CN103060539A - Method for controlling decarburization of fine heat-treated steel wire - Google Patents

Abstract

The invention discloses a method for controlling decarburization of a fine heat-treated steel wire. The method comprises the following steps of 1, removing excess soap powder on the surface of a fine steel wire by a cleaning ball, 2, feeding the fine steel wire into an open fire furnace after full drying, and 3, carrying out recarburization by an electroplating technology and setting of an inside atmosphere of the open fire furnace so that recarburization effects are obtained.

Description

The control method of a kind of thin specification thermal treatment steel wire decarburization

Technical field

The present invention relates to the control method of a kind of thin specification thermal treatment steel wire decarburization.

Background technology

The definition of decarburization: steel wire is in when heating, and carbon or the carbon in the cementite that the steel wire top layer is dissolved in Ovshinsky are combined with oxygen, the disengaging Steel Wire Surface, and namely the carbon on steel wire top layer is burnt, and its chemical equation is as follows:

　 2C+O _２＝２CO

　　　　C +CO ₂=2CO

Ｃ+H _２O＝CO+H _２

Ｃ+H _２＝CH ₄

The steel wire Decarburized layer comprises and closes Decarburized layer and part Decarburized layer (transition layer) two portions, and the part Decarburized layer refers to after Fully decarburized layer normally tissue place of Carbon Content Of Steel.In the not serious situation of decarburization, sometimes only see the part Decarburized layer and do not have Fully decarburized layer, but about the variation of Decarburized depth root a tree name steel wire composition, Microstructure and properties, adopt several different methods to measure, the Decarburized layer with metallurgical analysis method mensuration steel that actual production is the most frequently used.At present cutting steel wire copper facing silk decarburization produces reason: (1) steel Chemical Composition affects decarburization: the chemical ingredients of steel has a great impact decarburization, carbon content is higher in the steel, the risk of decarburization is just larger, and the elements such as W, AL, Si, Co all use steel decarburization risk to increase; (2) impact of Heating temperature: along with the raising of Heating temperature; the degree of depth of Decarburized layer constantly increases; when generally being lower than 1000 ℃; the iron scale on steel surface hinders the diffusion of carbon; decarburization is slower than oxidation; but along with temperature raises; on the one hand oxide skin formation speed increases, and the velocity of diffusion of carbon is accelerated under the oxide skin on the other hand, and decarburization was faster than oxidation on the contrary after oxide skin lost protective capability and reached a certain temperature this moment; the increase of soaking time and heating times; heat-up time is longer, heating times the more, Decarburized layer is darker; in heat-processed; because fuel composition; the different use in the products of combustion of combustion conditions and temperature contained different gas, thereby consists of different furnace atmospheres, has oxidisability that reductibility is arranged; they are different to the effect of steel wire, and oxidizing atmosphere causes oxidation and the decarburization of steel.The medium that wherein decarburization capacity is the strongest is H ₂O(vapour), secondly be CO ₂With O ₂, be H at last ₂Some gas then makes steel carburetting, such as CO and CH ₄The steel wire decarburization is on final finished quality and client's impact: (1) is on the impact of final product quality: again add man-hour decarburized steel silk because surface strength and lower hardness, can accelerate the wearing and tearing to mould, so that the mould consumption significantly rises, simultaneously since mould injured after, can use the surface copper pull-up to fall, the Steel Wire Surface matrix is exposed, and produce the very dark trace that draws in Steel Wire Surface, the simultaneously ovality of steel wire meeting severe overweight; (2) client's silicon wafer section yield impact: because silicon chip surface is to having stria and TTV requirement, the Steel Wire Surface scuffing can cause silicon chip to produce tool marks, directly causes silicon chip to be scrapped, and the defective meeting of steel wire ovality causes silicon chip to produce the defective and stria of TTV.Before electroplating thermal treatment, when steel wire carries out drawing, adopting borax is the carrier of powdered lubricant absorption as sodium, be conducive to guarantee steel wire surface quality, but can form one deck soap powder in Steel Wire Surface simultaneously that the soap powder main component is unnecessary borax, lubricant and foreign material etc., steel wire need enter degreasing tank and cleans before in entering stove, the part soap powder that the flush away Steel Wire Surface is adhered to is coated with the uniform borax content of last layer in Steel Wire Surface simultaneously, is conducive to steel wire and evenly absorbs heat.Because the little linear speed of wire gauge is fast, steel wire can not be removed the too much soap powder of Steel Wire Surface effectively in degreasing tank, can cause steel wire first district's Heating temperature in entering stove too fast, thereby has increased the risk of decarburization.Former mode is directly to adopt cold wind to purge the moisture content of removing Steel Wire Surface, and Steel Wire Surface moisture content can not get complete drying, and moisture content can constantly be brought in the stove, and the strongest medium of decarburization capacity is H ₂O(vapour), H ₂O(vapour) can the chemistry reflection directly occur with carbon produce CO and H ₂, can cause again first district's atmosphere to be reductibility, cause whole furnace pressure to change, cause whole furnace atmosphere to change, more increased the risk of decarburization, concrete reactive chemistry is as follows: C _(γ-Fe)+ H ₂O=CO+H ₂, Fe ₃C+H ₂O=3Fe+CO+ H ₂

Summary of the invention

The invention provides The control method of a kind of thin specification thermal treatment steel wire decarburization, itUtilize domestic direct-fired heater device fabrication from the characteristics of health and utilize small dimension steel wire heat absorption characteristics effectively to prevent the steel wire decarburization.

