Process for strengthening surfaces of inner and outer walls of non-magnetic drill collar and internal and external threads of joints at two ends

Abstract

The invention discloses a process for strengthening the inner and outer walls of a non-magnetic drill collar and the internal and external threads of joints at two ends, wherein the horizontal non-magnetic drill collar rotates around a fixed axis; the spray head of a shot-blasting machine is aligned to the start ends of the inner and outer walls of the non-magnetic drill collar respectively so as to spray pills; the spray head axially moves towards the other end; then, the spray head of the shot-blasting machine is aligned to the start ends of the internal and external threads of the joints at two ends respectively so as to spray pills; and then, the spray head axially moves towards the other end. Aiming at the characteristics of the non-magnetic material, ZIRPRO ceramic ultra-fine pills are selected; shot blasting is driven by compression air; work pieces have very obvious cold hardening effect under collision of dense and high-speed pills; in the event that the non-magnetic characteristics of the work-pieces are not changed, besides obviously increased hardness, the erosion resistance of a formed surface compact metal layer is also increased; and the process disclosed by the invention is used for reducing the cracking rate caused by stress corrosion while drilling a well, also increasing the wear-resisting property simultaneously, and being beneficial to increasing the service life of the non-magnetic drill collar.

Description

Technical field [0001] The present invention relates to a process method for strengthening the surface of metal pipe fittings. In particular, the present invention relates to a process method for strengthening the surface of a slender metal pipe with a length-to-diameter ratio greater than 100, especially for non-magnetic drill collars. The surface strengthening process of the inner and outer threads of the outer wall and the two-end joints belongs to the technical field of metal surface treatment. Background technique [0002] Non-magnetic drill collar is a kind of petroleum drilling tool, which is used to connect drill pipes and drill bits when used in drilling. Under current conditions, low-carbon high-chromium-manganese alloy steel is the best material for manufacturing non-magnetic drill collars. This kind of austenitic material has good low magnetic permeability and can be protected from magnetic field interference, providing a measurement environment free from magnetic fi...

AI Technical Summary

Problems solved by technology

[0003] The present invention mainly aims at the problems that the non-magnetic drill collars in the prior art are not wear-resistant and prone to stress corrosion cracking, and proposes a surface strengthening process for the inner and outer walls of the non-magnetic drill collar and the inner and outer threads of the joints at both ends without changing the material. The process method is reasonably arranged, easy to implement, and the efficiency is obviously increased, which greatly improves the service life of the non-magnetic drill collar

Images