CN102899450A

CN102899450A - Method for avoiding separation of fracture test samples

Info

Publication number: CN102899450A
Application number: CN2012103885332A
Authority: CN
Inventors: 刘丹; 韦明; 李红文; 刘利香; 胡丽周; 林建农; 韩全军; 郑京辉; 刘小军; 张威
Original assignee: Wuyang Iron and Steel Co Ltd; Hebei Iron and Steel Group Co Ltd
Current assignee: Wuyang Iron and Steel Co Ltd; Hebei Iron and Steel Group Co Ltd
Priority date: 2012-10-12
Filing date: 2012-10-12
Publication date: 2013-01-30
Anticipated expiration: 2032-10-12
Also published as: CN102899450B

Abstract

The invention discloses a method for avoiding the separation of fracture test samples of steel plates. The method comprises the following steps of: smelting, casting, stacking steel blanks for cooling slowly and stacking the steel plates for cooling slowly. By a smelting process, the quality of molten steel is improved, and the content of harmful elements of slag inclusion and the like is reduced; the quality of continuous casting blanks and the segregation are improved by means of the accelerated cooling of the continuous casting solidification tail end, the optimal distribution of continuous casting water-cooling amount, reasonable casting speed and the like; the problems of the internal stress, segregation and the like of the steel plates can be solved according to a stacking process of the steel plates; and for the steel plates of which the rolled thicknesses are more than or equal to 40 millimeters, the stacking process of the steel plates is added, so that the fracture separation of the steel plates of the thickness specifications is avoided.

Description

A kind of method that solves fracture sample separation phenomenon

Technical field

The present invention relates to a kind of method that solves fracture sample separation phenomenon.

Background technology

Along with being growing more intense of steel industry competition, quality product becomes the focus of competition among enterprises, more and more obtains the attention of each side.Ship plate is widely used in making the structure such as transport pipe, coastal power station, terminal facilities in ocean, coastal and navigating area, inland river boats and ships hull structure, dock, production vessel, the ocean.The internal soundness direct relation of ship plate security and the work-ing life of boats and ships, production vessel etc., is one of very strict steel sheet product of specification of quality." separation " (fracture layering and side crackle) in the deck of boat check refers to that the tension specimen separation that occurs tears phenomenon in the tension test process.The detachment defects of ship plate is the significant problem that the restriction steel plate uses, and the product that has had a strong impact on the deck of boat is paid and economic benefit.

Summary of the invention

For the problems referred to above, the object of the present invention is to provide a kind of processing method that solves fracture sample separation phenomenon.

In order to achieve the above object, the present invention has adopted a kind of technical scheme that solves the processing method of fracture sample separation phenomenon, and concrete steps are as follows:

(1) smelt: molten steel is first through electrosmelting, and electrosmelting does not allow to see the slag tapping; Then send into the refining of LF stove, feed the Al line more than 550 meters, white slag hold-time 〉=40min, lime consumption 〉=16kg/t steel, process and [Al] 〉=0.010% of skimming; The vacuum-treat of the complete rear bull ladle VD stove of refining, vacuum tightness is not more than 66Pa, destroys vacuum during vacuum hold-time 〉=10min, reduces to greatest extent nonmetallic inclusionsin steel, harmful element content, guarantees the purity of molten steel, and the control argon flow amount is at 100L/min;

(2) casting: after the vacuum breaking, water the steel superheating temperature and be controlled at 15～40 ℃, two cold-zone solidification end water strengthen, and steel billet are carried out cold by force, are about to continuous casting billet solidifying end, and the 13rd section to the 16th section water yield of continuous caster doubles;

(3) steel billet stacking slow cooling: after the steel billet casting, with company's steel billet of well cutting stacking slow cooling immediately, temperature is 700～800 ℃, and the slow cooling time is more than 30 hours, 150～170 ℃ of de-stacking temperature, steel billet cool to room temperature;

(4). the steel plate stacking slow cooling: heating steel billet is rolling to be carried out according to normal process, when steel plate is pricked rolling thickness 〉=40mm, steel plate stacking slow cooling, require steel plate head or shoulder to align as far as possible during stacking, stacking temperature 〉=500 ℃, the stacking time is more than 48 hours, 80 ℃ of de-stackings; When steel plate thickness＜40mm, need not stacking slow cooling.

Suitably can reduce some draw ring speed during the described continuous casting of step (2), the reduction amplitude is in 0.5m/min.

The described steel billet slow cooling time of step (3) is optimized, and the general slow cooling time is 36 hours.

This technique is fit to all steel grades (except containing the Cu steel), can effectively reduce steel plate internal stress, component segregation, improves the steel plate quality, and the fracture surface of sample pattern is normal, without separation phenomenon.By smelting technology, improve the content of the harmful elements such as steel quality and reduction inclusion; Accelerate cooling by the continuous casting and solidifying end, and the means such as continuous casting water-cooled amount optimization distribution and rational pulling rate, well improved continuous casting billet quality, improve segregation phenomena; Can solve the problems such as steel plate internal stress and segregation according to steel plate stacking technique; For the steel plate of rolling thickness 〉=40mm, increased steel plate stacking technique, successful solution the separation phenomenon of this thickness specification steel plate.

