Oct 19 2001
Chemical Formula
Fe, <0.15%C, 16-18%Cr, 6-8%Ni, <2%Mn, <1%Si, <0.045%P, <0.03%S
Introduction
Stainless steel grade 301 is usually supplied in the form of strips and wires, with a tensile strength of up to 1800 Mpa, to produce tempers ranging from 1/16 Hard to Full Hard. By subjecting grade 301 to controlled analysis it is capable of retaining sufficient ductility even in ½ hard conditions. This form of grade 301 may be used in aircraft, rail car components and architectural structures. Tempers of this grade, ranging from ¾ to full hard, may be used in applications requiring high wear resistance and spring features with simple form designs.
Grade 301L, which is the low carbon form of grade 301, is the ideal choice for applications that require good ductility. Grade 301LN is another variant. This contains a higher percentage of nitrogen and exhibits a higher work harden rate compared to standard 301. Only grade 301 is specified in ASTM A666. 301L and 301LN are represented by other conventions. Grade 301L is represented by JIS G4305 and 301LN by EN10088-2 as grade 1.4318.
Key Properties
The key properties listed in the below sections are for flat rolled products such as plate, sheet and coil - specified as Grade ASTM A666. For other grades, EN10088.2 and JISG4305, it is not necessary that the values and properties are identical.
Composition
Composition ranges of stainless steel grade 301 are tabulated below.
Table 1 - Composition ranges for 301 grade stainless steel
|
Grade
|
C
|
Mn
|
Si
|
P
|
S
|
Cr
|
Mo
|
Ni
|
N
|
|
301
ASTM A666
|
min.
max.
|
-
0.15
|
-
2.0
|
-
1.0
|
-
0.045
|
-
0.030
|
16.0
18.0
|
-
|
6.0
8.0
|
-
0.10
|
|
301L
JIS G4305
|
min.
max.
|
-
0.03
|
-
2.0
|
-
1.0
|
-
0.045
|
-
0.030
|
16.0
18.0
|
-
|
6.0
8.0
|
-
0.20
|
|
1.4318/301LN
EN 10088-2
|
min.
max.
|
-
0.03
|
-
2.0
|
-
1.0
|
-
0.045
|
-
0.015
|
16.5
18.5
|
-
|
6.0
8.0
|
0.10
0.20
|
Mechanical Properties
The mechanical properties of grade 301 stainless steels are listed in the table below. The bend test is obtained around a diameter of the bend factor multiplied by the steel thickness.
Table 2 - Mechanical properties of 301 grade stainless steel
|
Grade 301 Temper ASTM A666
|
Tensile Strength (MPa) min.
|
Yield Strength 0.2% Proof (MPa) min.
|
Elongation (% in 50mm) (thick.>0.76mm) min.
|
Bend Test (thickness > 1.27mm)
|
|
Bend Angle (°)
|
Factor
|
|
Annealed
|
758
|
276
|
60
|
-
|
-
|
|
1/16 Hard
|
620
|
310
|
40
|
180
|
1
|
|
1/8 Hard
|
690
|
380
|
40
|
180
|
1
|
|
1/4 Hard
|
862
|
514
|
25
|
90
|
2
|
|
1/2 Hard
|
1034
|
758
|
18
|
90
|
2
|
|
3/4 Hard
|
1205
|
930
|
12
|
90
|
3
|
|
Full Hard
|
1276
|
965
|
9
|
90
|
5
|
Physical Properties
Physical properties of grade 301 stainless steels are listed in the table below.
Table 3 - Physical properties of 301 grade stainless steel
|
Grade
|
Density (kg/m3)
|
Elastic Modulus (GPa)
|
Mean Coefficient of Thermal Expansion (μm/m/°C)
|
Thermal Conductivity (W/m.K)
|
Specific Heat 0-100°C
(J/kg.K)
|
Electrical Resistivity (nΩ.m)
|
|
0-100°C
|
0-315°C
|
0-538°C
|
at 100°C
|
at 500°C
|
|
301
|
7880
|
193
|
16.9
|
17.2
|
18.2
|
16.2
|
21.4
|
500
|
695
|
Grade Specification Comparison
Table 4 provides an approximate grade comparison for 301 stainless steels. The comparisons given in the table are of functionally similar materials. (For exact equivalents, the original specifications must be referred to).
Table 4 - Grade comparison for grade 301 stainless steel
|
Grade
|
UNS No
|
Old British
|
Euronorm
|
Swedish SS
|
Japanese JIS
|
|
BS
|
En
|
No
|
Name
|
|
301
|
S30100
|
301S21
|
-
|
1.4310
|
X10CrNi18-8
|
2331
|
SUS 301
|
Possible Alternative Grades
A list of the possible alternatives to grade 301 stainless steels is given in Table 5.
Table 5 - Possible alternative grades to 301 grade stainless steel
|
Grade
|
Reason for choosing the alternate grade
|
|
304
|
The lower work hardening rate of 304 is acceptable, giving better ductility required for forming.
|
|
316
|
A higher corrosion resistance is required, and the lower work hardening rate of 316 can be compensated for.
|
Corrosion Resistance
The resistance to corrosion offered by stainless steel grade 301 is similar to that offered by 304. This grade exhibits good resistance to corrosion in mildly corrosive environments at ambient temperatures.
Heat Resistance
Grade 301 exhibits good oxidation resistance for intermittent services up to 840°C and for continuous service up to 900°C.
Heat Treatment
Stainless steel grade 301 is subjected to solution treatment annealing in temperatures ranging from 1010oC to 1120°C followed by rapid cooling. For intermediate annealing a low temperature range is chosen. Thermal hardening does not suit this grade of stainless steel.
Cold Working
Stainless steel grade 301 and low carbon variants of this grade are predominantly used as high strength stainless steel. The work hardening rates of these grades are very high, in the range of a 14MPa increase per 1% reduction in area of cold work. As a result of this characteristic high strength can be achieved from cold rolling and roll forming operations.
Through such forming methods strain hardened austenite may be partially transformed to martensite. In spite of achieving such high strengths, the residual ductility in the alloy is capable of causing severe cold deformation. The alloy is non-magnetic in the annealed condition, but shows strong magnetism when cold worked.
Welding
Stainless steel grade 301 is suitable for all forms of standard welding methods. The use of grade 308L as filler metal is recommended. Welded parts in grade 301 must be subjected to annealing in order to attain maximum corrosion resistance. For grades 301L and 301LN annealing is not necessary after welding. The purpose of welding followed by annealing is to remove the high strength brought about by cold rolling.
The process of spot welding is used to assemble the cold rolled 301 components; this rapid welding technique does not hamper the overall strength of the component.
Applications
Some of the typical applications of grade 301 stainless steels are listed below:
- Making rail car structural components
- Air frame sections
- Highway trailer components
- Automotive wheel covers
- Wiper blade clips and holders
- Stove element clips
- Screen frames
- Toaster springs
- Curtain walls