Microstructure and Properties of Arc Welded Joint of NR360 Wear-resistant Steel Plate
1. Introduction
The NR360 wear-resistant steel plate is one of the high chromium scale wear resistant plates. Under the mechanical and thermal action of the welding process, its manufacture will cause chemical composition, structure, strength and toughness to change, thereby affecting the performance of the weld seam. The microstructure and properties of the manual arc welding joint of the NR360 wear-resistant steel plate were analyzed.
2. Process
For the manual arc welding of the NR360 wear-resistant steel plate, the welding method is selected, the preparatory process is carried out, and the welding process is completed. The specific process is as follows:
a) Selection of welding method: manual arc welding.
b) Pre-welding process: The pre-welding process is mainly to prepare the surface of the weldment. It is mainly to clean the dirt on the welding surface and its surrounding environment, pay attention to the preheating before welding to avoid thermal shock, and choose the appropriate welding wire and welding method according to the structure of the weldment.
c) Welding process: The welding process mainly uses AC power for welding, and it should pay attention to the selection of welding current, welding time and protecting gas according to different welding materials, welding positions and welding seams.
3. Microstructure
The microstructure of the weldment of the NR360 wear-resistant steel plate was examined by optical microscopy. After manual arc welding, the longitudinal section microstructure of the weld joint was mainly composed of ferrite grains and graphite particles. At the bottom of the groove, a small amount of δ ferrite at low temperature can be seen, and micro graphite can also be found. The shape of the graphite particles is spherical, distributed in the cementite (Fe3C) matrix, and the diameter of the graphite particles is relatively small, generally between 0.1μm-1μm.
Microstructure of NR360 wear-resistant steel plate manual arc welding joint
4. Performance
The friction welded joint of the NR360 wear-resistant steel plate was tested for its mechanical properties (tensile strength, hardness, etc.) and macro-performance (weld seam appearance, impact energy, etc.). The test results are shown in Table 1.
Table 1 Test Results of NR360 wear-resistant steel plate manual arc welding joint
Test items Test results Tensile strength (MPa) 490MPa Hardness (HRC) 47 Impact energy (J) 20J
From the above results, it can be acquired that the welding performance of the NR360 wear-resistant steel plate is good. The welded joint has a good tensile strength, hardness and impact energy, which fully meets the design requirements of the wear-resistant steel plate.
5. Conclusion
Through the microstructure and performance analysis of the NR360 wear-resistant steel plate manual arc welding joint, it can be seen that the welding joint has a good performance, and its tensile strength, hardness and impact energy meet the design requirements.
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