Manufacturing method of pup joint

Abstract

The invention relates to a manufacturing method of a pup joint, which is characterized by comprising the following processing steps: (1) thermal treatment, straightening and flaw detection of a pipe body: the thermal treatment process comprises quenching and tempering; after thermal treatment is completed, carrying out full-length straightening on the pipe body with a six-roller straightener; and carrying out full-length flaw detection on the pipe body with a flaw detector; (2) saw-cutting: saw-cutting the pipe body after thermal treatment, straightening and flaw detection into a short material with a sawing machine; (3) initial machining: flattening the saw mouth of the end surface of the short material on the sawing machine, machining an excircle of the obtained short material into Phi132 plus or minus 0.3mm with the sawing machine, and then polishing the inner surface of the short material pipe body at 80-120mm from a port with an automatic sharpening machine to remove surface scale; (4) welding: directly welding a male joint and a female joint with two ends of the short material pipe body respectively on a continuous welding machine; (5) thermal treatment of welding seams: quenching and tempering the welding seams with a medium-frequency induction coil; and (6) machining. The manufacturing method has stable welding process and lower machining cost.

Description

technical field [0001] The invention relates to a method for manufacturing a short drill rod, in particular to a method for manufacturing a short drill rod for oil drilling, and belongs to the technical field of oil drill rod manufacturing. Background technique [0002] As the length adjustment of the drill pipe and the transition connection between the drill pipe and the transition joint, the short drill pipe is widely used in domestic and foreign oil drilling; at present, there are generally two manufacturing methods for the short drill pipe manufacturing technology: [0003] 1. Overall processing: [0004] The processing flow is: selection of round steel → sawing → deep hole drilling → heat treatment → straightening → flaw detection → machining (male and female joint thread and shape processing, pipe body shape processing) → phosphating → finished product. [0005] The specific plan is: [0006] ① Selection and sawing of round steel: select forged round steel with a siz...

AI Technical Summary

Problems solved by technology

[0010] ⑤Phosphating: Mainly thread phosphating, but due to equipment conditions, only the overall length of phosphating can only be treated;

[0016] ②Pipe end thickening: thicken the pipe end; because the pipe is short, the existing pipe body fixture cannot be used when the pipe end is thickened, and a shorter fixture needs to be customized, and the shorter pipe body clamping section leads to The pipe body is easy to slip during the forging process, and it is difficult to ensure the quality of thickening;

[0018] ④ Straightening and flaw detection: cannot be done online, but can only be done manually;

[0019] ⑤Friction welding: directly weld the male joint and the female joint to both ends of the pipe body on the continuous welding machine; Set of centering fixtures and oil cylinders, only one set of fixtures are used for clamping, so there is also the phenomenon that the pipe body is easy to slip during upsetting during clamping, which cannot guarantee the welding quality, and at the same time, the welding straightness is out of tolerance

[0022] Compared with the overall processing, welding processing has lower material and production costs, but in the two processing procedures of pipe end thickening and friction welding, due to the raw materials and equipment status, the production is more difficult, and it is difficult to ensure the stability of production, resulting in Product straightness is low and product quality is not high; due to the limitation of the length of the thickened end, the number of times of re-welding is limited