Welding technology for nickel base alloy build-up welding of marine low-speed machine air valve sealing face

Abstract

The invention discloses a welding technology adopting consumable electrode pulse gas-shielded welding for nickel base alloy build-up welding of a marine low-speed machine air valve sealing face according to the base material characteristics of an air valve, the weldability of nickel base alloy, an annular ship type welding groove of the air valve sealing face and the use condition of the air valve. The consumable electrode pulse gas-shielded welding mode is adopted, the welding power, the welding parameters and the shielding gas constituents are proportioned, factors such as forming of welding liens, globular transferring, arc striking, arc quenching, the overlap amount, preheating and the interlayer temperature are controlled, and the welding defects such as air holes, incomplete fusion and porosity of nickel base alloy build-up welding of the sealing face can be overcome in the existing producing and machining process of the air valve of a marine diesel engine. Thus, the high-quality air valve can be obtained, the production cost of enterprises can be effectively lowered, and the production efficiency of the enterprises can be improved.

Description

technical field [0001] The invention relates to a nickel-based alloy welding process for the sealing surface of the gas valve of a low-speed marine engine, in particular to a welding process for surfacing the nickel-based alloy on the sealing surface of the gas valve by adopting the melting electrode pulse gas shielded welding method, which belongs to welding technology field. Background technique [0002] At present, the sealing surface of marine low-speed diesel engine valves is widely used in plasma arc powder (non-melting electrode gas shielded welding) for overlay welding of cobalt-based alloys or nickel-based alloys. Nickel-based alloys are superior to cobalt-based alloys in terms of corrosion resistance and other comprehensive properties, and are gradually becoming The development direction of overlay welding alloys for the sealing surface of marine low-speed diesel engine valves, among which Inconel718 nickel-based alloy has high yield strength, tensile strength and ...

AI Technical Summary

Problems solved by technology

However, the Inconel 718 alloy contains aluminum, titanium and other alloying elements, resulting in poor welding process performance, poor fluidity of the molten pool during the welding process, and difficult forming, and the sealing surface of the gas valve needs multi-layer surfacing welding. Traditional plasma arc powder surfacing welding is used. In actual production, nickel-based alloys are prone to welding defects such as pores, incomplete fusion and looseness between the weld layer and the weld bead, and the qualified rate of surfacing welding is low, resulting in rework or product scrapping, thereby increasing the production cost of the enterprise

In addition, the service environment of marine low-speed diesel engine valves is harsh, and they are subjected to high thermal loads and impact mechanical loads during work. The existence of welding defects in the alloy layer of the sealing surface is likely to cause early failure of the sealing surface of the valve and affect the normal operation of the diesel engine.

Images