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ASTM A193 Grade B7

This standard material specification of ASTM A193 grade B7 covers fasteners of chromium-molybdenum alloy steel. These fasteners found their use in chemical and petroleum construction applications. They are made after tempering (heat treatment) and quenching to acquire the ideal mechanical properties and hardness. B7 is one of the most grade used in ASTM A193 and is mainly implemented in zinc plating, zinc coating, hot-dip galvanizing, PTFE coating or coated, and xylan coating to prevent corrosion. They are chiefly used in high-pressure and temperature services like valves, flanges, pressure valves, and fittings.

A193 Grade B7

B7 Alloy steel, AISI 4140/4142 quenched and tempered

Mechanical properties

Size Tensile ksi, min Yield ksi, min Elong %, min RA % min HBW Rockwell
Up to 2-1/2 125 105 16 50 321 Max 35 HRC max
2-5/8 - 4 115 95 16 50
4-1/8 - 7 100 75 18 50

Chemical properties

Element B7 (AISI 4140)
Carbon 0.37 - 0.49%
Manganese 0.65 - 1.00%
Phosphorus, max 0.035%
Sulfur, max 0.040%
Silicon 0.15 - 0.35%
Chromium 0.80 - 1.10%
Nickel -
Molybdenum 0.15 - 0.25%

Compatible hardware

Bolt Grade Nut Washers
B7 A194 Grade 2H F436