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Method for controlling internal defect of large forging

A technology for forgings and spindles, which is applied in the field of quality control of large forgings, can solve problems such as cracks, improper control of forging parameters, and failure to give them, and achieves the effect of simple control methods and easy process design.

Inactive Publication Date: 2014-09-10
DEQIAN HANGZHONG FORGING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The second is that the improper control of forging parameters during forging causes excessive tensile stress, which promotes the expansion of the original defects of the steel ingot, or causes new crack defects at the weaker joint of the steel ingot matrix
However, a general method with general guiding significance has not been given, and there is no patent report on controlling the internal defects of large forgings.

Method used

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  • Method for controlling internal defect of large forging

Examples

Experimental program
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Effect test

Embodiment 1

[0032] Main shaft forging of high and medium pressure steam turbine

[0033] The weight of the forging is 18.145 tons, and the material is 30CrlMolV; forging the main shaft requires 3 fires, and a 27-ton steel ingot blank is selected.

[0034] The first fire: The billet is heated to 1280°C (furnace temperature), held for 16 hours and then out of the furnace for forging; at the same time, press the pliers, chamfer, and cut the bottom, removing about 1350kg.

[0035] The second fire: the billet is heated to 1300 ° C (furnace temperature) high temperature diffusion (heat preservation) for 30 hours and then out of the furnace for forging:

[0036] The first process: upsetting to a diameter of Φ1800mm;

[0037] The second process: pull the blank into a flat square of 1680mm×1400mm (section size);

[0038] The third process: forging according to the specified reduction, feeding amount and turning method; the reduction amount: 19% to 21% on both sides; the feeding amount and turnin...

Embodiment 2

[0046] High pressure fan shaft

[0047] The weight of the forging is 14.41 tons, and the material is 25CrNiMoV; the required steel ingot is 20 tons of octagonal ingot.

[0048] The spindle needs to be forged twice.

[0049] The first fire: heat 20 tons of steel ingots to 1280 ℃ (furnace temperature), keep warm for 10 hours, and then come out of the furnace for forging; press the pliers, chamfer, and cut the bottom about 1000kg.

[0050] The second fire: heat the billet chamfered into Φ l030mm to 1310°C (furnace temperature) and keep it for 25h (100°C higher than the conventional thermal diffusion temperature) for high temperature diffusion and then out of the furnace for forging;

[0051] The first step: upsetting the Φ 1030mm billet to a diameter of Φ1600mm×980mm;

[0052] The second working step: pull the billet with a diameter of Φ1600mm×980mm into a flat square with a cross-section of 1250mm×1500mm;

[0053] The third step: forging according to the aforementioned reduct...

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Abstract

The invention relates to a quality control method of a large forging. The aim is to provide a method with good defect controlling effect and stable forging quality. A method for controlling internal defects of the large forging comprises the steps of firstly heating blank material to 1275-1285 DEG C, keeping for 10-17h, discharging, firstly forging, pressing a clamp handle on the blank material, and removing the bottom; secondly heating the blank material to 1295-1320 DEG C for high-temperature diffusion treatment, keeping for 25-31h, discharging, and secondly forging the blank material according to specified reduction amount, feed value and turning mode; and forging the blank material into forging products according to technological requirements, or thirdly heating the blank material to 1275-1285 DEG C, keeping for 5-7h, discharging, thirdly forging the blank material according to specified reduction amount, feed value and turning mode, and forging the blank material into forging products.

Description

technical field [0001] The invention relates to the thermal processing industry, in particular to a quality control method for large forgings. Background technique [0002] The causes of internal defects of large forgings: First, the steel ingot itself; the production process of large forgings includes smelting, ingot casting, solidification, forging and heat treatment. Defects such as pores, inclusions, and segregation structures inevitably exist in steel ingots due to metallurgical and solidification characteristics, and the larger the steel ingot, the more serious the defects. The second is that improper control of forging parameters during forging causes excessive tensile stress, which promotes the expansion of the original defects of the steel ingot, or causes new crack defects at the weaker joint of the steel ingot matrix. [0003] The essence of internal defects in large forgings is the macroscopic inhomogeneity of material composition and structure. There are many ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B21J5/00
Inventor 叶君芳许寅生徐永华
Owner DEQIAN HANGZHONG FORGING
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