The present invention has adopted following technical scheme: the control method of a kind of thin specification thermal treatment steel wire decarburization, it may further comprise the steps: step 1, increase cleaning ball and remove the too much soap powder of Steel Wire Surface: at first increased the cleaning ball identical or close with wire gauge at unwrapping wire place steel wire and wiped the examination Steel Wire Surface, make Steel Wire Surface soap powder content obtain descending, avoided the too fast Steel Wire Surface that causes of rate of heating to produce decarburization; Step 2, the small dimension steel wire must make it fully dry before entering direct-fired heater: steel wire at first adopted before degreasing tank with cold wind and purges the moisture content of removing Steel Wire Surface, and then by two blow drying devices steel wire is carried out removing after the water operation so that the small dimension steel wire obtains abundant drying the second time: step 3, adopt the furnace atmosphere of electroplating technology and setting direct-fired heater, the direct-fired heater design is divided into five districts: 980 ℃ of the temperature in the first district, mixture pressure 200-400 mmH2O, furnace atmosphere 0-0.1CO%; 970 ℃ of the temperature of Second Region, mixture pressure 200-400 mmH2O, furnace atmosphere 1-2.0CO%; 965 ℃ of the temperature in the 3rd district, mixture pressure 100-300 mmH2O, furnace atmosphere 2-3.0CO%; 960 ℃ of the temperature in the 4th district, mixture pressure 50-150 mmH2O, furnace atmosphere 2.5-3.5CO%; 940 ℃ of the temperature in the 5th district, mixture pressure 50-150 mmH2O, furnace atmosphere 2.5-3.5CO%; Be in stronger oxidizing atmosphere at first district's steel wire, form like this oxide skin of one deck densification in Steel Wire Surface, the surface of part steel wire fully forms Fe3O4 after the oxidation, the non-abundant oxidation rear oxidation skin of another part steel wire is FeO and Fe2O3, the Steel Wire Surface of non-abundant oxidation is porous state, and carbon can be oxidized to the effusion of CO CO2 gas like this; Weaken gradually at Second Region and the 3rd district's oxidisability, reductibility is strengthened, strengthen to some extent than the Er San district again to the 4th district's reductibility, reach the strongest to the 5th district's reductibility, steel wire is in keeping warm mode, several districts move from the 5th district to the front can to make oxygen in the stove by the ladder design, steel wire in CO--CO2 mixed gas, the reaction formula of decarburization:

C（γ-Fe）+CO2

2CO （1）

Fe3C+CO2

3Fe+2CO （2）

This reaction is reversible reaction, the effect that namely produces decarburization and carburetting also depends on CO2/ CO ratio, for this reason third and fourth, five district's reductibilities are more and more stronger, namely the CO percentage composition is more and more higher, can formula (1) and the reaction of formula (2) carry out to the reversed reaction direction, reach the effect of carburetting.

The present invention has following beneficial effect: after having adopted above technical scheme, the present invention not only can make detection decarburization risk obviously be descended, a decarburization appears in 100 of every detections before improving, after improving 1000 decarburizations of every detection once, and the steel wire Decarburized depth that decarburization occurs drops to 0.1 μ m by 0.5 μ m; And wet and draw the operation condition of production to obtain taking a turn for the better, unacceptable product is significantly descended, and product qualified rate is promoted to 93% by 85%, and lumber recovery is increased to 93.5% by 83.5%; Through small dimension steel wire decarbonization degree is control effectively, service condition is improved and stablizes simultaneously, and client's good article rate promotes 2%, and particularly the defective ratio of silicon chip stria and TTV is clearly better.

Description of drawings

Fig. 1 is that the present invention sets furnace atmosphere ladder scatter chart.

