CN109487158A - A kind of high temperature pressure vessel is greater than the 18MnMoNbR steel plate and its production method of 200mm with thickness - Google Patents

Abstract

A kind of 18MnMoNbR steel plate the invention discloses high temperature pressure vessel with thickness greater than 200mm, pass through reasonable Design of Chemical Composition, and KR molten iron pretreatment, converter smelting, Argon processing, LF refining, VD refining, casting, steel billet cleaning, heating, hot rolling, heap is cold, the techniques such as heat treatment, P in strict control steel, the harmful element content of the influence steel plate plasticity and toughness such as S, pass through LF refining dross inclusion adsorption, VD vacuum outgas, steel billet slow cooling, strict control billet heating temperature simultaneously, strict implement " high temperature in the operation of rolling, low speed, big pressure " technique, using steel plate stacking slow cooling, heat treatment is using the methods of quenching+tempering, it ensure that 200mm thick steel plate internal residual stress minimizes, inside flaw detection is up-to-standard, performance indexes reaches standard requirements.

Description

A kind of high temperature pressure vessel thickness is greater than 18MnMoNbR steel plate and its life of 200mm Production method

Technical field

The present invention relates to super-thick steel plate production technical fields, and in particular to is greater than to a kind of high temperature pressure vessel with thickness The 18MnMoNbR steel plate and its production method of 200mm.

Background technique

18MnMoNbR is boiler and the dedicated low-alloy structural steel of pressure vessel.Intensity and yield tensile ratio with higher, heat Processing performance and high-temperature behavior are preferable, and production technology is simpler, and welding performance is good, and heat resistance is higher.18MnMoNbR steel is used for Manufacture high-pressure boiler drum and large-size chemical container；Also serve as the hydraulic turbine and the big axis of hydrogenerator and alterating and direct current arbor Deng.18MnMoNbR maximum gauge is 100mm in GB713-2014 standard, and as economy continues to develop, engineering machinery, water power are set Gradually to enlarged, first evolution, the development of intelligent direction, special heavy plate demand is significantly increased, how to adopt standby and pressure vessel Producing the excellent super-thick steel plate of performance quality with low cost process becomes problem of the pendulum in face of metallurgy industry.

Summary of the invention

In view of the above-mentioned problems, the object of the present invention is to provide a kind of high temperature pressure vessel with thickness greater than 200mm's 18MnMoNbR steel plate, steel plate intensity with higher and yield tensile ratio, hot-working character and high-temperature behavior are preferable, preferably meet The market demand can be made by the production method of low cost.

A kind of 18MnMoNbR steel plate it is a further object of the present invention to provide high temperature pressure vessel with thickness greater than 200mm Production method.

In order to achieve the above objectives, the technical solution adopted by the present invention is that: a kind of high temperature pressure vessel is greater than 200mm with thickness 18MnMoNbR steel plate, the chemical component (unit, wt%) comprising following mass percent: C:0.15~0.21, Si:0.20 ~0.40, Mn:1.30~1.55, Mo:0.45~0.65, P≤0.020, S≤0.008, Als:0.015~0.040, Nb: 0.030~0.050, Ti≤0.008, it is other be Fe and relict element, carbon equivalent ce V≤0.55 of above-mentioned chemical component, wherein CEV=C+Mn/6+ (Mo+V+Cr)/5+ (Ni+Cu)/15.

A kind of production method of the 18MnMoNbR steel plate of high temperature pressure vessel with thickness greater than 200mm, comes according to the following steps Realize: converter smelting, LF refining, VD vacuum outgas, molding casting, Heating Steel Ingots, controlled rolling, retarded cooling process control, at heat Manage technology controlling and process.

The present invention passes through reasonable Design of Chemical Composition and the pretreatment of KR molten iron, converter smelting, Argon processing, LF essence The techniques such as refining, VD refining, casting, steel billet cleaning, heating, the hot and cold processing of hot rolling, heap, P, S etc. influence steel plate in strict control steel The harmful element content of plasticity and toughness passes through LF refining dross inclusion adsorption, VD vacuum outgas, steel billet slow cooling, while strict control steel Base heating temperature, strict implement " high temperature, low speed, big pressure " technique in the operation of rolling, using steel plate stacking slow cooling, heat treatment is adopted With the methods of quenching+tempering, it ensure that 200mm thick steel plate internal residual stress minimizes, detect a flaw up-to-standard, Ge Xiangxing for inside Energy index reaches standard requirements.

