It is well known that ordinary structural steel electrodes are mainly used for welding ordinary carbon structural steel, and it is difficult to achieve satisfactory welding results by using it to weld cast iron. In the equipment maintenance work, the author explored a method of welding cast iron parts by using ordinary structural steel welding rods. After practice, the quality is reliable and the effect is ideal. It is suitable for the maintenance of small and medium-sized mechanical equipment with low performance requirements, especially applicable. Maintenance of agricultural machinery, agricultural tools and maintenance under emergency conditions. The usage points and operational precautions of the method are described.
The welding principle of the method: the ordinary structural steel welding rod and the copper material are co-melted, so that the copper material is added to the welding material. The change of the chemical composition of the weld filler material has fundamentally changed the weld quality and mechanical properties, thus achieving the purpose of welding cast iron.
After groping the test, we first wrapped the bare copper wire around the outer skin of the ordinary structural steel electrode, and then, according to the conventional method, the arc welding operation can achieve the intended purpose of melting the copper material into the weld material. That is, the bare copper wire uniformly wound on the outer circumference of the ordinary structural steel electrode is melted by using the high temperature generated in the welding zone during the welding process, and is continuously melted into the weld material as the welding operation continues.
In order to reduce costs, save resources, and protect the environment, replace the bare copper wire wrapped around the ordinary structural steel electrode with the waste ordinary copper core cable stripped with the outer skin, and use the waste cable with the core of multiple thin copper wires. optimal.
Welding parameters and precautions:
(1) The welding machine and welding current adopt 300A ordinary three-phase AC welding machine. The welding current is 120~150A.
(2) The welding rod is made of ordinary structural steel electrode, E5016 (J506), f 2.5~f 3.2mm. When winding the stranded bare copper wire of the waste cable on the outer circumference of the electrode, pay attention to the following points: 1 Winding direction, spirally uniform winding along the axis of the electrode (long axis). 2 The winding density can be determined according to the working nature, characteristics and shape of the workpiece to be welded. Under normal circumstances, it can be wound side by side. In special cases, it can be closely packed. 3 When winding, avoid too tight or too loose. When it is too tight, it will be easy to bounce in the welding. If it is too loose, it will accumulate unevenly. 4 The two strands of bare copper wire wound on the electrode should be specially noted. The strands of bare copper wire near the clamping end of the welding tongs and the welding rod must be handled properly. It should not be in contact with the welding rod core and the welding tongs to avoid short circuit. The welding operation continues. When winding, the wire should be pressed down so that the pressed wire ends at the end of the electrode (similar to the fishing hook tie), and the wire wound around the end of the electrode can be tied at the end of the electrode.
(3) The grooved plate adopts the X-shaped (with blunt edge) groove form; the round material adopts the U-shaped (with blunt edge) groove form. In order to achieve the purpose of positioning accurately and ensuring the largest possible welding depth, the thickness of the sheet member in the middle, the original portion of the axial portion of the round member should not be excessively large.
(4) Measures to avoid welding deformation During the welding process, it is necessary to turn over the weldment and alternate the front and back sides and multi-layer welding (the workpiece should be cooled for 3 to 5 minutes before each rollover) to prevent the weldment from being warped. Deformed. If there is a reference plane on the workpiece to be welded, it is better to fix it with the platen bolt and then weld it.
The use of ordinary structural steel welding rods to weld cast iron parts, seemingly unlikely, has been improved, and has become simple and easy, and has greatly reduced the cost, and received good economic and social benefits, we also tasted the real sweetness. .
[Weihai Technical College (Shandong 264200) Wang Changyi Weihai Jieli Machinery Processing Co., Ltd. (Shandong 264200)
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