Hot-dip galvanizing method for heat-treatment carburization workpieces

Abstract

The invention discloses a hot-dip galvanizing method for heat-treatment carburization workpieces. The method comprises the following steps: (1) performing pre-operation of cleaning a heat-treatment carburization workpiece; (2) controlling the heat-treatment carburization workpiece subjected to pre-operation to undergo hot-dip galvanizing operation at a dipping-plating temperature of 500+ / -50 DEG C for 35+ / -10 seconds so as to form a zinc-plated layer; (3) separating redundant liquid zinc from the heat-treatment carburization workpiece with the formed zinc-plated layer; and (4) subjecting the heat-treatment carburization workpiece from which the redundant liquid zinc is separated to two-stage impurity removal and cooling, namely soaking the heat-treatment carburization workpiece in ammoniachloride solution at 100 DEG C for impurity removal and cooling, taking out and then soaking the workpiece in cooling water at 60+ / -10 DEG C for second cooling. The steps can perform hot-dip galvanizing treatment on self-drilling screws or self-tapping screws and other heat-treatment carburization workpieces needing to adjust the surface and heart hardness thereof through the heat treatment of carburization so as to adjust the surface and heart hardness of the workpieces and improve anticorrosion and antirust effects.

Description

technical field [0001] The invention relates to a hot-dip galvanizing method for heat-treated carburized workpieces, especially refers to the heat-treated carburized workpieces that need to undergo carburizing heat treatment to adjust the hardness of the surface and core at the dipping temperature. The method of hot-dip galvanizing at 500±50°C and dipping time of 35±10 seconds. Background technique [0002] Iron and steel materials are indispensable and important resources in today's human life. However, due to their own characteristics, "corrosion" is always accompanied by steel materials, and steel materials are consumed all the time, especially in Taiwan, which is located in high temperature and high humidity. Under the harsh environment of the oceanic monsoon, the problem of "corrosion" is more serious than other areas. [0003] Many advanced countries and regions have noticed the seriousness of "corrosion" very early. It is estimated that the loss caused by corrosion p...

AI Technical Summary

Problems solved by technology

However, it seems that there is no major institution to face up to this problem in Taiwan

Therefore, it is very distressing to see "rust" landscapes everywhere caused by poor anti-corrosion technology or wrong anti-corrosion methods, and hot-dip galvanizing has been used for more than 150 years. There are about 20,000,000 tons of steel protected by hot-dip galvanizing in the world every year, and its maintenance value to human limited resources is really difficult to estimate (excerpted from the website of Taiwan Hot-dip Galvanizing Association http: / / www.galtw.org.tw / info.htm), currently in Taiwan, hot-dip galvanizing has been used on general screws and nuts to form a galvanized layer for anti-corrosion function for more than 30 years, but because hot-dip galvanizing must be performed at a temperature of about 500 ° C Carrying out at high temperature is itself a heat treatment operation, and general special workpieces usually undergo quenching and tempering heat treatment or carburizing heat treatment to adjust the hardness of the surface and core. Workpieces undergoing quenching and tempering heat treatment will change the composition particles inside the workpiece, Let the material of the workpiece meet the required grade requirements, so the quenching and tempering heat treatment will strengthen the hardness of the workpiece and stabilize the internal structure of the workpiece, while the carburizing heat treatment mainly uses carbon elements to penetrate into the surface of the workpiece, so that the workpiece forms a carburized layer and reaches the workpiece. The surface layer is hardened, which has little effect on the hardness of the core of the workpiece, but because the internal structure of the workpiece after quenching and tempering heat treatment is stable, it has little effect on the mechanical properties of the workpiece after hot-dip galvanizing, but for Heat-treated carburized workpieces such as tail screws or self-tapping screws need to undergo carburizing heat treatment to adjust their surface and core hardness. Since the carburized layer is thin and carburizing heat treatment has little effect on the hardness of the workpiece core, the heat treatment The immersion temperature of galvanizing, the length of immersion plating time, and the subsequent cooling operation often lead to changes in the mechanical properties of heat-treated carburized workpieces, which cannot meet the requirements of finished products. Therefore, only electroplating or mechanical galvanizing can be used to form galvanized The mechanical galvanizing method includes mechanical methods such as galvanizing, galvanizing or zinc spraying, but the thickness of the galvanized layer formed by the electroplating method is limited and the firmness is poor, while the mechanical galvanizing method is galvanizing, Both the galvanizing method and the galvanizing method have the disadvantage of poor uniformity, resulting in their anti-corrosion effect not being as good as hot-dip galvanizing

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