Embodiment

The control method of a kind of thin specification thermal treatment steel wire of the present invention decarburization, it may further comprise the steps: step 1, increase cleaning ball and remove the too much soap powder of Steel Wire Surface: at first increased the cleaning ball identical or close with wire gauge at unwrapping wire place steel wire and wiped the examination Steel Wire Surface, make Steel Wire Surface soap powder content obtain descending, avoided the too fast Steel Wire Surface that causes of rate of heating to produce decarburization; Step 2, the small dimension steel wire must make it fully dry before entering direct-fired heater: steel wire at first adopted before degreasing tank with cold wind and purges the moisture content of removing Steel Wire Surface, and then by two blow drying devices steel wire is carried out removing after the water operation so that the small dimension steel wire obtains abundant drying the second time: step 3, adopt the furnace atmosphere of electroplating technology and setting direct-fired heater, the direct-fired heater design is divided into five districts: 980 ℃ of the temperature in the first district, mixture pressure 200-400 mmH2O, furnace atmosphere 0-0.1CO%; 970 ℃ of the temperature of Second Region, mixture pressure 200-400 mmH2O, furnace atmosphere 1-2.0CO%; 965 ℃ of the temperature in the 3rd district, mixture pressure 100-300 mmH2O, furnace atmosphere 2-3.0CO%; 960 ℃ of the temperature in the 4th district, mixture pressure 50-150 mmH2O, furnace atmosphere 2.5-3.5CO%; 940 ℃ of the temperature in the 5th district, mixture pressure 50-150 mmH2O, furnace atmosphere 2.5-3.5CO%; Be in stronger oxidizing atmosphere at first district's steel wire, form like this oxide skin of one deck densification in Steel Wire Surface, the surface of part steel wire fully forms Fe3O4 after the oxidation, the non-abundant oxidation rear oxidation skin of another part steel wire is FeO and Fe2O3, the Steel Wire Surface of non-abundant oxidation is porous state, and carbon can be oxidized to the effusion of CO CO2 gas like this; Weaken gradually at Second Region and the 3rd district's oxidisability, reductibility is strengthened, strengthen to some extent than the Er San district again to the 4th district's reductibility, reach the strongest to the 5th district's reductibility, steel wire is in keeping warm mode, and in Fig. 1, several districts move from the 5th district to the front can to make oxygen in the stove by the ladder design, steel wire in CO--CO2 mixed gas, the reaction formula of decarburization:

C（γ-Fe）+CO2

2CO （1）

Fe3C+CO2

3Fe+2CO （2）

This reaction is reversible reaction, the effect that namely produces decarburization and carburetting also depends on CO2/ CO ratio, for this reason third and fourth, five district's reductibilities are more and more stronger, namely the CO percentage composition is more and more higher, can formula (1) and the reaction of formula (2) carry out to the reversed reaction direction, reach the effect of carburetting.

Claims (1)

1. the control method of one kind thin specification thermal treatment steel wire decarburization, it may further comprise the steps:

Step 1, increase cleaning ball and remove the too much soap powder of Steel Wire Surface: at first increased the cleaning ball identical or close with wire gauge at unwrapping wire place steel wire and wiped the examination Steel Wire Surface, make Steel Wire Surface soap powder content obtain descending, avoided the too fast Steel Wire Surface that causes of rate of heating to produce decarburization;

Step 2, the small dimension steel wire enters and must make before the direct-fired heater it fully dry: steel wire at first adopted before degreasing tank with cold wind and purges the moisture content of removing Steel Wire Surface, and then by two blow drying devices steel wire was carried out removing after the water operation so that the small dimension steel wire obtains abundant drying the second time:

Step 3 adopts electroplating technology and the furnace atmosphere of setting direct-fired heater, and the direct-fired heater design is divided into five districts: 980 ℃ of the temperature in the first district, mixture pressure 200-400 mmH2O, furnace atmosphere 0-0.1CO%; 970 ℃ of the temperature of Second Region, mixture pressure 200-400 mmH2O, furnace atmosphere 1-2.0CO%; 965 ℃ of the temperature in the 3rd district, mixture pressure 100-300 mmH2O, furnace atmosphere 2-3.0CO%; 960 ℃ of the temperature in the 4th district, mixture pressure 50-150 mmH2O, furnace atmosphere 2.5-3.5CO%; 940 ℃ of the temperature in the 5th district, mixture pressure 50-150 mmH2O, furnace atmosphere 2.5-3.5CO%; Be in stronger oxidizing atmosphere at first district's steel wire, form like this oxide skin of one deck densification in Steel Wire Surface, the surface of part steel wire fully forms Fe3O4 after the oxidation, the non-abundant oxidation rear oxidation skin of another part steel wire is FeO and Fe2O3, the Steel Wire Surface of non-abundant oxidation is porous state, and carbon can be oxidized to the effusion of CO CO2 gas like this; Weaken gradually at Second Region and the 3rd district's oxidisability, reductibility is strengthened, strengthen to some extent than the Er San district again to the 4th district's reductibility, reach the strongest to the 5th district's reductibility, steel wire is in keeping warm mode, several districts move from the 5th district to the front can to make oxygen in the stove by the ladder design, steel wire in CO--CO2 mixed gas, the reaction formula of decarburization:

C（γ-Fe）+CO2

2CO （1）

Fe3C+CO2

3Fe+2CO （2）

This reaction is reversible reaction, the effect that namely produces decarburization and carburetting also depends on CO2/ CO ratio, for this reason third and fourth, five district's reductibilities are more and more stronger, namely the CO percentage composition is more and more higher, can formula (1) and the reaction of formula (2) carry out to the reversed reaction direction, reach the effect of carburetting.

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