CN102409219B - Method for preparing stress HIC (hydrogen induced cracking) resistant steel based on carrier control technology - Google Patents

Abstract

The invention relates to a method for preparing stress HIC (hydrogen induced cracking) resistant steel based on carrier control technology. The method comprises the following steps: (1) mixing 1.0-1.5g of nano Cu, 1.0-1.5g of nano Al, 0.5-1.5g of nano Cr and 0.5-1.5g of nano BN to obtain nano mixed powder; and (2) putting the nano mixed powder and 100g of steel into a medium frequency induction melting furnace to be melted and carrying out casting to obtain a slab; and finally further processing the obtained slab, thus obtaining the stress HIC resistant steel. The method has the following beneficial effects: the stress HIC resistant steel is prepared by utilizing the relation, which is obtained through study, between the carrier density and the HIC resistance of the steel, namely, the stress HIC resistance of the steel is improved along with rise of the order of magnitude of concentration of the carrier in the steel; the preparation method is simple, has low requirement for equipment and is suitable for large scale production; and the obtained steel has high stress HIC resistance.

Description

The method for preparing anti-HIC stress cracking steel based on carrier control technique

Technical field

The invention belongs to the preparation field of anti-HIC stress cracking steel, particularly a kind of method for preparing anti-HIC stress cracking steel based on carrier control technique.

Background technology

Hydrogen brings out cracking refers to that metallic substance is separated out in by electrochemical corrosion course under the effect of sulfide hydrogen medium hydrogen and enters the inner notch cuttype crackle that produces of metallic substance.Growing of these crackles finally makes the metallic substance cracking.If crackle remains in the surface of tube wall, also can form hydrogen blistering at tube wall.Hydrogen brings out cracking can make pipe line steel ftracture suddenly in without any the situation of obvious omen, so it is destructive and hazardness is very big.Be security and the normal operation of guaranteeing steel, the research that antagonism hydrogen brings out the cracking performance influence factor is very necessary.

Usually resistance against hydrogen cracking HIC mainly says (modern pipe line steel belongs to low-carbon (LC) or ultralow-carbon microalloyed steel) for Low-carbon High Strength structure iron pressing pressure pipeline.This type of special-purpose steel (anti-HIC special-purpose steel) main raw trade mark of at present domestic production has: 16MnR (HIC), 20R (HIC), SA516 (HIC).Wherein the main alloying constituent of 16MnR is C, Si, Mn, P, S etc., and total alloy component content is no more than 3% of total mass.

Summary of the invention

Technical problem to be solved by this invention provides a kind of method for preparing anti-HIC stress cracking steel based on carrier control technique, the method has utilized the relation between carrier density and the 16MnR Properties of HIC resistance to prepare anti-HIC stress cracking steel, this preparation method is simple, cost is relatively low, less demanding to equipment is fit to large-scale production; The anti-HIC stress cracking performance of the anti-HIC stress cracking steel of gained is high.

Of the present inventionly a kind ofly prepare the method for anti-HIC stress cracking steel based on carrier control technique, comprising:

(1) preparation of nano mixed powder: nanometer Cu 1.0-1.5g, nanometer Al 1.0-1.5g, nanometer Cr 0.5-1.5g and nanometer BN 0.5-1.5g are mixed, get the nanometer mixed powder;

(2) with behind above-mentioned nanometer mixed powder and the 100g mixing of molten steel, carry out melting, casting obtains slab; At last the gained slab is further processed, namely got anti-HIC stress cracking high-strength steel.

The quality of nanometer Cu, nanometer Al, nanometer Cr and nanometer BN is respectively 1.0g, 1.0g, 0.5g and 0.5g in the nanometer mixed powder described in the step (1).

The quality of nanometer Cu, nanometer Al, nanometer Cr and nanometer BN is respectively 1.5g, 1.5g, 0.5g and 0.5g in the nanometer mixed powder described in the step (1).

The quality of nanometer Cu, nanometer Al, nanometer Cr and nanometer BN is respectively 1.0g, 1.0g, 1.5g and 1.5g in the nanometer mixed powder described in the step (1).

The quality of nanometer Cu, nanometer Al, nanometer Cr and nanometer BN is respectively 1.5g, 1.5g, 1.5g and 1.5g in the nanometer mixed powder described in the step (1).

The grade of steel of the steel described in the step (2) is 16MnR, 20R or SA516.

In the melting described in the step (2), smelting temperature is 1550-1600 ℃, and smelting time is 40-50min.

Melting described in the step (2) is for carrying out melting in medium frequency induction melting furnace.

Above-mentioned medium frequency induction melting furnace is antivacuum medium frequency induction melting furnace.

