Specifications
Surface Treatments
Certifications
- ISO 9001 - 2015 Certified
- PED 2014/68/EC
- NACE MR0175/ISO 15156-2
- NORSOK M-650
- DFAR
- MERKBLATT AD 2000 W2/W7/W10
ASTM A193/A193M Grade B5 Stud Bolts – UNS S50100
5% chromium martensitic stainless steel stud bolts for high-temperature, high-pressure bolting in refinery hydrogen and hot corrosion service environments.
ASTM A193/A193M Grade B5 Stud Bolts are manufactured from UNS S50100, a 5% chromium martensitic stainless steel alloy that provides a combination of elevated-temperature strength, hardness, and moderate corrosion resistance superior to carbon steel grades but without the austenitic microstructure of the B8 series. The martensitic structure, achieved through appropriate heat treatment, enables Grade B5 to deliver significantly higher hardness and tensile strength compared to austenitic stainless grades of similar size, while the 5% chromium content provides meaningful resistance to oxidation, sulfidation, and corrosion in hot process streams containing hydrogen, hydrogen sulfide, and other refinery gases at elevated temperatures. ASTM A193 specifies a maximum hardness limit for Grade B5 to provide assurance against hydrogen-induced stress corrosion cracking in hydrogen service environments, which is a critical safety consideration for refinery applications. These stud bolts are widely used in flange bolting on hot oil service, catalytic reformer reactors, hydrocracker units, and crude distillation columns across the petroleum refining and petrochemical processing industries.
ASTM A193/A193M Grade B5 Chemical Composition - Ferritic Steels
| Grade | Description and
UNS Designation |
C | Mn | P | S | Si | Cr | Mo |
|---|---|---|---|---|---|---|---|---|
| ASTM A193 Grade B5 | 5% Cr | 0.10 min | 1.00 | 0.040 | 0.030 | 1.00 | 4.0-6.0 | 0.40-0.65 |
| Product Analysis VariationB | 0.01 | 0.03 | 0.005 | 0.005 | 0.05 | 0.10 | 0.05 |
ASTM A193/A193M Grade B5 Mechanical Requirements - Ferritic Steels (Inch)
| Grade | Diameter, in. | Minimum Tempering Temperature, °F |
Tensile Strength, min, ksi | Yield Strength, min, 0.2 % offset, ksi |
Elongation in 4D, min, % | Reduction of Area, min, %Reduction of Area, min, % | Hardness, max |
|---|---|---|---|---|---|---|---|
| ASTM A193 Grade B5 | up to 4, incl | 1100 | 100 | 80 | 16 | 50 | . . . |
ASTM A193/A193M Grade B5 Mechanical Requirements - Ferritic Steels (Metric)
| Class | Diameter,
[mm] |
Min.Tempering
Temp. °C |
Tensile Strength,
min, MPa |
Yield Strength,min,
.2% offset, MPa |
Elongation in 4D,
min, % |
Reduction of Area, min, % | Hardness,
max |
|---|---|---|---|---|---|---|---|
| ASTM A193 Grade B5 | up to M100, incl | 593 | 690 | 550 | 16 | 50 | . . . |
ASTM A193/A193M Grade B5 Bolting Components Marking - Ferritic Steels
| Grade | Grade Symbol |
|---|---|
| ASTM A193 Grade B5 | TB B5 |
Related ASTM A193 Grades & ASME Companion Dimensions
Frequently Asked Questions
- What is ASTM A193 Grade B5?
- ASTM A193 Grade B5 is a bolting material covering 5% Cr-Mo (UNS S50100). Used in high-temperature, high-pressure flange, pressure-vessel and heat-exchanger bolting service per ASTM A193/A193M.
- What is the UNS designation for ASTM A193 Grade B5?
- The UNS designation for ASTM A193 Grade B5 is UNS S50100. This corresponds to 5% Cr-Mo. The UNS code is universal across ASTM, ASME (SA-193), PED 2014/68/EU and NORSOK material specifications.
- What is the service temperature range for Grade B5?
- B5 (5% Cr-Mo) is used for elevated-temperature service typically up to 550 °C (1022 °F), with creep-rupture data available to ASME B&PV Section II-D limits.
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