Quality Management

We will always do our best to repay
our customers with excellent quality

BOLT production process
  • 01 Raw material

    Process that inspect whether is suitalbe to the quality regulation of Dongah warehousing by hot rolling.

  • 02 Short&Drawing

    Material Scale Processing & forged operation of wire fods for monotonicity. To equalize the diameter.

  • 03 Forging

    Process that make shape of product through forging.

  • 04 Rolling

    Proccess that form screw form that is satisfied with conclusion condition through rolling.

  • 05 Continuos Heat Treatment

    Process that secure mechanical strenghth of product and is managed by the strict quality system of Dongah.

  • 06 Automatic inspection

    The process of checking defects (cracks, heterogeneous products, shape defects) during the process with an automated inspection machine.

  • 07 Product Assembly

    Process that assemble the regulated quantity to automation equipment that mix high-tensile, nut and washer.

NUT production process
  • 01 Material

    Manage circle steel that is the raw material of nut by first-in first-out and storage regulation.

  • 02 Forging

    Process that forge after heating by 1200 degress to mold nut in the defined form.

  • 03 Shot

    Process that remove the surface scale after forging.

  • 04 Tapping

    Form thread by cutting method on inside for conclusion condition of nut.

  • 05 Continuos Heat Treatment

    Process that secure mechanical strenghth of product and is managed by the strict quality system of Dongah.

  • 06 Automatic inspection

    The process of checking defects (cracks, heterogeneous products, shape defects) during the process with an automated inspection machine.

  • 07 Packing

    Process that assemble the regulated quantity to automation equipment that mix hight-tensile bolt, nut and washer.

(주)동아