experimental data on hydrogen pickup through calcium hydroxide and coke additions.