The present invention uses carrier control technique, and the relation between carrier density and the 16MnR Properties of HIC resistance is conducted in-depth research, and concrete operation step is as follows:

(1) the doped element batching mainly is Nano grade Cu, Al, Cr, BN, and nanometer Cu, nanometer Al, nanometer Cr, nanometer BN are weighed up 4 groups of ratio samples in different mass respectively, puts into dry light cup and mixes, and namely obtains 4 groups of nanometer mixed powders; Wherein the content of Cu, Al, Cr, BN is respectively 1.0g, 1.0g, 0.5g, 0.5g in 4 groups of nanometer mixed powders; 1.5g, 1.5g, 0.5g, 0.5g; 1.0g, 1.0g, 1.5g, 1.5g; 1.5g, 1.5g, 1.5g, 1.5g, number respectively 1,2,3 and 4;

(2) 4 groups of nanometer mixed powders in the step (1) are put into antivacuum medium frequency induction melting furnace with 100g 16MnR steel respectively and carry out non-vacuum melting, 1600 ℃ of smelting temperatures, smelting time 50min, then casting obtains 4 kinds of slabs (modification slab 1, modification slab 2, modification slab 3 and modification slab 4) respectively;

(3) a unmodified 16MnR steel of the 100g that is used for contrasting is put into antivacuum medium frequency induction melting furnace and carry out non-vacuum melting, 1600 ℃ of smelting temperatures, smelting time 50min, the unmodified slab of then casting to get;

(4) step (2) and (3) resulting slab are processed 5h 600 ℃ of lower homogenizing respectively, then under 1000 ℃, divide the thin plate that is rolled into respectively thick 4mm for 3 times through roller mill (L6500), once cold rolling again after the water-cooled; Again the steel plate after rolling is carried out anneal, at 800 ℃ of insulations of temperature 3h;

(5) the steel plate line after respectively step (4) is rolling cuts out the fritter of 10mm * 10mm size, is used for doing the current carrier test; Another major part is done anti-HIC experiment.

The test of carrier density, its concrete steps are as follows:

(1) take pat as the test electrode base material, behind epoxy sealing, gets one of them flat surface as working face, adopt thin abrasive paper for metallograph polishing, after dehydrated alcohol, acetone clean successively, drying, namely get test electrode, be positioned over test electrode in the moisture eliminator for subsequent use.

(2) electrode to be measured is soaked into the 10%Na that is prepared by analytical reagent and deionized water ₂SO ₄Solution, take saturated calomel electrode as reference electrode, platinum electrode is supporting electrode, carries out current potential-capacity measurement at the CHI660C electrochemical workstation of computer control, then data is drawn the Mott-Schottky analysis chart, and according to the Mott-Schottky relational expression:

The P type: $\frac{1}{{\mathrm{Csc}}^2}=\frac{2}{{\mathrm{\ϵ\ϵ}}_0{\mathrm{eN}}_D}(-U+U_{\mathrm{fb}}-\frac{\mathrm{kT}}{e})$

N-type: $\frac{1}{{\mathrm{Csc}}^2}=\frac{2}{{\mathrm{\ϵ\ϵ}}_{0}e{N}_D}({\mathrm{\ΔU}}_{\mathrm{SC}}-\frac{\mathrm{kT}}{e})=\frac{2}{{\mathrm{\ϵ\ϵ}}_{0}e{N}_D}(U-U_{\mathrm{fb}}-\frac{\mathrm{KT}}{e})$

Wherein, Csc is space charge layer capacitance, and ε is the specific inductivity (19.547 * 10 of organic-containing materials ^-13F/m), ε ₀For permittivity of vacuum (is 8.854 * 10 ^-12F/m), e is electron charge, N _DBe carrier density, U is externally-applied potential, U _FbBe flat-band potential, k is Boltzmann constant, and T is absolute temperature; Therefore, can obtain modification steel plate carrier density N by the straight-line segment slope of Mott-Schottky analysis chart _D

Table 1 is the carrier concentration value of steel plate before and after modification.

Carrier concentration before and after the modification of table 1. steel plate

Anti-HIC stress cracking test, concrete grammar is as follows:

(1) by the method in NACE TM0284-2003 " performance evaluation of pipeline and the anti-hydrogen induced cracking (HIC) of pressurized vessel " sample being carried out anti-HIC stress cracking performance tests.

(2) according to standard test methods, adopt the method for line cutting to cut open the check surface of the sample after soaking, after the split surface polishing, adopt the Big Gold phase microscope to observe crack distribution on each sample, measure the crackle size according to the method that Fig. 1 gives.

