What is it about?
The family of 18 % Ni maraging steels is known for its excellent combination of strength and toughness. Welding frequently comes into picture during fabrication. These steels are welded in the solution-annealed state; strengthening through precipitation hardening constitutes the post-weld heat treatment (PWHT). Welding of thick sections is often involved, which brings its own set of problems - large number of passes, prolonged welding time, high heat input, high degree of distortion, poor mechanical properties, particularly the unsatisfactory fracture toughness. Laser hybrid welding (LHW) is an advanced technique that combines the advantages of laser beam welding and arc welding and has been successfully applied to various materials and thicknesses. LHW is known to provide benefits through decreased welding duration, reduced number of passes, precisely regulated heat input and reduced distortion when working with thick sections. The present study deals with use of LHW for welding of 12 mm thick plates of maraging steel. It emerged that weld joints of required quality could be produced using LHW.
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Why is it important?
18 % Ni maraging steels find applications in strategic industries. Weldability is almost always an important requirement. Furthermore, weldability in thick sections is often a demand placed. The study has demonstrated that the steel could be welded satisfactorily in thick sections, using Laser Hybrid Welding (LHW). Weld joints of acceptable quality and demonstrating excellent strength - fracture toughness combination could be produced in 12 mm thick sections using LHW. In fact, the LHW technique yielded higher fracture toughness in weld joints compared to Gas Metal Arc Welding (GMAW) and Double Pulse-GMAW. The study has shown that appropriate choice of post-weld heat treatment can have a salutary effect on microstructure and mechanical properties of weld joints.
Perspectives
The results presented here are based on the doctoral work carried out by Dr Bibin Jose under the guidance of Dr M Manikandan, with Dr N Arivazhagan acting as the Project Advisor. Advanced Research Center International, Hyderabad, provided valuable support to carrying out this Research, by way of providing access to the Hybrid Welding Equipment for carrying out LHW. Mishra Dhatu Nigam Limited (MDNL) facilitated the testing of fracture toughness of the weld joints, as per aerospace standards. At this point, the researches carried out by L Subashini et al (2016, 2020), bringing out the promise held by Laser Arc Hybrid Welding of thick sections of maraging steel, are duly acknowledged.
Nageswara Rao Muktinutalapati
Read the Original
This page is a summary of: Laser Hybrid Welding—An Advanced Joining Technique for Welding of Thick Plates of Maraging Steel, Journal of Materials Engineering and Performance, November 2024, Springer Science + Business Media,
DOI: 10.1007/s11665-024-10409-6.
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