Laser welding and post weld treatment of modified 9Cr-1MoVNb steel.
Laser welding and post weld laser treatment of modified 9Cr-1MoVNb steels (Grade P91) were performed in this preliminary study to investigate the feasibility of using laser welding process as a potential alternative to arc welding methods for solving the Type IV cracking problem in P91 steel welds. The mechanical and metallurgical testing of the pulsed Nd:YAG laser-welded samples shows the following conclusions: (1) both bead-on-plate and circumferential butt welds made by a pulsed Nd:YAG laser show good welds that are free of microcracks and porosity. The narrow heat affected zone has a homogeneous grain structure without conventional soft hardness zone where the Type IV cracking occurs in conventional arc welds. (2) The laser weld tests also show that the same laser welder has the potential to be used as a multi-function tool for weld surface remelting, glazing or post weld tempering to reduce the weld surface defects and to increase the cracking resistance and toughness of the welds. (3) The Vicker hardness of laser welds in the weld and heat affected zone was 420-500 HV with peak hardness in the HAZ compared to 240 HV of base metal. Post weld laser treatment was able to slightly reduce the peak hardnessmore »
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- Resource Type:
- Technical Report
- Research Org:
- Argonne National Laboratory (ANL)
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- Country of Publication:
- United States
- 36 MATERIALS SCIENCE; ARC WELDING; DEFECTS; GLAZING MATERIALS; HARDNESS; HEAT AFFECTED ZONE; LASER WELDING; LASERS; POROSITY; STEELS; TEMPERING; TESTING; WELDED JOINTS
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