Forging forming technology for high-temperature steam pipeline of supercritical unit

Abstract

The invention discloses a forging forming technology for a high-temperature steam pipeline of a supercritical unit. The forging forming technology comprises the steps that firstly, a heat-resisting steel ingot is selected and used; secondly, the steel ingot is heated up to 580 DEG C to 620 DEG C, and heat preservation is carried out for 3 hours; the steel ingot is heated up to 830 DEG C to 870 DEG C at a rate ranging from 55 DEG C/h to 60 DEG C/h; heat preservation is carried out for 4 hours; the steel ingot is heated up to 1130 DEG C to 1170 DEG C at a rate ranging from 78 DEG C/h to 82 DEG C/h; heat preservation is carried out for 4 hours; the steel ingot is heated up to 1210 DEG C to 1250 DEG C at a rate ranging from 78 DEG C/h to 82 DEG C/h; heat preservation is carried out for 2 hours; thirdly, the heated steel ingot is taken from a furnace, the head and the tail of the steel ingot are chopped off; fourthly, upsetting is carried out on a forging stock, and an upset piece is drawn out to form a square flat forging stock; fifthly, a tilted three-way forge piece is formed by the forging stock; sixthly, a branch pipe hole is punched; seventhly, main pipe holes are punched at the two ends of a main pipe body of the tilted three-way forge piece respectively; eighthly, heat treatment is carried out after forging. According to the forming technology, the production efficiency is high, internal organizations of the forge piece is even and dense, the forming technology is applicable to forging forming of tilted three-way forge pieces of supercritical units and ultra supercritical units with various specifications.

Description

technical field [0001] The invention belongs to the technical field of forging, and in particular the invention relates to a free forging process for oblique triangles of main steam pipes of nuclear power or thermal power supercritical generating sets. Background technique [0002] Supercritical and ultra-supercritical generator sets are advanced and efficient power generation technologies that improve power generation efficiency by increasing steam parameters, and have significant energy-saving and environmental-improving effects. The pressure of the working medium at the outlet of the unit boiler exceeds or far exceeds the critical pressure of the working medium. The common main steam parameters of the supercritical units put into operation are 23.5-26.5MPa, 538-566°C, and the main steam parameters of the ultra-supercritical units even reach 35 MPa, 700°C or higher, so supercritical and ultra-supercritical units have unparalleled economics, and the efficiency of a single u...

AI Technical Summary

Problems solved by technology

First of all, the main and branch pipes, especially the main pipe holes, are deep and long holes. The punches are used to punch the holes, and the punches cannot be withdrawn from the blank, so it is difficult to punch the holes. Upsetting and elongating or forming; although domestic and foreign countries have begun to use forging and then machining to make oblique tees, that is, first forging a forged billet with its outline, and then conducting deep holes and deep holes on the forged billet. Drilling of branch pipe holes, and cutting and removal of outer profile materials, and finally form the finished oblique tee

Although this production process improves the mechanical properties of the oblique tee through forging and improves the internal structure defects of the material, it has many shortcomings: firstly, the utilization of materials is low, and most of the materials are machined and become waste materials that are difficult to reuse. Far more than the actual amount of material used, resulting in a great waste of high-quality alloy materials, the material utilization rate is often lower than 15%, and the larger the size of the inclined tee, the lower the utilization rate

Second, the technological process is complicated and the production efficiency is low. After the steel ingot is forged into a square blank, the main and branch pipe holes and the outer contour are processed. Since the main pipe and branch pipes are deep and long holes, they need to be drilled and then boring Hole to a predetermined size, so the workpiece needs to be transferred in multiple processes, the production cycle is long and the efficiency is low

Third, since the weight of the blank is several times the weight of the finished product, it is difficult to ensure the purity of molten steel d

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