| Carbon |
Manganese |
Silicon |
Chromium |
Nickel |
Other |
|
|
|
|
|
|
| 0.08 max |
2.00 max |
1.00 max |
17.00/
19.00 |
9.00/
13.00 |
* (See
below) |
Typical Mechanical Properties
Finish/
Condition |
Yield
Strength
psi |
Tensile
Strength
psi |
Elongation
in 2 in.,
% |
Hardness
Rockwell
B |
|
|
|
|
|
No. 1/2D Finish,
annealed |
51,000 |
98,000 |
45 |
86 |
No. 2/2B Finish,
skin passed |
52,000 |
100,000 |
45 |
90 |
Processing
Annealing
Cool rapidly from 1800-2000°F. Air cooling may be employs for light sections; otherwise, water quench from the annealing temperature.
Hardening
These grades can be hardened only by cold working. See table of Typical Mechanical Properties.
Stress Relieving
The recommended temperature for stress relieving is 400-750°F, although
temperatures up to 1500°F may be employed when time at temperature is kept
to a short period of one or two hours.
Hot Working
- Initial forging and pressing temperature - 2100-2300°F.
- Finishing temperature - 1700°F.
Forming
These grades can be formed into most shapes. However, as they will harden, an annealing treatment should precede and follow each severe cold forming operation.
* T347 - Cb + Ta 10 x C min., 1.00 max. T348 - Cb + Ta 10 x C min., 1.00 max., Ta 0.10 max., Co 0.20 max.
Density
lb./cu. in. |
Modulus of
Elasticity
in Tension
x 10^6, psi |
Specific
Heat
Btu/°F/lb |
Thermal
Conductivity
Btu/hr/ft^2/ft/ |
Mean Coefficient
of Thermal Expansion
per °F(x 10^-6) |
Melting
Point
Range |
Electrical
Resistivity
micro ohm-cm |
| 32-212 °F |
°F |
°F |
°F |
@ 70 °F |
| 0.29 |
28.0 |
0.12 |
212 |
932 |
32-212 |
32-600 |
32-1000 |
32-1200 |
2550/
2600 |
73 |
| 9.3 |
12.8 |
9.3 |
9.5 |
10.3 |
10.6 |
Elevated Temperature Strength
Creep Strength,
load for 1% elong.
10,000 hr,psi |
Temperature |
| 1000 °F |
1100 °F |
1200 °F |
1300 °F |
| 18,3000 |
14,000 |
9500 |
5200 |
Welding
Type 347 was designed for welding where parts will not be post-weld annealed. These grades can be welded using the electric arc, gas fusion or electrical resistance process. Types 347 and 348 electrodes and filler wires are used.
Stable carbides resulting from the combination of the carbon with the columbium allow the chromium to remain effective for corrosion resistance since carbon has a greater affinity for columbium than it does for chromium. This means that the full, beneficial corrosion-resisting effect of the chromium is available after welding.
Corrosion
Type 347, in common with Type 321, is resistant to intergranular corrosion. While it is not necessary to anneal welded parts, it should be remembered that this grade suffers from prolonged heating in the range of 800-1600° in severe corrosive service. The overall corrosion rate is about the same as that of Type 302 and is some what better than that of Type 321.
Oxidation
For continuous service, the maximum temperature is 1650°; for intermittent service, 1500?F.
