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ISO 9001:2015 · ASTM A193 B7/B16 · A320 L7 · A182 F11/F22

High Strength Alloy Steel Fasteners Manufacturer, Supplier & Exporter

Our alloy steel fasteners are manufactured per ASTM A193 specifications for high-temperature and high-pressure applications. We supply B7, B16, B8, B8M, 4340 and EN24 grade fasteners to oil & gas, power, and petrochemical industries.
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View Products

6

Grades

36

Products

-101°C

Min Temp

600°C

Max Temp

1000 MPa

Min tensile strength · B16 CrMoV per ASTM A193

Moderate

Use with coating or galvanizing · Cr-Mo alloy

7.85 g/cm³

Density · Cr-Mo alloy steel

The high-strength Cr-Mo alloy steel explained

What is Alloy Steel Fasteners?

Alloy steel fasteners are chromium-molybdenum (Cr-Mo) steel products to ASTM A193, A320 and A182 specifications, engineered for high-strength pressure vessel, steam turbine and refinery bolting service from cryogenic temperatures to 600°C. The Cr-Mo addition raises hardenability, provides solid-solution strengthening and improves oxidation and hydrogen embrittlement resistance compared to plain carbon steel. Alloy steel stud bolts and heavy hex nuts are the backbone of industrial pressure flange bolting across oil & gas, petrochemical and power generation industries. Grade B7 (ASTM A193, 4140 Cr-Mo alloy) is the most widely used pressure vessel fastener material, with 862 MPa tensile strength and high-temperature service to 427°C. B16 (CrMoV) and F22 (2.25Cr-1Mo) extend the service range to 538°C and 600°C respectively.
PropertySpecification
Base ElementIron (Fe)
Alloy SystemChromium-Molybdenum
GradesB7, B16, L7, F11, F22
Max Service Temperature600°C (F22)
Density7.85 g/cm³
ASTM StandardsA193, A320, A182

Alloy Steel grades — which do you need?

Multiple fastener grades and material grades are offered for Alloy Steel Fasteners, giving designers options in tensile strength, toughness, corrosion resistance, and temperature capability. Each variant suits specific industrial fasteners, engineering applications, and material selection priorities; compare the available grades below to match your operating conditions and industry standards.

Grade UNS Cr-Mo Key Property Max Temp Best Application
Alloy Steel 4340 UNS G43400 Ni-Cr-Mo Ultra-high strength 315°C Aerospace, heavy-duty shafts View grade
Alloy Steel B7 UNS G41400 1Cr-0.2Mo High strength, general 427°C Pressure vessels, flanges View grade
Alloy Steel B16 UNS G41150 1Cr-0.55Mo-V High-temp creep resistant 538°C Steam turbines, HRSG View grade
Alloy Steel B8 UNS S30400 — Corrosion resistant 870°C Chemical processing, food equipment View grade
Alloy Steel B8M UNS S31600 — Superior chloride resistance 925°C Marine, offshore, chemical plants View grade
Alloy Steel EN24 UNS G43400 Ni-Cr-Mo High fatigue strength 315°C Automotive, gears, shafts View grade
AISI 4340
ASTM A193 Grade B16
ASTM A193 Grade B7
ASTM A193 Grade B8
ASTM A193 Grade B8M
EN 24 (4340 Equiv.)

Alloy Steel Fasteners — International Standards & Material Certifications

Alloy Steel Fasteners from RealBolt Engineering Industries are manufactured to ASME SA-193 B7/B16, SA-194 2H/2HM, SA-320 L7/L7M, and SA-182 F11/F22 material standards. Every batch ships with EN 10204 MTC 3.1; L7 cryogenic grades include Charpy impact test certificates at −101°C, and hardness survey reports are available on request.
Standards
DIN 931 DIN 933 DIN 960 DIN 961 DIN 938 DIN 939 DIN 976-1 DIN 934 DIN 125A DIN 127 ISO 4014 ISO 4017 ISO 4032 ASME B18.2.1 ASME B18.31.2 ASME B18.2.2 IS 1364 IS 1367 SAE J429 SAE J995
Certifications
ISO 9001:2015 ASTM A193 Certified NABL Lab PED 2014/68/EU MTC 3.1 / 3.2

