STEEL Flashcards
Metals had little use in construction until the late _____, when ____ found limited use as a structural material.
18th century, cast iron.
By the early ___, wrought iron and cast iron were used for structural purposes but not extensively,
because _____ was brittle, and the production of _____ was modest and expensive.
19th century.
cast iron, wrought iron.
A breakthrough occurred in the 1850s when the ______ for removing impurities from molten iron was developed.
Bessemer process.
The process enabled steel, a greatly improved material, to be produced quickly and in large quantities, thus reducing its cost.
Bessemer process.
The _____ of steel enables designers to achieve much greater spans and heights than is possible in either wood or masonry construction.
In engineering terms, there is almost no limit to what steel can achieve.
Stiffness.
______ are those in which the chief ingredient is the chemical element iron (____).
Ferrous metals, ferrum.
To be useful, iron must be extracted from _____, have impurities removed and ingredients added to alter its properties, and finally be formed into usable products.
Mined ore.
It is free from impurities and other elements, is ductile and soft but generally not strong enough for structural purposes.
Pure iron.
It has good magnetic properties but oxidizes (rusts) easily and does not resist attack by acids and some chemicals.
Iron.
For commercial purposes, iron must have ___ added to improve its characteristics.
Alloying elements.
Iron can be hardened by heating and rapid cooling, and can be made more workable by _____, that is, heating it and then allowing it to cool slowly.
Annealing.
Iron containing almost no carbon is identified as a ______.
Wrought iron.
a very low-carbon iron that has no slag and is also toughszz, ductile, and soft.
Ingot iron.
_____ have carbon contents above 1.7% and include white, gray, and malleable types.
Cast irons.
______ have low silicon content and are cooled rapidly. They are hard and brittle and have few applications for construction uses.
White cast irons.
______ are produced by increasing silicon content and cooling the molten metal slowly.
They are tougher and softer than white cast iron, and ____ in color.
They may have additional elements, such as nickel, copper, and chromium.
They are widely used for all types of castings, such as sewer pipe, ornamental railings, and decorative lamp posts.
Gray cast irons, gray.
The basic oxygen furnace has a large pear-shaped vessel lined with refractory material.
Basic Oxygen Process.
The charge, consisting of _______, is added at the top.
Molten pig iron, metal, scraps, and fluxes.
A jet of _______ is shot into the vessel through a watercooled lance.
High-purity oxygen.
The heat of the molten pig iron is great enough to start a _______ between the oxygen and the carbon and other impurities.
This oxidation produces the heat necessary to melt the charge.
Chemical reaction.
