C
PM S45VN is a martensitic stainless steel designed to offer
unparalleled corrosion and wear resistance over CPM S35VN. Its innovative chemistry has been meticulously rebalanced to form more chromium carbides, while simultaneously ensuring more free chromium within the matrix. By incorporating Niobium and Nitrogen in lieu of some Vanadium and Carbon, this steel showcases an extraordinary fusion of edge retention, wear resistance, corrosion resistance, and toughness. These attributes make it the quintessential choice for an Everyday Carry (EDC) knife steel.
The
CPM process yields exceptionally homogeneous, high-caliber steel that boasts superior dimensional stability, grindability, and toughness, surpassing steels produced by traditional melting practices.
Typical Applications:
Long-Wearing Specialty Cutlery Plastic Injection and Extrusion Feed Screws and Dies Non-Return Valve Components Pelletizing Equipment Wear Components for Food and Chemical Processing Note: These applications are merely illustrative. Proper evaluation and study are essential to determine the suitability for your specific application.
Chemical Composition:
Physical Properties:
Elastic Modulus32 X 10^6 psi
(221 GPa)
Density0.27 lbs./in^3
(7.47 g/cm^3)
Thermal Conductivity
BTU/hr-ft-°F
W/m-°K
cal/cm-s-°C
200°F
93°C
10
17.31
4.13 X 10^-2
Coefficient of Thermal Expansion
°F
°C
in/in/°F
mm/mm/°C
7
0 - 400
(20 - 200)
6.1 X 10^-6
(11.0 X 10^-6)
70 - 600
(20 - 315)
6.4 X 10^-6
(11.5 X 10^-6)
Mechanical Properties:
Toughness(Transverse Charpy C-notch Testing)
While the longitudinal toughness of all four grades is approximately 25-28 ft. lbs., the transverse toughness of CPM grades is at least four times that of 440C and 154CM. This elevated transverse toughness demonstrates that CPM S45VN, CPM S35VN, and CPM S30V possess significantly higher resistance to chipping and breaking when subjected to side loading. For knifemaking, this enhanced toughness makes CPM particularly suitable for larger blades.
Edge Retention(CATRA Testing Relative to 440C)
T
The CATRA (Cutlery & Allied Trades Research Association) test machine conducts a standardized cutting operation, measuring the quantity of silica-impregnated cards that are cut. This metric serves as a relative wear resistance indicator, presented here in comparison to a 440C standard. *Estimate based upon market feedback.
Thermal Treatments:
Forging:
Forge at 2100°F (1150°C). Ensure not to forge below 1750°F (950°C).
Annealing:
Heat to 1650°F (900°C) and maintain for 2 hours, then cool gradually at a rate no faster than 25°F (15°C) per hour until 1100°F (595°C). Following this, allow the furnace to cool or cool in still air to room temperature.
Annealed Hardness: Approximately BHN 255
Stress Relieving Annealed Parts:
Heat to a temperature range of 1100-1300°F (595-705°C) and hold for 2 hours. Allow the furnace to cool or cool in still air. For hardened parts, heat to a temperature 25-50°F (15-30°C) below the original tempering temperature, hold for 2 hours, and then cool as before.
Straightening:
Best performed at a temperature range of 400-800°F (200-425°C). Hardening Preheat: Heat to 1550-1600°F (845-870°C) and equalize.
Austenitize:
Heat to 1900-2000°F (1035-1095°C) and maintain for 15-30 minutes. Quench using air or positive pressure (minimum 2 bar) until the temperature drops below 125°F (50°C). Alternatively, use salt or interrupted oil quenching to about 1000°F (540°C), followed by air cooling to below 125°F (50°C).
Temper:
Double temper at 400-750°F (200-400°C), holding for a minimum of 2 hours each time. (Refer to the table for specifics.) A freezing treatment can be applied between the first and second tempers to achieve maximum hardenability, but it must be followed by a temper.
NOTE: For optimal stress relieving, temper CPM S45VN at 1000-1025°F (540-550°C). Be aware that tempering within this range may slightly reduce corrosion resistance.
Size Change:
+0.05 to +0.10% when fully martensitic. The presence of retained austenite may reduce overall growth. Freezing treatments may be required to minimize retained austenite when tempering at 400-750°F (200-400°C).
Recommended Heat Treatment:
Austenitize at 1950°F (1065°C) and quench to below 125°F (50°C). Double temper at 600°F (315°C) for a minimum of 2 hours each temper. Allow the material to cool to hand-warm between tempers. A freezing treatment may be performed between tempers.
Target hardness: 59-61 HRC.
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