Embodiment

Embodiment 1

Steel grade AB/A specification: 18mm * 2650mm * 8000mm

A kind of processing method that solves fracture sample separation phenomenon of present embodiment, concrete steps are:

(1) smelt: molten steel is first through electrosmelting, and electrosmelting does not allow to see the slag tapping; Then send into the refining of LF stove, feed 578 meters on Al line, white slag hold-time 50min, lime consumption 1650kg, Si-Fe powder 82kg, process and [Al] 〉=0.010% of skimming; Add CaSi piece 70kg before the vacuum-treat of the complete rear bull ladle VD stove of refining, Fruit storage, vacuum tightness 66Pa, vacuum hold-time 15min, the control argon flow amount is at 100L/min;

(2) casting: after the vacuum breaking, water the steel superheating temperature and be controlled at 20 ℃, two cold-zone solidification end water strengthen, and steel billet are carried out cold by force, are about to continuous casting billet solidifying end, and the 13rd section to the 16th section water yield summation of continuous caster is increased to 1600m ³

(3) steel billet stacking slow cooling: after the steel billet casting, with the continuously cast bloom of well cutting stacking slow cooling immediately, temperature is 746 ℃, and the slow cooling time is 36 hours, 170 ℃ of de-stacking temperature, steel billet cool to room temperature; Heating steel billet, rolling technology are normally carried out.

The performance of the steel plate that the present embodiment method is produced: the thick performance 52%, 55%, 57% of drawing of steel plate.Reached the Z35 rank, (fracture layering and side crackle) phenomenon does not appear separating in steel plate tensile test piece.

Embodiment 2

Steel grade CCS/A specification: 53mm * 2470mm * 9620mm

(1) smelt: molten steel is first through electrosmelting, and electrosmelting does not allow to see the slag tapping; Then send into the refining of LF stove, feed 620 meters on Al line, white slag hold-time 55min, lime consumption 1762kg, Si-Fe powder 75kg, process and [Al] 〉=0.010% of skimming; Add CaSi piece 85kg before the vacuum-treat of the complete rear bull ladle VD stove of refining, Fruit storage, vacuum tightness 66Pa, vacuum hold-time 18min, the control argon flow amount is at 100L/min;

(2) casting: after the vacuum breaking, water the steel superheating temperature and be controlled at 22 ℃, two cold-zone solidification end water strengthen, and steel billet are carried out cold by force, are about to continuous casting billet solidifying end, and the 13rd section to the 16th section water yield summation of continuous caster is increased to 1562m ³

(3) steel billet stacking slow cooling: after the steel billet casting, with the continuously cast bloom of well cutting stacking slow cooling immediately, temperature is 782 ℃, and the slow cooling time is 36 hours, 163 ℃ of de-stacking temperature, steel billet cool to room temperature;

(4) heating steel billet, rolling technology are normally carried out, rolling after, the steel plate stacking slow cooling requires steel plate head or shoulder to align as far as possible during stacking, 553 ℃ of stacking temperature, 50 hours stacking time, 80 ℃ of de-stackings, flaw detection, normalizing after the de-stacking.

The plate property that the present embodiment method is produced: the thick performance 39%, 42%, 50% of drawing of steel plate, reached the Z35 rank, (fracture layering and side crackle) phenomenon does not appear separating in steel plate tensile test piece.

Claims

1. a method that solves fracture sample separation phenomenon is characterized in that, comprises the steps:

(1) smelt: then molten steel sends into the refining of LF stove first through electrosmelting, feeds the Al line more than 550 meters, white slag hold-time 〉=40min, lime consumption 〉=16kg/t steel, process and [Al] 〉=0.010% of skimming; The vacuum-treat of the complete rear bull ladle VD stove of refining, vacuum tightness is not more than 66Pa, destroys vacuum during vacuum hold-time 〉=10min, and the control argon flow amount is at 100L/min;

(2) casting: after the vacuum breaking, water the steel superheating temperature and be controlled at 15～40 ℃, the 13rd section to the 16th section water yield of continuous caster doubles;

The steel plate stacking slow cooling: heating steel billet is rolling, and when steel plate is pricked rolling thickness 〉=40mm, the steel plate stacking slow cooling requires steel plate head or shoulder to align as far as possible during stacking, stacking temperature 〉=500 ℃, and the stacking time is more than 48 hours; When steel plate thickness＜40mm, need not stacking slow cooling.

2. the method for solution fracture sample separation phenomenon according to claim 1 is characterized in that, step (1) also adds in the LF stove the Si-Fe powder, and consumption is at the 0.5kg/t steel.

3. the method for solution fracture sample separation phenomenon according to claim 1 is characterized in that, adds CaSi piece, consumption 〉=50kg/ stove in the step (1) before Fruit storage.

4. the method for solution fracture sample separation phenomenon according to claim 1 is characterized in that, casting speed reduces amplitude in 0.5m/min during the described continuous casting of step (2).

5. the method for solution fracture sample separation phenomenon according to claim 1 is characterized in that, the described steel billet slow cooling time of step (3) is 34～38 hours.