Sep 13 2012
Topics Covered
Introduction
Chemical Composition
Physical Properties
Mechanical Properties
Thermal Properties
Other Designations
Introduction
Chromium hot-work tool steels are designated as group H steels according to the AISI classification system. This series of steels start from H1 to H19.
H14 chromium hot-work steel has had tungsten added for improved high-temperature properties and a high heat resistance. It exhibits little size change during hardening and is suitable for long-run die castings dies.
This article will provide an overview of H14 chromium hot-work steels.
Chemical Composition
The following table shows the chemical composition of H14 tool steels.
| Element |
Content (%) |
| C |
0.35-0.45 |
| Mn |
0.20-0.50 |
| Si |
0.80-1.20 |
| Cr |
4.75-5.50 |
| Ni |
0.3 |
| Cu |
0.25 |
| P |
0.03 |
| S |
0.03 |
| W |
4.00-5.25 |
Physical Properties
The physical properties of H14 tool steels are given in the following table.
| Properties |
Metric |
Imperial |
| Density |
7.89 g/cm3 |
0.285 lb/in3 |
Mechanical Properties
The mechanical properties of H14 tool steels are tabulated below.
| Properties |
Metric |
Imperial |
| Hardness, Rockwell C (air cooled from 982°C, 30 mins) |
52 |
52 |
| Hardness, Rockwell C (air cooled from 1010°C, 30 mins) |
55 |
55 |
| Hardness, Rockwell C (air cooled from 1038°C, 30 mins) |
56 |
56 |
| Modulus of elasticity |
207 GPa |
30000 ksi |
| Charpy impact (V-notch; air cooled from 1010°C; 490°C temper temperature) |
12.9 J |
9.50 ft-lb |
| Charpy impact (V-notch; air cooled from 1010°C; 370°C temper temperature) |
16.3 J |
12.0 ft-lb |
| Charpy impact (V-notch; air cooled from 1010°C; 650°C temper temperature) |
17.6 J |
13.0 ft-lb |
| Machinability (1% carbon steel) |
70.0 - 75.0% |
70.0 - 75.0% |
| Poisson's ratio |
0.27-0.30 |
0.27-0.30 |
Thermal Properties
The following table shows the thermal properties of H14 tool steels.
| Properties |
Conditions |
| T (°C) |
Treatment |
| Thermal expansion |
11 x 10-6/ºC |
20-100 |
- |
Other Designations
Other designations that are equivalent to H14 tool steels include:
- ASTM A681
- FED QQ-T-570
- UNS T20814