Cold Rolled Special Steel Strips
Carbon Tool Steels
SK95M (SK4) | High Carbon Steel
Overview & Features
Carbon tool steel is the most widely used cold rolled carbon steel because of its good balance of workability, hardenability, product performance, and price. SK95 has a higher Carbon content and higher hardenability than SK85, so it is often used for higher grade applications.
Most SK materials are generally heat treated before or after processing.
Our materials are maintained to have optimum surface roughness after heat treatment, which allows us to achieve an ideal product finish after blackeing.
Examples of Applications
Springs, Hinges, Bandsaws, Thomson Blades/Pinnacle Blades, Horns, Tape Measures, Metal Washers, Spacers
Available Shapes
Manufacturable Range (COIL, SHEET)
Thickness
0.10-2.0mm
Width
3.0-300mm
Length
COIL or SHEET less than 2000mm
This is the manufacturing range of coils and sheets we manufacture.
Standards
Unless otherwise specified, we manufacture in accordance with JIS standards.
[Note] "M" at the end of JIS steel grade symbol means steel grade corresponding to JIS G3311 Cold rolled special steel strip, and M may be abbreviated in some cases.
Overseas standards are listed as equivalent or similar to our materials, so please use them as a reference.
JIS
SK95M (G3311), SK95 (G4802)
AISI/SAE
W1-9
UNS
T72301
*Other Equivalent Materials
［ISO］C90U ［EN］1.1274, 1.1535 ［
SAE/AISI］W1-9 1/2, W1-8 1/2 ［GB］T00100 (T10), T0090 (T9)
Chemical Composition
[Note] SK95 is the notation based on the latest JIS version, and (SK4) with brackets is the notation based on the old JIS standard.
The old name is still commonly used in Japan.
Physical Properties
The following values are typical values for high carbon steel(Fe-0.8C).
Density
7.84 g/cm³
Specific Heat
490 J/(kg・K)
Electrical Resistivity
18 μΩ・cm
Young's Modulus
208 GPa
Thermal Expansion
11.0×10-6/K（0～100℃）
Thermal Conductivity
50.2 W/(m・K)
Magnetism
Strong
Mechanical Properties
Although cold rolled special steel is usually supplied in a rolled condition (as-rolled or rolled finish), we can manufacture it from the softest annealed finish to the hardest full hardened finish. You can select the finish that best suits your needs and application.
Quenching and Tempering
SK95（SK4）is a steel grade that can be quenched.
The general quenching condition is ［Oil cooling at 790～850℃(Water Cooling at 760～820℃ ) ］.
After holding for tens of seconds to several minutes depending on sizes, shapes, required properties, and quenching method, cooling is performed.
Water cooling is harder to quench, but due to the risk of quenching distortion and quench cracking, oil cooling may be used in some cases.
Please select tempering temperature according to required hardness and toughness by referencing quenching and tempering curve.(Quenching and tempering curve of SK85 is below for reference purposes.)
Related Pages
Steels for Blades
Material which is used to make various blades such as razor blades, shaver blades, and medical blades. Depending on the application and required properties, you can choose from a variety of options such as high carbon steel or martensitic stainless steel.
Cold Rolled Special Steel Strips
We manufacture carbon steel (SC material) and carbon tool steel (SK material) that conform to "JIS G 3311 Cold Rolled Special Steel Strip" and "JIS G 4802 Cold Rolled Steel Strip for Springs", as well as our own composition-adjusted steel grades for special applications.
