Skip to main content
SpringerLink
Log in

Continuous cooling transformation diagram and mechanical properties in weld coarse-grain heat-affected zone of API X70 steel

  • Published:
Sādhanā Aims and scope Submit manuscript

Abstract

In the present work, continuous cooling transformation (CCT) of coarse-grained heat-affected zone (CGHAZ) and simulation of Charpy-sized impact specimens were performed using a Gleeble 3800 thermomechanical simulator. Results obtained from the dilation studies show significant effect of cooling rates on microstructure and low-temperature (–20 °C) Charpy impact toughness. Phase transformation temperatures (Ar3 and Ar1) and impact toughness decreased while hardness and amount of bainite increased with increasing cooling rates. At slow cooling condition (< 5 °Cs–1) quasi-polygonal ferrite and pearlite phases were observed in the microstructure. At medium cooling rate (5–25 °Cs–1), bainite and quasi-polygonal ferrite were obtained in the microstructure. For still faster cooling rates, microstructure was completely bainitic in nature. The microstructures were confirmed by hardness measurement where the hardness value for lower, medium and high cooling rates were 191–196, 213–214 and 234–253 HV, respectively. Charpy impact toughness increased with decrease in cooling rate due to the presence of softer ferrite phase.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Figure 8
Figure 9
Figure 10
Figure 11
Figure 12

Similar content being viewed by others

References

  1. Chen X, Lu H, Chen G and Wang X 2015 A comparison between fracture toughness at different locations of longitudinal submerged arc welded and spiral submerged arc welded joints of API X80 pipeline steels. Eng. Fract. Mech. 148: 110–121

    Article  Google Scholar 

  2. Yang Y, Shi L, Xu Z, Lu H, Chen X and Wang X 2015 Fracture toughness of the materials in welded joint of X80 pipeline steel. Eng. Fract. Mech. 148: 337–349

    Article  Google Scholar 

  3. Sung H K, Shin S Y, Cha W, Oh K, Lee S and Kim N J 2011 Effects of acicular ferrite on charpy impact properties in heat affected zones of oxide-containing API X80 linepipe steels. Mater. Sci. Eng. A 528: 3350–3357

    Article  Google Scholar 

  4. Yue X, Lippold J, Alexandrov B and Babu S 2012 Continuous cooling transformation behavior in the CGHAZ of naval steels. Weld. J. 91: 67–75

    Google Scholar 

  5. Singh M P, Arora K S, Shajan N, Pandu S R, Shome M, Kumar R and Shukla D 2019 Comparative analysis of continuous cooling transformation behaviour in CGHAZ of API X-80 and X-65 line pipe steels. J. Therm. Anal. Calorim. 137: 1155–1167

    Article  Google Scholar 

  6. Shome M, Gupta O P and Mohanty O N 2004 Effect of simulated thermal cycles on the microstructure of the heat-affected zone in HSLA-80 and HSLA-100 steel plates. Metall. Mater. Trans. A Phys. Metall. Mater. Sci. 35: 985–996

    Article  Google Scholar 

  7. Arora K S, Pandu S R, Shajan N, Pathak P and Shome M 2018 Microstructure and impact toughness of reheated coarse grain heat affected zones of API X65 and API X80 linepipe steels. Int. J. Press. Vessel. Pip. 163: 36–44

    Article  Google Scholar 

  8. Shome M and Mohanty O N 2006 Continuous cooling transformation diagrams applicable to the heat-affected zone of HSLA-80 and HSLA-100 steels. Metall. Mater. Trans. A Phys. Metall. Mater. Sci. 37: 2159–2169

    Article  Google Scholar 

  9. Kumar S, Nath S K and Kumar V 2016 Continuous cooling transformation behavior in the weld coarse grained heat affected zone and mechanical properties of Nb-microalloyed and HY85 steels. Mater. Des. 90: 177–184

    Article  Google Scholar 

  10. Thompson S W, Colvin D J and Krauss G 1996 Austenite decomposition during continuous cooling of an HSLA-80 plate steel. Metall. Mater. Trans. A Phys. Metall. Mater. Sci. 27: 1557–1571

    Article  Google Scholar 

  11. Sharma S K and Maheshwari S 2017 A review on welding of high strength oil and gas pipeline steels. J. Nat. Gas Sci. Eng. 38(203217): 2017

    Google Scholar 

  12. Klimpel A 2014 Assessment of the advisability of the use of steel pipes X70 and X80 for strategic pipelines of large diameters with respect to their weldability. Weld. Int. 28: 953–956

    Article  Google Scholar 

  13. Hui L, Liang J L, Feng Y L and Dong X H 2014 Microstructure transformation of X70 pipeline steel welding heat-affected zone. Rare Met. 33: 493–498

