CN104561837A - Steel plate made of pressure vessel steel ASTMA387CL11Gr2 and production method thereof - Google Patents

Abstract

The invention discloses a steel plate made of pressure vessel steel ASTMA387CL11Gr2, which can meet the use requirements of equipment, and a production method thereof. The steel plate made of the pressure vessel steel ASTMA387CL11Gr2 comprises the following chemical components in percentage by mass: 0.10 to 0.17 percent of C, less than or equal to 0.55 percent of Si, 0.40 to 0.65 percent of Mn, less than or equal to 0.008 percent of P, less than or equal to 0.003 percent of S, less than or equal to 0.20 percent of Ni, 1.20 to 1.50 percent of Cr, less than or equal to 0.10 percent of Cu, 0.45 to 0.65 percent of Mo, 0.025 to 0.050 percent of Al, less than or equal to 0.016 percent of As, less than or equal to 0.005 percent of Sn, less than or equal to 0.003 percent of Sb, less than or equal to 0.003 percent of O, less than or equal to 0.008 percent of N, less than or equal to 0.0002 percent of H and the balance of Fe and unavoidable impurities. According to the invention, the chemical components of the steel plate are designed by using Cr-Mo as the basic alloy elements; by the process route of converter steelmaking, LF (low frequency) furnace refining, VD (vacuum degassing) furnace vacuum degassing, rolling, fault detection, normalizing, tempering, steel plate finishing and performance examination, the suitable internal controlled composition is made, the fluctuation range of the chemical components is strictly controlled and stability of performance of the steel plate is ensured; the LF and VD processes are adopted to ensure cleanness of the steel; blending control and smelting operation are reinforced; the content of harmful elements such as Sn, Sb, As, O, N and H is effectively controlled; the temper embrittlement tendency is reduced; the high-temperature corrosion resistance of the steel is improved.

Description

A kind of pressure vessel steel ASTMA387CL11Gr2 steel plate and production method thereof

Technical field

The present invention relates to a kind of super-thick steel plate, particularly a kind of pressure vessel steel ASTMA387CL11Gr2 steel plate and production method thereof that can meet equipment.

Background technology

ASTMA387CL11Gr2 is widely used in the industries such as oil, chemical industry, power station, boiler, for making equipment and the components such as reactor, interchanger, oil gas tank, liquefied petroleum gas tank, nuclear power reactor pressure vessel.

Conventional ASTMA387CL11Gr2 does not generally require to face hydrogen performance, and requires lower to elements such as P, Sn, As, Sn.Along with equipment enlarging development, higher requirement is proposed to steel plate substance and thickness, in addition, because the process of thermal treatment difficulty of Plate Steel is comparatively large, it is narrow to there is specification limit in commercial ASTMA387CL11Gr2 steel plate, and the limit of up-to-date national regulations thickness is 100mm, the Technical facilities in production of Present Domestic and technology level, thickness guarantee very difficult more than 100mm plate property, cannot meet the growing slab market requirement, main dependence on import product.

Summary of the invention

The object of the present invention is to provide a kind of hydrogen-contacting equipment ASTMA387CL11Gr2 steel plate of heavy thickness, on the basis not reducing common Cr-Mo mechanical property of steel plate, making it both changes in quality has good resistant to hydrogen erosion ability, again for good low-temperature flexibility and welding property steel plate.

Above object realizes by following technical scheme: a kind of pressure vessel steel ASTMA387CL11Gr2 steel plate comprises the chemical composition of following mass percent: C0.10-0.17%, Si≤0.55%, Mn0.40-0.65%, P≤0.008%, S≤0.003%, Ni≤0.20%, Cr1.20-1.50%, Cu≤0.10%, Mo0.45-0.65%, Al0.025-0.050%, As≤0.016%, Sn≤0.005%, Sb≤0.003%, O≤0.003, N≤0.008%, H≤0.0002% all the other be Fe and inevitable impurity.

The function analysis of above-mentioned chemical element is as follows: C: be most basic strengthening element in steel, improves intensity, but C affects the welding property of steel and affects toughness; Si: as reductive agent and reductor in steelmaking process, favourable to the intensity and wear resistance improving steel plate; Mn: be solution strengthening element, all favourable to the intensity and toughness improving steel plate; P: unfavorable to welding, and there is certain cold shortness, in this steel grade, belong to harmful element, what should control is as far as possible low; S: easily form MnS type impurity, have certain red brittleness, belong to harmful element in this steel grade, what should control is as far as possible low; ni:appropriate adds the low-temperature impact toughness and reduction Cold Brittleness Transition Temperature that effectively can improve steel plate, increases the atmospheric corrosion resistance of steel; al: in steel-making, be used as deoxidation determine nitrogen agent, grain refining intensificatiom effect can be played; Cu has certain contribution to the erosion resistance of steel plate, weathering resistance, but also can cause the blue shortness phenomenon of steel, namely carries out ceiling restriction as impurity element herein, prevents the generation of blue shortness phenomenon; Cr can make C curve move to right, and improves the hardening capacity of steel plate, and improves armor plate strength by solid solution; Mo mainly plays a part to improve hardening capacity and anti-temper resistance; Impurity element P, S, O, N, H, As, Sn, Sb equal size all have the upper limit to require lower limit does not limit, reduce as far as possible under processing unit ability, steel be pure to reach, the even object of mechanical property.

