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PM S45VN is a martensitic stainless steel meticulously designed to offer
superior corrosion and wear resistance compared to CPM S35VN. Its enhanced chemistry has been rebalanced to create more chromium carbides, while simultaneously increasing the amount of free chromium within the matrix. By substituting Niobium and Nitrogen for some of the Vanadium and Carbon, an exceptional blend of edge retention, wear resistance, corrosion resistance, and toughness is achieved. This makes PM S45VN the ultimate choice for everyday carry (EDC) knife steel.
The
CPM process yields exceptionally homogeneous, high-quality steel, distinguished by superior dimensional stability, grindability, and toughness in comparison to steels produced through traditional melting methods.
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 illustrative applications. Each specific application should undergo independent study and evaluation to ensure suitability.
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 the CPM grades is substantially higher—four or more times that of 440C and 154CM. This increased transverse toughness suggests that CPM S45VN, CPM S35VN, and CPM S30V are significantly more resistant to chipping and breaking under side loading conditions. For knifemaking, this characteristic makes CPM particularly valuable for crafting larger blades.
Edge Retention(CATRA Testing Relative to 440C)
T
The CATRA (Cutlery & Allied Trades Research Association) test machine executes a standardized cutting operation, meticulously measuring the number of silica-impregnated cards that are severed. This process is highly regarded as an indicator of relative wear resistance, benchmarked against a 440C standard. *Estimate derived from extensive market feedback.
Thermal Treatments:
Forging:
Commence forging at 2100°F (1150°C) and ensure not to forge below 1750°F (950°C).
Annealing:
Heat uniformly to 1650°F (900°C) and hold for 2 hours. Cool slowly at a rate not exceeding 25°F (15°C) per hour to 1100°F (595°C), followed by furnace cooling or still air cooling to room temperature.
Annealed Hardness: Approximately BHN 255
Stress Relieving Annealed Parts:
For annealed parts, heat to 1100-1300°F (595-705°C) and maintain for 2 hours, then proceed with furnace or still air cooling. For hardened parts, heat to 25-50°F (15-30°C) below the original tempering temperature, hold for 2 hours, then furnace or still air cool.
Straightening:
Optimal straightening occurs when done warm, between 400-800°F (200-425°C). Preheat for hardening: Heat uniformly to 1550-1600°F (845-870°C) and equalize.
Austenitize:
Heat to 1900-2000°F (1035-1095°C) and maintain the temperature for 15-30 minutes. Quench using air or a positive pressure quench (minimum 2 bar) to below 125°F (50°C), or use salt or an interrupted oil quench to approximately 1000°F (540°C), then air cool to below 125°F (50°C).
Temper:
Double temper between 400-750°F (200-400°C), holding for a minimum of 2 hours each time. (Refer to Table) A freezing treatment may be applied between the first and second tempers to achieve maximum hardenability, always followed by at least one temper.
NOTE: For optimal stress relieving, CPM S45VN can be tempered at 1000-1025°F (540-550°C), though tempering in this range may slightly diminish corrosion resistance.
Size Change:
Expect an increase of +0.05 to +0.10% when fully martensitic. The presence of retained austenite might reduce the overall growth. To minimize retained austenite, freezing treatments may be essential when tempering between 400-750°F (200-400°C).
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. Cool to a hand-warm temperature between tempers. A freezing treatment can be implemented between tempers.
Target hardness: Aim for 59-61 HRC.
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