A resistance brazing method for shield machine tool

Abstract

Abstract The present invention relates to the technical field of welding, in particular to a resistance brazing method for a shield machine cutter. The resistance brazing 5 method for the shield machine cutter of the present invention comprises the steps of: performing a resistance brazing to an assembly assembled from a cutter body, an alloy and a silver-based brazing filler metal, wherein an electrode material for the resistance brazing comprises a graphite felt. According to the present invention, resistance brazing is applied to the brazing of the shield machine cutter, such that a .0 reliable and efficient brazing connection between the cutter body and an alloy cutter bit can be better realised, the brazing strength can be improved, and the service life of the shield machine cutter can be prolonged. Drawings alloy silver-based brazingfiller metal cutter body Fig. 1

Description

technical field [0001] The invention relates to the field of welding technology, in particular to a resistance brazing method for shield machine cutters. Background technique [0002] In the field of underground engineering, using shield tunnel boring machine (shield machine) for tunnel construction has the advantages of high automation, saving manpower, fast construction speed, one-time hole formation, not affected by climate, ground subsidence can be controlled during excavation, and damage to the environment can be reduced. Due to the influence of ground buildings and the fact that underwater excavation does not affect ground traffic and other characteristics, the application of shield tunneling method construction is becoming more and more extensive. In the case of a long tunnel line and a large buried depth, it is more economical and reasonable to use a shield machine for construction. The shield cutter head and cutter are parts that are in direct contact with cuttings...

AI Technical Summary

Problems solved by technology

Due to the skin effect of induction heating, the heating is uneven, and the temperature of the matrix and the cemented carbide in the middle area of ​​the cemented carbide tool used in the shield tunnel boring machine is low. To ensure the quality of brazing, it can only be heated for a long time, which makes part of the cemented carbide overheat. Cemented carbide has low coefficient of linear expansion, high hardness, high brittleness, and low thermal conductivity. Long-term and high-temperature heating can easily cause cemented carbide buttons to collapse, crack, and cause carbide to fall off, causing damage to the tool and making it impossible to dig.

The second is to use intermediate frequency brazing and flame brazing composite technology to heat the cutter body and hard alloy through intermediate frequency induction. However, due to the skin effect of induction heating, the heating is uneven. The temperature of high-quality alloys is low, and flame brazing is mainly used to heat areas with low temperatures. This brazing process is complicated and it is difficult to realize automatic production

At present, the induction heating brazing method is mostly used in the industry. Due to the skin effect of induction heating, the temperature difference between the inside and outside of the workpiece is large, which brings two fatal problems: 1) Due to the inconsistent linear expansion of the heating process, there is a large gap in the tool Internal stress; 2) It must be heated for a long time to transfer heat, resulting in external overheating and turbulent flow of solder

On the other hand, it leads to serious oxidation of the tool

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