Heat keeping and forging and blank cogging method for GH742 alloy large steel ingot

Abstract

The heat insulating, forging and blank cogging method of large GH742 alloy steel ingot features the high temperature adhesive of marketable glass powder with softening temperature over 800 deg.c and the heat insulating material of marketable asbestos blanket with aluminum silicate fiber; the steel ingot heat insulating process including spreading glass powder onto the asbestos blanket and coating the steel ingot after heating at 900 deg.c; the heat insulating period of 5-6 hr; the blank cogging of heating at high temperature with forging time not less than 5 min, reducing amount of 30 mm and deformation amount not less than 50 %; and the performance test of the formed alloy blank. The present invention solves the difficult problem of hot blank cogging and forming large GH742 alloy steel ingot.

Description

technical field [0001] The invention relates to a method for hot-processing a high-temperature alloy in the metallurgical industry, in particular to a method for forging a high-temperature alloy that is difficult to deform. Background technique [0002] Superalloys are important metal materials necessary for modern aero-engines and rocket engines. It can withstand greater stress and be used for a long time under high temperature (generally 600-900°C), oxidizing atmosphere and gas corrosion conditions. Due to the high degree of alloying of superalloys, it is very difficult to open billets by hot processing. The degree of alloying can preliminarily determine the thermal processing and forming properties of superalloys: superalloys with relatively low alloying degrees have low deformation resistance, good plastic deformation, and are relatively easy to be deformed by thermal processing; while high-temperature alloys with high alloying degrees, thermal processing The temperatu...

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Problems solved by technology

[0005] At present, among the common thermal insulation measures used for hot-working forging and blanking of GH742 alloy, the more feasible is the sheathing technology, that is, the forging machine sheathing forging. Slow down the cooling rate of the steel ingot, delay the thermal processing and deformation time of the steel ingot) and heat together, and then use the forging press, multiple fires (when forging deformation, the maximum deformation allowed for the hard-to-deform alloy is small, and the plastic deformation temperature It is very narrow and the hot processing time is very short, so it needs multiple forging) to hot-process and forge the steel ingots and metal pipes. Covering the steel ingot (or forging billet), the process is complicated, the production time is long, the cost is high, and the shape of the alloy billet is also limited (relatively speaking, the round alloy billet is relatively easy, and the square alloy billet is relatively easy. difficulty)

[0006] To sum up, the thermal processing blanking of large steel ingots (steel ingot diameters greater than 350mm) (in terms of domestic technical equipment conditions, hot processing forging billet blanking) has always been a difficult point in the production of GH742 alloys, which has seriously affected my country's aero-engine turbine discs. Localization of materials (at present, there is no report on the successful forging of large ingots and the use of die forging in China)

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