Described heavy thickness steel plate thickness is 150mm.

The production method of above-mentioned steel plate, comprises the following steps:

Smelting technology: molten steel is first through converter smelting, guarantee carbon >=0.05% of tapping, tapping P≤0.015%, sends into LF refining furnace, large bag temperature >=1600 DEG C, the large quantity of slag is taked to carry out slag making, guarantee that the white slag hold-time controls at 15min, the vacuum-treat of above VD stove, in described vacuum refinement, dwell time under≤67Pa controls, according to 2.7 ~ 3.0 meters of/ton of steel disposable feeding Si-Ca lines by >=20min.

Casting process: soft argon blowing time palpus guarantee >=5min; Argon to temperature meets after teeming temperature requires, opens to water pouring temperature and control (T1 is liquidus temperature) according to T1+ (35 ~ 45 DEG C) and control after closing the calm 5min of argon gas,

Heating process: steel ingot carries out that temperature is sent, Wen Qing, temperature dress, stewing steel 1 hour; For ensureing the abundant solid solution of alloying element, austenite crystal is tiny, and adopt low speed to burn steel, the holding temperature of dead soaking pit controls at 1200 DEG C ~ 1300 DEG C;

Rolling technology: adopt two-stage mode rolling, start rolling temperature 1000 DEG C ~ 1050 DEG C; One-phase finishing temperature is > 950 DEG C, single pass draught 40mm ~ 70mm, accumulative draft >=70%, two-stage start rolling temperature is < 900 DEG C, the steel thickness that dries in the air is finished product thickness+(60 ~ 80) mm, two-stage takes little pressure rolling, and finish rolling adds up draft > 45%, finishing temperature≤820 DEG C;

Water-cooling process: in described control is cold, red temperature < 700 DEG C, cools several times, and cooling rate controls at 1 ~ 8 DEG C/s, and red temperature controls at 660-700 DEG C.

Slow cooling: in described slow cooling, steel plate enters burial pit temperature >=450 DEG C; Heap cool time >=42 hour;

Thermal treatment process: after steel plate is detected a flaw, carries out normalizing+temper, normalizing temperature 920-930 DEG C, heat-up time 2min/mm, water-cooled is to normal temperature, and tempering temperature is 710 ± 10 DEG C, and total heat-up time, 2.2min/mm, adopted air cooling after tempering.

The present invention is that basic alloying element is to steel plate chemical composition design by Cr-Mo, by converter steelmaking-LF stove refining-VD stove vacuum outgas-rolling-flaw detection-normalizing-tempering-steel plate finishing-service check operational path, formulate suitable internal control composition, strict control chemical component fluctuation scope, guarantee the stable of plate property, LF+VD technique is adopted to ensure the cleanliness factor of steel, strengthen Charge Mixture Control and smelting operation, the harmful element content such as effective control Sn, Sb, As, O, N, H, reduce temper embrittlement tendency, improve the high temperature corrosion resistance of steel.

Steel plate of the present invention adopts two-stage controlled rolling process and II type controlled rolling process, solves mill milling insufficient pressure and the coarse grains that causes is uneven, impelling strength lowers problem; The rolling technology of steel plate of the present invention is simple, and easy handling, is suitable for having the ordinary steel ironworks of normalizing furnace, outer machine stove, car bottom furnace to produce.

The mechanical property of steel plate of the present invention after Simulated post-weld heat treatment reaches following requirements after testing: Rp0.2 > 310MPa, Rm515-690MPa, A >=22%, 20 DEG C of AKV >=80J, P+Sn≤0.015%, has good resistant to hydrogen corrosion and resistance to embrittlement energy.

Accompanying drawing explanation

Below in conjunction with accompanying drawing, the present invention is described further.

Fig. 1 is present invention process schema.

Fig. 2 is the metallographic structure figure (500X) after example 1 steel plate 1/4th place of the present invention organizes thermal treatment.

Fig. 3 is the metallographic structure figure (500X) after example 2 steel plate 1/4th place of the present invention organizes thermal treatment.

