Manufacturing technology of 718 alloy small-bore precise pipe

Abstract

The invention provides a manufacturing technology of a 718 alloy small-bore precise pipe. The manufacturing technology is characterized by comprising the following steps of (1) cold machining of an intermediate product, specifically, cold machining is conducted on the intermediate product by adopting combination of finish rolling and cold drawing, the finish rolling relative deflection of the intermediate product is 35-45%, the cold drawing relative deflection of the intermediate product is 20-30%, the rolling speed of finish rolling is 30-70 times / minute, and the rolling feeding quantity is 1.0-2.0mm / time; (2) intermediate heat treatment, specifically, bright annealing is conducted by adopting hydrogen protection, the intermediate annealing temperature range is 1,020-1,060 DEG C, the heatpreservation time is not shorter than 5 minutes, and rapid cooling is conducted after heat preservation is ended; and (3) heat treatment of a finished product, specifically: solution treatment or combination of solution treatment and aging treatment is adopted, the solution treatment is conducted by adopting bright heat treatment, and the aging treatment is conducted by adopting vacuum heat treatment. Through a deflection reasonable control technology, the cold machining effect is guaranteed, and the reasonable structure and performance are controlled through optimized intermediate heat treatment and the heat treatment of the finished product.

Description

technical field [0001] The invention relates to the technical field of alloy manufacturing, in particular to a manufacturing process of a 718 alloy small-diameter precision tube. Background technique [0002] Inconel718 alloy (hereinafter referred to as 718 alloy) is a precipitation hardening nickel-based superalloy containing niobium and molybdenum. The domestic brand is GH4169, and the American standard is UNS N07718. The alloy has excellent characteristics such as high strength, good toughness at high temperature, and good corrosion resistance in high and low temperature environments, and is widely used in important fields such as aerospace and oil exploration. In particular, many parts of modern aero-engines, such as turbine discs, blades, casings, shafts, stators, seals, supports, pipes, fasteners, etc., are made of 718 alloy. [0003] Due to the high strength of the 718 alloy, the yield strength of the annealed pipe at room temperature exceeds 400MPa, the tensile stre...

AI Technical Summary

Problems solved by technology

In addition, due to the relatively high high-temperature strength of the 718 alloy, it is difficult to obtain a pipe blank with ideal surface quality by using the traditional hot piercing process, and hot extrusion must be used to supply the blank.

At present, the suitable billet specifications for hot extrusion of 718 alloy are usually relatively large, generally with an outer diameter of more than 100 mm and a wall thickness of more than 10 mm. For ultra-small-diameter seamless pipes with a diameter of less than 8mm and a wall thickness of no more than 1mm, cold processing is more difficult

[0004] After consulting literature and domestic and foreign patents, there are no literature reports and patents related to the manufacturing process of 718 alloy small-diameter seamless pipes.

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