CN104726779B

CN104726779B - A kind of high Cr jessop and preparation method thereof

Info

Publication number: CN104726779B
Application number: CN201510190201.7A
Authority: CN
Inventors: 向志东; 杨蜜; 宋新莉; 贾涓; 朱上
Original assignee: Wuhan University of Science and Engineering WUSE
Current assignee: Wuhan University of Science and Engineering WUSE
Priority date: 2015-04-21
Filing date: 2015-04-21
Publication date: 2016-09-14
Anticipated expiration: 2035-04-21
Also published as: CN104726779A

Abstract

The present invention relates to a kind of high Cr jessop and preparation method thereof.Its technical scheme is: chemical composition and the content thereof of described high Cr jessop is: Cr is 8.5 ~ 9.5wt%；Co is 2.5 ~ 3.5wt%；W+Mo is 2.8 ~ 3.3wt%, wherein W be 1.5 ~ 2.5wt%, Mo be 0.5 ~ 1.5wt%；V is 0.15 ~ 0.25wt%；Nb is 0.05 ~ 0.1wt%；C is 0.001 ~ 0.01wt%；N is 0.01 ~ 0.05wt%；B is 0.003 ~ 0.01wt%；Surplus is ferrum and inevitable impurity.Chemical composition and content thereof by described high Cr jessop carry out dispensing, and melting in vaccum sensitive stove is cast into steel ingot, is rolled into sheet material；Again 1050 ~ 1100 DEG C of normalizings 0.8 ~ 1.2 hour, then it is tempered 0.8 ~ 1.2 hour at 760 ~ 800 DEG C, furnace cooling, prepares high Cr jessop.The creep rupture strength of its goods is significantly higher than existing 9 12Cr jessops, it is adaptable to operating temperature is structure and the parts steel of 650 DEG C.

Description

A kind of high Cr jessop and preparation method thereof

Technical field

The invention belongs to jessop technical field.It is specifically related to a kind of high Cr jessop and preparation side thereof Method.

Background technology

The discharge capacity saving the energy, the coal-fired utilization rate of raising and minimizing carbon dioxide is the main of steam power plant's development in the present age Direction, by Development of Ultra-Supercritical (USC) fired power generating unit and to improve the steam parameter (vapor (steam) temperature and pressure) of steam turbine be to solve The certainly maximally effective approach of problem above.In last decade, steam parameter brings up to 600 DEG C/30MPa from 530 DEG C/18MPa, generating Efficiency brings up to 42% ~ 47% from 30% ~ 35%, simultaneously CO₂Discharge capacity decreases 30%, to the whole world bring considerable economy and Environmental benefit.But, the high-temperature behavior to heat resisting steel that improves of steam parameter is had higher requirement, except requiring heat resisting steel Have outside the best oxidation-resistance property, it is often more important that require that it has higher high temperature and creep resistance intensity or the strongest Degree.

Nowadays, the high-temperature component of ultra supercritical coal-fired unit uses a series of 9 ~ 12Cr type (mass fraction of chromium is 9% ~ 12%) high chromium content ferrite series heat-resistant steel.This kind of jessop is after normalizing+tempering heat treatment, and supply of material state is organized as There is lath martensite and the M of high density dislocation₂₃C₆(Cr₂₃C₆) and MX [(V, Nb) (C, N)] precipitated phase.Due to M₂₃C₆And MX Precipitation strength, solid solution atom strengthening and high density dislocation strengthening so that this Series Steel from be on active service start just have preferable intensity. But during long service, M₂₃C₆Constantly it is roughened with Laves phase, while reducing solution strengthening effect, also can form Creep hole；Z phase Separating out and growing up and greatly weaken the dispersion-strengthened action of MX phase in the creep later stage, and increase Creep hole further The probability occurred, Z reduces role relative to croop property and is far longer than M₂₃C₆Phase and the roughening of Laves phase.Therefore, high Cr During jessop at high temperature long-play, creep strength can significantly reduce, it is easy to occurs creep rupture to cause Lost efficacy, thus affected the safety that equipment runs.The use temperature of existing 9 ~ 12Cr type jessop is not above 620 ℃.Jessop to be made for temperature higher than the environment of 620 DEG C, then its under the conditions of higher than 620 DEG C 100000 hours Creep rupture strength must reach 100MPa.And existing 9 ~ 12Cr type jessop is in the temperature environment higher than 620 DEG C Within 100000 hours, creep rupture strength can not meet this requirement.

Summary of the invention

It is contemplated that overcome prior art defect, it is therefore an objective to provide a kind of high Cr jessop and preparation side thereof Method, prepared high Cr jessop can be used for structural steel and the parts steel that operating temperature is 650 DEG C, particularly For manufacturing ultra supercritical steam turbine, internal combustion engine, high temperature chemical industry equipment and the nuclear-plant that operating temperature is 650 DEG C.

