ASTM A193 Grade B7 Stud Bolts Manufacturer in India | API 20E

NUBOTECK manufactures ASTM A193 Grade B7 Stud Bolts for critical bolted joints used in refineries, petrochemical plants, offshore platforms, LNG facilities, pressure vessels, valves, heat exchangers and piping systems.

Grade B7 is the most widely specified chromium-molybdenum alloy steel bolting material for high pressure and elevated temperature service.

What is ASTM A193 Grade B7?

ASTM A193 Grade B7 is a heat-treated chromium-molybdenum alloy steel bolting material intended for high temperature and high pressure service. It is extensively used for pressure vessels, flanges, valves, piping systems and other critical equipment operating in demanding industrial environments. Grade B7 stud bolts provide excellent strength, toughness and reliability, making them the preferred choice throughout the oil & gas industry.

Melting Practice

Melting Practice	ASTM Requirement	API-20E BSL-2	API-20E BSL-3
Basic-oxygen	Allowed	Not Allowed	Not Allowed
Electric-furnace	Allowed	Allowed	Allowed
Vacuum Induction Melting (VIM)	Allowed	Allowed	Allowed
Ingot casting	Allowed	Top pouring not permitted unless the VIM is used
Continuous casting	Allowed	Allowed	Not Allowed
Reduction Ratio	minimum of 4.0:1	minimum of 4.0:1	minimum of 10.0:1

Chemical Composition

Element	ASTM Requirement	API-20E BSL-2	API-20E BSL-3
Carbon	0.38 – 0.48
Sulfur	0.040 Max	0.025 Max	0.015 Max
Phosphorus	0.035 Max	0.025 Max	0.015 Max
Manganese	0.75 – 1.00
Silicon	0.15 – 0.35
Chromium	0.80 – 1.10
Molybdenum	0.15 – 0.25
Vanadium			0.05 Max
Niobium			0.05 Max
Boron (residual)		0.0005 Max	0.0005 Max

Mechanical Properties

Property	ASTM Requirement	API-20E Requirement
Tensile Strength	125 ksi (860 MPa)
Yield Strength (0.2% offset)	Min 105 ksi (725 MPa)	Max 135 ksi (920 MPa)
Elongation (4D minimum)	16%
Reduction of Area	50%
Hardness	35 HRC Max	34 HRC Max

Property

ASTM Requirement

API-20E Requirement

Tensile Strength

125 ksi (860 MPa)

Yield Strength (0.2% offset)

Min 105 ksi (725 MPa)

Max 135 ksi (920 MPa)

Elongation (4D minimum)

16%

Reduction of Area

50%

Hardness

35 HRC Max

34 HRC Max

Available Sizes

Diameter Range

1/2" to 2-1/2"

M12 to M64

Product Forms

Fully Threaded Stud Bolts
Tap End Studs
Double End Studs
Custom Length Studs
Special Machined Studs

Heat Treatment

ASTM A193 Grade B7 stud bolts are manufactured from chromium-molybdenum alloy steel and are quenched and tempered to achieve the required mechanical properties. Proper heat treatment ensures optimum strength, toughness and reliability for high-pressure service conditions.

Typical manufacturing sequence:

Raw Material Verification
Machining
Thread Rolling / Thread Cutting
Austenitizing
Quenching
Tempering
Inspection & Testing

Oil & Gas Applications

Wellhead Equipment
Christmas Trees
Production Equipment

Pressure Vessels
Heat Exchangers
Reactors

Refineries
Petrochemical Plants
Pipeline Systems

API 20E introduces enhanced requirements for manufacturing process control, qualification testing, traceability, metallurgical examination and documentation.

Nuts Complementing B7 Stud Bolts

Stud Bolt	API-20E BSL-1 Nut	API-20E BSL-2 Nut	API-20E BSL-3 Nut
ASTM A193 Grade B7	ASTM A194 Grade 2H, 7	ASTM A194 Grade 7	ASTM A194 Grade 7

Stud Bolt

API-20E BSL-1 Nut

API-20E BSL-2 Nut

API-20E BSL-3 Nut

ASTM A193 Grade B7

ASTM A194 Grade 2H, 7

ASTM A194 Grade 7

ASTM A193 Grade B7 Stud Bolts

High Temperature & High Pressure Alloy Steel Stud Bolts for Oil & Gas Applications