Hard-
Surfacing,
Building
Fusion
Welding
Carbon
Welding Non-Ferrous Metals
Heating
& Heat
Treating
Braze
Welding
Welding Cast Iron Welding Ferrous Metals
Brazing
&
Soldering
Equipment
Set-Up
Operation
Equipment
For
OXY-Acet
Structure
of
Steel
Mechanical
Properties
of Metals
Oxygen
&
Acetylene
OXY-Acet
Flame
Physical
Properties
of Metals
How Steels
Are
Classified
Expansion
&
Contraction
Prep
For
Welding
OXY-Acet
Welding
& Cutting
Safety
Practices
Manual
Cutting
Oxygen
Cutting By
Machine
Appendices
Testing
&
Inspecting
2
Fig. 20-1. Start with a piece of steel which has a hardness of between 150
and 170 Brinnell, heat it bright red, then cool it three different ways and get
three different results.
Heat Cool Result Heat bright red Cool slowly All is still at 150 to 170 Brinell Hardness Same as above Cool quickly by quenching in water 150 to 170 Brinell Hardness 375 to 400 Brinell Hardness Water quench Direction of travel 150 to 170 Brinell Hardness 375 to 400 Brinell Hardness