Standards by Component

Bolt & Nut

Stud bolts, nuts, and fastener material and dimension standards.

Primary Standards
ASTM A193ASTM A194ASTM A320

ASTM A193

ASTM

Alloy-Steel and Stainless Steel Bolting for High-Temperature/High-Pressure Service

Bolting materials such as B7 (alloy) and B8/B8M (stainless) for high-temperature or high-pressure flanged joints and pressure equipment.

BoltingGrade B7Grade B8/B8MMechanical Properties

ASTM A194

ASTM

Carbon and Alloy Steel Nuts for High-Pressure/High-Temperature Service

Nuts such as Grade 2H (carbon/alloy), 4/7 (alloy), and 8/8M (stainless) matched to A193/A320 bolting.

BoltingGrade 2HGrade 8/8MGrade 4/7

ASTM A320

ASTM

Alloy/Stainless Steel Bolting for Low-Temperature Service

Bolting (e.g. L7, L43, B8 Class 2) with mandatory impact toughness for low-temperature and cryogenic flanged joints.

BoltingGrade L7Impact TestedLow-Temperature

ASTM A307

ASTM

Carbon Steel Bolts and Studs

Carbon steel bolts, studs, and threaded rod (Grades A, B, C) of 60 ksi tensile for general and structural use.

BoltingGrades A/B/CGeneral Purpose60 ksi

ASME B18.2.1

ASME

Square, Hex, Heavy Hex Bolts and Screws (Inch Series)

Dimensions and tolerances for inch-series square, hex, heavy hex bolts and screws, including lag and flange screws.

BoltingHex BoltHeavy HexDimension

ASME B18.2.2

ASME

Nuts for General Applications (Inch Series)

Dimensions and tolerances for inch-series hex, heavy hex, square, flange, and coupling nuts.

BoltingHex NutHeavy Hex NutDimension

ISO 898

ISO

Mechanical Properties of Fasteners

Property classes (e.g. 8.8, 10.9, 12.9) and mechanical properties of carbon and alloy steel fasteners in the metric system.

BoltingProperty Class 8.8/10.9Mechanical PropertiesMetric

ISO 4032

ISO

Hexagon Regular Nuts (Metric)

Dimensions for metric hexagon regular (style 1) nuts, product grades A and B.

BoltingMetric Hex NutStyle 1Dimension

ISO 4014

ISO

Hexagon Head Bolts (Metric)

Dimensions for metric hexagon head bolts (partially threaded), product grades A and B.

BoltingMetric Hex BoltPartially ThreadedDimension

ISO 4017

ISO

Hexagon Head Screws (Metric, Fully Threaded)

Dimensions for fully threaded metric hexagon head screws (set screws / tap bolts), product grades A and B.

BoltingMetric Hex ScrewFully ThreadedDimension

ASME PCC-1

ASME

Pressure Boundary Bolted Flange Joint Assembly

Guidance for assembling, tightening, qualifying personnel, and troubleshooting pressure-boundary bolted flange joints.

BoltingJoint assembly procedureBolt load and tighteningAssembler qualification
Disclaimer: Disclaimer: This page provides a simplified engineering reference only. It is not a replacement for the official standard. For design, inspection, procurement, and construction, always refer to the latest official standard and the applicable project specification.