Method for controlling size and quantity of refined VN precipitated phases

A technology of precipitated phase and size, which is applied in the field of VN precipitated phase control, control and refinement of the size and quantity of VN precipitated phase, can solve the problems of unrecorded particle diameter range, etc., achieve the optimal number ratio, prevent grain slippage, improve stretching effect

Active Publication Date: 2015-01-28
WUHAN IRON & STEEL GRP ECHENG IRON & STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0011] However, the above patents and articles only record the size and shape of VN precipitates and their influence on the mechanical properties of steel, but do not record how to control the amount

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] First, during smelting, N element is added, so that the content of some elements in the steel (referred to as Invention Steel A) in this embodiment is [C]: 0.39%, [Cr]: 0.91%, [V]: 0.10%, [N ]: 0.0119%, the rest are Si, Mn, Al, Ti, Fe and impurities;

[0032] Converter smelting and continuous casting slab size: 200×200mm, the slab is heated at a temperature range of 1140-1165°C for 55 minutes;

[0033] The rolling start temperature is 1093°C, the Φ55mm round steel is rolled, and the final rolling temperature is 930°C;

[0034] After the final rolling, spray water to cool, and use the sealing state of the rolling raceway to make the rolled piece turn red, and stay in the range of 845-860°C for 1.7min, so that a large amount of VN is precipitated;

[0035] After exiting the sealed raceway, it is cooled by a cooling bed with a cooling rate of 0.82°C / s. After shearing and bundling, it enters the pit at 580°C for slow cooling.

[0036] In the inventive steel A, the VN prec...

Embodiment 2

[0041] First, during smelting, N element is added, so that the content of some elements in the steel (referred to as Invention Steel B) in this example is [C]: 0.50%, [Cr]: 0.95%, [V]: 0.20%, [N ]: 0.0070%, the rest is Si, Mn, Al, Ti, Fe and impurities;

[0042] Converter smelting and continuous casting slab size: 150×150mm, the slab is heated at a temperature of 1100-1120°C for 30 minutes;

[0043] The rolling start temperature is 1050°C, rolling Φ25mm round steel, and the final rolling temperature is 890°C;

[0044] After the final rolling, spray water to cool, and use the rolling raceway sealing state to make the rolled piece turn red, and stay in the range of 830-845°C for 2.1min, so that a large amount of VN is precipitated;

[0045] After exiting the sealed raceway, it is cooled by a cooling bed with a cooling rate of 0.95°C / s. After shearing and bundling, it is stack cooled at 550°C.

[0046] In the inventive steel B, the VN precipitated phase particles with a size ra...

Embodiment 3

[0051] First, during smelting, N element is added so that the content of some elements in the steel (referred to as Invention Steel C) in this example is [C]: 0.63%, [Cr]: 1.01%, [V]: 0.15%, [N ]: 0.0095%, the rest are Si, Mn, Al, Ti, Fe and impurities;

[0052] Converter smelting and continuous casting slab size: 240×240mm, the slab is heated at a temperature range of 1180-1195°C for 75 minutes;

[0053] The rolling start temperature is 1120°C, the Φ70mm round steel is rolled, and the final rolling temperature is 950°C;

[0054] After the final rolling, spray water to cool, and use the sealed state of the rolling raceway to make the rolled piece turn red, and stay in the range of 860-870°C for 1.3min, so that a large amount of VN is precipitated;

[0055] After exiting the sealed raceway, it is cooled by a cooling bed with a cooling rate of 0.70°C / s. After shearing and bundling, it enters the pit at 600°C for slow cooling.

[0056] In the inventive steel C, the VN precipita...

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Abstract

The invention discloses a method for controlling size and quantity of refined VN precipitated phases. The method comprises the following steps: smelting; continuously casting; heating; rolling; insulating and controlling cold, wherein the method specifically comprises the following steps: in the smelting step, blowing N2 gas into molten steel in a refining process to add N element, controlling [N] in steel at 0.0070-0.0120% and controlling [C] in steel at 0.37-0.65% and [V] at 0.10-0.30%; in the heating step, heating a steel blank and soaking and insulating; in the rolling step, controlling the open mill and finish roll temperatures; in the insulating step, controlling the insulating range and time; and in the step of controlling cold, controlling the cooling speed of a rolled piece to 550-600 DEG C and feeding the rolled piece to a pit to be slowly cooled or cooled in stack. Precipitating spontaneity and disordering are effectively controlled by virtue of a special process condition, so that the particle diameters of the VN precipitated phases in steel are concentrated and the quantity and proportion are optimal, thereby improving the yield strength, tensile strength and malleability of the steel.

Description

technical field [0001] The invention relates to a method for controlling VN precipitates in alloy steel containing vanadium (V) and nitrogen (N), in particular to a method for controlling the size and quantity of refined VN precipitates, and belongs to the technical field of iron and steel production. Background technique [0002] V is one of the forming elements for strengthening ferrite and γ-phase region. It has a strong affinity with C, N, and O, and forms corresponding stable compounds with it (such as V 4 C 3 , VN, V 2 o 3 Wait). V in steel mainly refines the structure and grain of steel, reduces the overheating sensitivity of steel, and improves the strength and toughness of steel. Secondly, when V dissolves into austenite at high temperature, it can increase the hardenability of steel. On the contrary, when it exists in the form of carbide, it can reduce the hardenability of steel. In addition, the compound of V is extremely stable at high temperature, which imp...

Claims

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Application Information

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IPC IPC(8): C21C7/072C21D8/02
Inventor 陈庆丰关云陈华强余爱华汪菊华张渊普杜方李献忠孙晶徐蔷药李伟万升
Owner WUHAN IRON & STEEL GRP ECHENG IRON & STEEL CO LTD
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