Carbon Steels For Different Tools
: HARDENING CARBON STEEL FOR TOOLS
: The Working Of Steel
All users of tool steels should carefully study the different qualities
of the steels they handle. Different uses requires different kinds of
steel for best results, and for the purpose of designating different
steels some makers have adopted the two terms temper, and quality,
to distinguish between them.
In this case temper refers to the amount of carbon which is combined
with the iron to make the metal
nto a steel. The quality means
the absence of phosphorous, sulphur and other impurities, these
depending on the ores and the methods of treatment.
Steel makers have various ways of designating carbon steels for
different purposes. Some of these systems involve the use of numbers,
that of the Latrobe Steel Company being given herewith. It will
be noted that the numbers are based on 20 points of carbon per
unit. The names given the different tempers are also of interest.
Other makers use different numbers.
The temper list follows:
LATROBE TEMPER LIST OF CARBON TOOL STEELS
No. 3 temper 0.60 to 0.69 per cent carbon
No. 3-1/2 temper 0.70 to 0.79 per cent carbon
No. 4 temper 0.80 to 0.89 per cent carbon
No. 4-1/2 temper 0.90 to 0.99 pet cent carbon
No. 5 temper 1.00 to 1.09 per cent carbon
No. 5-1/2 temper 1.10 to 1.19 per cent carbon
No. 6 temper 1.20 to 1.29 per cent carbon
No. 6-1/2 temper 1.30 to 1.39 per cent carbon
No. 7 temper 1.40 to 1.49 per cent carbon