CN104148562A - Cogging method for Ti2AlNb-based alloy ingot - Google Patents

Abstract

The invention discloses a cogging method for a Ti2AlNb-based alloy ingot. The cogging method comprises the steps that the Ti2AlNb-based alloy ingot is loaded on a wire cutting machine and manufactured into a Phi290*280mm bar; the Ti2AlNb-based alloy ingot is sleeved with alumina silicate fibers, placed into a high-temperature heating furnace to be heated to 1150 DEG C and then placed on a press after the temperature is kept for 80 minutes, and repeated upsetting and drawing are performed at the strain rate of 0.01S-1; the ingot is drawn out to 350mm after first fire, upset to 350mm after second fire, drawn out to 350mm after third fire, upset to 270mm after fourth fire and drawn out to 350mm after fifth fire, and air cooling is performed. The ingot is returned to the furnace to be heated to 1150 DEG C and the temperature is kept for 40 minutes for each fire, and the final forging temperature of each fire is guaranteed to be equal to or larger than 1050 DEG C. According to the method, the steady state deformation resistance of the Ti2AlNb-based alloy ingot is reduced in a fully dynamic recrystallization state, the technological plasticity is improved, cracking is prevented, a cast structure is smashed completely, and a uniform and dense forge structure is obtained.

Description

Ti 2the cogging method of AlNb base alloy cast ingot

Technical field

The present invention relates to a kind of cogging method of ingot casting, particularly related to Ti ₂the cogging method of AlNb base alloy cast ingot.

Background technology

Ti ₂alNb base alloy is a kind of novel lightweight high-temperature structural material, it is to have Ti, the intermetallic compound that Al and Nb form, such alloy is with O phase, B2/ β phase is two-phase or the three-phase composite tissue forming with α 2 mutually, there is density low, elastic modelling quantity is high, elevated temperature strength is high, fracture property is high, creep resistance is high, hot expansibility is low, the advantages such as nonmagnetic and fire resistance is good, compare with high-temperature titanium alloy and there is higher serviceability temperature, creep-resistant property and elevated temperature strength, its density and thermal coefficient of expansion are starkly lower than nickel base superalloy again, it is the preferably selection that replaces titanium alloy and high temperature alloy in following aerospace field, have broad application prospects.

Ti ₂although AlNb base alloy has many good qualities, but there is a fatal weakness, the malleability of this alloy is very poor, controls bad very easy generation forging crack.

Summary of the invention

The technical problem to be solved in the present invention is to provide a kind of forging method that adopts three pullings and twice jumping-up, realizes Ti ₂the cogging of AlNb base alloy cast ingot.The method can make Ti ₂alNb base alloy reduces its stead deformation drag, improves process plastic under the state of complete dynamic recrystallization, prevents cogging crackle, makes as-cast structure completely broken, obtains even, fine and close as-forged microstructure.

For solving the problems of the technologies described above, Ti of the present invention ₂the cogging method of AlNb base alloy cast ingot, its technical scheme comprises the following steps:

By Ti ₂on AlNb base alloy cast ingot, wire cutting machine is made the bar of a φ 290 * 280mm; Adopt alumina silicate fibre to Ti ₂alNb base alloy cast ingot carries out after jacket, inserts and in high-temperature heater, is heated to 1150 ℃ of insulations after 80 minutes on placement force machine, with 0.01S ^-1strain rate carry out repeatedly jumping-up, pulling: the first fire pulls out to 350mm, and the second fiery jumping-up is to 270mm, and the 3rd fire pulls out to 350mm, and the 4th fiery jumping-up is to 270mm, and the 5th fire pulls out to 350mm, air cooling; Between every fire time, melt down and be heated to 1150 ℃ of insulations 40 minutes, guarantee that the final forging temperature of every fire time should>=1050 ℃.

Compared with prior art, beneficial effect of the present invention is as follows:

Ti of the present invention ₂the cogging method of AlNb base alloy cast ingot, the deformation temperature interval that it adopts is 1050 ℃～1150 ℃, and this temperature range is B2 monophase field, when this temperature range distortion, there is the dynamic recrystallization of continuous recrystallization mechanism in B2 crystal grain, can broken as-cast structure by dynamic recrystallization.Meanwhile, under this condition, in the time of can guaranteeing ingot casting distortion, there is good process plastic, can guarantee that again this alloy has lower stead deformation drag when distortion.

Consider when forging, need to enhance productivity as far as possible, reduce the temperature drop of workpiece, and make Ti ₂alNb base alloy is recrystallization fully, and during cogging, selected strain rate is Ti ₂can there is the strain rate higher limit 0.01S of dynamic recrystallization in AlNb base alloy ^-1.

The present invention adopts the repeatedly cogging technics of pulling+jumping-up, makes in cogging process, and its total deformation arrives more than 50%, better broken Ti ₂alNb base As-cast Microstructure, forges and closes Ti ₂alNb base alloy internal flaw, makes microstructure homogenization.

The specific embodiment

Implement Ti of the present invention ₂the cogging method of AlNb base alloy cast ingot, need to provide the equipment such as forging high-temperature heating furnace, forcing press, manipulator.The specific embodiment is as follows:

Ti is provided ₂alNb base alloy cast ingot, its nominal chemical composition is: Ti-22Al-25Nb.

The cogging technics step of this alloy is as follows:

By Ti ₂on AlNb base alloy cast ingot, wire cutting machine is made the bar of a φ 290 * 280mm; Adopt alumina silicate fibre to Ti ₂alNb base alloy cast ingot carries out after jacket, inserts and in high-temperature heater, is heated to 1150 ℃ of insulations after 80 minutes on placement force machine, with 0.01S ^-1strain rate carry out repeatedly jumping-up, pulling: the first fire pulls out to 350mm, and the second fiery jumping-up is to 270mm, and the 3rd fire pulls out to 350mm, and the 4th fiery jumping-up is to 270mm, and the 5th fire pulls out to 350mm, air cooling; Between every fire time, melt down and be heated to 1150 ℃ of insulations 40 minutes, guarantee that the final forging temperature of every fire time should>=1050 ℃.

Claims (2)

1. a Ti ₂the cogging method of AlNb base alloy cast ingot, is characterized in that, comprises the following steps:

By Ti ₂on AlNb base alloy cast ingot, wire cutting machine is made the bar of a φ 290 * 280mm; Adopt alumina silicate fibre to Ti ₂alNb base alloy cast ingot carries out after jacket, inserts and in high-temperature heater, is heated to 1150 ℃ of insulations after 80 minutes on placement force machine, with 0.01S ^-1strain rate carry out repeatedly jumping-up, pulling: the first fire pulls out to 350mm, and the second fiery jumping-up is to 270mm, and the 3rd fire pulls out to 350mm, and the 4th fiery jumping-up is to 270mm, and the 5th fire pulls out to 350mm, air cooling; Between every fire time, melt down and be heated to 1150 ℃ of insulations 40 minutes, guarantee that the final forging temperature of every fire time should>=1050 ℃.

2. according to the Ti described in claim 1～2 ₂the cogging method of AlNb base alloy cast ingot, is characterized in that, described Ti ₂the nominal composition of AlNb base alloy is Ti-22Al-25Nb.