Table of Contents
Casting of Ingots
Steels made by BOF or furnace are solid for sequent process either as forged ingots or by continuous casting.
Steel ingots are massive separate castings advisement from but 1 ton up to around three hundred tons (the weight of a complete heat).
Ingot molds are made from high carbon iron and are tapered at the highest or bottom for removal of the solid casting.
The cross-section could conjointly be square, rectangular, or round, and so the perimeter is sometimes corrugated to extend expanse for quicker cooling.
The mold is placed on a platform referred to as a stool; when natural action the mould is raised, exploit the casting on the stool.
The hardening process for ingots also as different castings is delineated in as a result of ingots are such massive castings, the time needed for solidification and thus the associated shrinkage ar important.
Porousness caused by the reaction of carbon and oxygen to create CO throughout cooling and solidification could be a problem that has to be self-addressed in metal bar casting.
These gases are liberated from the liquid steel due to their reduced solubility with decreasing temperature.
Cast steels are usually treated to limit or stop CO gas evolution throughout natural action. wire drawings
The treatment involves adding parts like Si and Al that react with the O dissolved within the molten steel, so it’s not on the market for CO reaction.
The structure of the solid steel is thus freed from pores and different defects caused by gas formation.
Continuous Casting
Continuous casting is wide applied in atomic number 13 and copper production however its most noteworthy application is in steelmaking.
The process is substitution metal bar casting as a result of it dramatically will increase productivity.
Ingot casting may be a discrete method.
Because the molds are comparatively massive, natural action time is essential.
For an oversized steel metal bar, it should take ten to twelve hours for the casting to solidify.
The use of continuous casting reduces natural action time by associate order of magnitude.
The continuous casting method conjointly referred to as strand casting.
Molten steel is poured from a ladle into a short lived container referred to as a tundish, that dispenses the metal to 1 or additional continuous casting molds.
The steel begins to solidify at the outer regions because it travels down through the water cooled mould.
Water sprays accelerate the cooling method.
Steel is associate alloy of iron that contains carbon locomote by weight between 0.02% and 2.11% (most steels vary between zero.05% and 1.1% C).
It usually includes different alloying ingredients like manganese, chromium, nickel, and/or molybdenum; but it’s the carbon content that turns iron into steel.
Hundreds of compositions of steel ar on the market commercially.
For functions of organization here, the overwhelming majority of commercially vital steels will be grouped into the subsequent categories: (1) plain carbon steels, (2) low alloy steels, (3) unblemished steels, (4) tool steels, and (5) specialty steels.
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Plain Carbon Steels
These steels contain carbon because the principal alloying part, with solely little amounts of different parts (about 0.4% metal and lesser amounts of chemical element, phosphorus, and sulfur).
The strength of plain carbon steels will increase with carbon content.
Steel at temperature may be a mixture of solid solution (a) and compound (Fe3C).
The compound particles distributed throughout the solid solution act as obstacles to the movement of dislocations throughout slip; additional carbon results in more barriers, and more barriers mean stronger and more durable steel.
According to a designation theme developed by the yankee Iron and Steel Institute (AISI) and conjointly the Society of Automotive Engineers (SAE), plain carbon steels ar such by a four-digit variety system: 10XX, wherever ten indicates that the steel is apparent carbon, and XX indicates the p.c of carbon in hundredths of proportion points.
Low Alloy Steels
Low alloy steels ar iron–carbon alloys that contain further alloying parts in amounts totaling but about five-hitter by weight.
Owing to these additions, low alloy steels have mechanical properties that ar superior to those of the plain carbon steels for given applications.
Superior properties typically mean higher strength, hardness, hot hardness, wear resistance, toughness, and additional fascinating combinations of those properties.
Heat treatment is commonly required to notice these improved properties.