    Article  Google Scholar 

  14. Wang X N, Zhao Y J, Guo P F, Qi X N, Di H S, Zhang M and Chen C J 2019 Effect of heat input on M-A constituent and toughness of coarse grain heat-affected zone in an X100 pipeline steel. J. Mater. Eng. Perform. 28: 1810–1821

    Article  Google Scholar 

  15. Zhou P, Wang B, Wang L, Hu Y and Zhou L 2018 Effect of welding heat input on grain boundary evolution and toughness properties in CGHAZ of X90 pipeline steel. Mater. Sci. Eng. A 722: 112–121

    Article  Google Scholar 

  16. Wang X N, Chen X M, Wen F, Guo P F, Yang L, Yan Q and Di H S 2018 Effect of cooling time t8/5 on microstructure and toughness of Nb–Ti–Mo microalloyed C–Mn steel. J. Iron Steel Res. Int. 25: 1078–1085

    Article  Google Scholar 

  17. Lee S G, Sohn S S, Kim B, Kim W G, Um K K and Lee S 2018 Effects of martensite–austenite constituent on crack initiation and propagation in inter-critical heat-affected zone of high-strength low-alloy (HSLA) steel. Mater. Sci. Eng. A 715: 332–339

    Article  Google Scholar 

  18. Yang X, Di X, Liu X, Wang D and Li C 2019 Effects of heat input on microstructure and fracture toughness of simulated coarse-grained heat affected zone for HSLA steels. Mater. Charact. 155: 109818

    Article  Google Scholar 

  19. Chen X W, Tian P, Wen K, Li Z H, Xiao F R, Wang X and Liao B 2007 Study on microstructure and toughness of heat-affected zone of X70 pipeline steel. Met. Hotworking Technol. 36: 6–9

    Google Scholar 

  20. Zhang Y Q, Zhang H Q, Liu W M and Hou H 2009 Effects of Nb on microstructure and continuous cooling transformation of coarse grain heat-affected zone in 610 MPa class high-strength low-alloy structural steels. Mater. Sci. Eng. A 499: 182–186

    Article  Google Scholar 

  21. Park B J, Choi J M and Lee K J 2012 Analysis of phase transformations during continuous cooling by the first derivative of dilatation in low carbon steels. Mater. Charact. 64: 8–14

    Article  Google Scholar 

  22. Siefert J A, Leister B M and DuPont J N 2015 Considerations in development of CCT diagrams for complex ferritic materials. Mater. Sci. Technol. 31: 651–660

    Article  Google Scholar 

  23. Singh M, Kumar R, Shukla D K and Arora K S 2018 Phase transformation and impact toughness in HAZ of micro alloyed X80 line pipe steel. Mater. Res. Express 6: 026561

    Article  Google Scholar 

  24. Bhadeshia H 2013 About calculating the characteristics of the martensite–austenite constituent. In: Proceedings of the International Seminar on Welding High Strength Pipeline Steels. The Minerals, Metals and Materials Society (TMS), USA, pp. 99–106

  25. Bhadeshia H K D H and Honeycombe S R 2006 The bainite reaction steels: microstructure and properties. 3rd edn. Butterworth-Heinemann, Oxford, pp 129–154

    Google Scholar 

  26. Abbaszadeh K, Saghafian H and Kheirandish S 2012 Effect of bainite morphology on mechanical properties of the mixed bainite–martensite microstructure in D6AC steel. J. Mater. Sci. Technol. 28: 336–342

    Article  Google Scholar 

  27. Abbasi S, Esmailian M and Ahangarani S 2018 Investigation of the microstructure, micro-texture and mechanical properties of a HSLA steel, hot-rolled and quenched at different cooling rates. Metallogr. Microstruct. Anal. 7: 596–607

    Article  Google Scholar 

Download references

Author information

Author notes

  1. Ajit Kumar Naik and Rakesh Roshan equally contributed to this article.

Authors and Affiliations

  1. Department of Metallurgical and Materials Engineering, National Institute of Technology, Rourkela, 769 008, India

    Ajit Kumar Naik, Rakesh Roshan & Subash Chandra Mishra

  2. R&D, Tata Steel Limited, Jamshedpur, 831 001, India

    Kanwer Singh Arora & Nikhil Shajan

Authors
  1. Ajit Kumar Naik
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Rakesh Roshan
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Kanwer Singh Arora
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Nikhil Shajan
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Subash Chandra Mishra
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Ajit Kumar Naik.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Naik, A.K., Roshan, R., Arora, K.S. et al. Continuous cooling transformation diagram and mechanical properties in weld coarse-grain heat-affected zone of API X70 steel. Sādhanā 46, 88 (2021). https://doi.org/10.1007/s12046-021-01623-2

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • DOI: https://doi.org/10.1007/s12046-021-01623-2

Keywords

Search

Navigation