C
PM S45VN is a martensitic stainless steel meticulously engineered to offer
superior corrosion and wear resistance compared to CPM S35VN. Its rebalanced chemistry forms more chromium carbides, while retaining more free chromium in the matrix. The inclusion of Niobium and Nitrogen, substituting some Vanadium and Carbon, creates an optimal blend of edge retention, wear resistance, corrosion resistance, and toughness. This makes it the perfect material for an Everyday Carry (EDC) knife steel.
The
CPM process yields exceptionally homogeneous, high-quality steel, renowned for its superior dimensional stability, grindability, and toughness, surpassing steels produced by conventional melting methods.
Typical Applications:
Ideal for Long-Wearing Specialty Cutlery, Plastic Injection and Extrusion Feed Screws and Dies, Non-Return Valve Components, Pelletizing Equipment, and Wear Components for Food and Chemical Processing. Note: These applications are examples; undertake independent study and evaluation for your specific use.
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 X10
(11.0 X10)
70 - 600
(20 - 315)
6.4 X10
(11.5 X10)
Mechanical Properties:
Toughness(Transverse Charpy C-notch Testing)
The longitudinal toughness of all four grades is approximately 25-28 ft. lbs. However, the transverse toughness of the CPM grades is four times greater than that of 440C and 154CM. This enhanced transverse toughness ensures CPM S45VN, CPM S35VN, and CPM S30V are significantly more resistant to chipping and breaking under side load conditions. This characteristic is particularly beneficial in knifemaking for larger blades.
Edge Retention(CATRA Testing Relative to 440C)
T
The CATRA (Cutlery & Allied Trades Research Association) test machine performs a precise standard cutting operation, meticulously measuring the number of silica-impregnated cards sliced. This metric is regarded as a benchmark for relative wear resistance, presented in this table in comparison to a 440C standard. *Estimate based on comprehensive market feedback.
Thermal Treatments:
Forging:
2100°F (1150°C). Avoid forging at temperatures below 1750°F (950°C).
Annealing:
Heat uniformly to 1650°F (900°C), maintain for 2 hours, followed by a slow cool of no more than 25°F (15°C) per hour down to 1100°F (595°C). Finally, furnace cool or allow to cool in still air until room temperature is reached.
Annealed Hardness: Approximately BHN 255
Stress Relieving Annealed Parts:
For annealed parts, heat to 1100-1300°F (595-705°C), hold for 2 hours, then 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:
Best performed warm, within the temperature range of 400-800°F (200-425°C).
Hardening Preheat: Heat to 1550-1600°F (845-870°C) and allow the temperature to equalize.
Austenitize: Heat to 1900-2000°F (1035-1095°C) and hold for 15-30 minutes. For quenching, use air or positive pressure quench (minimum 2 bar) to below 125°F (50°C), or use a salt or interrupted oil quench down to approximately 1000°F (540°C), then air cool 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. A freezing treatment may be applied between the first and second tempers to achieve maximum hardenability, but ensure it is followed by at least one additional temper.
NOTE: For optimal stress relief, CPM S45VN can be tempered at 1000-1025°F (540-550°C). Be aware that tempering within this range may slightly reduce corrosion resistance.
Size Change:
Expect a size change of +0.05 to +0.10% when fully martensitic. The presence of retained austenite may decrease net growth. When tempering at 400-750°F (200-400°C), consider freezing treatments 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, cooling to hand warm between tempers. A freezing treatment may be included between tempers.
Aim hardness: Achieve a target hardness of 59-61 HRC.
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