A kind of 175MPa movable elbow material and heat treatment process
Technical field
The invention belongs to materials science field, be related specifically to a kind of oil field fracturing construction operation pressure 175MPa and it is following
Workable movable elbow material and its heat-treatment processing process.
Background technique
Due to factors such as the special geologic structures in China, when carrying out oil and gas development, required pressing crack construction operational pressure is flat
Mean value and peak are much higher than foreign level, especially in recent years, as the exploitation dynamics of unconventional energy resource continues to increase, I
State's deep-well, ultradeep well are continuously increased, and propose harsher performance requirement to the high pressure pipe joint system of pressure break equipment.Movable elbow
It is a kind of product that can be precisely controlled pressure break medium flow direction, due to its special structure, inner wall often occurs corroding and erosion, into
The leakage of one step thorn or Cracking Failure, are the most weak links of high pressure pipe joint system.It lives currently, domestic and international company can produce 140MPa
Dynamic elbow product.
In patent CN201810029961, in order to improve 140MPa and the above movable elbow safety, one kind is disclosed
Carbon fibre composite enhance super-pressure movable elbow, inner wall use Conventional alloys steel, using carbon fibre material cover elbow and
The outer surface of straight peen.
175MPa movable elbow product has not been reported in foreign countries, and the country also has no metal material and manufacturing method report.It is existing
140MPa and following movable elbow metal material, including carburizing alloy steel (such as 20CrNiMo, 20CrMnTi, 15CrNiMo,
18CrMnNiMo etc.) and quenched and tempered steel (such as 35CrMo, 42CrMo, 40CrNiMo, 40CrNi2Mo etc.), due to its obdurability, through hardening
Property, erosive wear resistance and anticorrosion stress-resistant limited capacity, it is difficult to perfect matching can no longer meet the construction of 175MPa fracturing work
Demand.In the existing structural alloy steel standard GB/T 3077-2015 in China, it is also difficult to which 175MPa pressure can be fully met by finding
Split the metal material of all mechanics design requirements of operation movable elbow.
Summary of the invention
It is an object of the invention to propose a kind of new movable elbow material, after the Elbow material is by heat treatment, highest
It is able to satisfy massive hydraulic fracturing job execution demand under 175MPa pressure.
To achieve the above object, the technical solution of the present invention is as follows:
A kind of 175MPa movable elbow material, it is characterised in that:
The weight percent of each element is as follows in the material: C0.12 ~ 0.20wt%, Cr0.4 ~ 0.7wt%, Ni1.4 ~ 2.0wt%,
Mn0.6 ~ 1.2wt%, Mo0.55 ~ 0.8wt%, Si≤0.25wt%, (Nb+V+Ti)≤0.15wt%, Cu≤0.2wt%, P≤
0.015wt%、S≤0.010wt%、Sn≤0.010wt%、Sb≤0.005wt%、As≤0.005wt%、H≤2ppm、O≤25ppm、
N≤80ppm, remaining is Fe and inevitable impurity.
