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Corrosion Resistance
Average Pitting Potential measurements from Polarization Curves run in 5% NaCl (Sodium Chloride) Solution at Room Temperature: (Higher voltage pitting potential indicates better corrosion resistance.)
Thermal Treatments
Preheat: Optional preheat stage for unbalanced geometries or complex designs - Heat to 1550-1600°F (845-870°C) Equalize.
Austenize: 1900-2000°F (1035-1095°C), hold time at temperature 15-30 minutes.
Quench: Air or positive pressure quench (2 bar minimum) to below 125°F (50°C), or salt or interrupted oil quench to about 1000°F (540°C), then air cool to below 125°F (50°C). Accelerated air quenching works well for thin sections, while minimizing warpage.
Tempering: Double temper at 400-750°F (200-400°C). Hold for 2 hours minimum each time. (See Table) A cryogenic treatment may be used between the first and second tempers. Cryogenic treatments help to attain maximum hardenability and must always be followed by at least one temper. NOTE: CPM S35VN may be tempered at 1000-1025°F (540-550°C)for optimum stress relieving, . Tempering in this range may result in a slightly lower corrosion resistance.
Cryogenic Treatments: Refrigeration treatments may improve long term dimensional stability by transforming retained austenite. Refrigeration treatments should generally be performed after the first temper, and must be followed by a temper.
Heat Treat Response
Austenizing Temp.
Tempering Temp
1900F
1950F
2000F
As Quenched
61
62
63
400F (200C)
58
58
60
600F (315C)
58
59
59
1000F (540C)
57
59
59
Min. Time
at Aust. Temp.
30 min.
30 min.
15 min.
Min. Number
of Tempers
2
2
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