Jul 16 2013
Topics Covered
Introduction
Chemical Composition
Physical Properties
Mechanical Properties
Thermal Properties
Other Designations
Introduction
Cold-work tool steels are high carbon steels that are further classified into three subgroups - oil-hardening steels, air-hardening steels, and high-carbon, high-chromium steels, Oil-hardening cold-work steels are also known as group O steels consisting of O1, O2, O6, and O7 types.
The following datasheet provides details about the O6 oil-hardening cold-work steel. Type O6 includes manganese, molybdenum, and silicon. The O6 tool steel reduces galling and seizing of fully hardened steel and improves machinability of annealed stock as graphite is present in its microstructure.
Chemical Composition
The following table shows the chemical composition of O6 tools steels.
|
Element |
Content (%) |
|
Carbon, C |
1.25-1.55 |
|
Silicon, Si |
0.55-1.50 |
|
Manganese, Mn |
0.30-1.10 |
|
Chromium, Cr |
0.3 |
|
Nickel, Ni |
0.3 |
|
Copper, Cu |
0.25 |
|
Molybdenum, Mo |
0.20-0.30 |
|
Phosphorus, P |
0.03 |
|
Sulfur, S |
0.03 |
Physical Properties
The physical properties of O6 tool steels are outlined in the following table.
|
Properties |
Metric |
Imperial |
|
Density |
7.67 g/cm3 |
0.277 lb/in3 |
Mechanical Properties
The mechanical properties of O6 steels are tabulated below.
|
Properties |
Metric |
Imperial |
|
Poisson's ratio (25°C) |
0.27-0.30 |
0.27-0.30 |
|
Elastic modulus |
190-210 GPa |
27557-30458 ksi |
|
Bulk modulus |
140 GPa |
20300 ksi |
|
Shear modulus |
80.0 GPa |
11600 ksi |
|
Hardness, Rockwell C (As hardened, 64.0 HRC at 120°C temper, 63.0 HRC at 150°C temper, 62.0 HRC at 175°C temper, 61 HRC at 190°C and 205°C temper, 60 HRC at 230°C temper, 59.5 HRC at 260°C temper, 58.5 HRC at 315°C temper. Oil quenched from 800°C, tempered for 1 hour) |
65 |
65 |
|
Hardness, Knoop (converted from Rockwell C hardness) |
850 |
850 |
|
Hardness, Brinell (converted from Rockwell C hardness) |
752 |
752 |
|
Hardness, Vickers (converted from Rockwell C hardness) |
|
|
|
Machinability (based on 100% machinability for 1% carbon tool steel) |
130 |
130 |
Thermal Properties
The table below shows the thermal properties of O6 tool steels.
|
Properties |
Metric |
Imperial |
|
Thermal expansion co-efficient (@25-250°C/77-482°F) |
12.48 mm/m°C |
6.933 min/in°F |
Other Designations
Other designations that are equivalent to O6 tool steels include:
-
ASTM A681
-
FED QQ-T-570
-
SAE J437
-
SAE J438
-
UNS T31506