A kind of heat treatment process of 175MPa movable elbow material:
It is characterized by: the technique specific steps are as follows:
(1), first normalizing, rear tempering: normalized treatment technological parameter are as follows: by blank at 400 DEG C are carried out to movable elbow material
Following shove charge is heated to 920 ~ 960 DEG C with the heating speed of≤100 DEG C/h, keeps the temperature 0.5 ~ 2h, come out and cool down, and use is air-cooled, wind
Stream or the cold mode of mist are cooled to 200 DEG C or less;Tempering technological parameter are as follows: by the blank after normalizing at 400 DEG C or less
Shove charge is heated to 620 ~ 680 DEG C, keeps the temperature 4 ~ 8h, comes out and cools down, be cooled to room temperature in such a way that air-cooled, distinguished and admirable or mist is cold;
(2), carburizing, quenching, tempering: carburizing process parameters are carried out again are as follows: pit carburizing furnace or multipurpose furnace are used, 920 ~
940 DEG C carry out strong carburizing, and soaking time 4-8 hours, carbon-potential control was 1.10 ~ 1.25%;In 920 ~ 940 DEG C of progress carbon spreads, protect
Warm time 3-6 hours, carbon-potential control was 0.85 ~ 1.05%;Carburizing quenching process parameter are as follows: after the completion of carburizing and diffusion, be furnace-cooled to
820 ~ 860 DEG C, 0.5 ~ 2h is kept the temperature, carbon-potential control is then quenched 0.80 ~ 0.95%, and the quenching type of cooling is oil
It is cold;Tempering process parameters after carburizing and quenching are as follows: after product is cooled to 80 DEG C or less, be tempered in time, tempering temperature be 180 ~
220 DEG C, soaking time 3-5h;
(3), cold treatment and tempering: cold treatment process parameter are finally carried out are as follows: using liquid nitrogen as refrigerant, will complete to seep
Product after carbon quenching and tempering is placed on -60 ~ -120 DEG C, to 1-3h, is then to slowly warm up to room temperature, is then returned
Fire processing, tempering technological parameter are as follows: tempering temperature is 180 ~ 220 DEG C, soaking time 3-5h.
The positive effect of the present invention are as follows:
1, the resulting alloy of the present invention has high intensity and toughness, relative to movable elbow common used material 20CrNiMo alloy,
Its intensity improves 20% or more, and impact flexibility improves 100% or more, and anticorrosion stress-resistant performance is strong, erosion weight loss under the conditions of unit
50% or more is reduced, highest is able to satisfy 175MPa pressing crack construction job requirements.
2, at 140MPa and following fracturing work operating condition, the movable elbow of the resulting material preparation of the present invention, which can be promoted, to be made
With 50% or more service life.
Specific embodiment
The present invention is further explained in the light of specific embodiments.
Embodiment one
It using electric arc furnace smelting+vacuum refining, is rolled after molding, and is prepared into movable elbow blank.Each component in resulting materials
Weight percent are as follows: C0.13wt%, Cr0.65wt%, Ni1.46wt%, Mn1.12wt%, Mo 0.64wt%, Si 0.16wt%,
Nb 0.077wt%、V 0.028wt%、Ti 0.011wt%、Cu 0.081wt%、P 0.011wt%、S 0.004wt%、Sn
0.005wt%, Sb 0.005wt%, As 0.005wt%, H 1.2ppm, O 13ppm, N 55ppm, remaining is for Fe and unavoidably
Impurity.
The heat treatment step of the movable elbow blanks are as follows:
(1), first normalizing, rear tempering are carried out to movable elbow material;Normalized treatment technological parameter are as follows: by blank at 400 DEG C
Following shove charge is heated to 920 DEG C with the heating speed of≤100 DEG C/h, keeps the temperature 2h, come out and cool down, cooling by the way of air-cooled
To 200 DEG C or less;Tempering technological parameter are as follows: by the blank after normalizing in 400 DEG C or less shove charges, be heated to 620 DEG C, heat preservation
8h comes out and cools down, and is cooled to room temperature by the way of air-cooled.
(2) carburizing, quenching, tempering, carburizing process parameters are carried out to product are as follows: using pit carburizing furnace at 920 DEG C
Strong carburizing is carried out, soaking time 8 hours, carbon-potential control was 1.15%;In 920 DEG C of progress carbon spreads, soaking time 3 hours, carbon potential
Control is 0.9%;Carburizing quenching process parameter are as follows: after the completion of carburizing and diffusion, be furnace-cooled to 820 DEG C, keep the temperature 2h, carbon-potential control exists
0.80%, it is then quenched, the quenching type of cooling is that oil is cold;Tempering process parameters after carburizing and quenching are as follows: product is cooled to
It after 80 DEG C or less, is tempered in time, tempering temperature is 180 DEG C, soaking time 5h;
3, cold treatment and tempering are carried out;Cold treatment process parameter are as follows: using liquid nitrogen as refrigerant, carburizing and quenching will be completed
And the product after tempering is placed on -60 DEG C, keeps 3h, is then to slowly warm up to room temperature, then carries out tempering, is tempered
Treatment process parameter are as follows: tempering temperature is 180 DEG C, soaking time 5h.
