Chemical Composition
|
Elements |
A354 Grades BC, BD |
A193 Grade B7 |
|
**See Note Below |
Chromium-Molybdenum |
|
Range percent |
Check variation
over percent |
Range percent |
Check variation
over or under percent |
|
Carbon... |
-- |
-- |
*0.38-0.48 |
0.02 |
|
Manganese... |
-- |
-- |
0.750-1.00 |
0.04 |
|
Phosphorus, max... |
0.04 |
0.005 |
0.04 |
0.005 over |
|
Sulphur, max... |
0.04 |
0.005 |
0.04 |
0.005 over |
|
Silicon... |
-- |
-- |
0.20-0.35 |
0.02 |
|
Chromium... |
-- |
-- |
0.80-1.10 |
0.05 |
|
Molybdenum... |
-- |
-- |
0.15-0.25 |
0.02 |
|
Elements |
A193 Grade B16
Chromium-Molybdenum-Vanadium |
|
Range percent |
Check variation
over or under percent |
|
Carbon... |
0.36-0.44 |
0.02 |
|
Manganese... |
0.45-0.70 |
0.03 |
|
Phosphorus, max... |
0.04 |
0.005 over |
|
Sulphur, max... |
0.04 |
0.005 over |
|
Silicon... |
0.20-0.35 |
0.02 |
|
Chromium... |
0.80-1.15 |
0.05 |
|
Molybdenum... |
0.50-0.65 |
0.03 |
|
Vanadium... |
0.25-0.35 |
0.03 |
|
Elements |
A320 Grade L7 |
A320 Grade L43 |
|
Chromium-Molybdenum
(AISI 4140, 4142, 4145) |
Nickel-Chromium-Molybdenum
(AISI 4340) |
|
Range percent |
Check variation
over percent |
Range percent |
Check variation
over or under percent |
|
Carbon... |
*0.38-0.48 |
0.02 |
0.38-0.148 |
0.02 |
|
Manganese... |
0.75-1.00 |
0.04 |
0.60-0.85 |
0.03 |
|
Phosphorus, max... |
0.04 |
0.005 over |
0.04 |
0.005 over |
|
Sulphur, max... |
0.04 |
0.005 over |
0.04 |
0.005 over |
|
Silicon... |
0.20-0.35 |
0.02 |
0.20-0.35 |
0.02 |
|
Nickel... |
-- |
-- |
1.65-2.00 |
0.05 |
|
Chromium... |
0.80-1.10 |
0.05 |
0.70-1.90 |
0.03 |
|
Molybdenum... |
0.15-0.25 |
0.02 |
0.20-0.30 |
0.02 |
*For bar sizes over 3-1/2 in. to 4 in., inclusive, the carbon content may be 0.50 pct. max.
** Any alloy steel capable of meeting the tensile requirements of Specification A354 may be used.
Tensile Requirements
|
Grade |
Diameter, in. |
Min
tempering
temp F |
Tensile
strength
min psi |
Yield
point
min psi |
Elongation
in 2 in.
min pct |
Reduction
of area
min pct |
|
A354 Grade BC |
{2-1/2 and under
{Over 2-1/2 to 4 incl. |
850 |
125,000 |
109,000 |
16 |
50 |
|
A354 Grade BD |
1-1/2 and under |
850 |
115,000 |
99,000 |
16 |
45 |
|
A193 Grade B7
Chromium-
Molybdenum |
{2-1/2 and under
{Over 2-1/2 to 4 incl.
{Over 4 to 7 incl. |
850 |
150,000 |
125,000 |
14 |
35 |
|
A193 Grade B16
Chromium-
Molybdenum-
Vanadium |
{2-1/2 and under
{Over 2-1/2 to 4 incl.
{Over 4 to 7 incl. |
1100
1100
1100 |
125,000
115,000
100,000 |
105,000
95,000
75,000 |
16
16
18 |
50
50
50 |
|
A320 Grade L7
Chromium-
Molybdenum |
2-1/2 and under |
-- |
125,000 |
105,000 |
16 |
50 |
|
A320 Grade L43
Nickel-Chromium-
Molybdenum |
4 and under |
-- |
125,000 |
105,000 |
16 |
50 |
Commonly used are the following grades of heat-treated alloy steel for high-pressure or extreme temperature service in diameters of 1/2 in. to 2 in., inclusive. Other grades and other diameters are available on special order.
ASTM A354, Grades BC and BD - heat-treated alloy steels for applications at normal atmospheric temperatures where high strength is required.
ASTM A193, Grade B7 - a heat-treated chromium-molybdenum steel widely used for medium high-temperature service.
ASTM A193, Grade B16 - a heat-treated chromium-molybdenum-vanadium steel for high-pressure, high-temperature service.
ASTM A320, Grade L7 - This grade is intended for low-temperature service down to minus 150ºF and has a minimum Charpy impact value of 15 ft-lb at this temperature. Sizes 2-1/2 in. and under.
ASTM A320, Grade L43 - The same properties offered by Grade L7 in sizes up to 2-1/2 are obtainable up to 4 in. in Grade L43. |