Embodiment

100mm ~ 150mm steel plate for large-thickness hydrogen-contacting equipment ASTMA387CL11Gr2 of the present invention, it is characterized in that by percentage to the quality, steel plate is by following elementary composition: C0.10-0.17%, Si≤0.55%, Mn0.40-0.65%, P≤0.008%, S≤0.003%, Ni≤0.20%, Cr1.20-1.50%, Cu≤0.10%, Mo0.45-0.65%, Al0.025-0.050%, As≤0.016%, Sn≤0.005%, Sb≤0.003%, O≤0.003, N≤0.008%, H≤0.0002% all the other be Fe and inevitable impurity.

The production method that the present invention takes comprises: converter smelting, LF refining, vacuum refinement, cast, Heating Steel Ingots, rolling, control are cold, slow cooling, thermal treatment.

The actual content of each composition of large-thickness hydrogen-contacting ASTMA387CL11Gr2 steel plate of the present invention, by percentage to the quality, as shown in table 1,

The each component content of table 1 large-thickness hydrogen-contacting steel ASTMA387CL11Gr2 and temper embrittlement sensitivity coefficient

Produce heavy thickness ASTMA387CL11Gr2 steel plate according to technical scheme of the present invention, carry out Mechanics Performance Testing to wherein part batch, its result is as shown in table 2.Experimental result shows, large-thickness hydrogen-contacting ASTMA387CL11Gr2 steel plate of the present invention has good comprehensive mechanical property, and intensity is high, good toughness, and anti-fatigue performance is excellent, can meet the requirement of hydrogen-contacting equipment steel completely, is applicable to producing in enormous quantities.

Table 2 heavy thickness faces the performance test results of equipment ASTMA387CL11Gr2 steel plate

table 3 normalizing+tempering+simulation postwelding mechanical property

Claims (2)

1. a pressure vessel steel ASTMA387CL11Gr2 steel plate, it comprises the chemical composition of following mass percent: C0.10-0.17%, Si≤0.55%, Mn0.40-0.65%, P≤0.008%, S≤0.003%, Ni≤0.20%, Cr1.20-1.50%, Cu≤0.10%, Mo0.45-0.65%, Al0.025-0.050%, As≤0.016%, Sn≤0.005%, Sb≤0.003%, O≤0.003, N≤0.008%, H≤0.0002% all the other be Fe and inevitable impurity.

2. a production method for pressure vessel steel ASTMA387CL11Gr2 steel plate as claimed in claim 1, its production method, comprises the following steps:

Smelting technology: molten steel is first through converter smelting, guarantee carbon >=0.05% of tapping, tapping P≤0.015%, sends into LF refining furnace, large bag temperature >=1600 DEG C, the large quantity of slag is taked to carry out slag making, guarantee that the white slag hold-time controls at 15min, the vacuum-treat of above VD stove, in described vacuum refinement, dwell time under≤67Pa controls, according to 2.7 ~ 3.0 meters of/ton of steel disposable feeding Si-Ca lines by >=20min;

Casting process: soft argon blowing time palpus guarantee >=5min; Argon to temperature meets after teeming temperature requires, opens to water pouring temperature and control according to T1+ (35 ~ 45 DEG C) after closing the calm 5min of argon gas; Heating process: steel ingot carries out that temperature is sent, Wen Qing, temperature dress, stewing steel 1 hour, and be ensure the abundant solid solution of alloying element, austenite crystal is tiny, and adopt low speed to burn steel, the holding temperature of dead soaking pit controls at 1200 DEG C ~ 1300 DEG C;

Rolling technology: adopt two-stage mode rolling, start rolling temperature 1000 DEG C ~ 1050 DEG C; One-phase finishing temperature is > 950 DEG C, single pass draught 40mm ~ 70mm, accumulative draft >=70%, two-stage start rolling temperature is < 900 DEG C, the steel thickness that dries in the air is finished product thickness+(60 ~ 80) mm, two-stage takes little pressure rolling, and finish rolling adds up draft > 45%, finishing temperature≤820 DEG C;

Water-cooling process: in described control is cold, red temperature < 700 DEG C, cools several times, and cooling rate controls at 1 ~ 8 DEG C/s, and red temperature controls at 660-700 DEG C;

Slow cooling: in described slow cooling, steel plate enters burial pit temperature >=450 DEG C; Heap cool time >=42 hour;

Thermal treatment process: after steel plate is detected a flaw, carries out normalizing+temper, normalizing temperature 920-930 DEG C, heat-up time 2min/mm, water-cooled is to normal temperature, and tempering temperature is 710 ± 10 DEG C, and total heat-up time, 2.2min/mm, adopted air cooling after tempering.