Manufacture method of ship rudder horn

Abstract

The invention discloses a method for producing a rudder horn of a ship, which can ensure that the technical and quality parameters of the rudder horn can achieve or override the material codes and requirements of foreign classification societies. The invention adopts the technical proposal so that a set of smelting technique is developed: ingredient selection, the control of smelting temperature,oxygen blast, and the control of argon blowing parameter, etc., are carried out so as to solve the problem of the control of the content of chemical elements, especially, ensure the content of aluminum and nitrogen to meet the requirement; the optimum casting technique is prepared: the design of the casting head and the pouring head and the selection of modeling material are carried out so as to avoid crack and shrinkage porosity, and meet the requirements on nondestructive examination of the cast and the size precision; a specific heat treatment technique is prepared: the selection of temperature and time for temperature rise, heat preservation and temperature decrease, especially the application of a temperature decrease method, so as to solve the problem of insufficient mechanical property of the cast, especially the low temperature impact property.

Description

1. Technical Field: [0001] The invention relates to a manufacturing method, in particular to a manufacturing method of a rudder arm of special grade steel for ships. 2. Background technology: [0002] The rudder arm is a key part of ship equipment. It has a large weight, a long length, and a wall thickness of 100-500 mm. In the specifications of foreign classification societies, special grades of steel are required for materials. [0003] The technical quality requirements of the products are as follows: [0004] 1) Chemical composition [0005] C≤0.23%, Si≤0.60%, Mn=1.20 to 1.60%, P≤0.035%, S≤0.035%, Cr≤0.30%, Mo≤0.08%, Cu≤0.3%, V≤0.03%, Al=0.015 -0.08%, (N%xAlacidsol%)x10 5 ≤60. [0006] 2) Mechanical properties [0007] Rm≥520Mpa, Rp0.2≥260Mpa, A4≥20%, Z≥25%, Kv≥27J (0℃). [0008] 3) The magnetic particle non-destructive testing and ultrasonic non-destructive testing of the surface and internal quality of the casting meet the requirements of ship inspection. [0009] The chemical com...

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Problems solved by technology

[0009] The chemical composition of the rudder arm has strict requirements on aluminum content, nitrogen content, and residual elements. It is difficult to smelt molten steel that meets the requirements in general smelting processes. In terms of mechanical properties, the impact performance is required to be greater than 27 joules at 0°C. Heat treatment process The formulation is also very critical, otherwise it is difficult to achieve the parameters, its length, weight, and wall thickness are very different, which brings difficulties to the formulation of the casting process, increases the tendency of cracks and shrinkage porosity, and the accuracy of dimensions is not easy to control, so A comprehensive and advanced approach must be taken to produce qualified products

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