Specific embodiment

Below with reference to embodiment, technical characteristic of the invention is further described.

Embodiment

A kind of 18MnMoNbR steel plate of the high temperature pressure vessel thickness greater than 200mm is produced, in terms of composition design, C, Si, Mn are the key elements for improving armor plate strength, and the intensity of steel can be improved, especially in alloy element of the Mo as steel Elevated temperature strength and toughness；Improve corrosion stability of the steel in acid-base solution and liquid metal；It improves the wearability of steel and improves through hardening Property, weldability and heat resistance；Niobium can refine the crystal grain of steel, the superheated susceptivity and temper brittleness of steel be reduced, in certain presence Under the conditions of, it can also improve the intensity and toughness and the drag etc. to creep of steel；The thickness 200mm or more in technical solution 18MnMoNbR steel plate includes the chemical component (unit, wt%) of following mass percent: C:0.15~0.21, Si:0.20~ 0.40, Mn:1.30~1.55, Mo:0.45~0.65, P≤0.020, S≤0.008, Als:0.015~0.040, Nb:0.035 ~0.055, Ti≤0.008, other is Fe and relict element.

Above-mentioned steel plate is realized according to the following steps in the specific production:

1) KR molten iron pre-processes: molten iron guarantees molten iron S≤0.008%, desulfurization temperature drop≤20 DEG C after KR stirring desulphurization；

2) converter smelting: enter furnace molten iron S≤0.008%, P≤0.060%, molten iron temperature >=1300 DEG C, dry is high-quality Prompt industrial scrap, converter charge weight cast 5~7 tons of controls of Yuing by steel is poured, do not allow Argon in tapping process, do not allow into molten steel Any deoxidier and alloy is added；Tapping terminates to use slag retaining cone pushing off the slag, if pushing off the slag fails, it is necessary to lift furnace in advance, it is ensured that converter Slag thickness control is in 20mm hereinafter, to avoid slag rephosphorization；

3) Argon is handled: aluminum steel is added after opening argon gas in molten steel to argon station immediately, and aluminum steel must vertically feed ladle, forbid It spirals and feeds ladle；Aluminum steel strong Argon 3min after being added (strong Argon standard with blow open the control of molten steel naked eye diameter summation 500~ Subject to 700mm) it is leaving from station afterwards, and ensure temperature leaving from station at 1570 DEG C or more；

4) LF refining: refining process whole process Argon, refining basicity of slag by 4.0~6.0 control, one heating 3min after, first plus Enter 50Kg calcium carbide, add 20~40Kg aluminum shot, hereafter 2~4 shovel aluminum shots is added with spade into ladle every 2min, to ensure Subject to clinker bleaches；Two heating are added the calcium carbide of 10~30Kg according to submerged arc effect every time, while every 2min spade to steel 1~3 shovel aluminum shot is added in packet, to ensure that entire two heating process maintains white slag；The addition of three heating deoxidiers regards clinker color It is added, maintains white slag；It requires dry slag number to be greater than in refining process 5 times, silicon-calcium wire is added before leaving from station, adding must before silicon-calcium wire Argon gas, using vacuum outgas, 1610 ± 10 DEG C of temperature leaving from station must be closed；

5) VD is refined: vacuum degree can reach≤67Pa, and the dwell time >=25min breaks 3~5min of soft blow after sky, soft blow Molten steel must not be exposed in the process, carries out determining H control after vacuumizing within 1.8PPm, and coverture guarantee is paved with molten steel face, Add and must shut off argon gas before coverture, 1560 ± 15 DEG C of temperature leaving from station；

6) molding guarantees that ingot mould status of equipment is good before pouring steel, it is ensured that it is online to use preceding ingot mould temperature≤180 DEG C, it pours Bi Hou, after first the carbonization rice husk in cap mouth is paved with oxygen pipe, then into each ingot add 40~80Kg carbonization rice husk, be used in combination Oxygen pipe is uniformly paved；It is poured in 60min, the carbonization rice husk that add 40Kg or more in time to every ingot guarantees cap oral area position Not show；It requires infusing in complete 1~2h simultaneously, adds the carbonization rice husk of 40~80Kg into each ingot mould to ensure that cap mouth is kept the temperature Effect；

