• View PDF
    Standard
  •   +91-22-66157017
  •   info@torqbolt.com
    • Home
    2. ASTM A193/A193M Grade B8LN Class 1

    ASTM A193/A193M Grade B8LN Class 1 Stud Bolts – UNS S30453

    Low carbon, nitrogen-alloyed 304LN stainless steel stud bolts combining weld sensitization resistance with enhanced yield strength.

    ASTM A193/A193M Grade B8LN Class 1 Stud Bolts are produced from UNS S30453, which is the nitrogen-enhanced version of the low-carbon 304L austenitic stainless steel. The dual benefits of reduced carbon content and controlled nitrogen addition make this grade particularly valuable — the low carbon minimizes the risk of sensitization during welding or high-temperature exposure, while the nitrogen compensates for the strength reduction typically associated with low-carbon variants by providing solid solution strengthening. Supplied in the solution annealed Class 1 condition under ASTM A193, these stud bolts offer tensile and yield strength levels that are superior to standard 304L while retaining excellent ductility, toughness at low temperatures, and corrosion resistance in a broad range of media. These fasteners are widely used in cryogenic pressure vessels, chemical process piping, food processing equipment, and other applications where both weld integrity and mechanical performance must be maintained without the need for post-weld heat treatment.

    ASTM A193/A193M Grade B8LN Class 1 Chemical Composition - Austenitic Steels

    Grade Description and UNS Designatio Classes C Mn P S Si Cr Ni N
    ASTM A193 Grade B8LN S30453 1, 1A, 1D 0.030 2.00 0.045 0.030 1.00 18.0-20.0 8.0-11.0 0.10-0.16
    Product Analysis VariationB 0.005 0.04 0.010 0.005 0.05 0.20 0.15 0.01
    • (A) Values are maximums unless a range or a minimum is indicated. Where ellipses appear in this table, there is no requirement and the element need not be determined or reported. The intentional addition of Bi, Se, Te, and Pb is not permitted.
    • (B) Product Analysis-Individual determinations sometimes vary from the specified limits as shown in the tables. The several determinations of any individual element in a heat may not vary both above and below the specified range. Product variation limits are over for maximums, over or under for ranges, and under for minimums, unless otherwise indicated.
    • (C) Typical steel compositions used for this grade include 4140, 4142, 4145, 4140H, 4142H, and 4145H.
    • (D) For bar sizes over 31/2 in. [90 mm], inclusive, the carbon content may be 0.50% max. For the B7M grade, a minimum carbon of 0.28% is permitted, provided that the required tensile properties are met in the section sizes involved, the use of AISI 4130 or 4130H is allowed.
    • (E) Total of soluble and insoluble.
    • (F) Columbium and Niobium are alternate names for element 41 in the Periodic Table of the Elements.

    ASTM A193/A193M Grade B8LN Class 1 Mechanical Requirements - Austenitic Steels (Inch)

    Grade Diameter,
    in.     		Heat TreatmentB Tensile Strength,
    min, ksi     		Yield Strength, min,
    0.2 % offset, ks     		Elongation in 4 D,min Reduction of Area, min Hardness,
    max
    ASTM A193 Grade B8LN Class 1 All diameters carbide solution treated 75 30 30 50 223 HBW or 96 HRBC
    • (A) To meet the tensile requirements, the Brinell hardness shall be over 200 HBW (93 HRB).
    • (B) Class 1 is solution treated. Class 1A is solution treated in the finished condition for corrosion resistance; heat treatment is critical due to physical property requirement. Class 2 is solution treated and strain hardened. Austenitic steels in the strain-hardened condition may not show uniform properties throughout the section particularly in sizes over 3/4 in. in diameter.
    • (C) For sizes3/4 in. in diameter and smaller, a maximum hardness of 241 HBW (100 HRB) is permitted.
    • (D) For diameters 11/2 and over, center (core) properties may be lower than indicated by test reports which are based on values determined at1/2 radius.

    ASTM A193/A193M Grade B8LN Class 1 Mechanical Requirements - Austenitic Steels (Metric)

    Grade Class ,
    mm     		Diameter Heat TreatmentB Tensile Strength,
    min,MPa     		Yield Strength, min,
    0.2 % offset, MPa     		Elongation in 4 D,min % Reduction of Area, min % Hardness,
    max
    ASTM A193 Grade B8LN Class 1 All diameters carbide solution treated 515 205 30 50 223 HBW or 96 HRBC
    • (A) To meet the tensile requirements, the Brinell hardness shall be over 200 HBW (93 HRB).
    • (B) Class 1 is solution treated. Class 1A is solution treated in the finished condition for corrosion resistance; heat treatment is critical due to physical property requirement. Class 2 is solution treated and strain hardened. Austenitic steels in the strain-hardened condition may not show uniform properties throughout the section particularly in sizes over M20 mm in diameter.
    • (C) For sizes M20 mm in diameter and smaller, a maximum hardness of 241 HBW (100 HRB) is permitted.
    • (D) For diameters M38 and over, center (core) properties may be lower than indicated by test reports which are based on values determined at1/2 radius.

    ASTM A193/A193M Grade B8LN Class 1 Bolting Components Marking - Austenitic Steels

    Grade Class Grade Symbol
    ASTM A193 Grade B8LN Class 1 TB B8F or TB B8LN

    Related ASTM A193 Grades & ASME Companion Dimensions

    Frequently Asked Questions

    What is ASTM A193 Grade B8LN Class 1?
    ASTM A193 Grade B8LN Class 1 is a bolting material covering 304LN low-carbon nitrogen-enhanced (UNS S30453). Class 1 — solution treated. 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 B8LN Class 1?
    The UNS designation for ASTM A193 Grade B8LN Class 1 is UNS S30453. This corresponds to 304LN low-carbon nitrogen-enhanced. The UNS code is universal across ASTM, ASME (SA-193), PED 2014/68/EU and NORSOK material specifications. The 'Class 1' designator denotes the heat treatment condition under ASTM A193 Table 3.
    Why specify the 'LN' suffix on Grade B8LN (Class 1)?
    The 'LN' suffix denotes Low-carbon (C ≤ 0.030%) with Nitrogen enhancement. The low carbon resists sensitization in welded service; the nitrogen restores the strength lost by reducing carbon, yielding the same 75 ksi UTS minimum as standard 304 austenitic bolting. Specific to ASTM A193 Grade B8LN Class 1: Class 1 — solution treated.
    Specifications
    Surface Treatments
    Certifications
    About Us
    Questions? Contact us.
    Showcase of our Microsites.
    Satisfaction Survey

    survey

    TUVRheinland CRETIFIED

    © TorqBolt P(Ltd) · Built with in INDIA.