Understanding STK / STKR Standards for Steel Pipes
What are STK / STKR?
In the construction and manufacturing industries, steel pipes are governed by various standards set by JIS (Japanese Industrial Standards). Two of the most widely used are STK and STKR. While both serve structural applications, they differ in shape and intended function : STK refers to circular structural pipes, where as STKR refers to square of rectangular (hollow section) structural pipes.
- STK (Steel Tube for Structure) → standard for round structural steel pipes used in building and infrastructure projects.
- STKR (Steel Tube for Structure Rectangular) → standard for square and rectangular structural steel pipes, often applied in light structural frameworks and fabrication.
In simple terms, STK is used for circular structural pipes, while STKR is used for square or rectangular structural hollow sections.
Link Between STK and SNI 0068
JIS G 3444 (STK) is Japan’s reference standard for structural steel pipes widely used across construction and manufacturing. It’s technical specifications closely align with SNI 0068, Indonesia’s national standard for structural steel pipes.
Due to this similarity, STK steel pipes are often used as an equivalent or alternative to SNI 0068 in many Indonesian projects. This allows industry players to adopt internationally recognized products while remaining compliant with national regulations.
Simply,
STK (JIS G 3444) is effectively equivalent to
SNI 0068 in terms of its function and applications as a structural steel pipe for buildings and infrastructure.
SPINDO Products: STK and STKR
SPINDO adopts JIS (Japanese Industrial Standards) as the reference for manufacturing structural steel pipes used across construction and manufacturing sectors. The two primary standards applied are JIS G 3444 (STK) and JIS G 3466 (STKR)
- JIS G 3444 (STK) → applied to SPINDO Structural Pipes, round pipes for construction, bridges, frameworks, columns, and scaffolding.
- JIS G 3466 (STKR) → applied to
SPINDO Hollow GI Pipes, square/rectangular galvanized pipes for canopies, fences, roofing frames, and steel furniture.
Technical Specifications of STK / STKR

- Grades: STK 290, STK 400, STK 500 → the numbers in each grade represent minimum tensile strength in MPa.
- Shapes: STK (round), STKR (square/rectangular).
- Equivalent Standards: STK (JIS G 3444) ≈ SNI 0068 for structural pipes.
Advantages of SPINDO STK / STKR Pipes

- International (JIS) & National (SNI 0068) compliance.
- Complete Variants: round structural pipes and hollow GI pipes.
- Guaranteed Strength: available in grades 290–500 MPa.
- Wide Applications: construction, infrastructure, and fabrication.
Conclusion
STK (JIS G 3444) is the Japanese standard for round structural steel pipes, equivalent to SNI 0068 in Indonesia, while STKR (JIS G 3466) is for square/rectangular structural pipes.
- SPINDO STK Pipes (JIS G 3444) = covers circular structural steel pipes whose characteristics closely align with Indonesia’s SNI 0068. These pipes are engineered for demanding applications in construction and infrastructure, including steel frameworks, bridges, poles, and scaffolding systems.
- SPINDO STKR Pipes (JIS G 3466) = cover square or rectangular structural steel tubes. They are often supplied as galvanized hollow sections (GI) for improved corrosion resistance. Typical applications include lightweight frames, canopies, fences, roof trusses, and fabricated steel furniture.
By choosing SPINDO structural pipes and hollow GI pipes, you ensure compliance with international and national standards, top quality material, and trusted performance in diverse projects.
