Cold Working Properties
The austenitic chromium-nickel stainless steels are cold formed (bent, drawn, shaped) and the cold forming imparts a higher strength than for the original starting annealed condition. It is not typical to heat these stainless steels for forming as is often done with carbon steel. The following are the designations of cold worked tempers as defined by ASTM A 666, Standard Specification for Austenitic Stainless Steel, Sheet, Strip, Plate & Flat Bar.
1/4 Hard, 1/2 Hard, 3/4 Hard, Full Hard
Reheating the cold worked austenitic stainless steels at temperatures below 370C (700F) increases the tensile strength. Reheating above 425C (900F) lowers the strength and increases the ductility.
Cold working increases the fatigue strength of the austenitic stainless steels. However, the fatigue strength of these cold worked alloys is reduced by notches, as compared to notched fatigue strength in the annealed condition.
| Fatigue Strength (Endurance Limits) of Cold Worked Stainless Steels |
| AISI Type |
Temper |
Endurance Limit - ksi |
| 301 |
Full Hard |
80 |
| 302 |
Full Hard |
75 |
| 303 |
1/4 Hard |
48 |
| 304 |
Annealed |
35 |
| 304 |
1/2 Hard |
70 |
| 304 |
3/4 Hard |
92 |
| 347 |
3/4 Hard |
88 |
Minimum Tensile Strength of Cold Rolled Sheet & Strip for 304
The other common 300 series alloys are similar. |
| Temper |
Tensile ksi |
Yield ksi |
Elong. % |
Rockwell C Hardness |
| 1/4 Hard |
125 |
75 |
23 |
25 |
| 1/2 Hard |
150 |
110 |
16 |
32 |
| 3/4 Hard |
175 |
135 |
11 |
37 |
| Full Hard |
185 |
140 |
8 |
41 |
| Extra Full Hard |
200 |
- |
- |
45 |
Tensile Strength of Cold Drawn Cr-Ni Stainless Steel Wire
Diameter Range of 0.126 - 0.375" |
| AISI TYPE |
TEMPER |
YIELD-ksi |
TENSILE-ksi |
ELONG.% |
| 302 |
1/4 hard |
90-125 |
120-140 |
15-25 |
| 1/2 hard |
120-150 |
145-176 |
10-17 |
| 3/4 hard |
150-180 |
170-200 |
5-10 |
| *Full hard |
180-220 |
190-230 |
2-5 |
| *Typical of wires used in making stranded wire rope |
| 304 |
1/4 hard |
90-110 |
120-140 |
20-30 |
| 1/2 hard |
120-140 |
130-170 |
10-18 |
| 3/4 hard |
140-170 |
170-200 |
5-10 |
| Full hard |
170-210 |
200-240 |
2-5 |
| 309S |
1/4 hard |
80-90 |
110-130 |
15-25 |
| 1/2 hard |
105-125 |
125-155 |
10-11 |
| 3/4 hard |
125-150 |
140-180 |
8-12 |
| Full hard |
150-185 |
160-190 |
4-8 |
| 310S |
1/4 hard |
80-90 |
110-130 |
15-25 |
| 1/2 hard |
105-125 |
125-155 |
10-11 |
| 3/4 hard |
125-150 |
140-180 |
8-12 |
| Full hard |
150-185 |
160-195 |
3-6 |
| 316 |
1/4 hard |
80-100 |
110-130 |
20-30 |
| 1/2 hard |
105-125 |
135-155 |
12-20 |
| 3/4 hard |
135-165 |
165-195 |
8-12 |
| Full hard |
155-185 |
185-215 |
3-6 |
| 321 |
1/4 hard |
90-110 |
120-140 |
20-30 |
| 1/2 hard |
120-140 |
150-170 |
10-18 |
| 3/4 hard |
140-170 |
170-200 |
5-10 |
| Full hard |
170-210 |
200-240 |
2-5 |
| 347 |
1/4 hard |
85-105 |
115-135 |
15-25 |
| 1/2 hard |
110-130 |
140-160 |
10-13 |
| 3/4 hard |
140-170 |
170-200 |
5-10 |
| Full hard |
160-190 |
190-220 |
3-6 |
TENSILE PROPERTIES OF AUSTENITIC STAINLESS STEELS
FOR VARIOUS AMOUNTS OF COLD WORKING |
| |
STRENGTH IN ksi for % COLD REDUCTION SHOWN |
| Alloy |
0 |
10% |
20% |
30% |
40% |
50% |
60% |
| 301 |
| Tensile |
120 |
150 |
168 |
184 |
198 |
210 |
222 |
| Yield |
40 |
87 |
120 |
148 |
170 |
185 |
202 |
| Elong. |
75% |
58% |
42% |
32% |
22% |
15% |
6% |
| 302 |
| Tensile |
93 |
108 |
122 |
138 |
152 |
168 |
180 |
| Yield |
37 |
91 |
107 |
120 |
134 |
147 |
160 |
| Elong. |
67% |
42% |
30% |
20% |
15% |
10% |
6% |
| 303 |
| Tensile |
91 |
106 |
125 |
148 |
171 |
196 |
n/a |
| Yield |
n/a |
n/a |
n/a |
n/a |
n/a |
n/a |
n/a |
| Elong. |
75% |
58% |
42% |
32% |
22% |
15% |
6% |
| 304 |
| Tensile |
86 |
98 |
113 |
130 |
146 |
158 |
169 |
| Yield |
34 |
69 |
97 |
120 |
135 |
145 |
152 |
| Elong. |
53% |
36% |
25% |
16% |
13% |
10% |
6% |
| 304L |
| Tensile |
83 |
106 |
122 |
138 |
154 |
170 |
n/a |
| Yield |
32 |
72 |
97 |
120 |
138 |
152 |
n/a |
| Elong. |
57% |
35% |
23% |
15% |
10% |
5% |
n/a |
| 309S |
| Tensile |
80 |
87 |
98 |
115 |
135 |
151 |
165 |
| Yield |
37 |
57 |
82 |
102 |
122 |
140 |
153 |
| Elong. |
55% |
45% |
30% |
14% |
9% |
5% |
3% |
| 310S |
| Tensile |
86 |
108 |
126 |
140 |
153 |
166 |
174 |
| Yield |
45 |
67 |
97 |
125 |
140 |
148 |
152 |
| Elong. |
45% |
29% |
15% |
8% |
6% |
5% |
5% |
| 316 |
| Tensile |
85 |
95 |
110 |
130 |
142 |
150 |
169 |
| Yield |
38 |
70 |
98 |
118 |
128 |
137 |
148 |
| Elong. |
60% |
40% |
21% |
12% |
8% |
6% |
5% |
| 321 |
| Tensile |
88 |
100 |
115 |
135 |
150 |
160 |
168 |
| Yield |
32 |
70 |
100 |
120 |
134 |
142 |
145 |
| Elong. |
55% |
45% |
26% |
13% |
8% |
5% |
4% |
| 347 |
| Tensile |
96 |
105 |
122 |
144 |
159 |
168 |
173 |
| Yield |
40 |
78 |
109 |
128 |
138 |
143 |
149 |
| Elong. |
50% |
33% |
12% |
8% |
7% |
6% |
5% |