Method of guaranteeing hardness of welded closed impeller after welding

Abstract

The invention provides a method of guaranteeing hardness of welded closed impeller after welding. The method is characterized in that aluminium alloy closed impeller, after a conventional machining and welding, is taken out of a salt bath furnace, put into a boiling water of 100 DEG C for fried salt treatment within two minutes, with a time being controlled in 30-50 minutes, and then is subjected to an artificial aging for 10-12 hours under a temperature of 160-180 DEG C, so that the hardness HB of the aluminium alloy closed impeller after welding is more than or equal to 100.

Description

technical field [0001] The invention relates to a method for ensuring the post-welding hardness of a welded closed impeller. The material of the closed impeller is generally aluminum alloy, and the required hardness is generally: HB≥100. Background technique [0002] The closed impeller is the key part of the turbine (Turbine) machinery, such as: the integral impeller of the centrifuge, the impeller of the water jet propulsion for the ship, etc. Widely used in aviation, aerospace (liquid rocket pump), navigation, military, scientific research, precision instruments, high-precision medical equipment and other fields, its quality directly affects its aerodynamic performance and mechanical efficiency. [0003] There are currently three processing methods for closed impellers: [0004] 1. Integral casting molding, the material structure of the parts is relatively loose, the strength is poor, and the bearing capacity is low; [0005] 2. Direct machining and forming, using cylin...

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Problems solved by technology

[0004] 1. Integral casting molding, the material structure of the parts is relatively loose, the strength is poor, and the bearing capacity is low;

[0005] 2. Direct machining and forming, using cylindrical bar material for machining and forming, the manufacturing technology is difficult, this type of impeller has certain limitations on the impeller structure, such as the flow channel should not be too narrow, the blade twist rate should not be too large, etc., otherwise the tool If you can't enter, you can't cut it naturally;

The welding method mainly adopts salt bath brazing, and the impeller welded by this method often has a certain influence on the hardness of the material, and it is difficult to guarantee the original hardness value of the material after welding

[0007] In the past, the hardness value of parts after salt bath brazing was guaranteed by heat treatment: quenching-tempering-aging. With this method, the processing quality of parts is difficult to control. For example, quenching is easy to cause cracks or cracks in parts materials. Desoldering phenomenon, in addition, the processing cycle of parts is long and the cost is high, it is difficult to meet the needs of the rapid development of military products