Embodiment two
It using electric arc furnace smelting+vacuum refining, is rolled after molding, and is prepared into movable elbow blank.Each component in resulting materials
Weight percent are as follows: C 0.19wt%, Cr 0.53wt%, Ni 1.63wt%, Mn 0.88wt%, Mo 0.59wt%, Si
0.18wt%、Nb 0.063wt%、V 0.027wt%、Ti 0.016wt%、Cu 0.09wt%、P 0.012wt%、S 0.004wt%、
Sn 0.005wt%, Sb 0.005wt%, As 0.005wt%, H 1.1ppm, O 12ppm, N 53ppm, remaining is Fe and can not keep away
The impurity exempted from.
The heat treatment step of the movable elbow blanks are as follows:
(1), first normalizing, rear tempering are carried out to movable elbow material;Normalized treatment technological parameter are as follows: by blank at 400 DEG C
Following shove charge is heated to 960 DEG C with the heating speed of≤100 DEG C/h, keeps the temperature 0.5h, come out and cool down, cold in such a way that mist is cold
But to 200 DEG C or less;Tempering technological parameter are as follows: by the blank after normalizing in 400 DEG C or less shove charges, be heated to 680 DEG C, protect
Warm 4h, comes out and cools down, and is cooled to room temperature in such a way that mist is cold.
(2) carburizing, quenching, tempering, carburizing process parameters are carried out to product are as follows: carry out at 940 DEG C using multipurpose furnace
Strong carburizing, soaking time 4 hours, carbon-potential control was 1.25%;In 940 DEG C of progress carbon spreads, soaking time 6 hours, carbon-potential control
1.0%;Carburizing quenching process parameter are as follows: after the completion of carburizing and diffusion, be furnace-cooled to 860 DEG C, keep the temperature 0.5h, carbon-potential control exists
0.90%, it is then quenched, the quenching type of cooling is that oil is cold;Tempering process parameters after carburizing and quenching are as follows: product is cooled to
It after 80 DEG C or less, is tempered in time, tempering temperature is 220 DEG C, soaking time 3h;
3, cold treatment and tempering are carried out;Cold treatment process parameter are as follows: using liquid nitrogen as refrigerant, carburizing and quenching will be completed
And the product after tempering is placed on -120 DEG C, keeps 1h, is then to slowly warm up to room temperature, then carries out tempering, returns
Fiery treatment process parameter are as follows: tempering temperature is 220 DEG C, soaking time 3h.
Embodiment three
It using electric arc furnace smelting+vacuum refining, is rolled after molding, and is prepared into movable elbow blank.Each component in resulting materials
Weight percent are as follows: C 0.15wt%, Cr 0.58wt%, Ni 1.87wt%, Mn 0.93wt%, Mo 0.71wt%, Si
0.12wt%、Nb 0.054wt%、V 0.049wt%、Ti 0.008wt%、Cu 0.063wt%、P 0.014wt%、S 0.005wt%、
Sn 0.005wt%, Sb 0.005wt%, As 0.005wt%, H 1.1ppm, O 14ppm, N 52ppm, remaining is Fe and can not keep away
The impurity exempted from.
The heat treatment step of the movable elbow blanks are as follows:
(1), first normalizing, rear tempering are carried out to movable elbow material;Normalized treatment technological parameter are as follows: by blank at 400 DEG C
Following shove charge is heated to 940 DEG C with the heating speed of≤100 DEG C/h, keeps the temperature 1h, come out and cool down, cooling by the way of air-cooled
To 200 DEG C or less;Tempering technological parameter are as follows: by the blank after normalizing in 400 DEG C or less shove charges, be heated to 650 DEG C, heat preservation
6h comes out and cools down, and is cooled to room temperature by the way of air-cooled.
