ASTM A193 Grade B7M Specifications
ASTM A 193 GR.B7M
Full thread Studs, Bolts.
Grade B7M is a heat-treated chromium- molybdenum alloy steel with minimum tensile requirement of asper Table below.
ASTM A193 specification covers requirements for chemical composition, mechanical properties, hardness, heat-treatment, recommended ASTM A194Gr. 2HM nuts.
Chemical Requirements @AISI 4110
|
Elements |
Range |
Product Variation, Over or Under |
Carbon |
0.37 – 0.49 |
0.02 |
Manganese |
0.65 – 1.10 |
0.04 |
Phosphorus, max |
0.035 |
0.005over |
Sulphur, max |
0.040 |
0.005over |
Silicon |
0.15-0.35 |
0.02 |
Chromium |
0.75-1.20 |
0.05 |
Molybdenum |
0.15-0.25 |
0.02 |
Mechanical Requirements- @Inch Sizes [Metric Sizes]
Diameter, Metric |
MinimumTempering Temperature,Fe/ºC |
Tensile Strength, Min, ksi [MPa] |
Yield Strength, Min, 0.2%offset, ksi [MPa] |
Elongation In 4D,Min, % |
Reduction of Area, Min, % |
4″ / M100 and under |
1150 [620] |
100 [690] |
80 [550] |
18 |
50 |
Over 4″ to 7″M100 -M175 |
1150 [620] |
100 [690] |
75 [515] |
18 |
50 |
Hardness – Max. |
||
4″/M100 and under |
235 HB |
99 HRB |
Over 4″-7″M100 to M175 |
235HB |
99 HRB |
Process Carried Out |
|
Stage I |
Hardening at 880ºC For 2 Hours in Electric Furnace. |
Stage II |
Quench in Hot oil 60 to 95ºC. |
Stage III |
As Quenched Hardness 52/54 HRC. |
Stage IV |
Tempering Temp.at 620ºC for 3Hrs. |
Stage V |
Cool in Air |