Alloys versus Tool Steel
There are a number of FACTS that need to be considered in understanding the
Hardness of Copper Alloys in comparison to Tool Steels as well as other metal alloys.
Typically, Copper Alloys are "age" or precipitation hardening alloys. This
means that when the alloy is manufactured, a time and temperature controlled process is
performed on the product that yields the "initial hardness" of the product.
An Increase in Hardness over the initial Hardness
Continued heating of the Copper Alloy to temperatures, in combination with the passage
of time, will further influence the hardness of copper alloys. Copper alloys that
are heated to temperatures below the "final" aging temperature used during
making the product, will normally have a continued "aging" effect which actually
raises the hardness level and adds toughness.
"Overaging" & Annealing
Heating a copper alloy to temperatures above the "final age" used at
manufacture will cause the material to "overage", which has an
softening effect. Heating Copper Alloys to their "critical" temperature,
generally about 1600 Degrees F, followed by a rapid quench in water will normally
"anneal" the copper alloy completely.
The Published Hardness Values of MoldStar Products
For convenience as well as what industry is accustomed too, we publish the Hardness
Values in Rockwell "C". These published values are actually the results of
testing either on the Rockwell "B" or Brinell (3000kg.) scales, then using
Conversion data based on ASTM140 and/or ASM Vol. 11 Reference Tables. This is also because
the Rockwell"C" test is known to be the least accurate in ranges less than 40
combined with "C" testing being the most applicable to Tool Steels, and not
Not a Factor
It is important to understand that it is the actual temperature that the alloy reaches,
rather than the "environmental" temperature that influences the hardness.
"Environmental" temperatures have little influence, if any.
Click here for HARDNESS CONVERSION TABLE
Click here for More
Information on ELEVATED TEMPERATURE EXPOSURE