For realizing object above, the technical solution used in the present invention is: the chemistry one-tenth of described high Cr jessop Divide and content is: Cr is 8.5 ~ 9.5wt%；Co is 2.5 ~ 3.5wt%；W+Mo is 2.8 ~ 3.3wt%, wherein W be 1.5 ~ 2.5wt%, Mo are 0.5 ~ 1.5wt%；V is 0.15 ~ 0.25wt%；Nb is 0.05 ~ 0.1wt%；C is 0.001 ~ 0.01wt%；N is 0.01~0.05wt%；B is 0.003 ~ 0.01wt%；Surplus is ferrum and inevitable impurity.

Chemical composition and content thereof by described high Cr jessop carry out dispensing, molten in vaccum sensitive stove Refining, is cast into steel ingot, is rolled into sheet material；Normalizing 0.8 ~ 1.2 hour under the conditions of 1050 ~ 1100 DEG C again, then at 760 ~ 800 DEG C Under the conditions of be tempered 0.8 ~ 1.2 hour, furnace cooling, prepare high Cr jessop.

Owing to using technique scheme, the present invention compared with prior art, has the advantage that

High Cr jessop carbon content prepared by the present invention is low, it is suppressed that M₂₃C₆Precipitation in drawing process, right Creep rupture strength is favourable；High Cr jessop nitrogen content prepared by the present invention is suitable, is not only formed tiny and stable The hardening constituent of VN and NbN, and stopped the precipitation in Z phase later stage under arms and grown up, it is to avoid the consuming excessively and produce of MX phase The weakening of dispersion-strengthened action, reduce the probability that Creep hole is formed, restrained effectively the fall of long term high temperature creep rupture strength Low；High Cr jessop molybdenum content prepared by the present invention is 0.8 ~ 1.5wt%, and W content is 1.5 ~ 2.2wt%, requires W simultaneously The total amount of+Mo is 2.8 ~ 3.2wt%, has given full play to compound solid solution strengthening and the precipitation strength effect of Laves phase of W, Mo.

High Cr jessop prepared by the present invention 100000 hours creep rupture strengths under the conditions of 650 DEG C are more than 100MPa, is significantly higher than the strongest existing 9-12Cr jessop (i.e. P92 steel) creep rupture strength under similarity condition (53MPa).

Therefore, the present invention is applicable to structural steel and the parts steel that operating temperature is 650 DEG C, is particularly well-suited to manufacture Operating temperature is ultra supercritical steam turbine, internal combustion engine, high temperature chemical industry equipment and the nuclear-plant of 650 DEG C.

Accompanying drawing explanation

Fig. 1 is the XRD line spectrum of a kind of high Cr jessop former state extraction precipitate prepared by the present invention；

Fig. 2 is the XRD line spectrum of sample extraction precipitate after high Cr jessop creep 5787.1h shown in Fig. 1 ruptures；

Fig. 3 is the stress Larson-Miller comparison diagram of high Cr jessop shown in Fig. 1 and P92 steel.

Detailed description of the invention

The invention will be further described with detailed description of the invention below in conjunction with the accompanying drawings, not the limit to its protection domain System.

Embodiment 1

A kind of high Cr jessop and preparation method thereof.The chemical composition of described high Cr jessop and containing Amount is: Cr is 8.5 ~ 9.0wt%；Co is 2.5 ~ 3.0wt%；W+Mo is 3.0 ~ 3.3wt%, wherein W be 2.0 ~ 2.5wt%, Mo be 0.5 ~1.0wt%；V is 0.15 ~ 0.2wt%；Nb is 0.05 ~ 0.08wt%；C is 0.001 ~ 0.006wt%；N is 0.03 ~ 0.05wt%；B is 0.003~0.007wt%；Surplus is ferrum and inevitable impurity.

Chemical composition and content thereof by described high Cr jessop carry out dispensing, molten in vaccum sensitive stove Refining, is cast into steel ingot, is rolled into sheet material；Normalizing 0.8 ~ 1.0 hour under the conditions of 1050 ~ 1080 DEG C again, then at 760 ~ 780 DEG C Under the conditions of be tempered 0.8 ~ 1.0 hour, furnace cooling, prepare high Cr jessop.

Embodiment 2

A kind of high Cr jessop and preparation method thereof.The chemical composition of described high Cr jessop and containing Amount is: Cr is 9.0 ~ 9.5wt%；Co is 3.0 ~ 3.5wt%；W+Mo is 2.8 ~ 3.0wt%, wherein W be 1.5 ~ 2.0wt%, Mo be 1.0 ~1.5wt%；V is 0.2 ~ 0.25wt%；Nb is 0.08 ~ 0.1wt%；C is 0.006 ~ 0.01wt%；N is 0.01 ~ 0.03wt%；B is 0.007~0.01wt%；Surplus is ferrum and inevitable impurity.

