The Working of Steel | Page 5

or from 1.00 to 1.50 per cent.
Nickel, chromium, etc., are always given in per cent, as a 3.5 per cent
nickel, which means exactly what it says--3-1/2 parts in 100. Bearing
this difference in mind all confusion will be avoided.
CLASSIFICATIONS OF STEEL
Among makers and sellers, carbon tool-steels are classed by "grade"
and "temper." The word grade is qualified by many adjectives of more
or less cryptic meaning, but in general they aim to denote the process

and care with which the steel is made.
Temper of a steel refers to the carbon content. This should preferably
be noted by "points," as just explained; but unfortunately, a 53-point
steel (containing 0.53 per cent carbon) may locally be called something
like "No. 3 temper."
A widely used method of classifying steels was originated by the
Society of Automotive Engineers. Each specification is represented by
a number of 4 digits, the first figure indicating the class, the second
figure the approximate percentage of predominant alloying element,
and the last two the average carbon content in points. Plain carbon
steels are class 1, nickel steels are class 2, nickel-chromium steels are
class 3, chromium steels are class 5, chromium-vanadium steels are
class 6, and silico-manganese steels are class 9. Thus by this system,
steel 2340 would be a 3 per cent nickel steel with 0.40 per cent carbon;
or steel 1025 would be a 0.25 plain carbon steel.
Steel makers have no uniform classification for the various kinds of
steel or steels used for different purposes. The following list shows the
names used by some of the well-known makers:
Air-hardening steel Chrome-vanadium steel Alloy steel Circular saw
plates Automobile steel Coal auger steel Awl steel Coal mining pick or
cutter steel Axe and hatchet steel Coal wedge steel Band knife steel
Cone steel Band saw steel Crucible cast steel Butcher saw steel
Crucible machinery steel Chisel steel Cutlery steel Chrome-nickel steel
Drawing die steel (Wortle)
Drill rod steel Patent, bush or hammer steel Facing and welding steel
Pick steel Fork steel Pivot steel Gin saw steel Plane bit steel Granite
wedge steel Quarry steel Gun barrel steel Razor steel Hack saw steel
Roll turning steel High-speed tool steel Saw steel Hot-rolled sheet steel
Scythe steel Lathe spindle steel Shear knife steel Lawn mower knife
steel Silico-manganese steel Machine knife steel Spindle steel Magnet
steel Spring steel Mining drill steel Tool holder steel Nail die shapes
Vanadium tool steel Nickel-chrome steel Vanadium-chrome steel Paper
knife steel Wortle steel

Passing to the tonnage specifications, the following table from
Tiemann's excellent pocket book on "Iron and Steel," will give an
approximate idea of the ordinary designations now in use:
Approximate Grades carbon range Common uses
Extra soft 0.08-0.18 Pipe, chain and other welding purposes; (dead soft)
case-hardening purposes; rivets; pressing and stamping purposes.
Structural (soft) 0.15-0.25 Structural plates, shapes and bars for
(medium) bridges, buildings, cars, locomotives; boiler (flange) steel;
drop forgings; bolts. Medium 0.20-0.35 Structural purposes (ships);
shafting; automobile parts; drop forgings. Medium hard 0.35-0.60
Locomotive and similar large forgings; car axles; rails. Hard 0.60-0.85
Wrought steel wheels for steam and electric railway service;
locomotive tires; rails; tools, such as sledges, hammers, pick points,
crowbars, etc. Spring 0.85-1.05 Automobile and other vehicle springs;
tools, such as hot and cold chisels, rock drills and shear blades. Spring
0.90-1.15 Railway springs; general machine shop tools.
CHAPTER II
COMPOSITION AND PROPERTIES OF STEEL
It is a remarkable fact that one can look through a dozen text books on
metallurgy and not find a definition of the word "steel." Some of them
describe the properties of many other irons and then allow you to guess
that everything else is steel. If it was difficult a hundred years ago to
give a good definition of the term when the metal was made by only
one or two processes, it is doubly difficult now, since the introduction
of so many new operations and furnaces.
We are in better shape to know what steel is than our forefathers. They
went through certain operations and they got a soft malleable, weldable
metal which would not harden; this they called iron. Certain other
operations gave them something which looked very much like iron, but
which would harden after quenching from a red heat. This was steel.
Not knowing the essential difference between the two, they must
distinguish by the process of manufacture. To-day we can make either

variety by several methods, and can convert either into the other at will,
back and forth as often as we wish; so we are able to distinguish
between the two more logically.
We know that iron is a chemical element--the chemists write it Fe for
short, after the Latin word "ferrum," meaning iron--it is one of those
substances which cannot be separated into anything else but itself. It