Sep 26 2012
Topics Covered
Introduction
Chemical Composition
Physical Properties
Mechanical Properties
Thermal Properties
Other Designations
Fabrication and Heat Treatment
Machinability
Forming
Welding
Forging
Annealing
Hardening
Applications
Introduction
Stainless steels are high-alloy steels. They have high corrosion
resistance due to high chromium content of about 4-30%. They are
classified in to three types such as ferritic, austenitic, and
martensitic steels based on their crystalline structure.
Grade 434 stainless steel contains added molybdenum to increase its
corrosion resistance. It is has performance and chemistry similar to
that of 430 stainless steel.
Chemical Composition
The following table shows the chemical composition of grade 434
stainless steel.
| Element |
Content
(%) |
| Iron, Fe |
81 |
| Chromium, Cr |
16 |
| Molybdenum, Mo |
1 |
| Silicon, Si |
1 |
| Manganese, Mn |
1 |
| Carbon, C |
0.12 |
| Phosphorous, P |
0.040 |
| Sulfur, S |
0.030 |
Physical Properties
The physical properties of grade 434 stainless steel are given in
the following table.
| Properties |
Metric |
Imperial |
| Density |
7.80 cm³ |
0.282 lb/in³ |
| Melting point |
1510°C |
2750°F |
Mechanical Properties
The following table outlines the mechanical properties of annealed
grade 434 stainless steel.
| Properties |
Metric |
Imperial |
| Tensile strength |
538 MPa |
78000 psi |
| Yield strength (@ strain 0.200%) |
441 MPa |
64000 psi |
| Elastic modulus |
200 GPa |
29008 ksi |
| Poisson's ratio |
0.27-0.30 |
0.27-0.30 |
| Elongation at break (in 50 mm) |
32% |
32% |
| Hardness, Rockwell B (converted
from Brinell hardness) |
89 |
89 |
Thermal Properties
The thermal properties of grade 434 stainless steel are displayed in
the following table.
| Properties |
Metric |
Imperial |
| Thermal expansion co-efficient (@
0-100°C/32-212°F) |
10.4 µm/m°C |
5.78 µin/in°F |
| Thermal conductivity (@ 100°C/212°F) |
26.1 W/mK |
181 BTU in/hr.ft².°F |
Other Designations
Other designations that are equivalent to grade 434 stainless steel
include:
- DIN 1.4113
- AFNOR Z 8 CD 17.01
- UNI X 8 CrMo 17
- JIS SUS 434
- SS 2325
- B.S. 434 S 19
- ASTM A65i
- SAE 51434
- SAE J405 (51434)
Fabrication and Heat Treatment
Machinability
Grade 434 stainless steel can be machined using all standard
procedures.
Forming
Blanking, shearing, and deep drawing operations can be successfully
performed due to its high ductility.
Welding
Grade 434 stainless steel can be welded using common techniques.
After welding, it should be thoroughly cleaned to increase corrosion
resistance property.
Forging
Grade 434 stainless steel can be forged at 1094 -1149°C
(2000-2100°F) after thorough soaking.
Annealing
Grade 434 stainless steel is annealed by soaking at 788 - 872°C
(1450-1600°F) followed by cooling in air.
Hardening
Grade 434 stainless steel does not react to heat treatment.
Applications
Grade 434 stainless steel is used in automotive trim applications
and other exterior environments.