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Precision Heat Treating
Fequently Asked Questions (FAQ) |
| Question: |
Our company has a part which
we would like heat treated to Rockwell C65. The part is made
of steel. What other information do you need in order to treat
the part? |
| Answer: |
Steel comes in thousands of varieties. We need to know what
grade of steel the part of made of (i.e. 4140) in order to
get the correct hardness. This information is available from
your steel supplier. Identification and traceability of the
type of steel should be maintained throughout production to
ensure proper hardness can be attained by the heat treater.
NOTE: "Cold rolled" and "hot rolled"
are not grades of steel. Generally the grade is expressed
as a number, like 4140. |
| Question: |
What if we do not know what type
of steel it is? |
| Answer: |
For a nominal fee, an outside
laboratory can analyze your steel to determine the type. |
| Question: |
Our finished part before heat
treating meets dimensional specification within 1/1000 inches.
Will heat treating disturb the dimensional stability of the
part? |
| Answer: |
The part's design must take into
account the heat treating process, during which the part will
expand and contract based on the type of material and part characteristics. |
| Question: |
Can you case harden our part
to a standard depth since we have no specification for case
depth? |
| Answer: |
Your design team needs to determine
the required case depth, not the heat treater. Acceptable depth
varies by application. For example, a drill bit may need 250/1000ths
depth while a certain small sliding mechanism may only need
case depth of 5/1000ths. |
| Question: |
We have certificates of analysis
from our steel supplier for our 4140 material. When the steel
is heat treated, our material did not reach 45/50 hardness though
material heat treated with it did. What's the problem? |
| Answer: |
Chances are the steel is not what your supplier says it is.
Certificates do not necessarily mean the material is what
the supplier says it is. Regularly send samples to an outside
lab to verify your supplier. Also read the data on the certificates.
Often the maximum carbon content (i.e. .02%) and hardenability
(i.e. RC22) place restrictions on what can be done by heat
treating and a different material may be necessary.
NOTE: If you are serious about heat treating, be serious
about your material supplier! |
| Question: |
Will my welded part encounter
a problem during heat treating? |
| Answer: |
Because the part will expand and
contract during heat treating, additional precautions such as
stress relieving need to be taken for welded parts to assure
that the parts do not separate or fracture. |
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