ASTM A193 B8M Bolts with A194 B8M Nuts

Reliability in the Most Severe Environments
Long Service Life and Low Maintenance Costs
Stable Performance in Weld‑Affected Zones

ASTM A193 B8M Bolts with ASTM A194 B8M Nuts Supplier

SSM provides ASTM A193 B8M bolts paired with ASTM A194 B8M heavy hex nuts, manufactured from austenitic stainless steel Type 316 (UNS S31600) for superior corrosion resistance. These fastening sets are specifically designed for service in chloride-containing, marine, chemical, and aggressive environments, offering reliable mechanical strength, excellent resistance to pitting and crevice corrosion, and secure flange connections in demanding industrial applications.

Bolt Diameter: 1/2″ to 4″
Bolt Length: 50 mm to 1000 mm (custom cutting per drawing)
Thread Type: Full thread or double-end thread; UNC or UNF as required
Nut Type: ASTM A194 B8M heavy hex nuts; one or two nuts per bolt
Surface Finish: Plain (natural stainless), passivated, PTFE / Xylan / Teflon coating

ASTM A193 B8M Class Options

B8M Class 1

Solution annealed condition
Standard strength level
Excellent corrosion resistance
Suitable for general 316 stainless steel bolting applications

B8M Class 2

Solution annealed and cold worked
Higher tensile and yield strength than Class 1
Recommended where higher preload and increased load-carrying capacity are required
Maintains superior corrosion resistance in aggressive environments

ASTM A193 B8M / ASTM A194 B8M Fasteners Technical Data

Material Overview

Bolt Material: ASTM A193 Grade B8M
Nut Material: ASTM A194 Grade B8M
Base Material: Austenitic stainless steel Type 316
UNS Designation: S31600
Magnetic Properties: Non-magnetic in solution-annealed condition (may show slight magnetism after cold working)

Class Designation (ASTM A193 B8M Bolts)

Class	Condition	Characteristics	Typical Use
Class 1	Solution annealed	Standard strength, maximum corrosion resistance	General 316 SS bolting
Class 2	Solution annealed + cold worked	Higher tensile & yield strength	Higher preload / higher stress joints

Chemical Composition (Typical, % max unless noted)

Element	Carbon (C)	Manganese (Mn)	Phosphorus (P)	Sulfur (S)	Silicon (Si)	Chromium (Cr)	Nickel (Ni)	Molybdenum (Mo)	Iron (Fe)
B8M (316 SS)	≤ 0.08	≤ 2.00	≤ 0.045	≤ 0.030	≤ 1.00	16.0 – 18.0	10.0 – 14.0	2.0 – 3.0	Balance

Mechanical Properties – Bolts (ASTM A193 B8M)

Property	Class 1	Class 2
Tensile Strength	min. 515 MPa (75 ksi)	min. 690 MPa (100 ksi)
Yield Strength (0.2%)	min. 205 MPa (30 ksi)	min. 450 MPa (65 ksi)
Elongation	≥ 30%	≥ 20%
Reduction of Area	≥ 50%	≥ 35%

Mechanical Properties – Nuts (ASTM A194 B8M)

Property	Requirement
Proof Load Stress	≥ 380 MPa (55 ksi)
Hardness	≤ 223 HB
Heat Treatment	Solution annealed

Nuts are suitable for mating with both B8M Class 1 and Class 2 bolts.

ASTM A193 B8M / ASTM A194 B8M Fasteners Applications

ASTM A193 B8M bolts used with ASTM A194 B8M heavy hex nuts are widely applied in chloride-rich, corrosive, and marine environments where superior corrosion resistance and reliable mechanical performance are required. Manufactured from Type 316 stainless steel, these fasteners provide excellent resistance to pitting, crevice corrosion, and chemical attack.

B8M Class 1: Suitable for general 316 stainless steel bolting with standard strength requirements.
B8M Class 2: Recommended where higher preload and improved load-carrying capacity are required.
Compatible with ASME B16.5 / ASME B16.47 flanges and pressure-containing joints.

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SSM has significant product advantages in manufacturing ASTM A193 B8M / ASTM A194 B8M Fasteners. Whether it’s quality or price, we will meet your needs.

ASTM A193 B8M / ASTM A194 B8M Fasteners Standards and Specifications

Category	Standard / Specification	Description
Bolt Material Standard	ASTM A193 Grade B8M (Class 1 / Class 2)	Austenitic stainless steel Type 316 stud bolts / hex bolts
Nut Material Standard	ASTM A194 Grade B8M	Austenitic stainless steel Type 316 heavy hex nuts
Washer Standard (Optional)	ASTM F436 (Type 316 SS or special SS as agreed)	Flat washers when specified (carbon steel F436 not recommended for SS assemblies)
Thread Standard	ASME B1.1	UNC / UNF thread form
Stud Bolt Dimensions	ASME B18.31.2	Dimensional requirements for stud bolts
Hex Bolt Dimensions (if applicable)	ASME B18.2.1	Dimensional requirements for hex head bolts
Heavy Hex Nut Dimensions	ASME B18.2.2	Dimensional requirements for heavy hex nuts
Mechanical Properties	ASTM A193 / ASTM A194	Tensile, yield, hardness, and proof load requirements
Flange Compatibility	ASME B16.5 / ASME B16.47	Pressure flange bolting requirements
Surface Treatment	ASTM A967 / ASTM A380	Passivation / chemical cleaning of stainless steel
PTFE / Xylan Coating	Per customer specification	Anti-galling, anti-corrosion, low-friction coating
Inspection & Testing	ASTM A193 / ASTM A194	Mechanical testing, marking, heat number traceability
Service Temperature	≤ 425 °C (800 °F)	Suitable for elevated-temperature stainless steel service

ASTM A193 B8M stud bolts combined with ASTM A194 B8M heavy hex nuts are corrosion-resistant austenitic stainless steel fasteners designed for service in chloride-bearing, corrosive, and elevated-temperature environments. Manufactured from Type 316 stainless steel, these fasteners provide reliable tensile strength, stable proof load performance, and secure flange connections in industrial systems where superior corrosion resistance is required.

These bolting sets are produced in accordance with ASTM material standards, with UNC/UNF threads per ASME B1.1 and dimensional compliance to the ASME B18 series. Surface conditions typically include plain (natural stainless), passivated finish, or PTFE / Xylan coatings to reduce galling and improve installation performance.

Applications include ASME B16.5 / ASME B16.47 flanges, pressure vessels, piping systems, valves, pumps, chemical and petrochemical plants, offshore and marine facilities, food and pharmaceutical equipment, power generation auxiliaries, and general industrial installations. Recommended service temperature is up to approximately 425 °C (800 °F), making ASTM A193 B8M / A194 B8M fasteners a dependable choice for corrosion-resistant, pressure-containing joints.

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