Drill rods include light drill rods and heavy drill rods. Depending on the manufacturer and type of drill rod, the production process is not quite the same. Today, we mainly share drill rods produced by friction welding process.

1. What is the friction welding process?

Friction welding process is a pressure welding method that uses the heat generated by mutual friction in the relative movement of the welded contact surfaces to bring the ends to a thermoplastic state, and then quickly top-forging to complete the welding.

2. What is a guide rod?

Friction welding process has been used in the production of guide rods. Guide rod is a kind of rod whose diameter is close to that of rock drill bit, and is usually installed in front of the first drill rod of rock drilling tools to ensure the straightness of drill hole. In addition, when drilling a large diameter, long depth downward hole with gas discharge, it is necessary to ensure the straightness of the hole, but also requires that the gap between the rod and the rock wall is small, so that the pressure of the gas discharge increases and quickly discharge rock debris from the bottom of the hole. Thererfore there are also cases where all rock drilling tools use guide rods.

3. Why use the friction welding process for guide rod?

Threads at both ends of guide rod adopt female/male thread quick-change design, and the aperture of the central water (gas) hole is small, while the central hole of the rod is large. It is impossible to use the same hollow steel bar process the drill rod with the diameter-changing structure of the center hole. Therefore, the only way to complete the production of drill rod is to use the process of welding the two end joints with drill rod. Friction welding technology is favored by the machining industry for its characteristics of higher strength of the welded parts than the non-welded parts, and it has become the preferred equipment for rock drill steel and rock drilling tools enterprises to process guide rod, GT60 drill rod, and large diameter tubular drill pipe.

4. The development of friction welding process to produce drill rod

Before 2002, drill rods produced by foreign rock drilling tools companies were processed with whole hollow steel, but around 2003, a kind of MF rod for open-air rock drilling jumbos called Sandvik TOUGH appeared on the rock drilling tools data of Sandvik, and it was stated that it was a new type of rods with high strength and toughness produced by friction welding technology.

After the introduction of friction welding technology to produce drill rods for drill jumbos, it soon attracted the attention of foreign rock drilling tools manufacturers. Now, a large part of drill rods of Sandvik and Atlas Copco with a diameter of 38 mm or above for open-air hydraulic rock drilling jumbos are produced by friction welding technology. It can be said that the production of drill rods for drill jumbos by friction welding technology is already a successful production process.