Jun 19 2013
Topics Covered
Introduction
Chemical Composition
Physical Properties
Mechanical Properties
Thermal Properties
Fabrication and Heat treatment
Machinability
Forging
Annealing
Stress Relieving
Tempering
Applications
Introduction
Tool steels are a kind of carbon and alloy steels that are well-suited for manufacturing tools. They are usually used in a heat-treated state. With a carbon content between 0.7 and 1.5%, tool steels are manufactured under carefully controlled conditions to produce the required quality. Tool steels are available in a number of grades for different applications.
AISI A11 tool steel is a high vanadium tool steel having wear resistance greater than most of the other tool steels, as well as good toughness and strength. It has improved response to heat treatment, easy grinding process and an expansion of about 0.0004 inches upon heating.
The data below will provide an overview of grade A11 tool steels.
Chemical Composition
The chemical composition of A11 tool steels is outlined in the following table.
|
Element |
Content (%) |
|
Iron, Fe |
78.21 - 81.35 |
|
Vanadium, V |
9.25 - 10.25 |
|
Chromium, Cr |
4.75 - 5.75 |
|
Carbon, C |
2.4 - 2.5 |
|
Molybdenum, Mo |
1.1 - 1.5 |
|
Silicon, Si |
0.75 - 1.1 |
|
Manganese, Mn |
0.35 - 0.6 |
|
Sulfur, S |
0.050 - 0.090 |
Physical Properties
The following table shows the physical properties of A11 tool steels.
|
Properties |
Metric |
Imperial |
|
Density |
7.39 g/cm3 |
0.267 lb/in3 |
|
Melting point |
1450 - 1510°C |
2642 - 2750°F |
Mechanical Properties
The mechanical properties of A11 tool steels are displayed in the following table.
|
Properties |
Metric |
Imperial |
|
Tensile strength |
5205 MPa |
754900 psi |
|
Modulus of elasticity |
200 GPa |
29000 ksi |
|
Hardness, Rockwell C |
59 |
59 |
|
Abrasion |
12 |
12 |
|
Izod impact unnotched |
39.3 J |
29 ft.lb |
Thermal Properties
The thermal properties of A11 tool steels are given in the following table
|
Properties |
Metric |
Imperial |
|
Thermal expansion co-efficient (@21-100°C/69.8-212°F) |
10.72 µm/m°C |
5.956 µin/in°F |
Fabrication and Heat treatment
Machinability
The machinability of A11 tool steels in the annealed condition can be rated between 35 and 40%.
Forging
A11 tool steels are slowly heated at 1093 - 1149°C (2000 - 2100°F). The forgings are then cooled slowly and annealed immediately upon cooling.
Annealing
A11 tool steels are heated at 871 - 899°C (1600 -1650°F) for 2 hours and cooled to 538°C (1000°F).
Stress Relieving
To relieve machining stresses, A11 tool steels are heated to a temperature of 621 - 677°C (1150 - 1250°F) and then slowly cooled in still air.
Tempering
A11 tool steels are immediately tempered after the completion of the quenching. Tempering is usually performed in the temperature range of 538 - 593°C (1000 - 1100°F).
Applications
The following are the list of applications of A11 tool steels:
-
Steel mill rolls
-
Pelletizer blades
-
Woodworking tools
-
Cold extrusion liners
-
Plastic injection molds
-
Slitter knives
-
Blanking dies and piercing dies.