Percent of retained austenite in CPM10V
Percent of retained austenite in CPM10V
(OP)
I'm reviewing some heat treat specifications for our company. I would prefer to specify results (i.e. hardness)rather than process (i.e. heat to 2100°F ...). However, we curently require cold treatment of CPM10V to -105 F.
Should I write the specifcation to state "62-64 Rockwell C hardness with less than X% retained austenite"? If so what number should I use for X percent? Or is it better to specify "Cool to -105°F and hold for six hours"?
What is the percent of retained austenite at various time/temperatures of cold treatments for CPM10V?
Should I write the specifcation to state "62-64 Rockwell C hardness with less than X% retained austenite"? If so what number should I use for X percent? Or is it better to specify "Cool to -105°F and hold for six hours"?
What is the percent of retained austenite at various time/temperatures of cold treatments for CPM10V?





RE: Percent of retained austenite in CPM10V
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Plymouth Tube
RE: Percent of retained austenite in CPM10V
RE: Percent of retained austenite in CPM10V
RE: Percent of retained austenite in CPM10V
I have suppliers with different equipment (e.g. vacuum vs nitrogen blanket furnace) so that is why I am trying to avoid specifying required equipment and processing. How do others specify heat treat processes? Any other suggestions are appreciated.
This is what I have drafted...
CPM10V
REQUIREMENTS
3.1 The resulting Rockwell C hardness shall be 60-62 HRC when tested in accordance with ASTM E18.
3.2 The process shall protect the material from exposure to oxygen to avoid scaling and decarburization.
3.3 The process shall include three tempers at 975 - 1025 F to relieve stresses.
3.4 The process shall include a cold treatment after the first temper to reduce the level of retained austenite to less than 3% by volume.
or
3.4 The process shall include a cold treatment after the first temper at -105 F or below for 6 hours.
3.5 The supplier shall be responsible for retaining documentation that shows the material has been heat treated in accordance with this specification for a period of six months after shipment.
OPTIONAL INFORMATION
4.1 Typical processing to achieve the required results consists of:
4.xxx Use of a furnace capable of a controlled temperature of at least 2200 F, with a controlled atmosphere of vacuum.
4.1.1 Preheat to 1500 - 1550 F and equalize.
4.1.2 Second preheat to 1850 - 1900 F and equalize.
4.1.3 High heat: Heat to 2100 F and hold for 15 - 20 minutes.
4.1.4 Pressure quench in nitrogen, helium or argon to 700 - 800 F and equalize.
4.1.5 Cool in air or gas to below 125 F.
4.1.5 Temper at 975 - 1025 F and hold for 2 hours.
4.1.6 Cold treatment at -105 F or below for 6 hours.
4.1.7 Temper at 975 - 1025 F and hold for 2 hours.
4.1.8 Air cool to ambient temperature
4.1.5 Temper at 975 - 1025 F and hold for 2 hours.
4.2 Provided the requirements are satisfied, alternate processing such as the following is acceptable:
4.2.1 Use of multiple furnaces.
4.2.2 Use of a furnace with an atmosphere of nitrogen.
4.2.2 Wrapping of the material in foil to limit exposure to oxygen.
4.2.3 Quench in circulated air.
4.3 Estimated longitudinal size change during heat treating: +.0004 in/in.