(2) carburizing, quenching, tempering, carburizing process parameters are carried out to product are as follows: carry out at 930 DEG C using multipurpose furnace
Strong carburizing, soaking time 6 hours, carbon-potential control was 1.20%;In 930 DEG C of progress carbon spreads, soaking time 5 hours, carbon-potential control
0.95%;Carburizing quenching process parameter are as follows: after the completion of carburizing and diffusion, be furnace-cooled to 840 DEG C, keep the temperature 1h, carbon-potential control exists
0.85%, it is then quenched, the quenching type of cooling is that oil is cold;Tempering process parameters after carburizing and quenching are as follows: product is cooled to
It after 80 DEG C or less, is tempered in time, tempering temperature is 200 DEG C, soaking time 4h;
3, cold treatment and tempering are carried out;Cold treatment process parameter are as follows: using liquid nitrogen as refrigerant, carburizing and quenching will be completed
And the product after tempering is placed on -90 DEG C, keeps 2h, is then to slowly warm up to room temperature, then carries out tempering, is tempered
Treatment process parameter are as follows: tempering temperature is 200 DEG C, soaking time 4h.
Tensile strength, yield strength, elongation percentage, -29 DEG C of punchings are carried out for the 175MPa movable elbow material of embodiment 1-3
It hits and absorbs function, anticorrosion stress-resistant performance and erosive wear resistance test, test result is as shown in table 1, and table 1 has listed file names with common work
The mechanical performance data of dynamic Elbow material 20CrNiMo alloy is as a comparison.Every mechanical property is carried out according to A370 standard.It is resistance to
Stress corrosion performance test is carried out according to simulation oil field acid fracturing operating condition, and the specific method is as follows: making material in 20%HCI
By being protected under the highest actual working stress of deisgn product (175MPa movable elbow highest stress be 630MPa) constant load in solution
It holds 720 hours, if not cracking, illustrates to be evaluated as qualification by experiment;If cracking, represents it and does not pass through test, be evaluated as not
It is qualified.Erosion test is also simulation oil field pressure break medium, method particularly includes: quartz sand is used to simulate pressure break medium, partial size 30
Mesh, impact angle be 30 degree, ratio containing sand be 14%, velocity of medium 20m/s, the erosion time 1 hour.
The material property testing result of 1 embodiment 1-3 of table
Embodiment |
Tensile strength MPa |
Yield strength MPa |
- 29 DEG C of impact absorbing energies |
Anticorrosion stress-resistant test |
Erosion weight loss g |
Average life h |
1 |
1380 |
1245 |
87 |
Pass through |
0.41 |
≥900 |
2 |
1400 |
1265 |
119 |
Pass through |
0.32 |
≥900 |
3 |
1410 |
1280 |
128 |
Pass through |
0.29 |
≥900 |
20CrNiMo |
1150 |
1030 |
36 |
Do not pass through |
0.85 |
≤550 |
The function of each element is as follows in gained steel alloy of the invention: C improves alloy hardness of steel, and cannot be too high, otherwise reduces tough
Property.Cr may insure the corrosion resistance of steel.Material harden ability can be improved in Ni, improves obdurability, and improves for various acid
Corrosion resistance.Mn can with deoxidation, form sulfide, increase harden ability and obdurability, while improve steel alloy abrasion resistance properties and
Erosive wear resistance.Harden ability and obdurability can be improved in Mo, can especially improve anticorrosion stress-resistant performance;Steel alloy can also be improved
Abrasion resistance properties and erosive wear resistance.Steel alloy can be improved to the corrosion resistance of acid in Cu, and improves the machinability of steel.
Nb, V and Ti are the alternative elements for adding one kind or two kinds or three kinds, they form carbide or nitride, inhibit alloy
Crystalline grain of steel is grown up, while strengthening matrix, improves the abrasion resistance properties and erosive wear resistance of steel alloy.Therefore steel alloy of the invention
Alloy has high obdurability, and anticorrosion stress-resistant performance and erosive wear resistance are strong, can improve movable elbow Product Safety and make
With the service life, movable elbow maximum working (operation) pressure (MWP) is made to be promoted to 175MPa from highest 140MPa before.