Characteristics and technology of laser welding of diamond segment

Laser welding occupies a very important position in the entire laser processing technology. Since the advent of the laser, its application potential in welding has been paid attention to and gradually realized. The main advantages of laser welding are:

1: Large melting depth, high speed, large fusion area per unit time, is an efficient welding method; In addition, the depth and width of the weld is relatively large, the heat-affected area is small, and the deformation of the weldment is small. It is especially suitable for the welding of precision heat-sensitive parts, which can eliminate the post-weld orthopedic processing technology;

2: And laser welding generally does not fill metal, and does not require solder;

3: Laser welding can be fully protected with inert gas, so the weld will not be polluted by the atmosphere, thereby enhancing the firmness and stability of the welding;

4: The welding system is highly flexible and easy to realize automatic operation.



The application prospect of laser welding is broad, and it is very meaningful to accelerate the development of related processes and technologies. Therefore, Lin Xing diamond tools began to touch the research and development and process improvement of laser welding technology in 2017. At present, the company already has a full set of laser welding technology, and Lin Xing diamond tools has a domestic first-line brand welding machine for welding diamond segments.

The diamond circular saw blade is composed of a blank blade and arc-shaped segment. The blank blade material is alloy steel, mainly 38CrM o Al, 30CrM oV, M45 steel, etc.,The serrations are iron-bond, cobalt-bond, nickel-bond or copper-bond powders mixed with diamond hot pressing and sintered segments. The process of combining the blank blade and the segment is the work to be completed by laser welding.  At present, our country mostly adopts high-frequency and silver soldering (mainly silver-copper soldering) welding method, the welding production efficiency is low, the joint heat resistance is not good, and the saw blade is prone to segment fall off (segment chipping) during use.

Developed countries such as the United States, Britain, and France began to study the process of laser welding diamond saw blades in the mid-1980s. Because of its non-collapsing, safe and reliable, high-temperature strength is much higher than that of traditional welding saw blades, It can realize the advantages of high-speed automatic production and no need for follow-up processing.

 

The domestic laser welding process has only been developed in recent years. Using 45 steel or 40Cr as the blank blade, although it has good weldability, the strength of the blank blade is not enough and easy to deform; using 65M n as the blank blade, the overall performance is good, and it is the national standard for diamond saw blade blank blades in my country. However, 65M n belongs to high-carbon steel. In the process of rapid heating and cooling, a large amount of high-carbon martensite is easily produced in the heat-affected zone. The weldability is poor and the welding performance cannot be guaranteed; therefore, special low-carbon steel is mostly used as the base material at present. If 65M n is to be used as the blank blade material, the laser welding of segment must be improved. At present, long-term tests have shown that a transition layer is introduced between the 65M n alloy steel and the diamond cutter head, and a molten pool is formed between the transition layer and the blank blade with a laser for high-speed melting and solidification, It can increase the strength of the seam, ensure the quality, and meet the requirements of use.