Chemical Analysis
(Effects of common alloying elements in steel)
By definition, steel is a combination of iron and carbon. Steel is alloyed with various elements to improve physical properties and to produce special properties, such as resistance to corrosion or heat. Specific effects of the addition of such elements are outlined below:
Carbon (C), although not usually considered as an alloying element, is the most important constituent of steel. It raises tensile strength, hardness, and resistance to wear and abrasion. It lowers ductility, toughness, and machinability.
Manganese (Mn) is a deoxidizer and degasifier and reacts with sulphur to improve forgeability. It increases tensile strength, hardness, hardenability, and resistance to wear. It decreases tendency toward soaling and distortion. It increases the rate of carbon-penetration in carburizing.
Phosphorus (P) increases strength and hardness and improves machinability. However, it adds marked brittleness or cold-shortness to steel.
Sulphur (S) improves machinability in free-cutting steels, but without sufficient manganese it produces brittleness at red heat. It decreases weldability, impact toughness, and ductility.
Silicon (Si) is a deoxidizer and degasifier. It increases tensile and yield strength, hardness, forgeability, and magnetic permeability.
Chromium (Cr) increases tensile strength, hardness, hardenability, toughness, resistance to wear and abrasion, resistance to corrosion, and scaling at elevated temperatures.
Nickel (Ni) increases strength and hardness without sacrificing ductility and toughness. It also increases resistance to corrosion and scaling at elevated temperatures when introduced in suitable quantities in high-chromium (stainless) steels.
Molybdenum (Mo) increases strength, hardness, hardenability, and toughness, as well as creep resistance and strength at elevated temperatures. It improves machinability and resistance to corrosion and it intensifies the effects of other alloying elements. In hot-work steels, it increases red-hardness properties.
Tungsten (W) increases strength, hardness, and toughness tungsten steels have superior hot-working and greater cutting efficiency at elevated temperatures.
Vanadium (V) increases strength, hardness, and resistance to shock impact. It retards grain growth, permitting higher quenching temperatures. It also enhances the red hardness properties of high-speed metal cutting tools and intensifies the individual effects of other major elements.
Cobalt (Co) increases strength and hardness and permits higher quenching temperatures. It also intensifies the individual effects if other major elements in more complex steels.
Aluminum (Al) is a deoxidizer and degasifier. It retards grain growth and is used to control austenitic grain site. In nitriding steels it aids in producing a uniformly hard and strong nitrided case when used in amounts 1.00%-1.25%.
Titanium, Columbium and Tantalum (Ti, Cb, Ta) are used as stabilizing elements in stainless steels. Each has a high affinity for carbon and forms carbides, which are uniformly dispersed throughout the steel. This, localized depletion of carbon at grain boundaries is prevented.
Lead (Pb) while not strictly an alloying element, is added to improve machining characteristics. It is almost completely insoluble in steel, and minute lead particles, well dispersed, reduce friction where the cutting edge contacts the work. Addition of lead also improves chip-breaking formations.
| TYPE |
(C) max |
(Mn) max |
(P) max |
(S) max |
(Si) max |
(Cr) |
(Ni) |
(Mo) |
COPPER |
OTHER |
| 13-8MO |
.05 |
.20 |
.010 |
.008 |
.10 |
12.25 /13.25 |
7.50 /8.50 |
2.00 /2.50 |
|
AL .90 /1.35, N .01 |
| 15-5PH |
.07 |
1.00 |
.040 |
.030 |
1.00 |
14.00 /15.50 |
3.50 /5.50 |
|
2.50/4.50 |
CB + TA .15/.45 |
| 17-4PH |
.07 |
1.00 |
.040 |
.030 |
1.00 |
15.00 /17.50 |
3.00 /5.00 |
|
3.00/5.00 |
CB + TA .15/.45 |
| XM-19 |
.06 |
4.00-6.00 |
.040 |
.030 |
1.00 |
20.50 -23.50 |
11.50 /13.50 |
1.50 -3.00 |
|
N .20-.40, CB .10-.30 V .10-.30 |
| |
|
|
|
|
|
|
|
|
|
| 302 |
.15 |
2.00 |
.045 |
.030 |
1.00 |
17.00 /19.00 |
8.00 /10.00 |
|
|
N .10 MAX |
| 303 |
.15 |
2.00 |
.20 |
.15/ Min. |
1.00 |
17.00/19.00 |
8.00 /10.00 |
|
|
|
| 303 SE |
.15 |
2.00 |
.20 |
.060 |
1.00 |
17.00 /19.00 |
8.00 /10.00 |
|
|
SE .15 MIN |
| 304 |
.08 |
2.00 |
.045 |
.030 |
1.00 |
18.00 /20.00 |
8.00 /10.50 |
|
|
N .10 MAX |
| 304 L |
.030 |
2.00 |
.045 |
.030 |
1.00 |
18.00 /20.00 |
8.00 /12.00 |
|
|
N .10 MAX |
| 309 |
.20 |
2.00 |
.045 |
.030 |
1.00 |
22.00 /24.00 |
12.00 /15.00 |
|
|
|
| 310 |
.25 |
2.00 |
.045 |
.030 |
1.50 |
24.00 /26.00 |
19.00 /22.00 |
|
|
|
| 316 |
.08 |
2.00 |
.045 |
.030 |
1.00 |
16.00 /18.00 |
10.00 /14.00 |
2.00 /3.00 |
|
N .10 MAX |
| 316 L |
.030 |
2.00 |
.045 |
.030 |
1.00 |
16.00 /18.00 |
10.00 /14.00 |
2.00 /3.00 |
|
N .10 MAX |
| 317 |
.08 |
2.00 |
.045 |
.030 |
1.00 |
18.00 /20.00 |
11.00 /15.00 |
3.00 /4.00 |
|
N .10 MAX |
| 317 L |
.03 |
2.00 |
.045 |
.030 |
1.00 |
18.00 /20.00 |
11.00 /15.00 |
3.00 /4.00 |
|
|
| 321 |
.08 |
2.00 |
.045 |
.030 |
1.00 |
17.00 /19.00 |
9.00 /12.00 |
|
|
TI 5X(C+N)-0.70 |
| 347 |
.08 |
2.00 |
.045 |
.030 |
1.00 |
17.00 /19.00 |
9.00 /13.00 |
|
|
CB + TA .10XC Min. |
| 410 |
.15 |
1.00 |
.040 |
.030 |
1.00 |
11.50 /13.50 |
|
|
|
|
| 416 |
.15 |
1.25 |
.040 |
.15 / Min. |
1.00 |
12.00 /14.00 |
|
|
|
|
| 420 |
.15 Min. |
1.00 |
.040 |
.030 |
1.00 |
12.00 /14.00 |
|
|
|
|
| 430 |
.12 |
1.00 |
.040 |
.030 |
1.00 |
16.00 /18.00 |
|
|
|
|
| 430 F |
.12 |
1.25 |
.060 |
.15 MIN |
1.00 |
16.00 /18.00 |
|
|
|
|
| 431 |
.20 |
1.00 |
.040 |
.030 |
1.00 |
15.00 /17.00 |
1.25/2.50 |
|
|
|
| 440 A |
.60/.75 |
1.00 |
.040 |
.030 |
1.00 |
16.00 /18.00 |
|
.75 |
|
|
| 440 C |
.95/1.20 |
1.00 |
.040 |
.030 |
1.00 |
16.00 /18.00 |
|
.75 |
|
|
|
