C
PM S45VN is a martensitic stainless steel designed to offer
improved corrosion and wear resistance over CPM S35VN. Its chemistry has been meticulously rebalanced to form more chromium carbides while simultaneously increasing the amount of free chromium in the matrix. By incorporating Niobium and Nitrogen in place of some of the Vanadium and Carbon, this steel achieves an excellent blend of edge retention, wear resistance, corrosion resistance, and toughness, making it the ideal choice for EDC knife steel.
The
CPM process produces exceptionally homogeneous, high-quality steel characterized by superior dimensional stability, grindability, and toughness, markedly outperforming steels produced through conventional 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 are some typical applications. Your specific application should be independently evaluated for suitability.
Chemical Composition:
Physical Properties:
Elastic Modulus32 X 10 psi
(221 GPa)
Density0.27 lbs./in³
(7.47 g/cm³)
Thermal Conductivity
BTU/hr-ft-°F
W/m-°K
cal/cm-s-°C
200°F
93°C
10
17.31
4.13 X 10²
Coefficient of Thermal Expansion
°F
°C
in/in/°F
mm/mm/°C
7
0 - 400
(20 - 200)
6.1 X 10
(11.0 X 10)
70 - 600
(20 - 315)
6.4 X 10
(11.5 X 10)
Mechanical Properties:
Toughness(Transverse Charpy C-notch Testing)
While the longitudinal toughness of these grades ranges from 25-28 ft. lbs., the transverse toughness of CPM grades is significantly higher—four or more times that of 440C and 154CM. This increased transverse toughness ensures that CPM S45VN, CPM S35VN, and CPM S30V are far more resistant to chipping and breaking, especially in applications exposed to side loading. In knifemaking, this means CPM steels are exceptional for crafting larger blades.
Edge Retention(CATRA Testing Relative to 440C)
T
The CATRA (Cutlery & Allied Trades Research Association) test machine executes a standard cutting operation and quantifies the number of silica-impregnated cards that are cut. This test is acknowledged as a metric of relative wear resistance and is documented in the table, benchmarked against a 440C standard. *Estimates are based on market feedback.
Thermal Treatments:
Forging:
Begin forging at 2100°F (1150°C). Ensure not to forge below 1750°F (950°C).
Annealing:
Heat the material to 1650°F (900°C) and maintain it for 2 hours. Follow with a gradual cool at a rate not exceeding 25°F (15°C) per hour down to 1100°F (595°C), then allow it to cool in a furnace or in still air until it reaches 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. Cool in a furnace or in still air. For hardened parts, heat to 25-50°F (15-30°C) below the original tempering temperature, hold for 2 hours, then cool in a furnace or in still air.
Straightening:
Optimal straightening is achieved at a warm temperature range of 400-800°F (200-425°C).
Hardening Preheat: Heat to 1550-1600°F (845-870°C) and equalize.
Austenitize: Heat to a range of 1900-2000°F (1035-1095°C) and maintain the temperature for 15-30 minutes. Quench in air or under positive pressure (minimum 2 bar) to below 125°F (50°C), or use a salt or interrupted oil quench to around 1000°F (540°C), followed by air cooling to below 125°F (50°C).
Temper:
Double temper at a temperature range of 400-750°F (200-400°C), maintaining for a minimum of 2 hours each time. (Refer to Table) A freezing treatment can be applied between the first and second tempers to attain maximum hardenability and must always be followed by at least one temper.
NOTE: For optimal stress relieving, CPM S45VN can be tempered at 1000-1025°F (540-550°C). Tempering within this range might slightly decrease corrosion resistance.
Size Change:
+0.05 to +0.10% when fully martensitic. The presence of retained austenite might reduce net growth. Freezing treatments might be necessary when tempering in the range of 400-750°F (200-400°C) to minimize retained austenite.
Recommended Heat Treatment:
Austenitize at 1950°F (1065°C). 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 warmth between tempers. A freezing treatment can be incorporated between tempers.
Targeted Hardness: Aim for a hardness of 59-61 HRC.
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