Hiap Teck Venture Bhd. · MYX:HIAPTEK
Hiap Teck Venture Bhd — Technical Presentation (February 2017)
37 slides from Hiap Teck Venture Bhd's technical presentation, Feb 23, 2017
Slide 1: Difference between Hot-Formed and Hot-Finished Steel Structural Hollow Sections
Difference between Hot-Formed and Hot- Finished Steel Structural Hollow Sections Chiew Sing-Ping Professor and Programme Director of Civil Engineering SINGAPORE INSTITUTE OF TECHNOLOGY 23 February 2017
Slide 2: Outline
Outline 1 Introduction 2 Experimental investigation 3 Test results 4 Conclusions
Slide 3: 1. Introduction
1. Introduction 1.1 Typical manufacturing methods for hollow sections 1.2 Comparison among common hollow sections 1.3 Objectives of current study
Slide 4: 1.1 Manufacturing methods for structural hollow sections
1.1 Manufacturing methods for structural hollow sections 2, Form-Square Weld-Square Process (Studied in this project) 1, Electric Resistance Welding Process 3, Submerged Arc Weld Process
Slide 5: Hot-Formed vs. Cold-Formed
Hot-Formed vs. Cold-Formed Hot-Formed Cold-Formed
Slide 6: Re-forming into rectangular hollow sections
Re-forming into rectangular hollow sections Usually comprises 4 conventional squeeze-roller stands
Slide 7: 1.2 Theoretical differences due to strain histories and thermal actions
1.2 Theoretical differences due to strain histories and thermal actions hot-formed & hot-finished Cold-formed • Tight corner profile • Large corner radius • Homogeneous material • High degree of cold working properties • High residual stress (bending • Good ductility and welding) • Low residual stre
Slide 8: Desired properties of structural steel
Desired properties of structural steel • Strength – ability to carry load • Ductility – ability to sustain permanent deformation without loss of strength • Toughness – ability to absorb damage without fracture • Weldability – ability to transfer load
Slide 9: 1.3 Objectives of current study
1.3 Objectives of current study • Comparison on the physical and mechanical properties of hot-formed, hot-finished and cold- formed rectangular hollow sections a. Geometrical differences b. Chemical compositions and weldability c. Strength and ductility d. toughness e. Residual stresses
Slide 10: 2. Experimental investigations
2. Experimental investigations 2.1 Geometrical measurement 2.2 Chemical composition test 2.3 Tensile test 2.4 Charpy v-notch impact test 2.5 Residual stress measurement
Slide 11: Research target
Research target • The hot-formed and hot-finished hollow sections: 180mm x 180mm x 12.5mm • The cold-formed hollow sections: 200mm x 200mm x 12.5mm Similar in appearance, different in properties
Slide 12: 2.1 Geometrical measurements
2.1 Geometrical measurements To check the surface delivery conditions and dimensional tolerances according to the corresponding production standards. Face 3 ro a. Surface discontinuities ri (imperfections and defects); Face 4 Face 2 b. Geometrical sizes; α ρ h o c. Geometrical parameters. t Weld Sea
Slide 13: 2.2 Chemical composition test
2.2 Chemical composition test • OES method: Optical Emission Spectroscopy Method by SPECTROTEST • Capable of detecting: C, Mn, Cu, P, S, Al, Ti, Si, Cr, Mo, V, and Ni.
Slide 14: 2.3 Tensile coupon tests
2.3 Tensile coupon tests • Coupons from the center area of Face 2, 3 and 4 and tested according to EN 10002-1:2001. • Measurement: strain gauge and extensometer. • Original gauge length: 80mm. • Conversion of elongation from non-proportional gauge length to proportional gauge length was 5.65 So done
Slide 15: 2.4 Charpy v-notch impact test
2.4 Charpy v-notch impact test • Three tests for each hollow section • Standard charpy specimens: 55x10x10 mm • Test temperature: -20 ºC 3 2 1
Slide 16: 2.5 Residual stress measurements
2.5 Residual stress measurements • (1) Sectioning test Measuring the opening distance after sectioning • (2) Semi-destructive hole drilling method Residual stresses within 2mm deep and 1mm diameter hole were measured along the perimeter Released strains by drilling were recoded for further analysis
Slide 17: Sectioning test
Sectioning test • Length of the specimen: 200mm • 3 cuts on each side • Cutting depth: 170mm 180 30 60 60 180
Slide 18: Hole drilling test
Hole drilling test RS-200 and data logger Drilled holes on the specimen
Slide 19: 3. Test results
3. Test results 3.1 Geometrical measurements 3.2 Chemical composition 3.3 Strength and ductility 3.4 Toughness 3.5 Residual stresses
Slide 20: 3.1 Geometrical measurements
3.1 Geometrical measurements • No surface discontinuities that were not allowed in EN 10210 and EN 10219 were found. • The cold-formed hollow section had the largest corner radii, followed by hot-finished and hot-formed hollow sections. Hollow bm tm (mm) ro,m ri,m 2r ro,m/tm ri,m/tm sections (mm) (m