Then with crack-sensitivity rate (CSR), crack length rate (CLR) and 3 parameters of crack thickness rate (CTR) index as evaluating material resistance against hydrogen cracking (HIC) performance quality.Calculation expression is as follows:

$\mathrm{CSR}=\frac{\mathrm{\Σ}(a\×b)}{W\×T}\×100\%$

$\mathrm{CLR}=\frac{\mathrm{\Σa}}{W}\×100\%$

$\mathrm{CTR}=\frac{\mathrm{\Σb}}{W}\×100\%$

A-crack length in the formula; The B-crack thickness; The W-specimen width; The T-sample thickness.

Test-results is as shown in table 2.

Table 25 kind of sample HIC test-results (%)

By the result as can be known, along with the rising of the carrier concentration order of magnitude, the anti-HIC stress cracking performance of steel plate also promotes thereupon.

Carry out modification by in steel, adding nano-powder among the present invention.

The present invention uses carrier control technique, and the relation between carrier density and the 16MnR Properties of HIC resistance is conducted in-depth research.By the anti-HIC steel of commercially available now several special uses is carried out the microalloy element modification, and calculate the carrier density of modified steel.Simultaneously measure by experiment the anti-HIC value of steel plate, thereby draw the carrier density of modified steel and the corresponding relation between the anti-HIC stress cracking.The result shows that along with the rising of the carrier concentration order of magnitude, anti-HIC stress also is improved thereupon in the 16MnR steel plate.Carrier concentration increases about 2 orders of magnitude, and several numerical value of the bad phenomenon that sign HIC causes can reduce accordingly to some extent.Hence one can see that, can significantly improve the anti-HIC stress cracking performance of steel by carrier control technique.

Beneficial effect:

(1) the present invention has utilized the relation between carrier density and the steel Properties of HIC resistance to prepare anti-HIC stress cracking steel,

This preparation method is simple, and cost is relatively low, and less demanding to equipment is fit to large-scale production;

(2) the anti-HIC stress cracking performance of the anti-HIC stress cracking steel of gained of the present invention is high.

Description of drawings

Fig. 1 is crack length and thickness measurement figure.

Embodiment

Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiment only to be used for explanation the present invention and be not used in and limit the scope of the invention.Should be understood that in addition those skilled in the art can make various changes or modifications the present invention after the content of having read the present invention's instruction, these equivalent form of values fall within the application's appended claims limited range equally.

Before embodiment, should carry out the Performance Detection without modified steel.

Embodiment 1

The 100g16MnR steel is put into a kind of antivacuum medium frequency induction melting furnace, and interpolation 1.0g nanometer Cu, 1.0g nanometer Al, 0.5g nanometer Cr, 0.5g nanometer BN carry out non-vacuum melting, 1600 ℃ of smelting temperatures, smelting time 50min; Casting obtains slab.Slab is processed through 600 ℃ * 5h homogenizing, divides the thin plate that is rolled into thick 4mm for 3 times through roller mill (L6500) under 1000 ℃, and is once cold rolling again after the water-cooled.

Steel plate after rolling is incubated the 3h anneal 800 ℃ of temperature.Then obtain the Mott-Schottky analysis chart of sample electrode to be measured, obtain modification steel plate carrier density N _D-1, see Table 3.By method in NACETM0284-2003 " performance evaluation of pipeline and the anti-hydrogen induced cracking (HIC) of pressurized vessel " sample is carried out anti-HIC stress cracking performance at last and test, see Table 4.

Embodiment 2

The 100g16MnR steel is put into a kind of antivacuum medium frequency induction melting furnace, and interpolation 1.5g nanometer Cu, 1.5g nanometer Al, 0.5g nanometer Cr, 0.5g nanometer BN carry out non-vacuum melting, 1600 ℃ of smelting temperatures, smelting time 50min; Casting obtains slab.Slab is processed through 600 ℃ * 5h homogenizing, divides the thin plate that is rolled into thick 4mm for 3 times through roller mill (L6500) under 1000 ℃, and is once cold rolling again after the water-cooled.

Steel plate after rolling is incubated the 3h anneal 800 ℃ of temperature.Then obtain the Mott-Schottky analysis chart of sample electrode to be measured, obtain modification steel plate carrier density N _D-2, see Table 3.By method in NACETM0284-2003 " performance evaluation of pipeline and the anti-hydrogen induced cracking (HIC) of pressurized vessel " sample is carried out anti-HIC stress cracking performance at last and test, see Table 4.