7) Heating Steel Ingots: stewing 650~700 DEG C, time 2h, 1000 DEG C or less heating rate≤120 DEG C/h of steel temperature, temperature Heating rate≤200 DEG C/h at 1000 DEG C of >, temperature keep the temperature 16h when rising to 1260 DEG C, tapping temperature is 1240 DEG C or so；

8) steel ingot rolls: accumulative reduction ratio >=55%, and 1020 DEG C~1120 DEG C of start rolling temperature；One stage is using big pressure Amount, reduction in pass are controlled in 40-50mm, and finishing temperature is at 950 DEG C~1000 DEG C, and the steel that dries in the air is with a thickness of 400mm or so, two-stage Start rolling temperature is at 880~920 DEG C, and the two-stage takes small pressure to roll, and finishing temperature is at 780 DEG C~810 DEG C to ensure original plate Shape；

9) heap is cold: rolling rear heap and enters burial pit progress stacking slow cooling, cold temperature >=350 DEG C of heap, stack cold time >=60 hour；Through Crossing high temperature stack cooling process can effectively avoid because being quickly cooled down the residual stress generated, while can substantially reduce containing for hydrogen in steel plate Amount improves flaw detection of steel plate.

10) be heat-treated: according to following parameter, quench+intercritical hardening+tempering after obtain the present invention

State	Holding temperature (DEG C)	Heat insulating coefficient (min/mm)	Cooling technique
				Quenching	920~930	2.0	It is quickly quenching into room temperature
Intercritical hardening	820~830	2.0	It is quickly quenching into room temperature
				Tempering	620~630	4.0	It is air-cooled

The embodiment of the present invention is by passing through converter smelting, LF refining, vacuum outgas, molding casting, Heating Steel Ingots, rolling The techniques such as system, stacking slow cooling, heat treatment obtain the 200mm thick steel plate of chemical component as described below, wherein chemical component and mechanics Performance is seen table 1 and table 2 below.

The chemical component (Wt%) of 1 200mm thickness 18MnMoNbR of table

C	Si	Mn	P	S	Als	V	Ti	Cr	Ni	Mo	Nb	Cu	CEV
														0.18	0.27	1.5	0.010	0.003	0.035	0.002	0.005	0.035	0.018	0.553	0.045	0.020	0.550

2 200mm thickness 18MnMoNbR mechanical property of table

Surface quality and flaw detection: plate surface quality produced is excellent, detects a flaw by JB/T 4730, meets II and wants It asks, has reached desired effect.

Described above is only presently preferred embodiments of the present invention, and above-mentioned specific embodiment is not limitation of the present invention, Retouching, modification or the equivalent replacement that all those skilled in the art are made as described above, belong to guarantor of the invention Protect range.

Claims (2)

1. the 18MnMoNbR steel plate that a kind of high temperature pressure vessel is greater than 200mm with thickness, it is characterised in that: include following quality The chemical component (unit, wt%) of percentage: C:0.15~0.21, Si:0.20~0.40, Mn:1.30~1.55, Mo:0.45 ~0.65, P≤0.020, S≤0.008, Als:0.015~0.040, Nb:0.030~0.050, Ti≤0.008, other is Fe And relict element, carbon equivalent ce V≤0.55 of above-mentioned chemical component, wherein CEV=C+Mn/6+ (Mo+V+Cr)/5+ (Ni+Cu)/ 15。

2. a kind of production method of 18MnMoNbR steel plate of high temperature pressure vessel with thickness greater than 200mm, it is characterised in that:

1) KR molten iron pre-processes: molten iron guarantees molten iron S≤0.008%, desulfurization temperature drop≤20 DEG C after KR stirring desulphurization；