Slide 21: 3.2 Chemical compositions
3.2 Chemical compositions C Mn Cu P S Al Ti Si Cr Mo V Ni CE Cold- 0.082 0.970 0.022 0.029 0.004 0.02 <0.001 0.160 0.026 0.006 0.004 0.020 0.280 formed BS EN ≤0.2 ≤1.6 ≤0.35 ≤0.04 ≤0.04 ≥0.02 ≤0.05 ≤0.6 ≤0.3 ≤0.2 ≤0.05 ≤0.8 ≤0.45 10219 Hot- 0.140 1.330 0.034 0.031 0.009 0.045 <0.001 0.340 0.033 0.00
Slide 22: Summary for chemical test
Summary for chemical test • All the elements contents were strictly within the ranges required by the corresponding standards. • The composition of the three sections are similar, except for small differences in C, Mn and Cu. • For weldablity in terms of CE values, cold-formed > hot-finished > hot-f
Slide 23: 3.3 Strengths and ductility
3.3 strengths and ductility Samples Yield Stress Tensile Tensile ratio Elongation (Mpa) Stress (Mpa) (%) F-2 529.3 562.2 1.06 23 Cold-formed F-3 511.0 551.6 1.08 22 F-4 523.0 563.7 1.08 22 F-2 411.8 536.1 1.30 30 Hot-formed F-3 403.4 521.9 1.29 31 F-4 416.7 535.1 1.28 32 F-2 440.9 531.2 1.20 27 Hot-
Slide 24: Typical stress-strain curves
Typical stress-strain curves 600 Stress (MPa) 500 400 300 200 Cold-Formed 100 Hot-Formed Hot-finished 0 0 5 10 15 20 25 30 35 Strain (%) Nominal yield strengths: Cold-formed steel: the 0.2% offset strength Hot-formed and Hot-finished: lower yield strength
Slide 25: Ductility in forms of Elongation
Ductility in forms of Elongation Cold-formed Hot-finished Hot-formed
Slide 26: Summary for tensile test
Summary for tensile test • cold-formed: the highest yield and tensile strength but the worst ductility • hot-formed: the lowest strength yet the best ductility • Hot-finished: between the other two • No obvious inhomogeneity in face strengths and ductility was observed (less than 5% except for face
Slide 27: 3.4 Toughness
3.4 Toughness Samples and Energy EN 10210 & Average (J) Positions (J) EN 10219 1 168.6 Cold-formed 2 255.4 172.8 S355J2H 3 94.4 1 56.9 Hot-formed 2 280.2 127.4 Min. 27 J S355J2H 3 45.0 1 143.1 Hot-finished 2 190.5 135.1 S355J2H 3 71.7
Slide 28: Charpy v-notch impact test result
Chapy v-notch impact test result Specimens from the cold-formed hollow section (position: 1,2,3) Specimens from the hot-formed hollow section (position: 1,2,3) Specimens from the hot-finished hollow section (position: 1,2,3)
Slide 29: Summary for toughness
Summary for toughness • The toughness values vary with their original positions and directions on the tubes. • Position 2 has the highest toughness, position 1 and 3 are comparable. • Overall, cold-formed S355J2H showed the highest toughness, while values of hot-formed and hot- finished S355J2H are
Slide 30: 3.5 Residual stresses
3.5 Residual stresses • The residual shear and axial stress distributions in terms of fr/fy are compared (divided by the actual yield strengths respectively) • In accordance with geometrical symmetry, the residual stress distribution trend exhibited high repeatability with period of 90° • Residual s
Slide 31: Sectioning test result
Sectioning test result Cold-formed Hot-formed Hot-finished 200mm 210mm 180mm 180mm 180mm 186mm (+5%) (0%) (+3.3%)
Slide 32: Residual stresses in the longitudinal direction
Residual stresses in the longitudinal direction Hot-finished and cold-formed: fr/fy 1 Cold-formed SHS 0.8 Hot-formed SHS Similar !!! Hot-finished SHS 0.6 0.4 0.2 0 0 45 90 135 180 225 270 315 360 -0.2 -0.4 Angle (°) Weld seam
Slide 33: Residual stresses in the perimeter direction
Residual stresses in the perimeter direction 0.6 fr/fy Cold-formed SHS Hot-formed SHS 0.4 Hot-finished SHS 0.2 0 0 45 90 135 180 225 270 315 360 -0.2 Hot-formed and hot-finished: -0.4 Similar !!! Angle (°)
Slide 34: Summary for residual stress
Summary for residual stress • Residual stress distributions in cold-formed section are highly inhomogeneous. • The amount of residual stress: cold-formed>hot-finished>hot-formed • The hot-finished section is not fully annealed as the hot-formed section
Slide 35: 4. Conclusions (1)
4. Conclusions (1) • The tested three hollow sections fully comply the corresponding production standards, but they are different from each other. • cold-formed S355J2H had the highest strength but the lowest ductility; hot-formed S355J2H had the lowest strength but the best ductility, while the hot
Slide 36: Conclusions (2)
Conclusions (2) • The cold-formed section contains the largest number of residual stress with the biggest variance, while the hot-formed contains the least. • The residual stresses at the corners and weld seams are the largest in most cases. • The residual stress distribution of the hot-finished sec
Slide 37: Thank You!
Thank You! SINGAPORE INSTITUTE OF SiT| TECHNOLOGY
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