ASTM A193 B7 Stud Bolt ASTM A194 Grade 2H Hex Nuts Specification

ASTM A193 B7 Stud Bolt & ASTM A194 Grade 2H Hex Nuts Specification

ASTM A193 Grade B7 stud bolts used together with ASTM A194 Grade 2H heavy hex nuts are high-strength alloy steel fasteners designed for high-temperature and high-pressure applications. This bolting combination is one of the most widely specified solutions for flanged joints, pressure vessels, valves, and piping systems in oil & gas, petrochemical, refinery, and power generation industries.

Manufactured in accordance with ASTM A193 / ASME SA193 and ASTM A194 / ASME SA194, B7 stud bolts with 2H nuts provide excellent mechanical strength, thermal stability, and long-term reliability under severe service conditions.

What Is ASTM A193 B7 & A194 2H?

  • ASTM A193 B7 is a chromium-molybdenum alloy steel grade, quenched and tempered to achieve high tensile and yield strength for elevated temperature service.

  • ASTM A194 Grade 2H is a heat-treated alloy steel heavy hex nut specifically designed to match the strength and hardness requirements of B7 stud bolts.

This combination ensures secure bolting performance, controlled hardness, and resistance to loosening in high-pressure environments.

Applicable Standards

  • ASTM A193 / ASME SA193 – Alloy steel bolting for high temperature or high pressure service

  • ASTM A194 / ASME SA194 – Carbon and alloy steel nuts

  • ASTM A962/A962M – Common requirements for bolting

  • ASME B1.1 – Unified inch screw threads

  • ASME B18.31.2 – Continuous thread studs

  • ASME B18.2.2 – Heavy hex nuts

  • ASME B16.5 – Stud bolt length reference for flanges

Size Range & Dimensional Standards

ASTM A193 B7 Stud Bolts

  • Diameter: 1/4″ – 4″

  • Length: As per ASME B16.5 or customer drawing

  • Thread Type: UNC / UNF / Metric (on request)

  • Thread Form: Rolled or cut threads

ASTM A194 Grade 2H Hex Nuts

  • Size: 1/4″ – 4″

  • Type: Heavy Hex Nut

  • Thread Fit: 2H

Chemical Composition ASTM A193 Grade B7

Element Composition (%)
Carbon (C) 0.37 – 0.49
Manganese (Mn) 0.65 – 1.10
Phosphorus (P) ≤ 0.035
Sulfur (S) ≤ 0.040
Silicon (Si) 0.15 – 0.35
Chromium (Cr) 0.75 – 1.20
Molybdenum (Mo) 0.15 – 0.25
Iron (Fe) Balance

ASTM A194 Grade 2H

Element Composition (%)
Carbon (C) ≤ 0.40
Manganese (Mn) 0.60 – 1.00
Phosphorus (P) ≤ 0.035
Sulfur (S) ≤ 0.040
Silicon (Si) 0.15 – 0.35
Chromium (Cr) 0.40 – 1.00
Molybdenum (Mo) 0.15 – 0.30
Iron (Fe) Balance

Mechanical Properties ASTM A193 Grade B7 Stud Bolts

Property Requirement
Tensile Strength ≥ 125 ksi (860 MPa)
Yield Strength ≥ 105 ksi (725 MPa)
Elongation ≥ 16%
Reduction of Area ≥ 50%
Maximum Hardness 35 HRC

ASTM A194 Grade 2H Hex Nuts

Property Requirement
Proof Load Stress ≥ 175 ksi (1205 MPa)
Hardness 24 – 35 HRC

Heat Treatment & Hardness Control

  • B7 Stud Bolts: Quenched and tempered

  • 2H Hex Nuts: Quenched and tempered

  • Hardness strictly controlled to meet ASTM requirements and prevent hydrogen-related failures

Surface Finish Options

ASTM A193 B7 stud bolts and A194 2H hex nuts are available with the following surface treatments:

  • Plain (Self Color)

  • Black Oxide

  • Zinc Plated

  • Hot-Dip Galvanized (HDG)

  • PTFE / Xylan / Fluoropolymer Coated

  • Phosphate Coated

Inspection & Certification

Mandatory Inspection

  • Chemical composition analysis

  • Tensile and yield strength testing

  • Elongation and reduction of area

  • Hardness testing

  • Dimensional inspection

Optional Testing

  • PMI (Positive Material Identification)

  • Ultrasonic Testing (UT)

  • Magnetic Particle Testing (MT)

Certification

  • EN 10204 3.1 Mill Test Certificate

  • Full heat number traceability

Typical Applications

  • Oil & gas pipelines

  • Refineries and petrochemical plants

  • Pressure vessels and heat exchangers

  • Valves and flanged joints

  • Power generation equipment

Download ASTM A193 B7 & ASTM A194 2H Specification PDF

Download 📄 File: ASTM_A193_B7_STUD_BOLT_A194_2H_HEX_NUTS_SPECIFICATION

Our Stud Bolt Products

ASTM A193 B7 Stud Bolt

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ASTM A194 2H Hex Nuts
ASTM A193 B7 A194 2H Specification
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