Weldability evaluation of high tensile plates using GMAW process

  • R. Datta
  • D. Mukerjee
  • K. L. Rohira
  • R. Veeraraghavan
Article

Abstract

High tensile plates, SAILMA-450 high impact (HI) (yield strength, 45 kg/mm2 minimum; ultimate tensile strength, 57 kg/mm2 minimum; elongation, 19% minimum; Charpy impact energy 2.0 kg.m at −20 °C minimum) were successfully developed at the Steel Authority of India Ltd., up to 32 mm plate thickness. Since then the steel has been extensively used for the fabrication of impellers, bridges, excavators, and mining machineries, where welding is an important processing step.

The present study deals with the weldability properties of SAILMA-450 HI plates employing the gas metal arc welding process and carbon dioxide gas. Implant and elastic restraint cracking tests were conducted to assess the cold cracking resistance of the weld joint under different welding conditions. The static fatigue limit values were found to be in excess of minimum specified yield strength at higher heat input levels (9.4 and 13.0 kJ/cm), indicating adequate cold cracking resistance. The critical restraint intensities, K cr, were found to vary between 720 and 1280 kg/mm2, indicating that the process can be utilized for fabrication of structures involving moderate to low restraint intensities (200 to 1000 kg/mm2). Lamellar tear tests conducted using full thickness plates at heat input levels ranging from 10 to 27 kJ/cm showed no incidence of lamellar tear upon visual, ultrasonic, and four-section macroexamination. These tests were repeated using machined plates, such that the midthickness of the plates (segregated zone) corresponded to the heat affected zone of the weld. No cracks were observed, indicating good lamellar tear resistance of the weld joint. Optimized welding conditions were formulated based on these tests. The weld joint was subjected to extensive tests to assess the physical properties and soundness of the weld joint. The weld joint exhibited good strength (64.7 kg/mm2) and impact toughness (5.7 and 3.5 kg.m at −20 °C for weld metal and heat affected zone properties. Crack tip opening displacement (CTOD) tests carried out for parent metal, heat-affected zone, and weld metal resulted in δm values of 0.41, 0.40, and 0.34 mm, respectively, which indicates adequate resistance to cleavage fracture. It was concluded that the weld joint conforms to the requirements of SAILMA-450 HI specification and ensures a high integrity of the fabricated products.

Keywords

cold cracking gas metal arc welding impact toughness lamellar tear restraint intensity thermomechanical controlled processing 

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References

  1. 1.
    T. Tanaka, Controlled Rolling of Steel Plate and Strip, Int. Met. Review, (No. 4), 1981, p 185–212Google Scholar
  2. 2.
    G.R. Speich, L.J. Cuddy, C.R. Gordon, and A.J. DeArdo, Formation of Ferrite from Controlled Rolled Austenite, Proc. Phase Trans. in Ferrous Alloys, TMS-AIME, 1984, p 341–390Google Scholar
  3. 3.
    A.J. DeArdo, Ferrite Formation from Thermomechanically Processed Austenite in HSLA Steels, Proc. High Strength Low Alloy Steels, South Coast Printers, NSW, 1986, p 70Google Scholar
  4. 4.
    C.I. Garcia and A.J. DeArdo, Formation of Austenite in 1.5% Mn Steels, Metall. Trans. A, Vol 12, 1981, p 521Google Scholar
  5. 5.
    D. Webster and J.A. Woodhead, Effect of 0.03% Nb on the Ferrite Grain Size of Mild Steels, J. Iron Steel Inst., Vol 202, 1964, p 987Google Scholar
  6. 6.
    I. Kozasu, C. Ouchi, T. Sampei, and T. Okita, Hot Rolling as a High Temperature Thermomechanical Process, Proc. Microalloying ’75, Union Carbide Corp., New York, 1977, p 120–135Google Scholar
  7. 7.
    A.J. DeArdo, Accelerated Cooling: A Physical Metallurgy Perspective, Can. Metall. Q., Vol 27, 1988, p 141Google Scholar
  8. 8.
    L.J. Cuddy, Grain Refinement of Nb Steels by Control of Recrystallization during Hot Rolling, Metall Trans. A, Vol 15, 1984, p 87–98Google Scholar
  9. 9.
    D.N. Crowther and B. Mintz, Influence of Grain Size on Hot Ductility of Plain Carbon Steels, Mater. Sci. Eng., Vol 2, 1986, p 951–955Google Scholar
  10. 10.
    C.I. Garcia and A.J. DeArdo, Structure and Properties of ULCB Plate Steels for Heavy Section Applications, Proc. Microalloyed HSLA Steels, ASM International, 1988, p 291–300Google Scholar
  11. 11.
    V. Ramaswamy, R. Datta, S.K. Chaudhuri, and S. Mishra, Recent Studies in Thermomechanical Processing of Microalloyed Steels, Proc. Emerging Tech. for New Mater. and Product Mix, Materials Week (Cincinnati, OH), 1991, p 261–268Google Scholar
  12. 12.
    S.K. Chaudhuri, R. Datta, A.K. De, and S. Mishra, Recent Efforts in High Strength Steel Development at SAIL, Trans. IIM, Vol 49 (No. 3), 1996, p 207–216Google Scholar
  13. 13.
    M.J. Cieslak, Cracking Phenomena Associated with Welding, ASM Handbook, Vol 6, Welding, Brazing, and Soldering, ASM International, 1993, p 88–96Google Scholar
  14. 14.
    H. Garnjon, Fundamentals of Welding Metallurgy, Abington Publishing, 1991, p 156Google Scholar
  15. 15.
    F.R. Coe, Welding Steels without Hydrogen Cracking, Fundamentals of Welding Metallurgy, American Society for Metals, 1973, p 24–39Google Scholar
  16. 16.
    P.E. Reynolds, Effect of Titanium Treatment on Grain Size Control in Low Alloy Steels, Ironmaking Steelmaking, Vol 18 (No. 1), 1991, p 52–58Google Scholar
  17. 17.
    A.J. DeArdo, Thermomechanical Processing: Advanced Materials and Progress, Met. Progr., Vol 1, 1988, p 71–73Google Scholar
  18. 18.
    International Institute of Welding (IIW) document, 830–73, 1973Google Scholar
  19. 19.
    R. Datta, D. Mukerjee, and S. Mishra, Thermomechanical Processing of High Tensile Plates and Associated Weldability Properties, THERMEC ’97, TMS Publications, 1997, p 327–337Google Scholar

Copyright information

© ASM International 1999

Authors and Affiliations

  • R. Datta
    • 1
  • D. Mukerjee
    • 1
  • K. L. Rohira
    • 2
  • R. Veeraraghavan
    • 2
  1. 1.Research and Development Centre for Iron and Steel, Steel Authority of India LimitedRanchiIndia
  2. 2.Welding Research Institute, BHELTiruchirapalliIndia

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