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A193 Grade B7 Anchor Bolts

While there is certainly nothing to preclude ASTM A193 B7 from being specified for anchor bolts – and Portland Bolt manufactures them quite often – the specification is not intended for anchor bolt use. ASTM F1554 Grade 105 is a specification specifically developed for anchor bolts and possesses virtually identical chemical and physical properties.

ASTM A193 is a specification that “covers alloy and stainless steel bolting material for pressure vessels, valves, flanges, and fittings for high temperature or high pressure service, or other special purpose applications.” A193 B7 is widely available and mass-produced in both heavy hex bolt and all-thread rod form, so it is a very familiar specification to engineers, contractors, fastener distributors, and bolt manufacturers. This may be one of the reasons it is so often called out for anchor bolt applications.

Another key reasons that A193 B7 is not the most suitable specification for anchor bolts is the requirement, per the A193 compliance with ASTM A962, that A193 fasteners 1″ diameter and larger shall be 8 thread pitch series (8 threads per inch), unless otherwise specified. While the “otherwise specified” language means that A193 anchor bolts can still be made with national coarse threads, the 8 TPI requirement could result in higher manufacturing costs and limited availability and higher costs on larger diameter nuts, particularly galvanized nuts. In fact, there is no standard, published oversizing allowance for 8 TPI galvanized nuts above 1-1/2″ diameter.

ASTM F1554 Grade 105 would be a more appropriate specification than A193 B7 if the application is anchor bolts. As mentioned above, F1554 is an anchor bolt specification. The chemical and mechanical properties are nearly identical. For diameters up to 2-1/2″, the minimum yield (105 ksi) and tensile (125 ksi) are exactly the same (although F1554 Grade 105 does have a maximum of 150 ksi tensile, while A193 has no maximum). Additionally, with F1554, there are no special thread pitch requirements.

24 thoughts on “A193 Grade B7 Anchor Bolts”

  1. Hi,

    i need to know what kind of tests are required for below anchor bolts ( A105 ) according to the ASTM
    property test?
    pull test?
    ??

    Thanks

    1. @Nima – I assume A105 refers to F1554 G105? If so, then the mechanical tests required are tensile, yield, elongation, and reduction of area. A charpy test is also available as a supplemental requirement.

  2. What is percentage of Carbon, Manganese, Silicon, Chromium and molybdenum chemical composition values present in the F1554 Gr 105 anchor rods?

    1. @Satheesh – The ASTM F1554 standard does not require any specific levels for the chemicals you mention. Different manufacturers may use different steels for their G105 anchors, so the chemical makeup may vary.

  3. Thanks for kind explanation.

    Is it possible to be gavanized or available to purchase galvanized anchor bolt in market?

    Thnaks for your kind response.

    Thanks and Regards

  4. Hello

    I have a query. what is the allowable tensile and shear stress of ASTM 193 grade B7 bolts that needs to be considered for design.

    Know the speficied minimum tension and yield stresses.

    regards
    shreesh

    1. @John – A193 B7 material is not normally a weldable material, so using a coupler may be a better solution. That said, an engineer should be consulted before any alteration is made.

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