STK290
STK290
Steel pipes made with STK290 (STK substance) are primarily used for the following applications.
Creating pillars (eaves pillars, outside pillars, etc.)
Piles of steel pipe
The building’s pillars are made of STK materials. Steel columns are usually hidden by decorative materials, so steel tubes (columns) with lower cross-section properties than square steel tubes are not used. If, however, the steel column’s form is visible from the outside, utilize a cylindrical steel pipe.
PRODUCT FEATURES
Chemical Composition of JIS G3444 STK290
Symbol of grade | C | Si | Mn | P | S |
STK290 | – | – | – | 0.050 max. | 0.050 max. |
Notes a) If necessary, alloying elements other than specified in this table may be added. b)For the tube of grade STK540 exceeding 12.5 mm in wall thickness, the chemical composition may be subject to the agreement between the purchaser and the manufacturer. | |||||
Mechanical Properties of JIS G3444 STK290
Symbol of Grade | Tensile Strength  N/mm² | Yield Point of Proof Stress  N/mm² | Tensile Strength in Weld Zone  N/mm² | Flattening | Bendability | |
Distance between Plates (H) | Bend Angle | Inside Radius | ||||
Applied outside diameter | ||||||
All outside diameters | All outside diameters | All outside diameters | All outside diameters | 50 mm max. | ||
STK290 | 290 min. | – | 290 min. |  2/3 D | 90° | 6 D |
NOTE 1  D of this table is the outside diameter of the tubes. NOTE 2  1 N/mm²—1 MPa Note a) Standard of bend angle shall be the start point of bending. | ||||||
STK290 Tensile Test Piece and the Minimum Value of Elongation
Symbol of grade | Tube Manufacturing Method | ||||
Seamless and butt welded | Electric resistance welded and automatic arc welded | All manufacturing methods | |||
Applied outside diameter | |||||
All outside diameters | 350 mm | Over 350 mm | All outside diameters | ||
Test Piece and Direction of Test Piece | |||||
No. 11 test piece No. 12 test piece | No. 11 test piece No. 12 test piece | No.5 test piece | No.4 test piece | ||
Tube axis direction | Tube axis direction | Perpendicular to tube axis direction | Tube axis direction | Perpendicular to tube axis direction | |
STK290 | 30 | 30 | 25 | 28 | 23 |
For the tubes of outside diameter 40 mm or under, the elongation value in this table shall not be applied. However, the test result for these tubes shall be recorded. Further, the elongation may be specified by agreement between the manufacturer and the purchaser. | |||||
Marking of JIS G3444 Steel Grade STK290
Each tube having passed the inspection shall be marked with the following items on each STK290 tube. For tubes of a smaller outside diameter or when there is a special request by the purchaser, marking may be applied on a bundle. The order of arrangement of the markings is not specified. When approved by the purchaser, part of the items may be omitted.
- Grade symbol
- A symbol representing the manufacturing process. The following symbol should be used to indicate the production technique. However, a space may be used in place of the dash.
- As welded steel tube with electric resistance: -E-G
- Hot finished electric resistance welded steel tube: Â -E-H
- Cold finished electric resistance welded steel tube: Â -E-C
- Butt-welded steel tube: Â -B
- Automatic arc welded steel tube: Â -A
- Measurements Outside diameter and wall thickness should be noted for dimensions.
- The manufacturer’s name or an abbreviation of the manufacturer’s name
- A symbol representing the coating kind (in the case of using coated steel sheet or coated steel strip). The maker and purchaser shall agree on the symbol’s abbreviation.
