razor blade steel strip
razor blade steel is a martensitic stainless chromium steel characterized by:
- Excellent metallurgical properties
- Close tolerances
- Smooth surface, extra accuracy on flatness and straightness
- Good blanking properties
- Good hardening properties
- Good grinding and honing properties, facilitating the manufacture of high quality edges
- Good corrosion resistance (hardened and tempered condition)
- Consistent material properties from coil to coil, from delivery to delivery
Chemical composition (nominal)
Chemical composition (nominal) %
| C | Si | Mn | P | S | Cr |
| 0.68 | 0.4 | 0.7 | ≤0.025 | ≤0.010 | 13 |
Forms of supply
Razor blade steel is supplied as cold rolled strip in coils. The tensile strength is 1070±100 MPa (155±14.5 ksi). The strip is supplied with a dull, very fine surface, slit edges and extra accuracy on straightness. Wide strip is slit into finished sizes in special slitters with cemented carbide tools, which give very high edge quality and very close width tolerances. A corrosion-preventive oil is applied to the strip. Coils are carefully packed, with various packing materials being used according to customer requirements, destination and method of transport.
Coil sizes
Razor blade strip is wound into pancake coils on plastic cores with an inner diameter of 280 mm (11,0 in.). The coils can be supplied in weights between 1 and 5 kg/mm strip width, which means an outer diameter from about 500 to 1000 mm (20-40 in.)
Dimensions and tolerances
| Strip thickness | Thickness tolerance | ||
| mm | in. | mm ± | in. ± |
| 0.076 | 0.0030 | 0.005 | 0.00020 |
| 0.099 | 0.0039 | 0.005 | 0.00020 |
Width
Widths range between 5 and 26 mm (0,2-1,0 in.).
Other dimensions and forms of supply can be supplied to meet specific requirements.
Properties after hardening
Hardness
The martensite content and the amount of retained austenite mainly determine the hardness in the hardened and tempered condition. Martensite becomes harder with increasing carbon content. The higher the austenitizing temperature, the higher the content of carbon in the subsequently formed martensite.
On the other hand, the more carbon in the matrix at austenitizing, the more austenite will be retained after quenching and deep freezing. Since austenite is softer than martensite, this will reduce the hardness.
These two contradictory effects indicate that for razor blade steel, there is an optimum combination of hardening temperature and time.
Corrosion resistance
Due to the dissolution of carbides during heat treatment, the chromium content of the matrix increases. Good corrosion resistance is achieved with a chromium content of 11-12 %. This is obtained by a heat treatment that leaves about 15 % of retained austenite after quenching and deep freezing, see figure 3.
Physical properties
The physical properties of a steel are related to a number of factors, including alloying elements, heat treatment and manufacturing route, but the data presented below can generally be used for rough calculations.
| Density | |
| g/cm3 | 7.7 |
| lb/in.3 | 0.28 |
