There are many steel grades of raw materials for rock drilling tools, and their properties vary greatly, and each steel grade has its suitable brazing process. If you do not know the steel grades, forging and heat treatment cannot be carried out. If all rock drilling tools are manufactured according to one process without differentiating steel types, their quality will not be guaranteed. Therefore, it is of great significance to identify the steel used for rock drilling tools.
The identification of steel for rock drilling tools is essential to analyze the chemical composition of the steel. Chemical composition analysis is the most reliable identification method, but when the conditions for chemical composition analysis are not available, how should it be identified?
Although there are many types of raw material steel for rock drilling tools, there are two main differences: first, the carbon content is different; second, carbon steel and alloy steel. Therefore, according to the chemical composition, the steel used for rock drilling tools can be divided into three categories: low-carbon steel, medium-carbon steel, and high-carbon steel. There are carbon steel and alloy steel in high carbon steel, while there is no carbon steel in medium and low carbon steel, and they are all alloy steel.
Identification method of steel for rock drilling tools
Spark identification
Spark identification is to qualitatively judge the chemical composition in steel according to the shape and color of the spark burst and then identify various steel types.
The tools for spark identification generally use grinding wheels. There are portable single-wheel grinding wheels and double-wheel fixed electric grinders. When identifying sparks again, be sure to avoid direct sunlight.
The sparks ejected from the grinding wheel have three parts, the spark near the root of the grinding wheel blade, the middle spark is called the middle spark, and the end spark is called the tail spark. Sparks are bursts, streamlines, and pollen. Among them, there are primary flowers, secondary flowers, and tertiary flowers.
Depending on the carbon content of the drill steel, the sparks are also different. Low-carbon steel has more streamlines and less popping. And the explosion is mostly secondary flowers, a small number of three flowers. The whole spark is relatively long, the streamline is thin, and the light is bright. There are more sparks in medium carbon steel, most of which are three times, with more streamlines and thinner sparks, shorter and yellow sparks. High-carbon steel has many fine streamlines, a lot of bursts, short sparks, dark red sparks at the root, and a lot of tertiary flowers.
Silicon-manganese-molybdenum brazing steel grades have the following characteristics when performing spark identification. Manganese-containing steel has a large amount of pollen in the middle of the spark, which is very obvious; silicon-containing steel streamlines are shot out section by section, bright and yellow; steel containing molybdenum, mainly has guns at the tail of the spark Spiny tail flowers; when containing sulfur, the sparks have a flower-centered fire cluster or a large bunch of sparks, and the flowers are bright.
Spark identification mainly depends on visual inspection, so the accuracy of the judgment depends on the number of practices and the accumulation of experience. The more practice, the more experience, and the more accurate judgment.
Fracture identification
The fracture of the brazing steel is the cross-section after the brazing steel is broken. Fracture identification is to judge the type of rock drilling tool steel according to the characteristics of the fracture. According to the fracture of brazing steel, carbon steel, and alloy steel can be distinguished. The fracture of carbon steel is rough and the shiny grains on the fracture can be seen clearly, and the entire fracture is gray-black. The fracture of alloy steel is fine, and grayish-white and the shiny grains cannot be seen.
In addition, it is also possible to identify the steel type of rock drilling tools according to the steel coating color and sound. Especially in the operation process of the brazing process, such as: when forging and heating, carbon steel is easy to heat, and alloy steel is not easy to heat.
In short, strengthening the identification of steel for rock drilling tools is not only the premise of correctly formulating and implementing the production process of rock drilling tools but also can ensure the reasonable use of steel for rock drilling tools.
