A method of using gas to purify steel ingot and reduce a segregation

A technology for gas purification and steel ingots, applied in the field of steel ingot manufacturing, can solve the problems of affecting the mechanical properties of materials, difficulty in operation, decrease in qualification rate, etc., and achieve the effect of increasing the adsorption area of ​​inclusions, improving the quality of steel ingots, and ensuring the argon blowing time.

Active Publication Date: 2011-12-07
中科西王特钢有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In recent years, although domestic steelmaking equipment has been continuously upgraded and improved, the quality inspection requirements for forgings have also been continuously improved, so the pass rate of products has not increased significantly, and some pass rates have declined instead. One of the most important reasons for this result First, there are large inclusions in steel ingots, so it is of great significance to solve the defects of large inclusions in steel ingots; for some steel types, such as rotor steel, MnS inclusions in A segregation will seriously affect the mechanical properties of the material and become the source of cracks. Therefore, reducing the A segregation in the steel ingot will further improve the quality of forgings
[0005] The large inclusions in the steel ingot are all foreign, most of them are slag, eroded refractory materials, mold slag, the main means to reduce these inclusions is refining outside the furnace, but once the foreign inclusions enter the ingot mold with the molten steel , other external means are rarely used to remove these large inclusions, the main reason is that the operation is difficult and the means of operation are few. In addition, if the external means are not appropriate, it will cause other internal quality defects of the steel ingot

Method used

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  • A method of using gas to purify steel ingot and reduce a segregation
  • A method of using gas to purify steel ingot and reduce a segregation
  • A method of using gas to purify steel ingot and reduce a segregation

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Experimental program
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Embodiment 1

[0037] 1. The steel ingot is made of No. 45 medium carbon steel, and the specific chemical composition is shown in Table 1. The ingot mold material is ordinary water glass sand; the height-to-diameter ratio of the riser is 2 (height-to-diameter ratio: H is the height of the riser, D is the diameter of the top of the riser, and d is the diameter of the root of the riser); the molten steel is fired at a high temperature, the temperature of the furnace is 1620-1640°C, the pouring temperature is 1580±10°C, and the cavity is filled with argon before pouring , pouring under the protection of argon; the steel ingots are fully baked before sand casting to prevent gas hole defects caused by gas generation. The design goal of the above process parameters is to ensure good internal quality of the steel ingot and prolong the solidification time of the steel ingot appropriately.

[0038] Chemical composition of table 145# steel (wt%)

[0039]

[0040] 2. Select two 500kg steel ingots...

Embodiment 2

[0049] The difference from Example 1 is:

[0050] In this example, the liquid mold flux can use SiO 2 -Al 2 o 3 -CaO-CaF 2 Slag system, by weight percentage, 20% SiO 2 ;25%Al 2 o 3 ;35%CaO;20%CaF 2 .

[0051] 1. The pouring weight of steel ingot is 700kg, and the specific size is Φ400mm×800mm.

[0052] 2. According to the specific size of the steel ingot, the rotary argon blowing ventilation equipment is designed, and three ventilation pipes are selected. The inner diameter of the ventilation pipes is

[0053] 3. The material of the ventilation pipe is corundum pipe, and the preheating temperature is 900°C.

[0054] 4. During the pouring process, extend the preheated air pipe from the top of the steel ingot riser to half of the height of the steel ingot, and keep the argon pressure at 3 standard atmospheric pressure. When the molten steel is full of the ingot mold, quickly add the ingot Liquid mold slag commonly used for risers of steel.

[0055] 5. The argon blow...

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Abstract

The invention relates to the field of steel ingot manufacture, in particular to a method for purifying steel ingots and relieving A-segregation by using gas. By rotary argon-blowing ventilating equipment is arranged at a steel ingot riser, impurities in the steel ingots are removed and A-segregation is relieved, so that a difficulty of impurity removal after the steel ingot are cast in the prior art is overcome and a new means for inhibiting the A-segregation in the steel ingot solidifying process is provided. The method mainly comprises a rotary argon blowing technology, a riser ventilating technology, and a technology of selecting adding positions, number and argon blowing time according to ingot shapes. In the method, after molten steel is cast into steel ingot molds, the impurities inthe steel ingots are removed and the A-segregation defect of the steel ingots is overcome by the rotary stirring argon-blowing technology, and the method is simple and practical for improving the internal quality of the steel ingots.

Description

technical field [0001] The invention relates to the field of steel ingot manufacturing, and specifically relates to a method for purifying steel ingots with gas and reducing A segregation. A rotary argon blowing ventilation device is added to a riser of the steel ingot to remove inclusions inside the steel ingot and reduce A segregation. Background technique [0002] Such as Figure 5 It can be seen from the schematic diagram of macro segregation of large steel ingots that macro segregation generally exists in steel ingots of various materials and tonnages. Macro segregation includes: positive segregation zone VI, positive segregation at the top of the ingot (riser segregation IV), and negative segregation at the bottom (Negative segregation pile III), middle "V" type positive segregation II and surrounding "A" type positive segregation I. The main reason for the formation of macro-segregation is that the solidification time of the steel ingot is too long. The greater the to...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21C7/072B22D7/00B22D7/12B22D27/20
Inventor 刘宏伟傅排先康秀红李殿中夏立军李依依
Owner 中科西王特钢有限公司
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