2) converter smelting: enter furnace molten iron S≤0.008%, P≤0.060%, molten iron temperature >=1300 DEG C, dry high-quality corner Expect that steel scrap, converter charge weight cast 5~7 tons of controls of Yuing by steel is poured, do not allow Argon in tapping process, do not allow to be added into molten steel Any deoxidier and alloy；Tapping terminates to use slag retaining cone pushing off the slag, if pushing off the slag fails, it is necessary to lift furnace in advance, it is ensured that converter slag Thickness control is in 20mm hereinafter, to avoid slag rephosphorization；

3) Argon is handled: aluminum steel is added after opening argon gas in molten steel to argon station immediately, and aluminum steel must vertically feed ladle, forbid to spiral Feed ladle；Aluminum steel strong Argon 3min after being added (strong Argon standard with blow open the control of molten steel naked eye diameter summation 500~ Subject to 700mm) it is leaving from station afterwards, and ensure temperature leaving from station at 1570 DEG C or more；

4) LF refining: refining process whole process Argon, refining basicity of slag are first added after one heats 3min by 4.0~6.0 controls 50Kg calcium carbide adds 20~40Kg aluminum shot, hereafter 2~4 shovel aluminum shots is added with spade into ladle every 2min, to ensure furnace Subject to slag bleaches；Two heating are added the calcium carbide of 10~30Kg according to submerged arc effect every time, while every 2min spade to ladle 1~3 shovel aluminum shot of middle addition, to ensure that entire two heating process maintains white slag；The addition of three heating deoxidiers adds depending on clinker color Enter, maintains white slag；It requires dry slag number to be greater than in refining process 5 times, silicon-calcium wire is added before leaving from station, add necessary before silicon-calcium wire Close argon gas, using vacuum outgas, 1610 ± 10 DEG C of temperature leaving from station；

5) VD is refined: vacuum degree can reach≤67Pa, and the dwell time >=25min breaks 3~5min of soft blow after sky, soft blow process Middle molten steel must not be exposed, carries out determining H control after vacuumizing within 1.8PPm, coverture guarantee is paved with molten steel face, adds and covers It must shut off argon gas before lid agent, 1560 ± 15 DEG C of temperature leaving from station；

6) molding guarantees that ingot mould status of equipment is good before pouring steel, it is ensured that it is online to use preceding ingot mould temperature≤180 DEG C, it is poured Afterwards, after first being paved the carbonization rice husk in cap mouth with oxygen pipe, then the carbonization rice husk of 40~80Kg is added into each ingot, and uses oxygen Pipe is uniformly paved；It is poured in 60min, the carbonization rice husk that add 40Kg or more in time to every ingot guarantees cap oral area position not Show；It requires infusing in complete 1~2h simultaneously, adds the carbonization rice husk of 40~80Kg into each ingot mould to ensure cap mouth heat preservation effect Fruit；

7) Heating Steel Ingots: stewing steel temperature 650~700 DEG C, time 2h, 1000 DEG C or less heating rate≤120 DEG C/h, temperature > Heating rate≤200 DEG C/h at 1000 DEG C, temperature keep the temperature 16h when rising to 1260 DEG C, tapping temperature is 1240 DEG C or so；

8) steel ingot rolls: accumulative reduction ratio >=55%, and 1020 DEG C~1120 DEG C of start rolling temperature；One stage used heavy reduction, road Secondary drafts control is in 40-50mm, and finishing temperature is at 950 DEG C~1000 DEG C, and the steel that dries in the air is with a thickness of 400mm or so, two-stage open rolling Temperature is at 880~920 DEG C, and the two-stage takes small pressure to roll, and finishing temperature is at 780 DEG C~810 DEG C to ensure original plate shape；

9) heap is cold: rolling rear heap and enters burial pit progress stacking slow cooling, cold temperature >=350 DEG C of heap, stack cold time >=60 hour；Through excessively high Warm stack cooling process can effectively avoid because being quickly cooled down the residual stress generated, while can substantially reduce the content of hydrogen in steel plate, change Kind flaw detection of steel plate.

10) be heat-treated: according to following parameter, quench+intercritical hardening+tempering after obtain the present invention.

State Holding temperature (DEG C) Heat insulating coefficient (min/mm) Cooling technique Quenching 920~930 2.0 It is quickly quenching into room temperature Intercritical hardening 820~830 2.0 It is quickly quenching into room temperature Tempering 620~630 4.0 It is air-cooled