CN104762559A - Method for producing steel plate for hydrogen-contacting equipment - Google Patents

Abstract

The invention discloses a method for producing a steel plate for hydrogen-contacting equipment. The process route adopted by the method includes smelting in a rotating furnace, LF refining, VD vacuum refining, continuous casting, plate blank heating, controlled rolling, direct quenching and heat treatment, and steel comprises, by mass, 0.10%-0.15% of C, 0.10% or less of Si, 0.30%-0.60% of Mn, 0.010% or less of P, 0.005% or less of S, 0.020%-0.050% of Alt, 2.0%-2.5% of Cr, 0.95%-1.10% of Mo, 0.01%-0.02% of Ti, 0.010% or less of Sn, 0.012% or less of P and Sn, and the balance Fe and residual elements. The method is used for producing 12Cr2Mo1R steel plates having the thicknesses ranging from 16mm to 100mm and guaranteeing flaw detection and mechanical property, and the actual mass and all properties of obtained products are excellent; after maximum simulation postweld heat treatment is conducted on the steel plate, the yield strength allowance of the steel plate ranges from 70 Mpa to 90 Mpa, the tensile strength allowance of the steel plate ranges from 35 Mpa to 60 Mpa, the impact performance at the low temperature of minus 30 DEG C is stable, and the allowance is large.

Description

A kind of production method of hydrogen-contacting equipment steel plate

Technical field

The invention belongs to smelting iron and steel and rolling technique, be specifically related to a kind of production method of hydrogen-contacting equipment steel plate.

Technical background

Face hydrogen steel mainly for the manufacture of high temperature (temperature > 250 DEG C), high pressure (hydrogen dividing potential drop > 1.4MPa), face hydrogen environment under the pressure vessel and equipment that uses, be widely used in the relevant industries such as petrochemical complex, Coal Chemical Industry, electric power.Wherein the overwhelming majority is for the manufacture of the hydrogenation unit in oil refining and chemical industry, also has small portion for facing separation under hydrogen environment, heat-exchange equipment and the device fabrication of penstock line etc.

What current China used faces hydrogen 12Cr2Mo1R steel plate except meeting except the requirement of GB713-2014, also need to ensure that the mechanical property of steel plate after Simulated post-weld heat treatment meets standard-required, and p-30 DEG C of low temperature impact properties, inclusion, harmful element, gas contents etc. propose higher requirement.

Controlled rolling (Controlled rolling) is by the conservative control to METAL HEATING PROCESS system, deformation system and temperature schedule in the operation of rolling, pyroplastic deformation is combined with solid-state phase changes, to obtain tiny grain structure, steel are made to have the rolling novel process of excellent comprehensive mechanical property.It can improve steel and organize crystal grain, improves the intensity of steel plate and low-temperature toughness, simultaneously can save energy, Simplified flowsheet, also can give full play to alloys producing.Direct quenching utilizes the rear waste heat that rolls of CrMo steel to be cooled to below bainite transformation temperature also finally to obtain the thermal treatment process of bainite from deformed austeaite steel.Because the abundant dissolving of controlled rolling process interalloy element adds austenitic hardening capacity, be conducive to direct quenching subsequently; Controlled rolling refinement austenite crystal, adds austenite deformation band, for follow-up phase transformation provides forming core point, is expected to obtain desirable tissue morphology in addition, thus obtains excellent intensity and toughness combination after tempering.

Summary of the invention

Object of the present invention is in a kind of production method of hydrogen-contacting equipment steel plate, and the method adopting controlled rolling+direct quenching+tempering to combine is produced 16 ~ 100mm guaranteed cost, protected the hydrogen-contacting equipment steel plate 12Cr2Mo1R steel of flaw detection.Steel plate is through maximum analog postweld heat treatment, and its yield strength surplus capacity is at 70 ~ 90Mpa, and tensile strength surplus capacity is at 35 ~ 60Mpa, and-30 DEG C of stable, rich amounts of low temperature impact properties are large.

The technical scheme of invention:

A production method for hydrogen-contacting equipment steel plate, adopts operational path to be converter smelting → LF refining → VD vacuum refinement → continuous casting → heating of plate blank → controlled rolling → direct quenching → thermal treatment.The chemical composition mass percent (wt.%) of steel is as follows: C=0.10 ~ 0.15, Si≤0.10, Mn=0.30 ~ 0.60, P≤0.010, S≤0.005, Alt=0.020 ~ 0.050, Cr=2.0 ~ 2.5, Mo=0.95 ~ 1.10, Ti=0.01 ~ 0.02, Sn≤0.010, P+Sn≤0.012; All the other are Fe and relict element.

