Oct 25 2012
Topics Covered
Introduction
Chemical Composition
Physical Properties
Mechanical Properties
Other Designations
Introduction
Molybdenum high-speed steels are designated as Group M steels
according to the AISI classification system. Over 95% of high-speed
steels manufactured in the US are group M steels. Tungsten is present
in all types from M1 to M10, except M6, and cobalt is not present in
any of these steels. Molybdenum high-speed steels have similar
performance when compared to tungsten high-speed steel. However, the
initial cost of molybdenum tool steels is low. Titanium nitride,
titanium carbide and several other coatings can be used in the tools
made of this kind of steels through physical vapor deposition process
to improve the performance and life span of the tool.
Chemical Composition
The following table shows the chemical composition of M43 molybdenum
high speed tool steel.
| Element |
Content
(%) |
Fe, Iron
|
Balance
|
| C |
1.15-1.25 |
| Mn |
0.20-0.40 |
| Si |
0.15-0.65 |
| Cr |
3.50-4.25 |
| Ni |
0.3 |
| Mo |
7.50-8.50 |
| W |
2.25-3.00 |
| V |
1.50-1.75 |
| Co |
7.75-8.75 |
| Cu |
0.25 |
| P |
0.03 |
| S |
0.03 |
Physical Properties
The physical properties of M43 molybdenum high speed tool steels are
given in the following table.
| Physical
properties |
Metric |
Imperial |
| Density |
7.7- 8.03 x 1000 kg/m3
|
0.48 - 0.50 x 1000 lb/ft3 |
Mechanical Properties
The mechanical properties of M43 molybdenum high speed tool steels
are tabulated below.
| Mechanical
properties |
Metric |
Imperial |
| Poisson's ratio |
0.27-0.30 |
0.27-0.30 |
| Elastic modulus |
190-210 GPa |
27557-30458 ksi |
Other Designations
Other designations that are equivalent to M43 molybdenum high speed
tool steel include:
- ASTM A600
- FED QQ-T-590
- UNS T11343