Embodiment 3

The 100g16MnR steel is put into a kind of antivacuum medium frequency induction melting furnace, and interpolation 1.0g nanometer Cu, 1.0g nanometer Al, 1.5g nanometer Cr, 1.5g nanometer BN carry out non-vacuum melting, 1550 ℃ of smelting temperatures, smelting time 45min; Casting obtains slab.Slab is processed through 600 ℃ * 5h homogenizing, divides the thin plate that is rolled into thick 4mm for 3 times through roller mill (L6500) under 1000 ℃, and is once cold rolling again after the water-cooled.

Steel plate after rolling is incubated the 3h anneal 800 ℃ of temperature.Then obtain the Mott-Schottky analysis chart of sample electrode to be measured, obtain modification steel plate carrier density N _D-3, see Table 3.By method in NACETM0284-2003 " performance evaluation of pipeline and the anti-hydrogen induced cracking (HIC) of pressurized vessel " sample is carried out anti-HIC stress cracking performance at last and test, see Table 4.

Embodiment 4

The 100g16MnR steel is put into a kind of antivacuum medium frequency induction melting furnace, and interpolation 1.5g nanometer Cu, 1.5g nanometer Al, 1.5g nanometer Cr, 1.5g nanometer BN carry out non-vacuum melting, 1580 ℃ of smelting temperatures, smelting time 40min; Casting obtains slab.Slab is processed through 600 ℃ * 5h homogenizing, divides the thin plate that is rolled into thick 4mm for 3 times through roller mill (L6500) under 1000 ℃, and is once cold rolling again after the water-cooled.

Steel plate after rolling is incubated the 3h anneal 800 ℃ of temperature.Then obtain sample electrode Mott-Schottky to be measured analysis chart, obtain modification steel plate carrier density N _D-4, see Table 3.By method in NACE TM0284-2003 " performance evaluation of pipeline and the anti-hydrogen induced cracking (HIC) of pressurized vessel " sample is carried out anti-HIC stress cracking performance at last and test, see Table 4.

Carrier concentration before and after the modification of table 3 steel plate

Table 4HIC test-results (%)

Claims (7)

1. one kind prepares the method for anti-HIC stress cracking steel based on carrier control technique, comprising:

(1) nanometer Cu 1.0-1.5g, nanometer Al 1.0-1.5g, nanometer Cr 0.5-1.5g and nanometer BN 0.5-1.5g are mixed, get the nanometer mixed powder;

(2) with behind above-mentioned nanometer mixed powder and the 100g mixing of molten steel, at temperature 1550-1600 ℃, time 40-50min carries out melting, and casting obtains slab; At last the gained slab is further processed, namely got anti-HIC stress cracking steel;

The grade of steel of the molten steel described in the step (2) is 16MnR, 20R or SA516; Described further being processed as 600 ℃ of lower homogenizing processed 5h, then divides the thin plate that is rolled into respectively thick 4mm for 3 times through roller mill L6500 under 1000 ℃, and be once cold rolling again after the water-cooled; Again the steel plate after rolling is carried out anneal, at 800 ℃ of insulations of temperature 3h.

2. according to claim 1ly a kind ofly prepare the method for anti-HIC stress cracking steel based on carrier control technique, it is characterized in that: the quality of nanometer Cu, nanometer Al, nanometer Cr and nanometer BN is respectively 1.0g, 1.0g, 0.5g and 0.5g in the nanometer mixed powder described in the step (1).

3. according to claim 1ly a kind ofly prepare the method for anti-HIC stress cracking steel based on carrier control technique, it is characterized in that: the quality of nanometer Cu, nanometer Al, nanometer Cr and nanometer BN is respectively 1.5g, 1.5g, 0.5g and 0.5g in the nanometer mixed powder described in the step (1).

4. according to claim 1ly a kind ofly prepare the method for anti-HIC stress cracking steel based on carrier control technique, it is characterized in that: the quality of nanometer Cu, nanometer Al, nanometer Cr and nanometer BN is respectively 1.0g, 1.0g, 1.5g and 1.5g in the nanometer mixed powder described in the step (1).

5. according to claim 1ly a kind ofly prepare the method for anti-HIC stress cracking steel based on carrier control technique, it is characterized in that: the quality of nanometer Cu, nanometer Al, nanometer Cr and nanometer BN is respectively 1.5g, 1.5g, 1.5g and 1.5g in the nanometer mixed powder described in the step (1).

6. according to claim 1ly a kind ofly prepare the method for anti-HIC stress cracking steel based on carrier control technique, it is characterized in that: the melting described in the step (2) is for carrying out melting in medium frequency induction melting furnace.

7. according to claim 6ly a kind ofly prepare the method for anti-HIC stress cracking steel based on carrier control technique, it is characterized in that: described medium frequency induction melting furnace is antivacuum medium frequency induction melting furnace.

Images