Comprise following processing step:

A. converter smelting: guarantee C >=0.05% of tapping, P≤0.006%, tapping temperature >=1580 DEG C; Avoid tapping process slag;

B. LF refining: guarantee that the white slag hold-time controls at more than 20min; Carry out secondary before the departures of LF stove and take off P, control P≤0.004%;

C. VD vacuum refinement: the guarantor vacuum time >=23min under≤67Pa; VD carries out Calcium treatment after breaking sky;

D. continuous casting: continuous casting adopts section to be 260mm or 300mm, continuous casting carries out whole process protection casting, and teeming temperature is pressed liquidus temperature+(45 ~ 55 DEG C) and controlled;

E. heating of plate blank: after slab rolls off the production line, cooling in heap 12 ~ 16 hours temperature send shove charge; Slab heats in walking-beam furnace, and temperature controls at 1100 ~ 1250 DEG C;

F. controlled rolling: adopt the rolling of CR mode, start rolling temperature 1000 ~ 1150 DEG C; One-phase finishing temperature > 950 DEG C, after ensureing, three percentage pass reductions are more than 15%; Two-stage start rolling temperature is at 880 ~ 910 DEG C, and finish rolling adds up draft > 48%, finishing temperature >=850 DEG C;

G. direct quenching: enter water temp >=850 DEG C, red temperature < 200 DEG C, cooling rate controls at 3 ~ 8 DEG C/s;

H. thermal treatment: adopt tempering process, tempering temperature 700 ~ 730 DEG C, soaking time 3.5 ~ 6min/mm.

Inventive principle and chemical element consumption control mechanism:

C: carbon is in steel alloy, and normal and other alloying element forms carbide, can play strengthening effect, but at high temperature, some carbide easily decomposes under room temperature or lesser temps, produces detrimentally affect to creep resistance and creep rupture strength.Particularly facing under hydrogen service condition, the generation of hydrogen attack can be aggravated.

Si: helpful to the intensity improving steel, but easily promote temper embrittlement, content should be as far as possible low.

Mn: be solution strengthening element, all favourable to the intensity and toughness improving steel plate, but easily promote temper embrittlement, when ensureing hardness of steel, content should be low.

P: for suppressing temper embrittlement susceptibility and reducing cold short tendency, content should be as far as possible low.

S: the raising of unfavorable upper mounting plate energy and toughness, and have hot cracking tendency, content should be as far as possible low.

Sn: one of important impurity element affecting temper brittleness, should strictly control, and content should be as far as possible low.

The present invention is by selecting big cross section continuously cast bloom to ensure compression ratio, and on composition, the strict content controlling each harmful element, ensures the cleanliness factor of steel by LF+VD technique; Controlled rolling+direct quenching+temper is adopted to make the grain fineness number of steel reach 7.5 ~ 9.0 grades.By effective enforcement of above-mentioned measure, successfully produce 16mm ~ 100mm and protected flaw detection, protect the hydrogen-contacting equipment 12Cr2Mo1R steel plate of mechanical property.The present invention is strictly performed by above-mentioned production technique by heat treated whole process from converter smelting to steel plate, the quality in kind properties obtaining product is excellent: steel plate is through maximum analog postweld heat treatment, its yield strength surplus capacity is at 70 ~ 90Mpa, tensile strength surplus capacity is at 35 ~ 60Mpa, and-30 DEG C of stable, rich amounts of low temperature impact properties are large.

Embodiment

Below in conjunction with embodiment, the present invention will be further described.

Embodiment 1 ~ 4, thickness is that 16mm ~ 100mm protects flaw detection, protects mechanical property hydrogen-contacting equipment 12Cr2Mo1R steel plate, adopts operational path to be converter smelting → LF refining → VD vacuum refinement → continuous casting → heating of plate blank → controlled rolling → direct quenching → thermal treatment.The chemical composition mass percent (wt%) of steel is as follows: C=0.10 ~ 0.15, Si≤0.10, Mn=0.30 ~ 0.60, P≤0.010, S≤0.005, Alt=0.020 ~ 0.050, Cr=2.0 ~ 2.5, Mo=0.95 ~ 1.10, Ti=0.01 ~ 0.02, Sn≤0.010, P+Sn≤0.012; All the other are Fe and relict element.

