JIS G 3445

What is JIS G 3445?

JIS G 3445 is a standard number of Japanese Industrial Standard (JIS).
It is used to specify the requirements for seamless steel pipes for carbon steel mechanical structures. These steel tubes are commonly used in mechanical structures, automobile manufacturing, bicycle manufacturing, precision mechanics and other mechanical engineering applications.

The main purpose of the JIS G 3445 standard is to ensure that seamless steel tubes for machine structures have sufficient strength, durability, and adaptability to meet the needs of various machine applications. These pipes are characterized by a seamless fabrication. That allows them to perform well when subjected to pressure, torque and other mechanical stresses.


  • Outer diameter: 19.05mm to 114.3mm
  • Wall thickness: 2.0mm to 14mm.

The steel grades we offer include STKM11A, STKM12(A,B,C), STKM13(A,B,C), and STKM14(A,B,C).

JIS G 3445 standard applies to carbon steel seamless pipes for machine structures. They are widely used in various mechanical engineering applications. Such as auto parts, bicycle frames, precision machine parts, etc. The properties of these pipes make them excellent when subjected to mechanical stress, thereby supporting the manufacture of a wide variety of mechanical equipment and products.
We provide a variety of surface coatings, end types, joint methods, and machining services to suit your specific needs. With UNIASEN, you receive a product that is customized to your specifications. We ensure maximum efficiency and performance.