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FAQ

  • What is the common raw material of Stainless self drilling screw?
    • Self drilling hex head screw, self drilling pan head and flat head screw are normally made from Stainless 410.

  • My engineer is looking for Heavy structure hex bolt A325X, but I could only find A325-Type1 in Thai market. So are these the same thing?
    • Yes, they are technically the same thing. The letter "X", "N", and "SC" are used to identify the type of connection that A325 bolt will be used in. So your engineer will simply require the same standard of A325 heavy hex structural bolt, but these bolts will be used in three different connection types.

      A325X specifies that A325 bolts will be used in a bearing type connection where threads will not be included in the shear plane. Whereas A325N means that threads are included in the shear plane.

      A325SC, SC stands for "slip critical connection". A325SC is unlike A325X nor A325N as A325SC bolts are not being used in shear, but the tension from the connection resists the shearing force.
      N=Bearing type connection with threads included in the shear plane.
      X=Bearing type connection with threads excluded from the shear plane.
      SC=Slip critical connection, where the tension from the connection resists the shearing force.

      So in conclusion, the "N", "X", and "SC" which follow A325 are here just to specify the type of connections that A325 bolts will be used in.

  • What is a Grade 8.8 steel fastener?
    • A grade 8.8 fastener as specify in ISO 898-1 for bolt and ISO 898-1 for bolt and ISO 898-2 for nuts.
      A grade 8.8 fastener can be manufactured from any material whose mechanical properties meet or exceed the requirements set in the ISO 898 standard.

      According to the ISO 898, fasteners are categorised into many grades. (Grade 4.6, 5.6, 8.8, 10.9 and 12.9)
      This designation system is base on two numbers.
      The first number specifies the tensile strength of metric bolt(N/m?)/100. The second number is the ratio of Proof/yield stress to the Tensile Strength. Express in percentage.

      *For example

       

      Nominal ultimate Tensile strength (UTS)

      Proof/yield stress

      8.8

      800 N/m?

      640N/m? (derive from 800X 0.8)

       

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