Failure Analysis of Rod Friction Welding

Friction welding is a solid phase pressure welding where the component is heated near the melting temperature. Friction welding has many advantages, such as high strength, there is no melt welding defects, high productivity, energy conservation, saving raw
materials and reduce the labor intensity, etc., and thus widely used. Good friction welding joints due to welding forging, although the welding The strength of the seam and the near seam is equal to or higher than that of the base material. At present, to ensure the comprehensive mechanical properties of welds is the focus of today's friction welding technology research. In order to improve the toughness of the weld, in recent years, the research mainly focused on two aspects: First, control the base material inclusions content; Second, optimize the friction welding process parameters. Friction welding technology at home and abroad to produce hollow sucker rod and solid sucker rod connection has been widely used. The friction welding process will directly affect the toughness of the joint and the service life of the sucker rod. Due to the existence of poor stability in the production process and lack of experience, can not be a good way to ensure the quality of the hollow sucker rod friction welded joints, so that the use of joints in the fracture occurred when there is a direct impact on the life of the sucker rod , Resulting in great economic losses, but also related to the safety of oil production.

Friction welding welding oil drill pipe there are two main ways: one is the joint and the same material with the same, or the same or different heat treatment process; the other is the joint and body dissimilar materials, heterogeneous friction welding pipe fittings Low alloy steel, while the body is the use of ordinary carbon steel, or joints using high-strength alloy steel, and the use of low-alloy steel pipe. As the larger force of the screw joint parts than the tube with a good material, and the quality of the joint only 4.5% of the quality of the entire oil drill pipe, significant savings in the material, reducing the oil drill pipe manufacturing.

At present, foreign friction welding machine for oil drill pipe is mainly driven by continuous drive and inertia. These two types of welding machines are basically standardized and serialized. The monitoring system of welding machine has been widely used in computer monitoring. In addition to time control, deformation control, energy control, but also the development of a number of special process control technology, such as friction torque and temperature monitoring technology. In order to facilitate the automation of the welding production process, abroad also studied a series of related technologies and peripherals, such as different types of flashover devices or loading and unloading devices,
non-destructive testing technology. The maximum forging force can be up to 3500kN, the welding machine can be equipped with computer control system, can save different specifications of the oil drill pipe full set of friction welding process parameters, welding oil drill pipe by welding After the heat treatment mechanical properties in full compliance with the United States API (American Petroleum Institute, American Petroleum Institute) standards. The same for the oil drill pipe welding inertia friction welding machine up to 2660kN maximum welding capacity of 6 5/8 "N80 steel level of the oil drill pipe.Compared with the continuous drive friction welding machine, Inertial friction welding machine has the advantage of less control parameters (only control the moment of inertia and pressure), welding heat affected zone is narrow.As with the continuous drive friction welding machine, inertia friction welding machine can also be equipped with computer control system, and can store different specifications of oil Drill pipe full set of friction welding process parameters, preservation and printing process parameters, and can be equipped with internal weld punching device, welding oil drill pipe after welding heat treatment mechanical performance indicators are also fully in line with the US API standard.