Alloy Steel Fasteners Applications — Industries & Use Cases

Alloy Steel Fasteners from RealBolt Engineering Industries are specified by engineers and procurement teams across demanding industries where high-temperature creep strength, high proof load, and hydrogen embrittlement resistance for pressure vessel and steam turbine bolting is critical to fastener performance and service life. Primary end-use sectors for Alloy Steel Fasteners include oil and gas pressure vessels, power generation steam turbines, petrochemical refinery units, and cryogenic LNG service — click each industry below to see specific application details and recommended grades.
ASTM A193 B7 stud bolts and A194 2H heavy hex nuts are the most widely used alloy steel fastener combination for process flanges, pressure vessels, heat exchangers and compressors in oil & gas facilities per ASME B31.3.
ASTM A193 B16 (CrMoV) stud bolts are specified for high-temperature steam turbine casings, main steam valve covers and HP/IP turbine flange bolting to 538°C. ASTM A182 F22 is used for hot reheat piping flanges.
ASTM A182 F22 (2.25Cr-1Mo) is the standard for hydrocracker reactor flanges, catalytic reformer piping and HRSG pressure parts where hydrogen embrittlement resistance and elevated temperature creep strength are required.
ASTM A320 L7 alloy steel stud bolts are tested to -101°C for LNG heat exchangers, ethylene cold boxes and cryogenic storage sphere bolting where standard B7 material would be brittle.
F11 (1.25Cr-0.5Mo) and F22 flanges and stud bolts are used in catalytic cracking units, atmospheric and vacuum distillation towers and crude oil heater header bolting.

Alloy Steel vs Carbon Steel vs Stainless Steel

This comparison table guides engineers and project specifiers in selecting between Alloy Steel, Carbon Steel, and Stainless Steel Fasteners based on maximum service temperature, minimum tensile strength, high-temperature creep resistance, corrosion protection requirement, applicable ASTM design code, and relative material cost for pressure vessel, flange, and structural bolting applications. Use this data to make an informed alloy selection for your specific operating environment, design code, and budget — or contact RealBolt’s technical team for a project-specific recommendation.
Property Alloy Steel B7 Carbon Steel 8.8 SS A193 B8M
Max service temp 427°C 200°C 800°C
Tensile strength (min) 862 MPa 800 MPa 515 MPa
Corrosion resistance Low (needs coating) Very Low Good
High-temp creep resistance Good Poor Poor
Relative cost Low-Medium Lowest Medium
Primary standard ASTM A193 B7 ISO 898-1 8.8 ASTM A193 B8M

Verdict: Alloy Steel B7 is the standard for pressure vessel and process flange bolting to 427°C. Carbon Steel 8.8 covers structural assembly with applied corrosion protection. SS B8M is chosen when process fluid contact demands corrosion resistance.

Need Alloy Steel fasteners? Get a competitive price today.

Partner with RealBolt Engineering Industries for certified Alloy Steel Fasteners backed by full EN 10204 material test reports, competitive pricing, and reliable global delivery from our Mumbai facility. Our technical and commercial team supports specification across ASTM A193 B7, B16, A320 L7, and A182 F11/F22 Alloy Steel Fasteners — supplying stud bolts and heavy hex nuts in sizes M12–M100 and ½″–4″ with full hardness test certificates, Charpy impact reports for cryogenic L7, and EN 10204 3.1/3.2 material test documentation. Request a quote today and receive a competitive price within 24 hours.
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Alloy Steel Fasteners — Common Questions Answered by Our Technical Team

Browse the expert answers below to the most frequently asked questions about Alloy Steel Fasteners — covering B7 vs B16 selection, ASTM A193 vs A320 standards, L7 cryogenic impact test requirements, hydrogen embrittlement risk with galvanizing, F22 for hydrocracker service, allowable stress tables, and documentation including NABL-accredited hardness and tensile test certificates. If your question is not answered here, contact the RealBolt technical team directly for grade-specific guidance, project support, and competitive pricing on Alloy Steel Fasteners.
The most widely used combination per ASME B31.3 and ASME VIII is ASTM A193 Grade B7 fully threaded stud bolts with ASTM A194 Grade 2H heavy hex nuts. For temperatures above 425°C, ASTM A193 B16 (CrMoV) stud bolts with A194 Grade 4 or Grade 7 nuts are specified.
A193 B7 (AISI 4140/4142 Cr-Mo) has 862 MPa tensile strength and is rated to 427°C. A193 B16 (CrMoV alloy) has 1000 MPa tensile and is rated to 538°C due to vanadium addition that improves creep rupture strength. B16 is specified for steam turbine casings, main stop valves and high-pressure steam lines above 427°C.
ASTM A320 L7 is the low-temperature version of A193 B7. It is tested with a Charpy V-notch impact test at -101°C (-150°F) to verify ductility for cryogenic service. Required for LNG processing equipment, ethylene cold boxes, cryogenic storage sphere bolting and other applications below -45°C.
Caution: Hot-dip galvanizing (HDG) of high-strength alloy steel fasteners above 8.8 grade can cause hydrogen embrittlement. ASTM A193 B7 fasteners (proof load > 1034 MPa) should not be HDG per ASTM F2329. For corrosion protection, specify mechanically galvanized (ASTM B695), thermally sprayed zinc, or electro-zinc with post-bake hydrogen embrittlement relief.

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