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CPM S45VN is a high-performance martensitic stainless steel meticulously engineered to deliver unparalleled benefits.
With enhanced corrosion and wear resistance surpassing that of CPM S35VN, its updated chemistry fosters the formation of more chromium carbides while retaining ample free chromium within the matrix. The strategic use of Niobium and Nitrogen in place of some Vanadium and Carbon endows it with an impeccable blend of edge retention, wear resistance, corrosion resistance, and toughness. This makes it the quintessential choice for everyday carry (EDC) knife steel.
The
CPM process ensures the production of exceptionally homogeneous, high-caliber steel, boasting superior dimensional stability, grindability, and toughness compared to those produced via conventional melting techniques.
Typical Applications:
This steel is 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 are typical applications. Always conduct an independent study and evaluation to ensure suitability for your specific application.
Chemical Composition:
Physical Properties:
Elastic Modulus32 X 10^6 psi
(221 GPa)
Density0.27 lbs./in³
(7.47 g/cm³)
Thermal Conductivity
BTU/hr-ft-°F
W/m-K
cal/cm-s-°C
At 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 all four grades ranges between 25-28 ft. lbs., the CPM grades exhibit transverse toughness four or more times greater than that of 440C and 154CM. This superior transverse toughness indicates that CPM S45VN, CPM S35VN, and CPM S30V are significantly more resistant to chipping and breaking when subjected to side loading. In the realm of knifemaking, this characteristic makes CPM exceptionally suited for larger blades.
Edge Retention(CATRA Testing Relative to 440C)
T
The renowned CATRA (Cutlery & Allied Trades Research Association) test machine executes a precise and standardized cutting operation. It quantifies the number of silica-impregnated cards sliced, serving as a metric for comparative wear resistance. This resistance is measured against a 440C standard and presented in the table below. *Estimates are based on extensive market feedback.
Advanced Thermal Treatments::
Forging Specifications:
Forge at an exact temperature of 2100°F (1150°C). Avoid forging below 1750°F (950°C) to maintain material integrity.
Annealing Process:
Heat gradually to 1650°F (900°C) and maintain for 2 hours. Cool slowly at a maximum rate of 25°F (15°C) per hour until reaching 1100°F (595°C). Follow with furnace cooling or let cool in still air to ambient temperature.
Annealed Hardness: Estimated at approximately BHN 255.
Stress Relieving Annealed Components:
Heat to a temperature range of 1100-1300°F (595-705°C), hold for 2 hours, then furnace cool or allow to cool in still air. For hardened components, heat to 25-50°F (15-30°C) below the original tempering temperature, hold for 2 hours, and then cool in still air or via furnace.
Straightening Techniques:
Optimal results are achieved when performed warm, within a temperature range of 400-800°F (200-425°C). Preheat for Hardening: Gradually heat to 1550-1600°F (845-870°C) and equalize.
Austenitizing Process:
Heat to 1900-2000°F (1035-1095°C) for a duration of 15-30 minutes. Quenching: Use air or positive pressure quenching (a minimum of 2 bars) to lower the temperature below 125°F (50°C), or employ salt or interrupted oil quenching to approximately 1000°F (540°C), followed by air cooling to below 125°F (50°C).
Tempering Protocol:
Double temper within a range of 400-750°F (200-400°C), ensuring a minimum hold time of 2 hours for each cycle. For enhanced hardness, a freezing treatment can be incorporated between the first and second temper. Such treatments maximize hardenability and must be followed by an additional tempering cycle.
Important Note: To achieve optimal stress relief, temper CPM S45VN at 1000-1025°F (540-550°C). Be aware, tempering within this range may induce minor reductions in corrosion resistance.
Dimensional Size Change:
Expect a size increment of +0.05 to +0.10% when the material is fully martensitic. The presence of retained austenite can mitigate net growth. When tempering between 400-750°F (200-400°C), freezing treatments may be necessary to minimize retained austenite content.
Recommended Heat Treatment Procedure:
Austenitize at a precise temperature of 1950°F (1065°C). Quench to below 125°F (50°C). Execute double tempering at 600°F (315°C) for a minimum of 2 hours per cycle. Permit cooling to hand-warm temperatures between tempers. Integrate a freezing treatment between tempers, if desired.
Target Hardness: Aim for a robust 59-61 HRC.
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