Comprise following processing step:

A. converter smelting: guarantee C >=0.05% of tapping, P≤0.006%, tapping temperature >=1580 DEG C; Avoid tapping process slag;

B. LF refining: guarantee that the white slag hold-time controls at more than 20min; Carry out secondary before the departures of LF stove and take off P, control P≤0.004%;

C. VD vacuum refinement: the guarantor vacuum time >=23min under≤67Pa; VD carries out Calcium treatment after breaking sky;

D. continuous casting: continuous casting adopts section to be 260mm or 300mm, continuous casting carries out whole process protection casting, and teeming temperature is pressed liquidus temperature+(45 ~ 55 DEG C) and controlled;

E. heating of plate blank: after slab rolls off the production line, cooling in heap 12 ~ 16 hours temperature send shove charge; Slab heats in walking-beam furnace, and temperature controls at 1100 ~ 1250 DEG C;

F. controlled rolling: adopt the rolling of CR mode, start rolling temperature 1000 ~ 1150 DEG C; One-phase finishing temperature > 950 DEG C, after ensureing, three percentage pass reductions are more than 15%; Two-stage start rolling temperature is at 880 ~ 910 DEG C, and finish rolling adds up draft > 48%, finishing temperature >=850 DEG C;

G. direct quenching: enter water temp >=850 DEG C, red temperature < 200 DEG C, cooling rate controls at 3 ~ 8 DEG C/s;

H. thermal treatment: adopt tempering process, tempering temperature 700 ~ 730 DEG C, soaking time 3.5 ~ 6min/mm.

According to four embodiment 12Cr2Mo1R Finished Steels of aforesaid method test, chemical constitution is as table 1; Mechanics properties testing result is as table 2, and in table, T is steel plate thickness.

Table 1 embodiment chemical constitution (wt.%)

Table 2 embodiment mechanics properties testing result

Product surface quality is excellent, outer inspection qualification rate 100%, I level flaw detection qualification rate 100%, properties percent of pass 100%, sample is through maximum analog postweld heat treatment end to end for steel plate, and 1/2 thickness of slab place yield strength surplus capacity is at more than 100Mpa, and tensile strength surplus capacity is at 35 ~ 60Mpa,-30 DEG C are impacted basic at more than 250J, meet the technical requirements that 12Cr2Mo1R faces hydrogen steel completely.

Claims (1)

1. the production method of a hydrogen-contacting equipment steel plate, operational path is adopted to be converter smelting → LF refining → VD vacuum refinement → continuous casting → heating of plate blank → controlled rolling → direct quenching → thermal treatment, it is characterized in that: the chemical composition mass percent of steel is C=0.10 ~ 0.15, Si≤0.10, Mn=0.30 ~ 0.60, P≤0.010, S≤0.005, Alt=0.020 ~ 0.050, Cr=2.0 ~ 2.5, Mo=0.95 ~ 1.10, Ti=0.01 ~ 0.02, Sn≤0.010, P+Sn≤0.012, all the other are Fe and relict element;

Comprise following processing step:

A. converter smelting: guarantee C >=0.05% of tapping, P≤0.006%, tapping temperature >=1580 DEG C, avoid tapping process slag;

B. LF refining: guarantee that the white slag hold-time controls at more than 20min, carries out secondary before the departures of LF stove and takes off P, control P≤0.004%;

C. VD vacuum refinement: the guarantor vacuum time >=23min under≤67Pa; VD carries out Calcium treatment after breaking sky;

D. continuous casting: continuous casting adopts section to be 260mm or 300mm, continuous casting carries out whole process protection casting, and teeming temperature is pressed liquidus temperature+(45 ~ 55 DEG C) and controlled;

E. heating of plate blank: after slab rolls off the production line, cooling in heap 12 ~ 16 hours temperature send shove charge, and slab heats in walking-beam furnace, and temperature controls at 1100 ~ 1250 DEG C;

F. controlled rolling: adopt the rolling of CR mode, start rolling temperature 1000 ~ 1150 DEG C, one-phase finishing temperature > 950 DEG C, after ensureing, three percentage pass reductions are more than 15%, two-stage start rolling temperature is at 880 ~ 910 DEG C, finish rolling adds up draft > 48%, finishing temperature >=850 DEG C;

G. direct quenching: enter water temp >=850 DEG C, red temperature < 200 DEG C, cooling rate controls at 3 ~ 8 DEG C/s;

H. thermal treatment: adopt tempering process, tempering temperature 700 ~ 730 DEG C, soaking time 3.5 ~ 6min/mm.