Oct 25 2012
Topics Covered
Introduction
Chemical Composition
Physical Properties
Mechanical Properties
Thermal Properties
Other Designations
Introduction
High-speed tool steels are of two types, namely molybdenum
high-speed steels and tungsten high-speed steels. The molybdenum
high-speed steels are also referred to as Group M steels. In the United
States, 95% or more of all manufactured high-speed steels are the Group
M steels. The high-speed tool steel types have equal performance but
the molybdenum high-speed steels have relatively lower initial cost. To
enhance performance and tool service life, tools made of high-speed
tool steel can be coated with titanium carbide, titanium nitride, and
other coatings using the physical vapor deposition process.
There are many types of molybdenum high-speed steels. The following
data sheet will provide details relating to M30 molybdenum high-speed
steel (UNS T11330).
Chemical Composition
The following table shows the chemical composition of M30 steels.
| Element |
Content
(%) |
Fe
|
Balance
|
| C |
0.75-0.85 |
| Mn |
0.15-0.40 |
| Si |
0.20-0.45 |
| Cr |
3.50-4.25 |
| Ni |
0.3 |
| Mo |
7.75-9.00 |
| W |
1.30-2.30 |
| V |
1.00-1.40 |
| Co |
4.50-5.50 |
| Cu |
0.25 |
| P |
0.03 |
| S |
0.03 |
Physical Properties
The physical properties of M30 steels are outlined in the following
table.
| Physical properties |
Conditions |
| T
(°C) |
Treatment |
| Density |
8.01 x 1000 kg/m3 |
25 |
- |
Mechanical Properties
The mechanical properties of M30 steels are tabulated below.
| Mechanical properties |
Conditions |
| T
(°C) |
Treatment |
| Poisson's ratio |
0.27-0.30 |
25 |
- |
| Elastic modulus |
27557-30458 ksi |
25 |
- |
Thermal Properties
The table below shows the thermal properties of M30 steels.
| Thermal properties |
Conditions |
| T
(°C) |
Treatment |
| Thermal expansion |
11.2 x 10-6/ºC |
20-425 |
- |
Other Designations
Other designations that are equivalent to AISI M30 molybdenum
high-speed tool steels include:
- ASTM A600
- FED QQ-T-590
- UNS T11330