What happened to ASTM A307 Grade C?

One change with regard to specifications that will have a significant impact on the construction fastener industry is the August 2007 elimination of the grade C designation within the ASTM A307 specification. ASTM A307 is the standard specification for low carbon steel construction fasteners. Until recently, A307 had three grades A, B, and C. Grade A covers bolts for general applications, grade B covers heavy hex bolts and studs for cast iron flanges, while grade C covered unheaded anchor bolts, either bent or straight, intended for structural anchorage purposes. Last year’s elimination of A307 grade C is the result of a virtually identical specification, F1554 grade 36 developed in 1994, replacing it.

Although A307 grade C and F1554 grade 36 are virtually identical, there are some subtle yet very important differences. The ASTM F1554 specification was introduced in 1994 and covers anchor bolts designed to anchor structural supports to concrete foundations. F1554 grade 36 is manufactured from low carbon steel just like ASTM A307 grade C was but in addition to being a bent or straight anchor bolt, can also be a headed bolt that is embedded in concrete and used for anchoring purposes. Most commercially available all thread rod that meets ASTM A307 and is used for anchor bolts will not meet ASTM F1554 grade 36. Additionally, imported A307 hex bolts that are commonly embedded in concrete and used as anchor bolts will not meet F1554 grade 36. However, many fastener distributors and even some manufacturers who do not have a thorough understanding of the differences between ASTM A307 grade C and F1554 grade 36 continue to provide A307 bolts believing they will cross-certify to ASTM F1554 grade 36 which is simply not the case in most instances. It is important to be aware of the differences between these two specifications to limit exposure to unnecessary liability.

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    This is to Greg or anyone who can answer. I have a bolt with the following markings…..”307″ (without an “A”) and then…..”E + N”. Except the “+” looks more like a cross. Can you answer the following:

    1. Is “307” the same as ASTM “A307”?
    2. Who is the manufacturer with bolt markings “E + N”

    Thank you,

    @Steve- The ASTM A307 standard requires a letter after the 307, either A or B. So this is either a bolt not 100% made per the standard, or it is some other private label marking that coincidentally has a similar marking. As for the E+N, we were not able to find that marking in our database, so it is either an unregistered marking or a very old one.

    I have a Carriage Bolt with three lines and the Lettering UH on the head. Can you tell me what that means?
    I purchased replacement bolts but they only have a RFF marked on the top. Are these bolts compatible?

    @Steven- The three radial lines means that the bolt is manufactured per SAE J429 grade 5. The UH on the first and the RFF on the second are the manufacturer’s identifications. Since the second bolt does not have additional markings, we’d say it was made per SAE J429 grade 2 which is a low carbon, low strength bolt. The grade 5 is high strength and heat treated, so they are not similar.

    @Hameed- A36 is a raw material standard, whereas A307C is an old anchor bolt standard. The marking required for A307C is green paint, or an A307C stamp. There are no marking requirements for A36.

    @Sarah- F1554 has three grades, G36, G55, and G105. The old ASTM A307 grade C is equivalent to F1554 grade 36.


    whats the diference betwen ASTM A-36 and 307 Gr.C?

    i see the mechanical properties ASTM A-36 and 307Gr.C is the same.

    @Alceu – The main difference is that A36 is a raw material standard, whereas A307 Gr.C (which has since been replaced by F1554 gr.36) is a fastener standard. Many times A307 bolts are made from A36 steel, but it is not required.

    What is the difference is between an A307 heavy headed hex bolt vs an F1554, Gr36 heavy hex head bolt? I have yet to hear from anybody what the real difference is, if any.

    I ahve received an inquiry for A307 GR-C stud bolts with nuts. Since I have never heard this grade, I have forwarded the same to one of the manufacturer. They have come back to me with ASTM A193 B7 / ASTM A194 2H grade. Please advise on this if I can can offer this grade to my client….?

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