Chemical composition and content thereof by described high Cr jessop carry out dispensing, molten in vaccum sensitive stove Refining, is cast into steel ingot, is rolled into sheet material；Normalizing 1.0 ~ 1.2 hours under the conditions of 1080 ~ 1100 DEG C again, then at 780 ~ 800 DEG C Under the conditions of be tempered 1.0 ~ 1.2 hours, furnace cooling, prepare high Cr jessop.

Embodiment 3

A kind of high Cr jessop and preparation method thereof.The chemical composition of described high Cr jessop and containing Amount is: Cr is 8.8 ~ 9.2wt%；Co is 2.7 ~ 3.2wt%；W+Mo is 2.9 ~ 3.2wt%, wherein W be 1.8 ~ 2.3wt%, Mo be 0.8 ~1.3wt%；V is 0.18 ~ 0.23wt%；Nb is 0.06 ~ 0.08wt%；C is 0.003 ~ 0.007wt%；N is 0.02 ~ 0.04wt%；B It is 0.005 ~ 0.008wt%；Surplus is ferrum and inevitable impurity.

Chemical composition and content thereof by described high Cr jessop carry out dispensing, molten in vaccum sensitive stove Refining, is cast into steel ingot, is rolled into sheet material；Normalizing 0.9 ~ 1.1 hour under the conditions of 1060 ~ 1090 DEG C again, then at 770 ~ 790 DEG C Under the conditions of be tempered 0.9 ~ 1.1 hour, furnace cooling, prepare high Cr jessop.

The present invention compared with prior art, has the advantage that

Fig. 1 is the XRD line spectrum of a kind of high Cr jessop former state extraction precipitate of embodiment 1 preparation.From Fig. 1 It can be seen that there is no M₂₃C₆Phase, illustrates that this high Cr jessop carbon content prepared by embodiment 1 is low, it is suppressed that M₂₃C₆ Precipitation in drawing process, favourable to creep rupture strength；

Fig. 2 is that the jessop shown in Fig. 1 tries after creep test 5787.1h fracture under the conditions of 650 DEG C/190MPa The XRD line spectrum of sample extraction precipitate.From Fig. 1 and Fig. 2 in general, drawing process has separated out MX phase, creep process has been analysed Go out Laves phase and do not had Z phase to separate out in the creep later stage.From this, this high Cr jessop of embodiment 1 preparation Nitrogen content is suitable, not only forms the hardening constituent of tiny and stable VN and NbN, and stopped the Z phase later stage under arms precipitation and Grow up, it is to avoid the consuming excessively of MX phase and the weakening of dispersion-strengthened action that produces, reduce the probability that Creep hole is formed, Restrained effectively the reduction of long term high temperature creep rupture strength.

High Cr jessop molybdenum content prepared by this detailed description of the invention is 0.8 ~ 1.5wt%, W content is 1.5 ~ 2.2wt%, require that the total amount of W+Mo is 2.8 ~ 3.2wt% simultaneously, has given full play to compound solid solution strengthening and the Laves phase of W, Mo Precipitation strength effect.

Fig. 3 is the stress Larson-Miller parameter pass of a kind of high Cr jessop shown in Fig. 1 and P92 steel It it is comparison diagram.From figure 3, it can be seen that under the conditions of 650 DEG C 100000 hours of the high Cr jessop prepared of the present invention Creep rupture strength is more than 100MPa, is significantly higher than the strongest existing 9-12Cr jessop (i.e. P92 steel) under similarity condition Creep rupture strength (53MPa).

Claims

1. one kind high Cr jessop, it is characterised in that the chemical composition of described high Cr jessop and content thereof It is: Cr is 8.5 ~ 9.5wt%；Co is 2.5 ~ 3.5wt%；W+Mo is 2.8 ~ 3.3wt%, wherein W be 1.5 ~ 2.5wt%, Mo be 0.5 ~ 1.5wt%；V is 0.15 ~ 0.25wt%；Nb is 0.05 ~ 0.1wt%；C is 0.001 ~ 0.01wt%；N is 0.01 ~ 0.05wt%；B is 0.003~0.01wt%；Surplus is ferrum and inevitable impurity.

The preparation method of high Cr jessop the most as claimed in claim 1, it is characterised in that by described high Cr ferrite The chemical composition of heat resisting steel and content thereof carry out dispensing, and melting in vaccum sensitive stove is cast into steel ingot, is rolled into sheet material；Again Normalizing 0.8 ~ 1.2 hour under the conditions of 1050 ~ 1100 DEG C, is then tempered 0.8 ~ 1.2 hour, with stove under the conditions of 760 ~ 800 DEG C Cooling, prepares high Cr jessop.